Known fondly as Professor Farlow, Bill Farlow has been Coast to Coast Magazine's technical editor for more than a decade. A full-time RVer, Farlow spends his time traveling the country, writing, speaking at rallies and other RV gatherings, and meeting and talking to RVers. The author of a number of RVing how-to books, Farlow also contributes the popular Under the Hood column in Coast to Coast Magazine. Check out some recent columns by clicking on the topics below.
Big Trucks
Drive Like a Pro
Shock Absorbers
Shopping for an RV
Suspensions Systems
Synthetic Oil, Part One
Synthetic Oil, Part Two
Tires
Bill Farlow's books are available by sending a check or money order to B.F. Publishing, PMB 1238, 112 Rainbow Drive, Livingston, Texas 77399-1012.
Guide to Buying a Medium Duty Truck ($11.95)
Professor Farlow's Guide to RVing, Volume 1 ($14.95)
Freedom Unlimited-The Fun and Facts of Fulltime RVing ($11.95)
Snowbirds and Winter Texans ($14)
Big Trucks for Big Fifth Wheels
Americans have a seemingly insatiable appetite for something bigger. Some people might even say we're spoiled. I clearly remember a discussion with my brother back in 1965. We agreed that there was absolutely no reason for anyone to want a trailer longer than 22 feet. Now I'm sitting in one that measures a gnat's eyelash under 40 feet. But times have changed, I tell myself. In 1965 we were weekenders and summer vacation RVers. Now we're full-timers, along with more than 2 million other Americans, and it's easy to convince ourselves that we needed more space.
But more space means more weight, and more weight means more power and more brakes. Only a couple of pickups have a gross combined weight rating of 20,000 pounds. Subtract 7,500 pounds for an average loaded weight of the truck, and you have a tow rating of 12,500 pounds. How long is a fifth wheel that weighs 12,500 pounds? Anything over 32-feet may bump the line.
At first glance, big trucks look like big bucks. But a big truck-a medium-duty truck or larger-can be had for less than the cost of two pickups. Now don't run for the door. The good part is that the big truck will still be going strong when you've gone through several pickups. It'll probably outlast you and be part of your estate. Sounds like a bargain to me.
Another factor to consider is safety. The brakes on big trucks are rated in excess of 40,000 pounds. Compare that with the ratings for brakes in pickups. Have you ever tried stopping your pickup and heavy fifth wheel with the truck brakes alone? Don't, because they won't. I've driven my truck and fifth wheel with only the truck brakes and found it stopped more quickly than when towed with a pickup and the trailer brakes working. By the way, my gross combined weight is a bit over 36,000 pounds.
"But, Farlow, those things are big. How do you get to the supermarket?" Sure, they look big, but most big trucks with a crewcab or sleeper will be the same length and width as a crewcab dually pickup. Yes, big trucks are taller. That means an extra step up into the cab. It also means you're looking over most traffic in front of you. And that means, if you should have an accident, you'll be sitting above the major damage.
"Okay, Farlow, you've convinced me they aren't as big as they look, but where do you find that empty 40-acre field to turn around in?" Surprise! I can make good money betting pickup owners that a medium-duty truck will turn inside their pickup. My Kodiak would make a U-turn in just over three lanes. Try that in your pickup. The sharp turning radius means easier driving in traffic, but it also means easier maneuvering when backing into a campsite.
"What about vehicle registration?" Well, that varies from state to state. My truck is presently registered as a recreational vehicle in New Mexico. Most states require you to register a gross-weight rating for the truck. Remember, that means the weight of the truck and everything it carries, not what it tows. Find the actual weight of the loaded truck, add the actual pin weight of the fifth wheel, and add another 1,000 pounds or so to give yourself a safe cushion if you should ever be forced to go over the scales. And don't worry about how the truck was registered before you bought it. You have the right to change the category.
As far as crossing the scales is concerned, you can make life a little easier for yourself. The examiners really don't want us crossing the scales-yet. But if they see what looks like a commercial vehicle running past the scales, they may come after you. Have someone letter each side of the sleeper with "RECREATIONAL VEHICLE" and just below that indicate "NOT FOR HIRE." This has no legal basis and is not required, but it may save you some arguing time.
As for the legal driver's license, requirements vary slightly from state to state, but most require a class A non- commercial license if the combined weight of truck and trailer is 26,001 pounds or more and the trailer weighs more than 10,000 pounds. You'll have to take a written and driving test, similar to that test you took when you were 16, but the manual tells you the questions and proper answers.
Finally, there's the matter of insurance. It's always best to stay with an insurance company that knows and understands the recreational vehicle market. My truck and trailer are registered with National Alliance, the Camping World partner. Correspondence with them indicates that they're in the process of reviewing their policy toward these larger trucks. I'll let you know what develops. Another company that's RV friendly is National General, the company behind the Protection Coast to Coast program.
If you're towing a trailer weighing 13,000 pounds or more, you need a tow vehicle larger than a pickup.
Back to Under the Hood
Drive Like a Pro
Some of you aren't going to like this message. Some of you aren't going to like it so much that you'll write me a strongly worded letter. But a larger group, most of you I think, will agree with me.
With that warning, let's get to the message. Recent letters to another RV magazine distress me. The main subject of discussion was how badly truck drivers drive and what a menace they pose for us. I'll state right up front, as I've said many times, I'd rather drive with a bunch of truckers than with a bunch of RVers. So you might as well start cooking the tar and collecting the feathers. In the interest of a fair fight, can I get you to hold off on the tar and feathers a few minutes and read my viewpoint?
My reason for preferring to drive with truckers is that they're predictable. Many RVers are about as predictable as the weather. I've been watching RVers drive for over 40 years, and I can be fairly certain of some behaviors.
