Quote:
Originally Posted by ForBruce
Ok --there are some that will climb all over me for my reasoning...but i am a rather safe than sorry man.....
my F-250 with "High Capacity trailer tow package" has the exact same rear axle (dana275) as a f350 and upon examining the springs they are also the same as the 350.
so what is the weakest link here....... the tires which are rated 3640 lb. each or a total rear axle tire weight of 7280
2020 F-250 diesel 3.55 rear
upon weighing the REAR AXLE of just the truck following were found:
Empty truck alone 3460 lbs
new from dealer unloaded truck and trailer rear axle is 6740 lb (#385br 2021 high country)
loaded truck and trailer 7100 (rear truck axle )
2 rear tires rated 7280 total gives me 180 lb extra the tires can handle.
but what happens when you hit a few bumps in the road with 2660 lb pin (plus hitch of about 260lbs) all of a sudden the weight on the rear tires can hit up to 400lb more and stress side walls or blow out tires.
with tires rated 4080 and totaling 8160 i now have a lea way of 1060 lbs
the highway ride is smooth and quiet.
I rest my case.......WHY WORRY
be kind guys
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No worries, and I'm not saying you're wrong; but I do think it is unnecessary. The caution though is that at times increasing the capacity on one component can have a negative effect on other components.
For example, on a suspension thread on this forum, someone with one of the shorter Montana's asked about upgrading the suspension from 7000lbs to 8000lbs. The answer from the factory and the upfitter was that this was not necessary and would result in making the ride harsher...
To dig into the tire example here a bit more... all of the suspension component ratings have a margin of error. So, when you hit those bumps in the road, all of the components will experience a sudden increase in load, and as you noted this could temporarily exceed their rating. That would include the tires, but also bearings, axle, springs, shackles, frame mounts, etc.
The potential danger you've created is that by increasing the tire rating, the tire may pass more of that load on to the suspension; IOW, you may have made the tire safer, but the rest of the suspension less safe.
For a more extreme example of this, a few years ago some had upgraded to 19.5" rims and the higher rated semi tires on their RAM SRW trucks. But after a lot of miles were put on, some experienced early bearing failures.
In your case, I believe you are still completely safe, but I'm not convinced you are safer than when you started.
But, I'm no expert, so I stand to be corrected
Brad