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Old 12-02-2020, 03:50 PM   #1
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Alternate tire sizes? what about drive/steer?

My rig shipped with Michelin 235/80/22.5 tires. The PO added new tires at some point. They kept original spec Michelins for the front but put Goodyear (and one Bridgestone??) 245/75/22.5 for the rear (I assume they did this to avoid buying Michelins). Despite being a tiny bit different, the rears have plenty of room between them and don't appear to have any other issues relating to size.

But just how different can you go on tire sizes? And other than price, is there any real reason you'd choose an "off-size" tire?

Finally, is it absolutely necessary to have different tread designs between front and rear? I sort of get that you shouldn't put drive tires on the front if you can help it.

Can you put steer tires on the back?

Is "all-position" a compromise? Are steer tires mandatory?

All of the tires are aging out at seven or eight years so I'm going to get new ones. I'm looking at Toyo, Falken and Sumitomo, which are "all position" in 245/75/22.5 size, I think. Its a HUGE purchase and not one I take lightly.
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Old 12-02-2020, 04:02 PM   #2
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The 235/80 is priparitary to Michelin. No other brand has that size. The 245/75/22.5 is the accepted replacement size. I chose Toyo's to replace my Michelins as have many other RV owners. You can use a steer tire all around if you want to. You just shouldn't use a rear specific on the front.
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Old 12-02-2020, 04:09 PM   #3
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Most often steer tires; are all position, and there is no problem using them on front and rear .
Most every class A chassis would leave the factory that way.

Overall diameter and RPM ( Revolutions Per Mile ; in tire talk ) and load carrying capacity are the biggest factors .
RPM for anti-lock brake operation , if you check the two sizes you have you'll probably find they match , or are VERY close.
Do not consider any tire that doesn't exceed the factory tire load spec; weight carrying capacity at psi !

Because my coach is a 28,000 lb. snow magnet , I have traction tires all around , a little noisy but when faced with 6" of snow on the interstate; on nearly every trip , I'll take every handling advantage I can get.
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Old 12-02-2020, 04:11 PM   #4
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Deprived --

When it comes to tires I follow the manufacturer required tire size and don't deviate as tires are "the" key safety feature of a motorhome. Trying to save some money by using different size tires, purchasing "off brand" tires, mixing tires brands, etc. I don't think is worth the risk.

A year ago I needed a new set of tires for my motorhome when the four year old OEM Michelin XZE 2+ tires developed premature side wall cracking. Through FMCA's tire discount program I was able to purchase a new set of six Hankook AH37 "all positions" tires in the Freightliner specified size for my coach -- 275/70R22.5 The cost a year ago was $380 per tire plus taxes and installation.

The cost for the Hankooks was ~40% less than the cost for a set of Continentals or Michelins. I only use my motorhome for long weekend get aways so I drive less than 5,000 miles per year meaning the lower price Hanhooks meet and exceed my needs. I've noticed very little difference in ride quality between the Hankooks and the OEM Michelins.

There are several posts on iRV2.com dating back to 2014 about the 235/80R22.5 size tire which is a "Michelin only" tire size. The discussion from those previous posts stated a 245/75R22.5 is the "replacment" tire from other manufacturers for the Michelin 235/80R22.5 The Good Year G670 RV Tire 245/75R22.5 may be worth considering for your coach --> https://rvtires.com/shop/goodyear-g6...v=7516fd43adaa and the Good Year site --> https://www.goodyearrvtires.com/tire-selector.aspx

Hope this info helps!
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Old 12-02-2020, 04:30 PM   #5
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As long as the load and speed rating meets or exceeds the oem spec tire you'll be fine with a 245/75/22.5. The 235/80/22.5's are a Michelin thing, and most tire shops do not carry them unless special ordered at a premium price.
The tire size diameter is nearly identical in rpm specs. Personally I'd run the Toyo's in the 245/75/22.5 if it was me, and use steers all the way around for the smoothest, best tracking ride. Other opinions will vary, but one thing for sure, Toyo's perform well and are priced right. You could buy the Michelins but as others have stated, sidewall cracking is common and may likely require early replacement. Why reward them with a premium price coupled with underwhelming longevity? Toyo, Hankook, Bridgestone etc are far from "off brand" tires.
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Old 12-02-2020, 07:13 PM   #6
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Alpine36 add Sailun truck tires to your list. They have the same construction as Michelin truck tires. I see many OTR semi's running them on the steer axle. I bought 6 275/70R22.5, LR H installed on MH for $1,280 in 2017. I can tell no difference from the Goodyear G670's they replaced.
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Old 12-03-2020, 07:05 AM   #7
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In response to your comments - the Toyo M154 245/75R22.5 has become a great metric substitute for the Michelin 235/80R22.5. Both tires have the same ply (14ply) the same single max load, the same tread pattern and same revolutions per mile (meaning no change to speedometer).
Safe travels to you and your family.
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Old 12-03-2020, 07:32 AM   #8
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Thanks to everyone for the excellent and helpful replies. I'm leaning towards the Toyos and have found a reputable dealer not too far away that does truck and motorhomes.

Something from the Toyo brochure surprised me: They recommend keeping the tires at max press rather than keeping them at a pressure based on corner weight. I'm kind of surprised by this - I've always managed my pressure by weight which I periodically get done at the Escapees park nearby.

I get their point but this doesn't seem like a good idea. My rig handles badly when the front tires are at max.
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Old 12-03-2020, 07:47 AM   #9
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Thanks to everyone for the excellent and helpful replies. I'm leaning towards the Toyos and have found a reputable dealer not too far away that does truck and motorhomes.

Something from the Toyo brochure surprised me: They recommend keeping the tires at max press rather than keeping them at a pressure based on corner weight. I'm kind of surprised by this - I've always managed my pressure by weight which I periodically get done at the Escapees park nearby.

I get their point but this doesn't seem like a good idea. My rig handles badly when the front tires are at max.

Suspect this is more a "disclaimer" written more by their corporate attorney than by the tire engineer who designed them.


Probably their way of saying that most owners don't pay much attention to tire inflation and over-inflated is safer than under-inflation and we don't want law suits based on tire failure.


From an attorney's perspective, probably an excellent recommendation. May have caused the tire engineers some sleepless nights, however!
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Old 12-03-2020, 09:34 AM   #10
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Many motorhome owners inflate tires by weight, then add an additional 5 to 10 psi as a safety measure. Works well for my Toyos.
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Old 12-03-2020, 01:31 PM   #11
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I have traction tires all around
That's interesting. What tires are you running?
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Old 12-03-2020, 01:32 PM   #12
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...inflate tires by weight, then add an additional 5 to 10 psi as a safety measure.
Excellent advice.
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Old 12-03-2020, 05:57 PM   #13
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“ When it comes to tires I follow the manufacturer required tire size and don't deviate as tires are "the" key safety feature of a motorhome. Trying to save some money by using different size tires, purchasing "off brand" tires, mixing tires brands, etc. I don't think is worth the risk.”

When you have to run 115 in the front tires and only 80 in the drive and 70 in the tag tires, did the manufacture get it right putting 295/80/22.5 on every where? When I went with 315s (cost more) on the front (decreased psi -12) there was no reason to stay with 295s on the rear. A 11R22.5 is probably the most common truck tire size and it’s the same diameter as a 295 for $150 less X 6 = $900 savings... guess what I put on the rear.
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