If I pass an RVer, I can be fairly certain he won't signal when I've cleared him and it's safe to pull back in the right-hand lane. If an RVer passes me, I can be fairly certain he'll never see my signal that he has cleared because he won't look in his mirrors until he's 300 yards down the road. Meanwhile, a bunch of cars and trucks has lined up behind him waiting to pass. Or maybe he'll cut me off by returning to the right lane too soon because he hasn't looked in his mirror but just guesses he has cleared me.
Truckers recognize that their mirrors are an important aid to safe driving, and they use them. In fact, one major trucking company requires that its drivers make a continuing scan from right mirror to left mirror every five seconds. Failure to do so on a check ride is grounds for a warning or dismissal. RVers, on the other hand, frequently have inadequate mirrors and infrequently use them.
One letter writer claimed that truckers are unfriendly and seldom stop to offer assistance. I've found just the opposite. Truckers are interested in what we drive and in our lifestyle. I've found they're more likely to stop and offer assistance than RVers. That conclusion is based on driving an average of nearly 40,000 miles per year over the past 35 years.
Let's look at how that trucker managed to get into the driver's seat for a moment. Most have driven thousands of miles with an instructor before they can even take the test for a license. They've learned how to handle heavy loads, large rigs, bad weather, heavy traffic and driving emergencies. RVers climb out of their compact car, write a check for their 35-foot motorhome or fifth-wheel and tow truck, and, with no training and no testing of their knowledge and ability, climb in and drive off. It's called on-the-job training.
Suggest to an RVer that he ought to have some training and pass a test for a license to drive his 15,000 to 35,000 pounds of RV, and he gets indignant. Tell me which driver is more likely to know what he's doing and more likely to be a safe and careful driver. In most states, even a motorcyclist has to pass a written and driving test, regardless of how many miles he has driven a car before he can legally ride. Why not an RVer?
Yes, I'll agree that there are some bad truck drivers out there. Even the most professional truck driver will tell you that about 10 percent of truck drivers should be off the road. Some drive too fast. But so do some RVers. But which would you rather meet on the road, a trained and experienced driver or one with no training and little experience?
Now let's change the course a bit. The facts are simple and clear. We RVers must share the road with truckers and commuters and motorcycles and a whole bunch of other traffic. It does no good to start writing hate mail about truckers. Instead we should take a look at the way they drive and copy a few techniques.
First, get a good set of mirrors and properly adjust them. If you can't see the rear corners of your rig, your mirrors are no good. Throw away those funny little clip-ons for your pickup. They're dangerous, because they lead you to believe you've got a set of mirrors when you don't. Also, get rid of that tiny bull's-eye and get one at least 6 inches in diameter-8 inches is much better-for each side of your rig. You'll never know how useful it is until you've driven with one a few miles in traffic. Then use those mirrors.
When you pass another vehicle, use your left-turn signal when you pull out and start grabbing glances in your right-hand mirror when you're beginning to clear. When you see the other driver flashing his lights, use your turn signal to indicate you're returning to the right-hand lane. And then flash your lights to thank him for his assistance. He didn't signal? Thank him anyway, especially if it's a truck. That lets him know that you're a professional driver and that at least a few RVers know the rules of the road.
When another RVer or a trucker passes you, flash your lights on and off to let him know he has cleared you. I like to watch the truck's right-hand mirror to see when he's looking and flash my lights on and off. At night, don't flash your brights. Remember how a following driver's bright lights can momentarily blind you? It's even worse with a truck's large mirrors. Instead, when he has cleared you, just turn your lights off for a second. You can still see the road and he can more easily see your signal.
Stay out of the passing lane, unless you have a good reason for being there. It's a passing lane, not a cruising lane, unless you're driving faster than other traffic. Sure, you may be driving the legal limit and think no one has any business driving faster. You may be right, but you're also making a bunch of other drivers angry.
When you're parked in a rest area with truckers, take a moment to say "Good morning" or "Nice rig you've got there" or something pleasant. You'll be surprised how often you can get a conversation started, and you'll be surprised how many truckers are counting the years until they can join you.
Last night we were watching a program on the tube about road rage. Probably most of us have either been a participant or an observer of some irrational behavior while driving. There are lots of theories about how and why road rage occurs, but no one seems to know for sure. I suspect that a lot of it has to do with driving behavior we don't understand. We don't know why the other guy did what he did, and it makes no sense to us. We become irritated at what seems to us irrational behavior and let our irritation show. Things just escalate from there to dangerous behavior. That's the way it is between truckers and us. We don't understand why they do what they do, and they don't understand our behavior. Some of it is just thoughtlessness and is easily corrected if we'll only be courteous while driving.
There's too much hate in the world without our adding to it by complaining about a whole group of other people who in many ways are just like us. After all, our rigs are as big as many trucks, and in a very real sense we're truck drivers too. Maybe it can all be resolved by us behaving the way we'd like other drivers to behave. And keep in mind that those truckers are working hard, often under very difficult conditions, to make our way of life possible. Let's show them-and ourselves-that we can drive like pros.
Back to Under the Hood
Shock Absorbers
Shock absorbers are among the least understood mechanisms on our RVs. We know they're down there somewhere. We know they have something to do with the way our rigs ride. We know they have to be replaced at some unspecified time. But most of us don't know what they really do or how they do it. Maybe, with a bit of luck, we can clear things up a bit.
Obviously, there has to be some sort of flexible connection between the axles in our RVs, or the ride would be impossibly rough. Imagine a farm wagon at 60 MPH. Springs of some sort are that flexible connection. They allow the axles to move over bumps without transferring the energy of the whole bump to the body of the RV and to the passengers-us. But springs alone don't provide a very good ride.
