Barthmobile Portal
Also looking for tire advice.

This topic can be found at:
https://www.barthmobile.com/eve/forums/a/tpc/f/3631087061/m/7041097503

03-13-2008, 08:13 PM
Don in Niagara
Also looking for tire advice.
We also need tire advice. One front tire on the coach needs replacing due to sidewall cracking. The current tires are Yokohamas 265/75 R 22.5. The local truck tire guy has been around to the usual suppliers here in Phoenix and can't find any in that size dia. to sidewall ratio. None available at the 75% range it seems.
He recommends 255/80Rs instead because they are a more common motorhome size and of course we'd have to get both fronts done.
Will they do the job? If we go with a pair of them what brand would be your fave?
The 265/75R Yokos are rated at 5205lbs single @ 120psi cold. This is well above the coaches front G.A.W.R. of 9000 lbs.
FWIW ....the rears are 255/70R 22.5s and in good shape.
Thanks for any advice.
Don and Patty


1990 Regency 34'
Cummins 6CTA 8.3 240hp
Spartan Chassis,
4 speed Allison MT643
03-13-2008, 08:28 PM
Nick Cagle
Don,
Based on what the other guys are telling me, I'm going to go with the 11R22.5. You could change the front two now and the others later. If you have a Sam's Wholesale in Canada or Phoenix, they have a 11R22.5 for about $250.00US. I don't know anything about the tires but plan on investigating them further before I buy.
Good Luck,
Nick
03-13-2008, 11:59 PM
Don in Niagara
Hi Nick
Wouldn't that give me quite a bit of difference between the diameter of the fronts compared to the 255/70s on the rear? Would that matter?
Don


1990 Regency 34'
Cummins 6CTA 8.3 240hp
Spartan Chassis,
4 speed Allison MT643
03-14-2008, 07:36 AM
Nick Cagle
quote:
Originally posted by Don in Niagara:
Hi Nick
Wouldn't that give me quite a bit of difference between the diameter of the fronts compared to the 255/70s on the rear? Would that matter?
Don


Don, According the specs I've found the 255/70 are 36.7" tall and the 11R are 41.3" tall. That is a large difference and I don't think I would want it permanently but I don't think it would be a problem for a short time. I would only do it if you plan on replacing the rear tires soon. The coaches air leveling suspension should help compensate for the difference until you change the rear. BTW, Bridgestone makes a 265/75 tire.
Good luck,
Nick
03-14-2008, 09:50 AM
bill h
quote:
Originally posted by Nick Cagle:

Don, According the specs I've found the 255/70 are 36.7" tall and the 11R are 41.3" tall. That is a large difference. Nick


That is a very large difference, indeed. A similar comparison on my 19.5 tires had a much smaller difference. I did the numbers (assuming an aspect ratio of 1 for the 11R) and came out with a much smaller difference. Perhaps my math is faulty this early.


.

84 30T PeeThirty-Something, 502 powered
03-14-2008, 10:37 AM
Don in Niagara
Nick
I think I will go with the 255/80Rs. They are readily available and the rears are fine so hopefully will provide a few more years of use. When they go I'll replace them with 255/80Rs too. For some reason it ever dawned on me to check the data tag yesterday, the tires called for on all 6 wheels are 255/80Rs. I don't see anything wrong with going with what the factory called for.
Thanks for all the help guys.
Don
quote:
Originally posted by Nick Cagle:
Don, According the specs I've found the 255/70 are 36.7" tall and the 11R are 41.3" tall. That is a large difference and I don't think I would want it permanently but I don't think it would be a problem for a short time. I would only do it if you plan on replacing the rear tires soon. The coaches air leveling suspension should help compensate for the difference until you change the rear. BTW, Bridgestone makes a 265/75 tire.
Good luck,
Nick



1990 Regency 34'
Cummins 6CTA 8.3 240hp
Spartan Chassis,
4 speed Allison MT643
03-14-2008, 06:57 PM
Gary Carter
That is 4.6 inches in diameter, but 2.3 inches of increased height. Or 2.3" above the axle and 2.3" below.

I still like the 11R22.5. When I replaced the tires on our Breakaway last year I almost bought new wheels and put 22.5s on. Ended up staying with the 8R19.5


'92 Barth Breakaway - 30'
5.9 Cummins (6B) 300+ HP
2000 Allison
Front entrance
03-14-2008, 10:21 PM
MWrench
I don't think you could have gotten 22.5 in the wheel house. On the front I have a bit of rub with 19.5 in a tight turn, I replaced them with 225 70R19.5 and they are slightly smaller and don't quite touch when in a turn. I stayed with 8R19.5 on the rear 'cause I didn't want to add 50 RPM at cruise because of the smaller diameter.

On the back, I have very little clearance from the rear of the tire to the back of the wheel house. Could never get 22.5 in there.

If I could find 6 bolt Budd wheels 19.5 that are 7-7.75 inch wide, I would go with 245R70 19.5 G rated all the way around but wheels like that don't exist!


Ed
94 30' Breakaway #3864
30-BS-6B side entry
New Cummins 5.9L, 375+ HP
Allison 6 speed
Spartan chassis
K9DVC
Tankless water heater
03-15-2008, 12:47 AM
Rusty
I tend to be inclined to go with the chassis manufacturer's specs., believing (rightly, wrongly, or otherwise) that it knows what it's doing. That's a bit easier for me, since 8R19.5s are pretty much de rigueur for the smaller Class As. Bumping the ride level 2.6" might seem to increase mileage due to slower engine RPM, but it also allows more air flow (and resistance) under the coach. This is totally a WAG, but I'd guess that fuel efficiency wouldn't increase by a measurable amount.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

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