Coast Resorts Open Roads Forum: calculating trailer vs 5th wheel towing capacity question
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 > calculating trailer vs 5th wheel towing capacity question

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Ron Gratz

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Posted: 04/12/14 08:50am Link  |  Quote  |  Print  |  Notify Moderator

Golden_HVAC wrote:

So what you are asking is why does Ford limit the conventional trailers to only 18,500 pounds?

I think it has to do with the ability of the hitch system, rather than the possibility that the transmission, brakes, rear axle or other truck systems will be overloaded by towing a conventional trailer that is 19,000 pounds.
Based on page 25 of the 2014 Ford Towing Guide, it appears that the maximum allowable conventional trailer weight depends on "Hitch Receiver Capacity" which depends on rear axle, engine, and wheelbase:

12,500-lb. – F-250/350 SRW – (N/A with 6.7L diesel with 156", 158" and 172" wheelbases)
14,000-lb. – F-250/350 SRW with 6.7L diesel engine – (156", 158" and 172" wheelbases only)
15,000-lb. – F-350 DRW – (except F-350 DRW with 6.7L diesel engine/172" wheelbase)
18,500-lb. – F-350 DRW w/6.7L diesel engine – (172" wheelbase only)
18,500-lb. – F-450

Maximum allowable 5er pin weight, OTOH, seems to correlate closely with GCWR minus Curb Weight.

Ron

Old-Biscuit

Verde Valley

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Posted: 04/12/14 11:09am Link  |  Quote  |  Print  |  Notify Moderator

Ron Gratz wrote:

Golden_HVAC wrote:

So what you are asking is why does Ford limit the conventional trailers to only 18,500 pounds?

I think it has to do with the ability of the hitch system, rather than the possibility that the transmission, brakes, rear axle or other truck systems will be overloaded by towing a conventional trailer that is 19,000 pounds.
Based on page 25 of the 2014 Ford Towing Guide, it appears that the maximum allowable conventional trailer weight depends on "Hitch Receiver Capacity" which depends on rear axle, engine, and wheelbase:

12,500-lb. – F-250/350 SRW – (N/A with 6.7L diesel with 156", 158" and 172" wheelbases)
14,000-lb. – F-250/350 SRW with 6.7L diesel engine – (156", 158" and 172" wheelbases only)
15,000-lb. – F-350 DRW – (except F-350 DRW with 6.7L diesel engine/172" wheelbase)
18,500-lb. – F-350 DRW w/6.7L diesel engine – (172" wheelbase only)
18,500-lb. – F-450

Maximum allowable 5er pin weight, OTOH, seems to correlate closely with GCWR minus Curb Weight.

Ron


Then there is all the fine print/caveats which makes tow rating numbers magical.
Maximum trailer weights in pounds for properly equipped vehicles with no cargo
May vary depending on model, trim and/or power-train.
Maximum Loaded Trailer Weight assumes a towing vehicle with any mandatory options, no cargo, tongue load of 10-15 (conventional
trailer) or king pin weight of 15-25% (fifth-wheel trailer), and driver only (150 pounds).
Weight of additional options, passengers, cargo and hitch must be deducted from this weight.


Real numbers are GVWR, Axle Ratings, Max Tire Load Ratings and 'actual' payload number. Figure out those numbers then you KNOW what your tow vehicle is really capable of towing within it's ratings.


Is it time for your medication or mine?


2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
On the Road Debt Free April '07
Off the road still Debt Free Jan. '14

outwestbound

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Posted: 04/12/14 12:17pm Link  |  Quote  |  Print  |  Notify Moderator

JIMNLIN wrote:

Quote:

Ford's 2014 diesel F350, auto transmission 4x4 6.7L DRW 3.73 axle ratio......
and
RAM's comparable 2014 3500 AISIN (auto transmission) DRW 3.73 is rated to tow 23,500,


Actually your not comparing apples to apples here. The Aisin transmission uses a 1:1 direct gear ratio and requires a 4.10 axle ratio to achieve max tow ratings of 29000 lbs.

Fords Torqshift 6R140 has gear splits on both sides of 1:1 so with the 3.73 rear axle ratio operates like a 4.xxx-4.30 axle ratio (depending on transmission gear selection) to achieve max towing rating.

The Ram Body Builders Guide clicky link shows all the tow rating for each configured package truck.
Look in the notes and it mentions over 17000 lb requires a GN or 5th wheel hitch for a 3500 Ram.
If your buying a fith wheel trailer I wouldn't worry about conventional trailer (TT) weights.


Thanks, good point on the transmission differences and I didn't have that chart. I read up on the transmission gear splits and this makes good sense. I think I'll be happy with the AISIN/4.10 combination. I'm certain I'll like the 4.10 vs 3.73 in mountains. I'm curious to determine the speed that gets me the best fuel efficiency on flat interstate highways; guessing 60 MPH; kinda slow, but ok I guess with a 15,000 pound load.

dezl_dr

Gallipolis, Ohio

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Posted: 04/19/14 10:27pm Link  |  Quote  |  Print  |  Notify Moderator

I was towing 70 with 17,000 load, it was fine. The 3.73 in the Ford was about perfect. All the new trucks have way more power than anyone needs.


2014 F-350 DRW, 2010 Elite Suites 38'


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