New Tow Ratings

[Crabman]

I noticed in the current issue of Trailer Life that with the new Big Three tow ratings there is a greater allowance for fifth wheels then "conventional trailers". Had never noticed this before, not sure when they started doing that. Here is an example in this Chevy link, the fifth wheel towrating for the 2500 HD with 6.0/4.10 is 1200 more lbs then the conventional trailer. With the diesel the difference is even more. Have they been doing it this way awhile or is this something new? One has to wonder if the previous years vehicles also would tow a larger fifth wheel then the ratings of the time.

http://www.chevrolet.com/silverado-2...ndard_box.html

[mcfarmall]

Could it be that with a 5er the "tongue" (pin) weight is more or less directly above the axle whereas with a conventional "bumper" pull situation the weight is 3 or 4 feet aft of the axle. This distance is a force multiplying lever arm that would apply more downward force on the axle for a given tongue weight.

For example, if a 500lb downward force on the hitch ball makes your bumper drop 2", the same 500lb downward force directly above the axle might only drop the bumper 1.5"

[tinlizzie23]

Interesting thought, mcfarmall. That sounds plausible, considering that the farther you are away from the pivot, the more leverage you have. Would really like to know if this is indeed something that they suddenly realized, and would therefore apply to older trucks and 5ers. Thanks for the heads up, Lee. Believe I will contact Ford on this and see what they say. If I get a reply, I'll post it.

[Crabman]

Yeah I would think it would have to have something to do with the distribution of the weight over the axle, never saw this before in tow ratings.

[LiftedAWDAstro]

Been that way for a at least 10 years. Having the weight over the axle is the reason. Keeps the front end on the ground better. Plus the hitches themselves are usually only rated to 12k max with WDH.

[Crabman]

Those ratings are not in my owners manual, only one trailer tow rating, with no mention of a separate fifth wheels rating.

BUT I found this little side note on the CampingLife tow ratings database page. "A higher tow rating is listed for pickups that tow fifth-wheel trailers. See your dealer for more information." When I typed in my vehicle the 5th wheel rating was not included in the results, so maybe there is a higher rating for fifth wheels even on older vehicles, its just was not in the manuals or tow rating info sites.

[dmax_83]

Hmmm.... My owners manual lists two ratings (5er and Bumper Pull).

[29BHS ECO]

There are a lot of people out there that will see the higher of the "tow ratings", and not see the " 5th wheel heading" and try to pull the highest rating with thier tv. Larry

[dlfeather]

I think it is more related to the factory bumper mount hitch. If you look at the numbers in the example above, you see that the 6.0 gasser is rated at 9700 with the 3.73 axle on both TT and 5er. The 4.10 axle bumps it up to 13000 TT and 14200 on the 5er. The 13000 is the same for the 6.6 diesel on the bumper pull, and the 17400 on the 5er. I have not seen the actual hitch rating on a 2013 Chevy, but I bet if you look at the stickers on the hitch it will say 13000 max. I would not be afraid to pull a heavier TT, but I would get a heavier class v rated hitch.

[BlueHaul]

My 2003 F-250 also has two "ratings" in the owners manual for travel trailer and 5'er.

[Crabman]

Looks like as usual Crabman is behind the curve on things if this stuff has been out there that long................

[tinlizzie23]

In response to this thread, I did a search on Ford Super Duty F250/350 trucks from 2003 to 2013. All years have separate weight ratings for bumper vs 5th wheel. However, there seem to be inconsistencies. Looking at the same truck (crew cab, 4X4, V-10, 3:73 rear), for 2003-4, max weights are the same for bumper and 5th wheel. Then from 2005-10, axle ratio was changed to 4:10 (3:73 no longer available), but max weights varied from 1,400# to 1,600# more for 5th wheels than bumper, with same truck. Finally, for 2011-13, V-10 was eliminated for the V-8, but this time, for the same truck, weight capacity was lower by 100# for 5th wheels.

So I wrote to Ford, stating that I didn't understand why, for the same truck, the weight limit would be sometimes the same, sometimes more for 5th wheel, and sometimes less for 5th wheel. Logic tells me that the relationship should be the same, regardless of the equipment, so long as we are comparing apples with apples, with the only difference being the location of the hitch.

Will post results of inquiry, if and when I get one.