Some people think shock absorbers help to carry the load. They don't. All they do is what the name says. They absorb some of the road shock. They also eliminate most of the aftershock. Shock absorbers work in conjunction with the vehicle's suspension springs to keep the tires in contact with the road. The wrong shock or a worn shock can cause a vehicle to dive under hard braking conditions and can cause the vehicle to squat during acceleration. A hard turn with improper or worn shocks can result in excessive body roll, poor vehicle control and increased tire wear.
Modern shock absorbers consist of a cylinder, closed at both ends, with a piston that fits inside with a rod fastened to the piston and extending through a seal at one end of the cylinder. Fill the whole cylinder with fluid, and you have a shock absorber. (OK, you guys who know where we're going, just keep quiet a moment.) Attach the end of the rod to the axle and the other end of the cylinder to the body frame, and you've just installed a shock absorber. Put one at each wheel and drive down the road. No improvement, right? We forgot something.
Start over and make another set, but this time drill a small hole through the piston so it can move if you push hard enough. Now some of the energy produced when the wheel hits a bump is absorbed as the piston moves in the cylinder. Keep playing with the size of the hole in the piston, and you'll finally get a shock absorber that absorbs most of the road shock. Because energy is absorbed as the piston moves in both directions, you get a good ride. Obviously, shock-absorber engineers vary the size of the cylinder and the hole in the piston according to the weight of the vehicle and the speed that they think it will travel. The expected terrain will also have its effect on the sizes.
That, very roughly, is the way most shock absorbers are made. As you might expect, things are not always that simple. If the road is very rough, the action of the piston becomes severe, and the fluid filling the cylinder will foam, forming bubbles. Bubbles are compressible and ruin the intended action of the shock absorber. One way engineers combat this foaming is to only partially fill the cylinder with fluid and then add an inert gas under enough pressure to keep the fluid from foaming. In general, gas-filled shock absorbers have superior ride qualities and cost more than shocks without gas. There are even adjustable shocks that let you adjust the action to suit your individual needs.
Until recently there were only one or two brands of gas-filled shocks on the market. Now most companies have their own designs. The best shocks for our market are fairly large in diameter, but it's easy to make a shock look larger than it is. Just install a large-diameter shell. Check the literature for the actual size. Also, remember that good shocks give you not only a good ride but good control.
Like all things mechanical, shock absorbers eventually wear out and need to be replaced. How can you tell when yours have reached the end of their useful life? First, make a close look at your shocks a part of your monthly inspection of the underside of your rig. Any indication of a leak is reason to start shopping, regardless of mileage. If you find no leaks, climb out from under and put all your weight on the center of one bumper. Push down as hard as you can, and then suddenly remove your weight. The bumper should rise slightly once and return to its original position. If it shows more than two rebounds, you need new shocks. Repeat the test at the other end of the rig. Always replace both shocks on an axle to help maintain control while driving.
The question of whether shocks are needed on trailers keeps coming up. Some trailer suspension manufacturers claim shocks aren't needed with their suspension systems. Ask yourself a simple question: do trailer wheels hit bumps? Unless you've invented some device that allows the trailer to float along with no contact with the road or with the wind and air from passing traffic, your trailer needs shocks. If you care about your trailer and its contents, it needs shocks. Some manufacturers try to save a few bucks by omitting shock absorbers. You pay more than the cost of shocks by repairing damage to the trailer and its contents and through your irritation at having to replace things that get thrown around. Most trailer manufacturers will sell you a set of shocks complete with a kit for attaching them. If there's no kit, one can easily be made by the RV repairperson.
Finally, there's the matter of insurance. It's always best to stay with an insurance company that knows and understands the recreational vehicle market. My truck and trailer are registered with National Alliance, the Camping World partner. Correspondence with them indicates that they're in the process of reviewing their policy toward these larger trucks. I'll let you know what develops. Another company that's RV friendly is National General, the company behind the Protection Coast to Coast program.
A good set of shock absorbers can make a tremendous difference in the way an RV rides and handles. Check yours regularly and replace as needed.
Back to Under the Hood
Shopping for an RV
Buying an RV today is light years different from the way it was when I bought my first one back in the Dark Ages of 1962. I was told about a dealer in Elkhart who had some small trailers. Some dealer. He had two. Something called a Garway. Both had a pullout bed called a gaucho at the rear end and a convertible dinette and "kitchen" in front. One had a cabover bed. It turned out that this cabover style was very popular for about five years. It looked a little like a pickup camper on wheels. We bought the cabover. Cost with electric brake-controller and Reese hitch: $900.
Three years later we sold it and bought a 16-foot Trotwood. Floor plan was the same. In fact, I don't remember seeing a different floor plan until sometime in the '70s. Selecting a floor plan was easy. Whatcha got? We'll take it.
Same with the exterior. Everything was aluminum, and there were no fancy graphics, just the company name. Most of those old company names have gone to the great RV park in the sky. No more Garway or Trotwood. Gone are Palace and Century and Streamline, Vagabond, Travco, GMC and Apollo. I don't even remember the name of the first trailer I had with a toilet, but I do remember the size of the holding tank: 10 gallons, including both black and gray water. Try that for a weekend with four people, including two kids.
Finding an RV dealer in those days wasn't much easier than looking for gold. There were no Buyer's Guides like the one you're holding in your hands. The yellow pages didn't show much. Dealers were likely to look like a back alley used-car lot. Now dealers have beautiful showrooms and acres of new and used motorhomes and trailers just waiting your selection. Brands have proliferated like rabbits, each with multiple models and a whole bunch of different sizes and floor plans.
