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Tire size replacement for the 12R22.5

Yahoo Message Number: 29793
Hi Group:

I am ready for new tires on my coach and have seen two metric sizes mentioned as a replacement for the 12R 22.5 Toyo tire. Should it be replaced with a 295/80R22.5 or a 315/80R22.5? I have seen both tire sizes mentioned in similar discussions.

Bruce B

Carlsbad, CA

2002 CC Allure #30757

Re: Tire size replacement for the 12R22.5

Reply #1 –
Yahoo Message Number: 29796
Go to this web site it gives very good information on tire sizes.
Looks like the 295/80 are a bit tall the RPM is over 500 so the speedometer would be in error. The 315/80 is close to the 12R RPM (487) at 492 and the load capacity is better. (max load single tire 9090#). They require 9" rims.

http://www.dickmantires.com/default.html
I upgrades from 10R to 275/80 and got a huge increase in tire margin.

Jack Foster Allure 30076

Quote
Hi Group:
> I am ready for new tires on my coach and have seen two metric sizes
mentioned as a

Quote
replacement for the 12R 22.5 Toyo tire. Should it be replaced with
a 295/80R22.5 or a

Quote
315/80R22.5? I have seen both tire sizes mentioned in similar

discussions.

Re: Tire size replacement for the 12R22.5

Reply #2 –
Yahoo Message Number: 29806
In your case I believe the 295R will be more than adequate. The 315R was used on Magnas and Affinities with the 18,000 lb front axle. Even with the 42' Allure I believe your front axle has a 14,000+ rating and the 295 will handle that. Should you reprogram the engine ecm for the difference in in tire circumfrance? Some will say yes, others no. The difference is 13 revolutions per mile, or about 2.6 % smaller is the 295 vs the 12r and 315r which are almost identical. TWI

Re: Tire size replacement for the 12R22.5

Reply #3 –
Yahoo Message Number: 29815
Bruce,

I went with 295/80R 22.5 Michelin XZA2 Energy tires to replace my 12R Toyos. Load range is slightly higher than previous Toyo. Diameter is a little less, so your speedometer will read faster until you have Cummins update your engine computer with the new tire sizes.
I think that 315's might cause some rubbing issues with the suspension or body.
Rob

2002 Intrigue #11480

Quote
I am ready for new tires on my coach and have seen two metric sizes
mentioned as a

Quote
replacement for the 12R 22.5 Toyo tire. Should it be replaced with
a 295/80R22.5 or a

Quote
315/80R22.5? I have seen both tire sizes mentioned in similar

discussions.

Re: Tire size replacement for the 12R22.5

Reply #4 –
Yahoo Message Number: 29829
Would it be wrong to to put a 315 on the front axle for the additional safety factor and put 12R22.5 back on the dual and tag. They are only 0.4 inches different in height. (On the dickman tire site it said there is a service bulletin out to mount the 315 on a 8.25inch rim)

How would this affect the way the coach handled or drove. Would the ride height need to be readjusted.

Just a thought.

Kevin

05 Intrigue
11886

--- intrigue11480 rbessinger@...> wrote:

Quote
Bruce,

I went with 295/80R 22.5 Michelin XZA2 Energy tires > to replace my 12R

Toyos. Load range is slightly higher than previous > Toyo. Diameter is

a little less, so your speedometer will read faster > until you have

Cummins update your engine computer with the new > tire sizes.

I think that 315's might cause some rubbing issues > with the suspension
or body.

Rob

2002 Intrigue #11480

> I am ready for new tires on my coach and have seen > two metric sizes
mentioned as a

> replacement for the 12R 22.5 Toyo tire. Should it > be replaced with
a 295/80R22.5 or a

> 315/80R22.5? I have seen both tire sizes > mentioned in similar
discussions.
>
>

> Bruce B

> Carlsbad, CA

> 2002 CC Allure #30757
>
Don't get soaked. Take a quick peek at the forecast with Search weather shortcut.

http://tools.search.yahoo.com/shortcuts/#loc_weather

Re: Tire size replacement for the 12R22.5

Reply #5 –
Yahoo Message Number: 29837
I was thinking of putting the 315's on the front and the tag, the 12rs on the drive. Then I would have a second pair to rotate. Have never had to rotate duals. But have had to rotate the front to tag.
TWI 2004 Intrigue 11731.

