SRW Tires

Dave...I don't think it is the E rating determining your capacity. You need to look at the tire load carrying numbers. In a 245/17 size, with narrow wheels, not a lot of options.

While you may find a few tires in 17", with a bit more capacity, than OEM, you would find many options by moving to 18" wheels/tires.

In my area, most dealers, when ordering for their sales lot, order with 18" similar tires and wheels on the 250s, as on the 350s.

One thing to consider with your 6.2 gas, is the larger, more capable, tires/wheels, will reduce the advantage of your 4.30 gears.

Jerry

With todays 18" and 20" LT E in the 3800-4000 lb range tires the weak link is OEM wheels and OEM rear spring pack ratings.

F250's come with 17" or 18" and 20" wheels so moving up to LT E in a 20" wheel gains a lot of capacity over 17" sizes.

Dave, you're on the right track, but the key is this:

valhalla360 wrote:
You may need to change tire size to get the higher ratings...

You are correct that the RAWR on SRW trucks is mostly the product of twice the rear tire rating. However, not all E rated tires are rated the same...

I happened to be looking at Nitto Ridge Grapplers so we can use that as an example. Look HERE at the load rating table for 17" tires. The highest load-rated tire is the LT285/75-17E at 3195 lbs.

Now look HERE at the ratings for 18" tires...that same tire in LT 285/75-18E is rated at 4080 lbs.

In this example going from 17" to 18" with the same 285/75-E tires nets up an increase of 1,770 in RAWR just from the tires.

Make sense?

That is what I am talking about Rob.

I don't see how the 350"s can be advertised as big load carriers if the tires are the same E rating as 250's. :h

Putting sticker numbers, Spring packs, Timbrens, Air bags and what's considered legal weight aside for a minute, aren't the two real determining factors what a truck can handle the GAWR and the Max tire weight rating with the tires truly being the weak link because the axels can really handle more than their rating? Maybe I'm missing something but if I had the same E rated tires with weight ratings of 3,750 pounds on a 3/4 ton and a one ton truck, regardless of what was added to beef things up, isn't the max payload of both trucks 7,500 pounds? Isn't the tire ratings usually the weak link in max weight capability in heavy duty trucks?

You may need to change tire size to get the higher ratings (don't forget to check the rim rating also).

Newer models are different but for a very long time when looking at SRW, the difference was the spring pack being stronger in the F350 but otherwise, they were essentially identical trucks.

So if you bump up the spring pack to match the F350 and make sure the rims and tires match, you for practical purposes have an F350.