Speaking of floor plans, RV designers are as busy as a disturbed bunch of fire ants. Want a trailer with a front kitchen and rear bedroom? Dozens are out there. Rather have a center kitchen, front bedroom and rear living room? No problem, except making up your mind which one you want. How about a fifth-wheel with a front kitchen? It's yours for the asking. Crave an island kitchen? Got it. How about a motorhome with a bedroom that drops down from the ceiling at night and disappears during the day? It's available. Diesel-pusher? Just sign on the dotted line.
And take a look at those slide-outs. Ten years ago they were tiny spaces available only on fifth-wheel trailers. Now many fifth-wheels have three, and if your motorhome doesn't have at least one slide-out your neighbors look at you a little strangely. Our Alfa has three, and stepping inside is almost like walking into a small apartment. There's even one company that's building a popup camper with a slide-out.
As for amenities, if you want, it it's available. Need a king-size bed? No problem. How about a computer workstation? Everybody's got them. Like to have your piano keyboard set up all the time so you can run off a little Chopin at a moment's notice? Just get rid of one of the lounge chairs, and you've got the space. Tired of doing dishes and traipsing to the laundromat? A dishwasher and washer-dryer are yours for the asking. Looking for a fifth-wheel with a built-in air conditioner? Why didn't you say so?
Need a 25-inch television in your motorhome? Ho-hum. Why not order a 32-inch screen? One company supplies you with two satellite dishes, one mounted on the roof and the other portable for times the roof may be under a bunch of trees. If you like to have your trash and garbage in a small, compact bundle, just ask for the optional garbage compactor. Prefer hydronic heating instead of hot air for your motorhome? You can have it. There's even a company that offers a built-in fireplace for those frosty nights when you want to cuddle up on a bearskin rug.
Is there a single source of information on what's available in new-model RVs? Would I raise the question if I didn't have an answer? All you have to do is turn the page. You're holding one of the best RV Buyer's Guides available. Look through it slowly, but, remember, it's only an outline. Compare features and floor plans and prices and then check out the manufacturers' Web sites. Once you've narrowed your options, call the manufacturers and ask for the dealers nearest you. You're heading in the right direction for pleasant days and quiet nights.
Back to Under the Hood
Suspension Systems
Have you ever looked closely at the suspension system on your trailer? You should, because it's the only thing between the trailer and the road. The type and condition of the suspension determines whether the trailer and its contents get a soft ride or not. Let's take a look at the different suspension systems and the various components, starting at the ground level and work our way up.
First there are the tires. Your tires take a real beating. They have to flex with every bump, but if they flex too much they become overheated and start disintegrating. If you've got LT235/85R-16 tires, a common size on larger trailers, they turn 655 RPM at 60 MPH. Imagine the force when a chunk of tread flies off. If you're unlucky enough to have the tread come off in one piece, you can depend on it taking out some of the trailer. The first time I had that happen, the tire took out a storage box and the underbelly from the axle back.
The next time it took out another storage box. The third one removed part of the slide-out. Why did I have all this trouble? Wrong tires for the application.
Almost without exception trailer tires are steel-belted, just like the ones on our pickups and vans. They work well on light trucks, but not so well on heavy trailers. Why? Trailer tires operate under maximum load 99 percent of the time. Many are overloaded. That forces them to flex, even at maximum-inflation pressure. Due to the design and location of the steel belt, the flexing is concentrated at the edge of the belt. That means the heat is concentrated at the edge of the belt. After a short while, the heat causes the tire to take a permanent vacation, and pieces start flying.
There is an answer: buy all-steel tires instead of steel-belted. The steel runs from bead to bead, eliminating the concentration of heat. But there's a small problem. I've been unable to find 15-inch all-steel tires. Lots of trailers, especially smaller trailers and some triple axles, are sold with 15-inch tires. But unless the axles are too close together, it's usually possible to install six-hole 16-inch wheels on the same hubs. Order your new trailer with 16-inch wheels. If there's room for the larger tire, you can install 16-inch wheels on your present hubs. You get better tires, they don't have to operate at 100 percent of their rated load, and you also get about 1 1/2 inches more ground clearance. Hey, manufacturers, are you listening? We want 16-inch wheels and tires.
The next component is the axle itself. The next trailer that shows up at the dealer's repair shop with a bent axle won't be the first one. If your axles bend, don't straighten them. Replace them with the next higher rated axle.
The next component in your suspension system is the brakes, but we're going to skip brakes today except for a quick hint. If you switch to heavier duty axles, why not also get larger brakes at the same time?
Now we're at the springs. Springs are supposed to transfer the bumps from the road to the trailer softly. There should be enough room for the axles to move vertically without hitting anything while absorbing the force of the bumps. There are four basic types of springs: leaf springs, torsion bars, rubber blocks and air.
Leaf springs are the least expensive. They've been around in one form or another since two days after the invention of the automobile. One end of the spring is attached to the frame, the axle is attached to the middle of the spring, and the other end of the spring is attached to the frame with a semi-flexible shackle. When the tire hits a bump the center of the spring is forced up, the shackle allows that end of the axle to move slightly back and forth, and some of the bump shock is dissipated by the small amount of friction involved. The main bump energy is absorbed or damped by shock absorbers. Don't have shock absorbers on your trailer? You should.
Leaf springs work fairly well when new. The problem is that there's lots of pressure on the attachment points at each end of the spring, and these shackles and hangers wear rapidly. When worn enough-which can occur in as little as 10,000 miles-things start coming apart. If you've got nothing else to do, imagine one end of your axle coming loose. Not nice to think about. The usual answer is to inspect your spring shackles and hangers carefully every 10,000 miles or so. Check the bolts and bolt holes. At the first sign of wear replace all worn parts.
