SRW Tires

BurbMan wrote:

StirCrazy wrote:
when I bought mine to get the 11500 gvw package you had to get the 20" wheel option otherwise you could only get a 11000 gvw truck.

I have 12,300 GVWR with 18" factory wheels.

is that a cab and chassi? there was no option for that when I bought mine? or maybe it is because I was looking for a crew cab 4x4. i didn't look at any 2wd models...

Steve

If your friend used the same OEM wheels, I wonder how much it was due to improper sizing. I'm guessing he went up in both diameter and width, which may be the reason for poor handling.

Not saying it's impossible for a particular D-rated tire to bounce more, just haven't seen that myself.

Friends with a F350 4x4 SRW SB bought a big Alpha 40’ toy hauler. He wanted bigger tires than the stock E Michelin’s to look cool with more aggressive tread.

LS installed the Open Country D tires stating they had more load carrying capacity.

They headed to SoCal and by the time they got back to NW WA the tires were nearly worn out and the ride was horrible and BOUNCY. He went to LS and tore them a new one. They replaced the tires and placed them on different wheels so he could run around and look cool but Still have a set that he put on when towing longer distances.

I warned him about the tires before he left. He said oh you just hate LS. When he came home he stopped by to tell his story and apologized for not listening to me.

They said it was very scary at times. The Michelin E’s did not bounce.

RoyJ wrote:

Cummins12V98 wrote:

Not a good idea. You can get a D in a bigger size and carry more weight than an E but the D will be a very bouncy tire.

Les Schwab was famous for that switcharoo.

Remember though, even the letters are arbitrary - there are E tires that are rated 65 psi.

The actual ply construction are also all over the place. There's no guarantee a D "bounces" more than an E. I've had mud terrain Ds with much stiffer sidewall plys than highway Es.

I've not found D tires that carry the same weight as an E tire to be bouncy. Comparing a D 265-75-16 vs E rated 245-75 and 235-85-16's. All three are rated at 3000-3040 lbs. I found the 265s to be the better handling tire with that load. E rated 265's did not do any better with just 65 lbs in them. They both carried the load the same.

Wider lower profile tires IMHO generally carry a load better than a taller profile of the same diameter.

Marty

Cummins12V98 wrote:

Not a good idea. You can get a D in a bigger size and carry more weight than an E but the D will be a very bouncy tire.

Les Schwab was famous for that switcharoo.

Remember though, even the letters are arbitrary - there are E tires that are rated 65 psi.

The actual ply construction are also all over the place. There's no guarantee a D "bounces" more than an E. I've had mud terrain Ds with much stiffer sidewall plys than highway Es.

valhalla360 wrote:

RobWNY wrote:
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?

Personally, I stopped looking at Letter Grade Ratings. It's an outdated system based on when they made stronger tires by adding more plys to the tire.

Look for Load Ratings that meet your needs.

But it's also the springs in many cases that are also a limiting factor. The axle itself is usually the same. The GAWR is the weakest link in the rear suspension, not necessarily the axle itself.

Not a good idea. You can get a D in a bigger size and carry more weight than an E but the D will be a very bouncy tire.

Les Schwab was famous for that switcharoo.

Always check your rim capacity also. I bought a SRW F350, I checked the tire capacity of Nitto 20" tires, it is 3750lb each. The rims that came with the truck were rated at 2640lb. I did not know this until I had cracked a rim (weight or off road hazard).
I now have 4 k rims.

The Ford Super Duty brochure showed that the F-250 used a lighter capacity axle from 2011 through about 2015. There was a great debate online with most contending that the same axle is used in both the 250 and 350 SRW for mass production cost saving.

Ford tech guys over on FTE forums say the F250/F350 SRW 6.7 diesel gets the same rear axle with the larger diameter axle shafts.

They also say its the F250 gasser engine with much less torque get the smaller rear axle (smaller diameter axle shafts).

Make sense as axle shafts on the full floater rear ends has nothing to do with carrying weight. The axle shafts just twists the gears.
The two bearings in the axle tube ends carry the load.

My opinion--yours may vary. Most of below comes from knowledge of 2011 through 2016—recent years may have changed some of this, although I haven’t noticed much as I look at recent years documentation.

The Ford Super Duty brochure showed that the F-250 used a lighter capacity axle from 2011 through about 2015. There was a great debate online with most contending that the same axle is used in both the 250 and 350 SRW for mass production cost saving. It is possible that the lighter axle was used for 2011 Job 1 250s to use up existing supplies from 2010. However, everyone now believes that the axles are the same from at least 2012 and possibly 2011. The F-250 is typically derated to 9900 or 10,000 lb. GVWR even though it can physically handle more. This allows insurance and licensing cost savings in some states. The F-350 since 2011 adds the auxiliary spring and that’s about it other than labeling. So, yes, in agreement with most of above, tires are likely to be the limiting factor. I have noticed in recent years that the 20” tires can get as much as 14,400 GVWR.

I think 18's are really the way to go. Many tire options, you get more side wall height to protect the wheels if your off road at all. It is typically pretty easy to find a set of take off wheels at tire stores from guys that have put custom wheels on as Grit Dog stated.