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Topic: Lets talk about the diff between 19.5 and 22.5's on Gassers
Posted By: Txsurfer on 12/19/17 08:27am

Aside from IMO better looks what are the benefits to units with 22.5 wheels on Class A gas units? Can you convert a 19.5 set-up to 22.5's?

2017 F250 PSD 4X4
2015 Livin Lite Axxcess 24FBA
2016 Honda Pioneer 1000-5 Deluxe

Posted By: mike brez on 12/19/17 08:43am

Carry more weight

1998 36 foot Country Coach Magna #5499 Single slide
Gillig chassis with a series 40
02 Ford F250 7.3 with a few mods
2015 Wrangler JKU

Posted By: 10forty2 on 12/19/17 08:45am

I would think that the 22.5s have a higher weight capacity, but that's ultimately going to be limited by your chassis rating. I would also think that the larger tires would ride significantly better and may wear a little better. As for converting them, there is probably an adapter that would need to be used to attach to the hubs. With that alone, I would NOT want to convert. Anything that needs an adapter becomes a weak point.

1999 Holiday Rambler Endeavor, 36' Gasser
Triton V10, Ford F53 Chassis
-----------------------------------------


Posted By: Ready2BRetired on 12/19/17 08:58am

If you choose to convert keep in mind you will be changing your applied axle ratio. Tire diameters are figured in as criteria in determining performance values beyond just the tire capacity ratings.

Posted By: wolfe10 on 12/19/17 09:27am

Ready2BRetired wrote:

If you choose to convert keep in mind you will be changing your applied axle ratio. Tire diameters are figured in as criteria in determining performance values beyond just the tire capacity ratings.


Yes, read that BIG change in effective rear axle ratio.

Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

Diesel RV Club:http://www.dieselrvclub.org/

Posted By: MrWizard on 12/19/17 09:42am

Chassis weight, tire wear
And no, i don't think you can get 22.5 to fit your 19.5 RV
Unless you want to try and lift it up to look like a Monster Truck

Price is significant higher per tire
Just read some of the tire threads taking brands and pricing

I can explain it to you.
But I Can Not understand it for you !
....

Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s


Posted By: tderonne on 12/19/17 09:43am

Ford has varied a bit over the years, but typically uses the same axle ratio where both a 19.5" and 22.5" wheel is used. But the 19.5" and 22.5" wheels have different bolt patterns, so it's not a simple swap.

Tim

2004 Winnebago Adventurer 31Y
Ford chassis

Posted By: DrewE on 12/19/17 10:13am

Pros: higher weighty rating (but probably not too useful if converting since the rest of the chassis isn't uprated magically), somewhat better ride, perhaps longer life.

Cons: higher cost, heavier weight (which makes it much harder to change a tire in the case of a flat, as well as having some performance penalties that probably don't amount to too much on a motorhome), larger size makes storing a spare rather more difficult.

Many 22.5 setups use a much higher lug not torque than smaller tires and wheels, too, which in turn requires significantly heavier duty tools to manipulate.

Different, but not necessarily pro or con: the diameter is larger, which means a different effective axle ratio, more ground clearance, a higher center of gravity, and possibly interference with the wheel wells or fenders (probably most likely in front).

I would not convert a motorhome I had.




Posted By: Ava on 12/19/17 10:42am

I dont think the chassis engineers design and determine weight limits, gear ratios and wheel sizes by throwing darts at a picture of each.

Posted By: Dale.Traveling on 12/19/17 11:25am

Cost to gain wasn't in it for me when I looked into it. Hardware along was pushing $1000 per tire (replacement tire and rim) using polished aluminum on four of the six tires. There was an owner on a different forum that posted images of his 30' or so Winnebago class A with 22.5's. A bit odd looking with how high the coach was. Plus the last step off the stairs was a long way down.

2006 Hurricane 31D built on a 2006 Ford F53


Posted By: Txsurfer on 12/19/17 11:43am

Ava wrote:

I dont think the chassis engineers design and determine weight limits, gear ratios and wheel sizes by throwing darts at a picture of each.


It does appear on RV trader that some models are offered in either 19.5 or 22.5 - mainly on the mid-tier products.

Posted By: Bumpyroad on 12/19/17 01:46pm

I thought I wanted 22.5s and then priced the difference. lost my desire.
bumpy




Posted By: rk911 on 12/19/17 03:34pm

mike brez wrote:

Carry more weight

on a chassis designed for those tires, sure. but can the GVWR of a chassis be increased just by swapping 19.5 tires for 22.5 tires? I'm no expert but that doesn't sound right. seems to me that there more components of the chassis would be involved in calculating the GVWR of a chassis than just the tires.