Torsion suspension systems use a trailing arm with one end of the arm fastened to the trailer frame through a rubber pack. The wheel is attached to the other end of the trailing arm. Torsion systems can work very well when properly installed and equipped with shock absorbers. Properly installed means that the trailing arm is about 10 degrees lower at the wheel end than at the front end. Torsion systems must also have shock absorbers.
Mor/ryde is the only company I know that builds a trailer suspension system based on rubber blocks in shear to soften the ride. They've been at it for years, but a few years ago they developed a new system that is not only available for aftermarket installation but also allows simple wheel alignment, something not true of other systems. My present trailer, an Alfa Gold, has leaf springs. At the first sign of worn shackles, I intend to make an appointment with Mor/ryde (219-293-1581) to have its new suspension system installed.
That brings us to air suspension. The only company I know that uses air suspension on travel trailers and fifth-wheels is Auto-Mate in Los Banos, California (209-826-1521). It's a great system, and if I were buying an Automate fifth wheel-a very well-built trailer-I'd certainly order it with air suspension. Auto-Mate also does aftermarket installations of its air suspension. If you want the ultimate suspension, this is probably the best bet.
All four suspension systems work well when new. Leaf springs have the shortest life expectancy and deliver the poorest ride, even when new. But they cost the least and are the most often used. The remaining three systems all deliver an excellent ride when properly installed. All three have a long life expectancy. The choice is up to you.
Back to Under the Hood
Synthetic Oil, Part 1
For a variety of reasons, synthetic lubricants have recently attracted a lot of attention. For one thing, synthetics have proven to be, for want of a better term, more slippery. With so much emphasis on increased miles per gallon, anything that can reduce friction and increase fuel mileage has come under serious consideration. Less has been said about decreased wear from using synthetics and even less about a factor that may be the most important, the ecological implications. Today we'll take a look at the possibilities of decreased wear and the ecological implications of using synthetic lubricants.
With the almost complete shift of military and commercial aircraft to jet and turbine engines several years ago, lubrication engineers were faced with new problems. These engines ran at considerably higher temperatures than conventional engines, and moving parts ran at much higher speeds. Too, the engines were very expensive, and anything that could be done to increase engine life was welcome. Conventional lubricants simply weren't up to the heat and pressures found in jet and turbine engines. Synthetics proved to be the answer. Synthetics could laugh at temperatures that killed conventional lubricants, and pressure also had little effect.
Synthetics have been used in military and commercial aviation for decades, but only recently have they been seriously looked at by owners of cars and trucks. One reason was simple economics. Synthetics are expensive. There has been little doubt that they offer superior lubrication and longer engine life, but are they worth the extra cost when the vehicle will be disposed of in 100,000 miles or so? The answer for most car and light-truck owners has been a resounding "No." But suppose synthetics cost no more than conventional lubricants. Would you then be interested?
As petroleum engineers investigated their own products, one thing became increasingly clear. Petroleum lubricants, particularly engine oils, tended to pollute themselves. The combination of high temperatures and oxygen caused a breakdown of engine oil. Also, even with the best petroleum-based engine oils, there's significant wear to engine parts. These small wear particles and unavoidable contamination from handling continued to circulate through the engine, with the oil causing more engine wear. True, engine-oil filtration was doing a pretty good job of removing particles over 20 microns, but smaller particles continued to circulate.
Why not make the filters finer so they could remove these smaller particles? At first it was felt that the smaller particles did no harm. That has recently been proven false. Some engineers even claim that these smaller particles 1 to 20 microns in size cause the most wear. But the main reason for not increasing filtration effectiveness is that engines use a full-flow filtration system. That means that, as oil is circulated through the engine, it all has to pass through the filter. Making the filtration medium fine enough to remove smaller particles would restrict the flow of oil too much, and critical parts would experience increased wear. Coupled with the fact that conventional oils tended to oxidize, it was decided that it was better to simply drain and replace engine oil every 3,000 to 7,000 miles, depending on engine type and use.
If your engine held six quarts of oil, and you had to add a quart every 1,000 miles and you changed oil every 4,000 miles, that meant you were using nine quarts of oil every 4,000 miles or nearly three quarts per 1,000 miles, something that no one wants to think about. No one wants to think about the necessity of finding someone to change your oil every 4,000 miles or the service charge for the change. Also, no one wants to think about how that used engine oil is disposed of. Yes, the EPA requires it be disposed of properly. That means it is supposed to be cleaned up and converted to some sort of product for reuse. But a tremendous amount of used engine oil is simply poured on the ground or on a gravel driveway to be picked up by the next rainfall and carried into our drinking water.
For the past 20 years or so, there's been a rumor that by using synthetic engine oil you could stretch oil changes to 25,000 miles. Many owners have played with the idea, but most get a bit chicken after a while and start worrying about their engines and go back to short changes of conventional oil. But a small group has been doing something else. They've been eliminating oil changes almost completely.
Synthetics don't oxidize. Keep them clean and they can be used for extremely long periods. How do you keep them clean? You can't reduce the filtration size of full-flow filters to less than 20 microns. But you can add another filtration system. It's called a bypass system, and it uses a filter that removes particles down to 1 micron or less. The bypass filter simply allows a small portion of the engine oil to pass through as it circulates. All oil will pass through the bypass filter every few minutes. The engine continues to get its full flow of oil, and the oil is cleaned of virtually all contaminants. Synthetic engine oil can be used almost forever with such a system.
