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Old 08-04-2012, 02:14 PM   #1
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Taller tires in rear.

I have a 2001 Dynasty which has duals and a tag. The front tires are one year old Goodyear G399 LHS (H rated) size 295x75x22.5. Tag has two Roadmaster 2 year old rm120A (g rated) 295x75 tires.
I am replacing 4 tires on the drive.
I am buying through the FMCA Michelin program and can either get 275x80 (.788" narrower than OE) and .049 shorter. Or my preference would be to plus size to 295x80 For the drive which would be same width as OE BUT 1.17" taller (diameter) than OE and taller than the tag and front which would remain at 295x75. Any issue with coach having taller drive tires than the tag and front?
I could replace the two year old tags with the plus size as the new drives and leave shorter goodyears in the front.
I am within the 3% rule but mixing sizes on the coach (but not the axle) concerns me. It drives great and I don't want to mess that up

Comments? Ideas? issues?
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Old 08-04-2012, 02:50 PM   #2
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If you must, get the 275x80's.. Over 1" taller is prolly way too much
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Old 08-04-2012, 03:44 PM   #3
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Quote:
Originally Posted by Jeff753 View Post
I have a 2001 Dynasty which has duals and a tag. The front tires are one year old Goodyear G399 LHS (H rated) size 295x75x22.5. Tag has two Roadmaster 2 year old rm120A (g rated) 295x75 tires.
I am replacing 4 tires on the drive.
I am buying through the FMCA Michelin program and can either get 275x80 (.788" narrower than OE) and .049 shorter. Or my preference would be to plus size to 295x80 For the drive which would be same width as OE BUT 1.17" taller (diameter) than OE and taller than the tag and front which would remain at 295x75. Any issue with coach having taller drive tires than the tag and front?
I could replace the two year old tags with the plus size as the new drives and leave shorter goodyears in the front.
I am within the 3% rule but mixing sizes on the coach (but not the axle) concerns me. It drives great and I don't want to mess that up

Comments? Ideas? issues?
Hi Jeff, as an old cross country retired trucker, I woul think that the difference should not matter since you have air ride suspension. The air leveling valve should compensate for the difference. But by all means, keep the same size per axle. But it looks like it would make more sense to keep them the same size so they could be rotated with your tag. I am sure you will get more mileage from the drive tires than the tag. Yes, I know that sounds backwards., but I have seen over 100,000 miles difference on 18 wheelers, between trailer and drive tires. Michelin is a fine tire, but the only advantage I coould ever see was in tread life, and that usually is not a concern on an RV. Age deterioration is just as great on a Michelin as lower priced tires. Just my thoughts. Michelin tells you to have the tires checked by a professional after 5 years. hope this helps. old trucker.
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Old 08-04-2012, 08:36 PM   #4
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Quote:
Originally Posted by Jeff753 View Post
I have a 2001 Dynasty which has duals and a tag. The front tires are one year old Goodyear G399 LHS (H rated) size 295x75x22.5. Tag has two Roadmaster 2 year old rm120A (g rated) 295x75 tires.
I am replacing 4 tires on the drive.
I am buying through the FMCA Michelin program and can either get 275x80 (.788" narrower than OE) and .049 shorter. Or my preference would be to plus size to 295x80 For the drive which would be same width as OE BUT 1.17" taller (diameter) than OE and taller than the tag and front which would remain at 295x75. Any issue with coach having taller drive tires than the tag and front?
I could replace the two year old tags with the plus size as the new drives and leave shorter goodyears in the front.
I am within the 3% rule but mixing sizes on the coach (but not the axle) concerns me. It drives great and I don't want to mess that up

Comments? Ideas? issues?

You didn't mention Load. Either actual or the capacity of the new tires.

I did a quick check and it it appears that both of the new sizes can carry a load a bit heavier than your current size. Please be sure to compare your actual corner load with the tire capacity.
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Old 08-05-2012, 10:37 AM   #5
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The current tires are H rated on the front and g on the back. The new tires will be h. If I only buy 4 I will put them on the dual drives and move the roadmaster g rated tires to the tag. Any concern with drives being one inch taller than the tags?

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Originally Posted by Tireman9 View Post
You didn't mention Load. Either actual or the capacity of the new tires.

I did a quick check and it it appears that both of the new sizes can carry a load a bit heavier than your current size. Please be sure to compare your actual corner load with the tire capacity.
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Old 08-05-2012, 08:07 PM   #6
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The current tires are H rated on the front and g on the back. The new tires will be h. If I only buy 4 I will put them on the dual drives and move the roadmaster g rated tires to the tag. Any concern with drives being one inch taller than the tags?
Do you know how to adjust the load on your tag? If you get your weights balanced (Front, Drive & Tag) correctly I see no reason why the slight difference would be of concern. Adjusting the load will adjust the ride height.

Do you have specs of the % load the tag should carry?
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Old 08-06-2012, 11:43 AM   #7
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If there is too much difference in height, you may need to readjust the tag suspension to keep it supporting the proper share of the weight. The Roadmaster chassis people at Monaco should be able to advise how to do that. But if they are pretty close, you probably won't notice much difference.
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Old 08-06-2012, 08:13 PM   #8
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Jeff,
I would consider adjusting the tag linkage like Gary suggested. Since your drive tires are going to be taller (but minimal), lower the tag suspension by one link and then use the tag pressure adjustment to get the weight correct. Go through the scales a couple of time to get it right. I don't see any problem with that setup as long as the ride height is good.
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