Tire size

[2nomads]

Hey all, I live out in the country in Vergina and am having trouble finding a replacement tire for my 235X80X22.5 Mich. Does anyone have the experience of replacing these tires with a good name brand of the equal height and dia. Any help would be great. Tire dealers around here aren't much help.

[Floridakamper]

Some of us have replaced the 235/80's with 245x75x22.5 Sumitomo ST718. I have and I've been happy with the Japanese made tire. They are cheaper and a good tire.

[lavamanz]

I have the 255/70R22.5 16ply Load Range H on my unit. Toyo M122 is the current brand/model in the 255/70R22.5 size & is what I have on the front. I still have the Toyo M120 on the duallys. M122 replace the M120 Toyo

[Floridakamper]

lavamanz, the OP is asking a question about replacement tires for a workhorse chassis. I think you're a DP on a FL chassis. That info could screw him up.

[gruelens]

Below is a link to what I did to replace my tires on a Workhorse chassis.

http://www.irv2.com/forums/f22/chang...ze-181046.html

[Floridakamper]

Looks like lavamanz 255/70R22.5 wouldn't cause a problem on a workhorse chassis. Thanks for enlightening this bonehead.

[gruelens]

Thanks for enlightening this bonehead.

Nobody is a bonehead for asking a genuine question. I knew little about this until I started doing homework in preparation for replacing aged out tires. The calculator below helped me in my decision.

Tire Size Calculator - Compare Tire Sizes

[edgray]

Originally Posted by Floridakamper

Looks like lavamanz 255/70R22.5 wouldn't cause a problem on a workhorse chassis. Thanks for enlightening this bonehead.

I have never heard of any Workhorse owner changing from the OE 235/80R22.5 to a 255/70R22.5, but I think the differences would be significant. I suggest you go to the Michelin site and compare the differences-especially regarding the minimum spacing required between the duals.

The link provided above to "compare" won't accept the 22.5 when I tried it.

[gruelens]

Originally Posted by edgray

I have never heard of any Workhorse owner changing from the OE 235/80R22.5 to a 255/70R22.5, but I think the differences would be significant. I suggest you go to the Michelin site and compare the differences-especially regarding the minimum spacing required between the duals.

The link provided above to "compare" won't accept the 22.5 when I tried it.

No, the differences are not significant in size. That is one of the reasons I made the change. There is a fraction of an inch difference in height and width. There is NO problem with dual spacing on my standard Workhorse rims. The 255 tires are rated for my rim width.

The 235 tires are only available from a few manufacturers. As a result, they are pricey and harder to find if road service is needed. My new tires are a common truck size and easily found and more affordable. The 255 tires can handle the same weight with a lower psi. I could not find any problems with making the switch away from the 235 tires.

Just because someone has never heard of something is not a reason to negate the idea. Below is a link to see the conversion stats.

235/80-R22.5 vs 255/70-R22.5 Tire Comparison - Tire Size Calculator

[Floridakamper]

Originally Posted by gruelens

Below is a link to see the conversion stats.

235/80-R22.5 vs 255/70-R22.5 Tire Comparison - Tire Size Calculator

If I understand the calculator, the 255/70's are almost one inch wider. That doesn't seem insignificant in the dual position even if it it's working for you. Thanks for making the case that I'm not a bonehead but trust me, at times.....

[Triker56]

No, the differences are not significant in size. That is one of the reasons I made the change. There is a fraction of an inch difference in height and width. There is NO problem with dual spacing on my standard Workhorse rims. The 255 tires are rated for my rim width.

The 255/70 is smaller at a diameter of 36.7" then the 235/80 37.1"
That will increase the odometer miles, but may be a good thing when using it for MPG.

The 245/75 are the closest in size to the 235/80's at 37.1"-37.4" depending on the manufacture.
Another choice if his MH is getting at max weight. Is 275/70 at 37.6"

When the size is 22.5" rims, it doesn't make any difference if they are on a gas or diesel MH. The tires are made to fit on either.

[edgray]

Originally Posted by gruelens

No, the differences are not significant in size. That is one of the reasons I made the change. There is a fraction of an inch difference in height and width. There is NO problem with dual spacing on my standard Workhorse rims. The 255 tires are rated for my rim width.

The 235 tires are only available from a few manufacturers. As a result, they are pricey and harder to find if road service is needed. My new tires are a common truck size and easily found and more affordable. The 255 tires can handle the same weight with a lower psi. I could not find any problems with making the switch away from the 235 tires.

Just because someone has never heard of something is not a reason to negate the idea. Below is a link to see the conversion stats.

235/80-R22.5 vs 255/70-R22.5 Tire Comparison - Tire Size Calculator

George: thanks for providing the tire comparison with the sizes filled in....I don't know why I could not get it to work for me.

Sorry if you felt my suggestion to research dual spacing was "negating" your post. That was not my intent.

What I don't see in the comparison you provided is the dual spacing, which is a safety concern. The fact that a tire size is approved for a specific rim width isn't the issue, but rather my concern is how much space is left between the tires when mounted in a dual application. The sidewalls don't have to be touching to create a situation where inadequate heat dissipation becomes an issue. There are spacers that can be added between the mating rim surfaces to provide the dual spacing required for adequate heat dissipation. Adding these spacers can sometimes require the installation of longer mounting studs, but that is fairly easy to do.

FWIW, I think that only Michelin makes the OE 235/80R22.5 size, and I'm aware that many RVers have changed to other brands and sizes. I just hope that doing so does not create a hazardous situation for those folks .

In a feeble attempt to add some humor here....just because they make brightly colored plaid pants that fit my 40 inch "rim size" doesn't mean I should be wearing them in public.

[gruelens]

Sorry if you felt my suggestion to research dual spacing was "negating" your post. That was not my intent.

Apology accepted edgray.

I have 2.25" between dual tires with the 255/70/22.5 tires. I took my rim width and researched which tire sizes are suitable for dual application prior to purchase. Note ........ I have a Workhorse W25.5 chassis.

By no means am I trying to convince anyone what direction to go with tires. I wanted to share that I was pleased with a decision I made to purchase 255/70/22.5 Firestone FS560 tires to replace my factory size. I personally am happy to be rid of the proprietary Michelin size tire (235). I like the heavier sidewall construction which reduces chance of damage due to curbing. I like the increased carrying capacity/load range which enables me to run at a lower psi. I like knowing that a standard truck size is easier to find in case of needed replacement. I like the money saved by my decision. Note...... I had a tire dealer at Quartzsite AZ tell me that I needed to put Michelin RV tires back on my MH for replacement or "I would be very sorry".

[Triker56]

For Minimum Dual Spacing you measure from center of tire to center of tire on the Duals.

The 235/80 is 10.3"
The 255/70 is 11.3"-11.6"
The 245/75 is? Neither Michelin or Good Year make that size in a 75.
The 275/70 is 11.9"