Well, maybe. Even with the best of lubricants, some engine wear is going to occur. Also, there's always the possibility of something going wrong inside the engine. Maybe a copper bearing cracks or a small chip falls off or any of a thousand things goes wrong. With conventional oil changes, these small particles are removed with the used oil and you never know about them. With synthetics and no oil changes, they're removed by the filters, and you would still never know about them until something goes seriously wrong. Not to fear. There is an answer.
Draw off a small sample of engine oil every 10,000 to 20,000 miles-you set up the interval that you're comfortable with-and have it analyzed. The lab will send you back a thorough report showing the amounts of a wide variety of contaminants and a suggestion to either continue using the oil or replace it. Contrary to conventional procedure, you know what's happening inside your engine, and you never need to change oil until the lab finds a problem developing.
How soon is that? That depends on a lot of things. But there are reports of cars and trucks going hundreds of thousands of miles without changing the oil. One over-the-road truck went over 400,000 miles without changing the oil. Then, out of curiosity, the engine was torn down and the parts were carefully inspected and measured. All parts were found to be in nearly new condition and didn't need replacement.
The conclusion, I think, is clear. Use a top-quality synthetic engine oil with a quality bypass filtration system, change filters at normal intervals, have the oil analyzed at regular intervals by the same lab, and you may never again have to change oil. You start with a full crankcase of oil, add a quart as needed, and that's it. You've cut your engine-oil use to just replacement, and you have no used oil to dispose of. You've brought the cost of synthetic engine oil down to about the same or a bit less than conventional oil, and gotten rid of the need to dispose of your used oil. Also, you've increased engine life because of better lubrication. You may also have increased fuel mileage because of decreased engine friction.
If you want to go all-synthetic, you can find lubricants for transmission, differential, and all grease applications including wheel bearings. Synthetic transmission lubricants are especially interesting because they not only decrease transmission temperatures but also withstand high temperatures much better than conventional fluids.
Where do you find all these things? You can find synthetic engine oil at any auto-parts store or counter, but you won't find synthetic diesel engine oil there, nor will you find the necessary bypass filters. Again, not to fear. One of the early developers of synthetic lubricants for the military was Amsoil of Superior, Wisconsin. Today, Amsoil is the leading supplier of synthetic lubricants to people like us. They have kits for installing bypass filters, and they perform analysis of oil samples. Amsoil has a specialized synthetic for every application. I'm using Amsoil's 15W40 diesel synthetic and bypass filters in my latest truck, Big Red. But Big Red isn't my first truck to get the Amsoil treatment. I've used it since 1991 with excellent results.
If you decide to try synthetic engine oil, I have a couple of suggestions. Start a new engine with the first oil change. When you install the bypass kit, put a T fitting in the line from the filter back to the engine. Run a piece of tubing with a shutoff valve off the side of the T fitting. That makes it easy to get your samples. Amsoil has two sampling kits. One goes to its own lab. The other goes to a lab in Cleveland. I prefer the Cleveland lab for no reason except that I think it gives me a bit more objectivity. I suggest that you start sampling at 10,000 miles and change to 20,000 miles after you're comfortable.
I believe in synthetic lubricants, and I believe that Amsoil is presently the best place to get them. For more information about Amsoil, call (800) 777-8491. The phone representative will give you the name of a local dealer you can contact for your first purchase. You can also check out Amsoil's Web site, www.amsoil.com.
Back to Under the Hood
Synthetic Oil, Part 2
Seldom has a column of mine drawn more response than my November-December 1999 one on the use of synthetic lubricants. Most questions were concerned with the bypass filtration system and whether it made sense to change an engine with several thousand miles on it to synthetic oil. By now most people have read enough material on the improved lubricating qualities of synthetic oil and are wondering if it would be good for them to make the switch. Some writers-and, of course, the consultants at the synthetic oil companies-would say "Sure. Go ahead." I'm not so sure that's true in all cases. Let's look at a few of the considerations.
There are at least three types of engines we're using: gasoline, lightweight diesel and heavy diesel. Given good maintenance, gasoline engines should last for about 175,000 miles, with a few lucky ones going to a bit more. That means the engine is usually about half gone at 80,000 miles. Does it pay to change a gasoline engine with 70,000 to 80,000 miles to synthetic oil? Would you be satisfied with driving an 80,000-mile engine for, say, another 200,000 miles? That's what it amounts to. Changing an engine from conventional oil to synthetic oil in effect radically reduces wear, but it doesn't stop wear. The engine is still going to wear out. It just takes longer with synthetic oil.
There's also the problem of engine accessories. Gasoline engines, even the very best of them, are considered to be throwaway engines. Ignition systems, water and fuel pumps, gaskets, cooling systems, fuel-injection systems and wiring systems are all built with the expectation of being discarded somewhere around 150,000 to 200,000 miles. Further, depending on its construction, even a gasoline engine is subject to the diesel engine nemesis, cavitation erosion. Under normal conditions it isn't a problem with gasoline engines, because we expect them to quit at less than 200,000 miles and no one even talks about treating coolant water in a gasoline engine to inhibit cavitation erosion.
But, if you're going to improve the lubrication with the expectation of getting 300,000 or more miles from your gasoline engine, you have to consider cavitation erosion as a factor. That means treating the coolant with DCA from your big-truck dealer. It also means changing the coolant at least every two years with distilled water. Do you really want all that hassle with an engine that's going to need a new water pump, several fuel pumps, several new ignition wiring systems, etc.? Only you can answer that.