Rich
Ham Radio, Sport Pilot, Retired 9-1-1 Call Center Administrator
_________________________________
2016 Itasca Suncruiser 38Q
'46 Willys CJ2A
'23 Jeep Wrangler JL
'10 Jeep Liberty KK
& MaggieThe Wonder Beagle

Posted By: chuckftboy on 12/19/17 03:36pm

I have owned both. a 35 foot coach with 19.5's and a 37 with 22.5's. The 22.5's were a better ride but only because the coach was heavier. I prefer the larger wheels but it would never be the deciding factor in coach choice.
As for the conversion, probably not one of the best decisions one could make.

2019 Horizon 42Q Maxum Chassis w/tag
Cummins L-9 450 HP / Allison 3000
2006 Jeep TJ and 2011 Chevy Traverse Tows

Posted By: Dale.Traveling on 12/19/17 06:04pm

Found the post. The owner is a bit of a Mad Hatter if you read thru his postings.

[image]

IRV2 Changing from 19.5 to 22.5 wheels and tires

Posted By: willald on 12/20/17 06:56am

I've driven rigs with both 19.5 and 22.5" tires. Difference in ride, handling is negligible. As already said, the better ride is probably much more because of the weight of the coach, not because of the tire size.

Really, in many cases you don't have much of a choice, anyway. Once a coach gets beyond a certain weight, size range, its going to have 22.5" tires to safely handle the weight. You really don't have a choice when you go beyond a certain point, weight wise.

One thing I really, really like about our coach and its 19.5" tires: They are soooo much easier to work with, if you ever want to remove a tire or change one yourself! Literally, I can change one by myself, with only simple tools - bottle jack, right size wrench/socket, and a 'breaker bar' to bust the lug bolts loose and help move the tire around once its off. Thats it. You won't do that with a 22.5" tire, without much more expensive (and not very portable) tools, and just about needing two people to do it. Also, if you ever decide to carry a spare, you can do so muuuch easier with 19.5" wheels/tires than 22.5".

With that said, tire size wouldn't be a deal breaker for me either way, provided the tires are sized correctly for the weight involved. I would just accept that if I one day decide to step up to a bigger, heavier coach, part of the price for that would be I'd have to deal with more expensive, more difficult to work with, 22.5" tires.

Will and Cheryl
2021 Newmar Baystar 3014 on F53 (7.3 V8) Chassis ("Brook")
2018 Jeep Wrangler JK ("Wilbur")

Posted By: fred42 on 12/20/17 10:40am

One downside of 22.5s not yet mentioned is wheel cut. Each year could vary, but based on the 2018 F-53 spec:

16k-20k GVWR - 19.5 wheels, 50 degree wheel cut.

22k GVWR - offers both wheel sizes: 50 Degrees–19.5 42 Degrees–22.5

24k-26k - 22.5 wheels, 50 degree wheel cut

I would suspect if you converted a 16k-22k to 22.5s you would go back to 42 degrees wheel cut. I suspect the 22k optionally puts a cut limiter of some sort on the 22.5s. If you just converted, perhaps it would scrub? Perhaps the bolt pattern conversion part would push the the wheel out an inch to match the wider track of the 24-26k chassis and you would be fine.

* This post was edited 12/20/17 12:17pm by fred42 *

2007 Tiffin Allegro 28DA


Posted By: Txsurfer on 12/20/17 03:55pm

All good points. Thanks for your help..

Posted By: bobkatmsu on 12/21/17 08:42am

Ava wrote:

I dont think the chassis engineers design and determine weight limits, gear ratios and wheel sizes by throwing darts at a picture of each.
Amen

2010 Newmar Dutch Star DP
2014 Jeep Wrangler Sahara

Posted By: tropical36 on 12/21/17 09:36am

Txsurfer wrote:

Aside from IMO better looks what are the benefits to units with 22.5 wheels on Class A gas units? Can you convert a 19.5 set-up to 22.5's?

It's always better not to have or need max pressure to match the inflation chart axle weights and especially if you add 10-15lbs or so, for a cushion, like I do.
Hence, the larger tire, may be required to achieve this. Other than that, I don't really see the benefit.

"We are often so caught up in our destination that we forget to appreciate the journey."

07 Revolution LE 40E_Spartan MM_06 400HP C9 CAT_Allison 3000.

Dinghy_2010 Jeep Wrangler JKU ISLANDER.

1998 36ft. National Tropi-Cal Chevy Model 6350 (Sold)


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