Tires on Duallys

bajajoaquin

Adventurer
I just bought a 4x4 Class C that’s in need of tires. It’s got 2012 date-coded 225/75R-16 Michelin LTXs on there now. I don’t know the lift over stock E-450, but it’s not much.

I think it’s got a 9600-lb rear axle which is 2400 lb per tire. The 225s seem to all be 2600 lb per tire. For traction and perhaps the ability to air down some, I’d like to go with 245/75R16s which are 3,000 lb per tire.

I don’t know rim size yet, but what are the chances I can make that upgrade? If I need new rims, think that’s worth it?

Any thoughts on how much I’d be able to air down? Goal would be to make the 5-8 mph brutal washboard vibration into reasonable 15 mph driving. Also to get in and out of near-beach camp spots in Baja (not on the beach but traversing the soft spots on the approach).2B9FED41-1B3D-44EC-B790-398766C2C585.jpeg
 

1000arms

Well-known member
I just bought a 4x4 Class C that’s in need of tires. It’s got 2012 date-coded 225/75R-16 Michelin LTXs on there now. I don’t know the lift over stock E-450, but it’s not much.

I think it’s got a 9600-lb rear axle which is 2400 lb per tire. The 225s seem to all be 2600 lb per tire. For traction and perhaps the ability to air down some, I’d like to go with 245/75R16s which are 3,000 lb per tire.

I don’t know rim size yet, but what are the chances I can make that upgrade? If I need new rims, think that’s worth it?

Any thoughts on how much I’d be able to air down? Goal would be to make the 5-8 mph brutal washboard vibration into reasonable 15 mph driving. Also to get in and out of near-beach camp spots in Baja (not on the beach but traversing the soft spots on the approach).View attachment 679569
I suggest you see if LT235/85R16/E tires will fit. The are a bit wider and a bit taller than what you have, but are a fairly common size for DRW trucks and vans.

Be careful of tires rubbing together airing down DRWs. The LT245/85R16/E are a bit wider than, but also shorter than, the LT235/85R16/E tires I suggested checking.

The LT235/85R16/E "BFGOODRICH®COMMERCIAL T/A® TRACTION" tires have a max payload of 3042 lbs at 80PSI for a singe tire. Probably 200lbs less when used as DRWs.

Scroll way down to see the specs:


 

bajajoaquin

Adventurer
Thanks. Rubbing sidewalls was my major concern as the only duallys I’ve had have been class A and diesel pusher motor homes which were never aired down.

When you say check to see if they will fit, do you mean I can ask a reputable shop or am I just going to be stuck mounting them and seeing?
 

1000arms

Well-known member
You are welcome. :)

I suggest starting by looking over your vehicle to see how much room you have for taller and/or wider tires. Consider full suspension compression combined with full turning of the steering wheel, especially for the front tires.

I suggest you air down your current DRW tires in your driveway, or the nearest safe, flat, level driveway you can get permission to use, to check for tire rub. :)

Once you have visually looked things over yourself, you could then check with a reputable shop.

The LT235/85R16/E tires I suggested should hold up your vehicle with less pressure than your current tires, but, they are wider than your current tires, which means the DRW tires will be closer together than your current tires, before airing down. The tires you asked about are even wider, which adds to the problem.

You could look at LT215/85R16/E tires, which are narrower than your current tires, to give a bit more room for airing down, but, it might not make enough of a difference. If they would work for you, keep in mind that your front tires would then be a bit narrower too.

 
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bajajoaquin

Adventurer
I’m going to take it next week to a local shop. I talked to them about how to figure this out and he told me that he’s got conversion books he can refer to and we would work through it.

The camper isn’t here at home so it’s not easy for me to get out and check it out.

After tires and belts and hoses, it goes to the gear shop for ARB air locker and dual compressor. I’ll probably do the solar installation myself.
 

bajajoaquin

Adventurer
Yep, great idea except I have no driveway. It is, however, one of the things I’ll be sure to do at the shop when we go over it.
 

bajajoaquin

Adventurer
Yep. I’m going to do it at the shop. Two reasons: they have adequate air to go back up, and I want them to feel like they have some skin in the game if it doesn’t work. I’ve found that if you just say “put this on,” they will and then leave you to the results. But if you say, “this is what I’m trying to achieve, what do you recommend?” That you get greater support.

In procurement terms, it’s the difference between a design spec and a performance spec.
 

bajajoaquin

Adventurer
Going with 285s as planned. Talked it over with the shop and we’re pretty confident. I mean, if we are wrong, I’ll add a spacer or buy wider wheels since that’s about the size I want so it came down to that anyway.

Also watched some UJoint vids and he seems to put 285s on stock wheels pretty regularly. No telling, of course, if they have the same wheels I do, but it’s still a good sign.

We pulled the cover off the spare and the guy laughed. “They haven’t made that tire in more than 10 years.” Date code was 2001. So I’m buying 7 tires and not 6.
 
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