The second type of engine we're using is the lightweight diesel engine for Ford motorhomes and Chevy/GMC and Ford pickups and vans. These are built somewhat heavier than the corresponding gasoline engines, and given reasonable care they should last significantly longer. It's not unusual for one of these engines to run for 300,000 miles with conventional oil. But when my Ford diesel took a permanent vacation at 165,000 miles, the Ford "customer satisfaction" guy asked, "What did you expect?" Apparently, Ford sees these engines as being replaced at around 150,000 to 200,000 miles.
One very important factor in getting long mileage from all diesel engines is the regular, routine testing of the coolant and treatment with DCA. Regardless of what your dealer or the "guy down at the courthouse" says, if you don't treat the water, you'll be visited by cavitation erosion sooner or later. The bill will be the cost of a new engine.
The third type of engine is the heavy-duty diesel made by Cummins, Caterpillar and International. These engines are built much heavier than the other two types and are intended to go for 700,000 to 1,000,000 miles before overhaul. There will be occasional replacement of such components as fuel pumps and injectors, water pumps and radiators, but even these components are built of much heavier construction than their cousins in gasoline and light-duty diesel engines. Does it pay to change one of these engines with 500,000 miles to synthetic oil? If the engine is running as it should be and showing no heavy use of oil-anything under a quart per 1,000 miles-I'd say yes, without hesitation.
When I bought my International 9200, Big Red, it had 550,000 miles on the odometer. It was using very little oil, was running good and appeared to be able to last for another 200,000 miles before needing an overhaul. I changed to Amsoil synthetic 15W40 at 560,000 miles and installed an Amsoil bypass filtration system. Oil consumption didn't change. I expect the engine to last for another 400,000 miles. One feature that frequently gets overlooked with these engines is that they can usually be completely overhauled to virtually new engine status for around $6,000, sometimes less.
Two other frequently asked questions were, what does a bypass filtration system do and why install one? You don't have to install a bypass filter. The choice is yours. With a gasoline or lightweight diesel engine, you could easily change to synthetic oil with the present filtration system and just change oil every 20,000 to 25,000 miles, assuming you're using Amsoil diesel 15W40 or something comparable. But that means you're faced with disposing of several quarts of dirty oil every oil change. Oil changes can be safely eliminated with a bypass filtration system. To me that's a big advantage, and with larger diesels it becomes almost essential because of the quantities of oil.
One letter writer argued that even the full-flow filters presently used have a bypass feature. Why install a new bypass system? Whoa, there. The bypass valve in a full-flow filter is there to avoid the catastrophe that would occur if the filter became clogged and didn't permit oil to flow to the engine bearings. Bypass on a full-flow filter means no filtration at all. That's no good. A bypass filtration system is used in addition to the full-flow filter. As the oil circulates through the engine, a small amount is continually bled off the main line and sent through the bypass filter. Full-flow filters remove particles larger than 20 microns. The small stuff continues to circulate. A bypass filter removes particles down to 5 microns, sometimes even smaller. This takes out virtually all the wear-size particles, and its use is essential if you want to eliminate oil changes.
With the bypass filter system, you still replace the full-flow filter at normal intervals, usually 10,000 miles. Replace the bypass filters when needed. How can you tell when the bypass filter needs to be changed? The kid in the front row has the answer. The touch test. If oil is circulating through the bypass filter, it'll be warm to the touch. When you first install a bypass filter, use the touch test when the engine is warm after running for an hour and form a mental image of how warm the filter is. That's your test. When the filter is no longer that warm after an hour or so, change the filter. That will usually be around 15,000 miles or more.
Another essential element for eliminating oil changes is routine analysis. Draw off a sample every 15,000 to 20,000 miles and send it off for analysis. The laboratory will test it for all the normal wear particles plus a bunch of stuff you never expected to be in your oil, and the lab report will tell you whether the oil and/or filters need to be changed. Pick a lab and stay with it, because the technicians there will build a computer record for your engine. You can buy analysis service from Amsoil or most large diesel-engine dealers.
A final question raised by several letter writers was when to start using synthetics. It all depends. In a light-diesel or gasoline engine, I'd start with the first oil change. By that time the pistons and cylinder walls should have become friendly or "broken in." Changing to synthetic oil at that time will keep the pistons, cylinder walls and bearings in nearly new condition for a long, long time.
With heavy diesels the answer isn't quite so simple. Some are so finely matched at the factory that little break in is necessary; with others it takes longer. One new diesel I had used a lot of oil for the first 8,000 miles or so and then quit. By 10,000 miles oil consumption was down to nearly zero. I've had diesel drivers say that it took their engines 30,000 miles to break in. So when do you make the switch? If the new engine isn't using oil at 10,000 miles, usually the factory-recommended interval, change to synthetics. If the engine is still using oil, wait until oil consumption drops off and then make the change to synthetics. If the engine is still using a quart or more per 1,000 miles at 30,000 miles, take it back to the dealer and file a complaint.
Back to Under the Hood
Tires
When you're going down the road, there's only one thing between you and disaster-your tires. And, yet, it's amazing how many RVers keep their tires too long, buy cheap tires and give little attention to selecting the right tires.
We expect tires to cushion the ride. What we really want is a tire that makes us feel like we're riding on air. In a sense we are. The air in a tire can be thought of as an air cushion. The greater the air pressure, the firmer the ride. Which brings us to tire-inflation pressures. What's the best inflation pressure for your tires? A hint: it's not necessarily the pressure stamped on the tire sidewall. That's the pressure at which the tire can safely carry its maximum designed load.
For example, tires with a load range E rating carry their maximum designed load at 80-pounds pressure. The actual load varies according to the size of the tire. If you have load-range E tires, should you inflate to 80-pounds pressure? Maybe. Maybe not. It all depends on the actual load on the tire. Notice I said tire, not tires. The only way you can know the correct inflation pressure for your tires is to get the actual load weight on each tire.