Re: Tire size replacement for the 12R22.5

Reply #6 –
Yahoo Message Number: 29844
TWI,

You should check with a reputable truck tire dealer to determine if your aluminum wheels are OK for the 315/80R22.5 tire. Our 2000 Magna came with 12R22.5 tires on the front & back, but the fronts were on a different wheel than the rears. Our front wheels had smaller cooling holes that the rears, and were also the correct size for the 315/80R22.5 tires. I was told back then that the Affinitys came with the 315 tires on the front, because the front axle weight was higher than the Magna, but I could change (when it came time to replace our front tires) to the 315/80R22.5 size and run them at a lower pressure than the 12R22.5 (for equal load carrying capacity) and have a better ride. We did that in May 2006.

Brad Ward

2000 Magna 5916

Quote from: TWI
I was thinking of putting the 315's on the front and the tag, the
12rs on the drive. Then I would have a second pair to rotate. Have never had to rotate duals. But have had to rotate the front to tag.
TWI 2004 Intrigue 11731.

Re: Tire size replacement for the 12R22.5

Reply #7 –
Yahoo Message Number: 29851
TWI,

Would having two slightly different size tires on the tag and duals cause any problem? It sounds like a good idea. Who would know the answer to this question?

Thanks,

kevin

O5 Intrigue

--- TWI cmarshall@...> wrote:

Quote
I was thinking of putting the 315's on the front and > the tag, the 12rs on the drive. Then I would have a > second pair to rotate. Have never had to rotate > duals. But have had to rotate the front to tag. TWI > 2004 Intrigue 11731.

Re: Tire size replacement for the 12R22.5

Reply #8 –
Yahoo Message Number: 29855
Hi Rob:

I thought I read on the Michelin web site that the XZ2 12R22.5 was the designation for the 12 inch version of the ZXA2 energy tire. Any reason why you chose to go with the 295/80R22.5 vs the XZ2 12R22.5?

The dimensions of the XZ2 12R22.5 are nearly identical to the original Toyo tire that I have.

Bruce B

2002 Allure #30757

SMI Air Force One Braking system

Reply #9 –
Yahoo Message Number: 29857
I had the oportunity to take a look at SMI's AirForceOne brake system at the rally at Jekyll Island. It seems to be less invasive on the OEM systems than the M&G and a few others. It uses it's own vacuum source so the force on the pedal can be minimized when braking. It does tap in to the air of the coach but it has a electronic check valve to stop any air loss from the coach if the air line to the car should become disconnected.

I was wondering if any of you guys have any experience with this system or what your opinions are

Kevin

05 Intrigue
11886

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Re: Tire size replacement for the 12R22.5

Reply #10 –
Yahoo Message Number: 29885
Bruce,

I have heard from dealers and read on several message boards that 12R22.5 size tires are not that common with service centers. More tires are going to metric sizing. Also, with truckers mainly running 11R22.5 or larger 24.5, the 12R22.5 might be hard to locate if I have a flat on the side of the highway in the middle of nowhere. The 295/80R22.5 seems to be more readily available.
There also is a newer XZA3 Energy tire, but only available in 11R or 275 metric widths.
Rob

2002 Intrigue #11480

Quote
Hi Rob:

I thought I read on the Michelin web site that the XZ2 12R22.5 was
the designation for the 12

Quote
inch version of the ZXA2 energy tire. Any reason why you chose to
go with the 295/80R22.5

Quote
vs the XZ2 12R22.5?

The dimensions of the XZ2 12R22.5 are nearly identical to the
original Toyo tire that I have.