Ford E450 Tire Size

Hi,

They came from 235/85R16 and I'm running Toyo tires on them on the advice of my tire seller.

rondi wrote:
pianotuna--where did you get your new wheels? Do you know what the max air pressure is for them? Ron

pnichols--one of the main reasons is to increase the Load Rating from E, which is a 10 ply tire to an F or a G. You can't do that with the stock wheels--which are matched to the tire limit of 80psi--per my local ford dealer's parts dept.

In my case the weight on my rear axle is over the 9600lb limit with virtually nothing added in the rig--it came overweight from the factory! I guess there is no law or regulation that forbids that--but common sense should. I had 2 leaves each side added to the stock 11 leaf spring pack to raise the rear a couple of inches--and they did that. Ford is the one to blame here. The E450 they spec at 14,500lbs and provide LR-E wheels & tires, whereas an F350 (rear axle copied from the online spec=9650 lbs. (F-350 DRW)) and has 17," 18" or 20" (F-250/F-350) truck tires and this isn't even an F450. Ford knows their rig will be overloaded and probably tell the dealers--just watch all the class c rigs come in for the chassis work that you'll get :)
The rigs made today are almost identical to the ones made in the first part of this century.

And remember--very, very few rv owners even know about these forums, and are driving around unaware they are overloaded. We know some.
Ron

pianotuna--where did you get your new wheels? Do you know what the max air pressure is for them?

In my prior post I mentioned i considered the Hankook 7.50R16LT tire which is a Load Range G tire, but has the same load rating at 80psi as my stock tires. since the wheels are probably rated at only 80psi (this from my local Ford parts dept) i canceled that order and now I'm considering the 17.5 commercial duty real truck tires.

Ron

Hi,

In my case staying with 16 inch still meant new wheels. Of course more load carrying capacity for the tire does nothing for the axle ratings.

Going to a 17.5 inch possibly is better because the dual spacing remains the same so there is less stress on the axle. But tire cost also goes through the roof compared to 235/85r16.

I would not want to have anything taller nor wider than what I have now. There is not a lot of "spare space" in the rear wheel wells.

I roll a lot of distance and will wear out the tires before they "age out".

But then again, playing devil's advocate, my brakes cooled WAY WAY WAY better.

Lots to ponder...

I'm curious as to why larger wheels on an E450?

Additional weight-carrying capacity can be gained by merely increasing the tire size but staying with the 16 inch wheels.

Is it perhaps because ground clearance, entrance height, or wheel well clearance may become undesirable - by increasing 16 inch tire size too much to gain weight carrying capacity - where going to a larger diameter wheel doesn't? :h

P.S. Increasing wheel size does make for a harsher ride because there is a smaller air chamber between the road surface and the metal rim.

Hi cal47,

I was able to get new wheels to allow for the correct offset and went to 235/85r16. They had 20% more weight capacity over all, istr. It slightly improved fuel economy and like you my "clock" is now wrong by similar amounts.

I had no blow outs but my tires had 66000 miles on them and were ten years old.

The extra height really helped with the tail dragging on ramps at gas stations. It is now a rare occurrence.

cal47 wrote:
Pianotuna with my setup there is a 4mph difference example 55 mph= 59 mph. As I stated before, I went with this tire/wheel setup for safty reasons. My MH was close to weight limit without putting anything in it. With 16" tires I had a blowout at least once every vacation. These were american tires, Mich, Goodyear & firestone. I'll stick with what I have now, couldn't be happier.

Are there any updates to this thread. My rig is also overweight on the rear axle and I'd like see what others have done.

My first thought was to replace the current LT22575R16 LR-E with F19 7.50r16LT LR-G from Hankook, but to get a higher load rating I would need to exceed the 80psi the wheels are probably rated at. So the 2nd choice would be what cal47 did--go with 17.5 tires. I have only 3/4" spacing with the stock, and a 235 would cause the tires to rub and is asking for blowouts!

tia, Ron

Pianotuna with my setup there is a 4mph difference example 55 mph= 59 mph. As I stated before, I went with this tire/wheel setup for safty reasons. My MH was close to weight limit without putting anything in it. With 16" tires I had a blowout at least once every vacation. These were american tires, Mich, Goodyear & firestone. I'll stick with what I have now, couldn't be happier.

The way I would want to run Load Range G tires on my Class C would be to find them available for my OEM 16 inch rims - which they aren't - and in a size not much wider so as to not reduce sidewall spacing in the duals. I'd then run them with no more than 80 lbs. PSI so as to stay within the OEM rim specs.

What Load Range G tires using the above approach would buy me is:

1) Saving of new rim costs and any new rim fitment problems.

2) Switching to much more rugged and puncture-resistant (especially from sharp rocks) tires, since Load Range G tires are 14 ply rated ... where Load Range E tires are only 10 ply rated.

3) Probably more load carrying capacity per tire at 80 lbs. PSI than Load Range E tires are spec'd for at 80 lbs. PSI.

4) A rougher/stiffer ride (due to the thicker/stronger sidewalls) in the rear of my E450 than I'm getting with my current Load Range E tires even though I would still be using the same 80 lbs. of pressure in the Load Range G duals.

5) A heavier tire to deal with if I ever had to change one myself out in the middle of nowhere.

6) Probably a highway tread instead of my current preferred M&S tread - since I do go offroad a bit.