One way to do that is to have someone with the proper scales weigh your rig. A'Weigh We Go is such a company. John Anderson founded the company several years ago when he discovered that there was almost no tire information available to RVers. He or one of his representatives can be found at most of the larger RV rallies.
Another way, not quite as accurate but easier to find, is to get an axle weight at a truck-stop scale. Once you've found the actual weight on each axle, you can determine the inflation necessary to carry that weight. Go to your local tire dealer and ask to see his inflation-pressure chart. Don't just ask him for the correct pressure and accept what he says. Ask to see the chart. No one can remember the actual inflation pressures for all the different size and different load-range ratings available.
Suppose you have LT235/85R16 tires with a load-range rating of E and the load on your rear axle with duals is 9,500 pounds. Checking the chart will show that you need to inflate to 65 pounds of pressure for the load. To be safe, you inflate an additional 5 pounds. Write down the pressure in your logbook so you'll remember.
But suppose the axle load is 13,000 pounds. Checking the chart you will find that 11,112 pounds is the maximum load for an axle with dual tires of that size. You're overloaded, pal, and faced with some tough choices. It might be possible to find tires the same size with a load-range rating of F, but there are some other factors to consider. First, wheels also have a designed maximum-load rating, and it isn't likely that your wheels will take the extra load for very long.
Wheels don't break? I've got news. Check behind any large tire shop, and you'll see a whole bunch of wheels that split. Would you really like to be driving down the expressway when one of your wheels splits?
Second, the whole axle-brakes, wheels, springs, axle housing, bearings-was designed for a maximum load. You've just exceeded it. The only safe answer-and remember there are other people sharing the road-is to start getting rid of some of that stuff.
When should you replace your tires? When they're worn out and the tread is down to 1/16 inch? Maybe. Maybe not. Tires aren't built to last forever. They start breaking down in response to light and particles in the air the instant they're removed from the mold. You'll probably be surprised to learn that many tire companies consider the life of their tires to be five years, whether the tire is actually used or not. That means the tire you buy at a small tire shop may be near the end of its life when you buy it.
I had such an experience a few years ago. I didn't bother to check the four new tires I bought. A year later one of the tires lost its tread. When I checked, I discovered it was much older than the other three tires.
By federal law all tires must be stamped with the date of manufacture. If you look on the sidewall, you'll see DOT followed by some letters and numbers. The last three digits show the date of manufacture. The last digit is the last digit in the year of manufacture. If the digit is 8, it means the tire was built in 1998. The two digits just in front of the year digit show the week of that year. 428 means the tire was built in the 42nd week of 1998. How can you tell it wasn't built in 1988? For the decade of the '90s, there's a small arrow point following the year digit. Don't ask what they're going to do for the next decade.
You shouldn't accept a new tire that's more than six months old. You should also seriously consider replacing any tires you have that are five years old or older, even though there's plenty of tread left. After all, isn't your miserable life worth more than a new set of tires? Okay, maybe not, but there are other people out there on the road with you, and it's just possible they place a higher value on their lives. Think about it.
Also, think about the quality of tire you're buying. It may make sense to buy an off-brand, cheap tire for a car that's only going to be used to drive to the nearest supermarket and will never be driven faster than 35 MPH. But your RV will usually get a bit farther from home and be driven a little faster. Too, if a tire on your RV fails, you'll likely be several hundred miles from where you bought your cheap tires. How will you negotiate an adjustment? It makes sense to me to buy a nationally advertised and distributed top quality tire. Remember, that tire is the only thing that keeps you on the road.
The last several years have seen a rash of tire failures on trailers. I once had five tires disintegrate in the first year and a half I owned a new trailer. Finally, I traced the trouble to the wrong choice of tire by the trailer manufacturer. It wasn't his fault. He had bought the tires recommended by the tire salesman who wanted to make the sale and bid the wrong tires.
For years we have been told about the advantages of steel-belted tires. They're safer, we're told. They last longer, we're told. They may be great for some applications, but not for heavy trailers or motorhomes. The reason is simple. We usually load our tires to near their maximum load rating. Even if they're properly inflated, the flexing will be concentrated at the edges of the steel belt. That will be the major interior wear zone on the tire, and that will be where the tire fails.
The answer is to use all-steel tires rather than steel-belted. The flexing will be more evenly distributed with all-steel tires. I've talked with several RVers who have made the switch and experienced far fewer tire failures. Unfortunately, I haven't found a tire company that builds all-steel tires for 15-inch wheels.
Tread design is important, too. It often makes sense to select a mildly aggressive tread for the driving wheels on your motorhome or tow vehicle. Such a tread can make the difference if you wander onto wet grass or a bit of mud. Trailer tires, on the other hand, don't need an aggressive tread. But they do need a tread designed to get rid of the water as quickly as possible. So do the tires on the steering wheels.
One thing you don't want is to have your rig hydroplane. Never happens to an RV? A couple of days ago I talked with a friend whose motorhome hydroplaned at only 35 MPH and cost him a whole new front end for his motorhome. Select steering tires for their ability to shed water.
How about balancing your new tires? No one will argue that you shouldn't balance all the tires on your motorhome or tow vehicle. But you will find lots of people who ought to know better who'll say it isn't necessary to balance trailer tires. That's because no one rides in the trailer. If they did, they'd immediately realize that unbalanced trailer tires can make everything in the trailer take a beating. Get those tires balanced.
Your tires are the only contact your rig has with the road. They supply the traction for moving and stopping. They also are the contact for steering your RV. With so much riding on the integrity of your tires, doesn't it make sense to buy the best and take care of them?
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