Community Forums

Graniteman · 06-03-2013, 08:27 PM

So I am researching tires since my XZA2's are aged out. I have a few questions.

I read where some are increasing to a taller size ie; going from 215s to 315s so that they can run lower tire pressures. I realize that you would need to check clearances from undercarriage and suspension parts. And that putting them on the rear would throw the speedo and odometer off. I am wondering, would the ride height need to be reset? If so wouldn't that create a spongier ride?

2) Is there anyone who likes Michelin tires? I have been happy with My A2's but it seems like many have had more bad experiences than good.

Mr_D · 06-03-2013, 08:38 PM

I put 305/70's on the front, just to have the tire capacity that the new axle has. Don't really notice any better ride even though I now run 100 psi vs 120 on the 275's. On the rear I still have the 275/70's and run 85 psi as they're not anywhere near their rating.
In most cases, if you go to 305's all that way around, you will need to replace all the wheels too. I wanted Alcoa's so I replace all six wheels, 4 used Alcoa's and 2 matching steel for the inner duals. The larger tires require a wider wheel and different offset.

Graniteman · 06-04-2013, 01:47 PM

Quote:

Originally Posted by Mr_D

I put 305/70's on the front, just to have the tire capacity that the new axle has. Don't really notice any better ride even though I now run 100 psi vs 120 on the 275's. On the rear I still have the 275/70's and run 85 psi as they're not anywhere near their rating.
In most cases, if you go to 305's all that way around, you will need to replace all the wheels too. I wanted Alcoa's so I replace all six wheels, 4 used Alcoa's and 2 matching steel for the inner duals. The larger tires require a wider wheel and different offset.

Did you reset your leveling valve on the front to return the ride height to the factory spec?

desobelman · 06-04-2013, 03:17 PM

i would stay with the size tire the chassis manufacturer put on as they are calibrated to the projected weight, ride height of the RV.

As to the Michelins, my curretn rig had original Michelins on it when purchased. I drove for a year with NO problems. Replaced due to age and some sidewall cracking on inner dually. They were, due to the age, rougher riding than the new ones, as the rubber hardens with age. New Michelin, 235/80R 22.5 XRVs are great! Smoother ride, and I expect a long life from then.

In my humble experience, Michelins have far fewer problems than some others. Hankooks seem to be of excellent quality as well. I have several friends who put Hankooks on their rigs, have driven many miles and are very happy.

With the FMCA/Michelin tire program, you can get Michelins at a very competitive price.

Happy Trails!

Darryl

Mr_D · 06-04-2013, 03:25 PM

Quote:

Originally Posted by Graniteman

Did you reset your leveling valve on the front to return the ride height to the factory spec?

Why? The size of the tire makes no difference in the ride height setting!
Ride height is set between points on the suspension and not from the ground. That is why it's so important to have the ride height correct before doing a front end alignment.

rhusak · 06-04-2013, 04:05 PM

Hi all..
It's not just a matter of upsizing the tires.. The wheels have to be of the proper width for the larger cross section tires..
Just stick with the OE size tires...
Ron

Gary RVRoamer · 06-04-2013, 05:03 PM

A taller tire can be offset by using a lower profile ratio, e,g, changing from an '80' to a "75" or "70". But making any change in tire size requires that you - or the person making the size change decision - know a lot about tire design and sizing as well as the space available in the body of your coach. It should not be done casually.

Ride height is not effected, but front end alignment, speedo calibration, wheel (rim) size, dual spacing, and other things may be. That's part of the reason you can't just say "give me a taller size".

Graniteman · 06-05-2013, 11:26 AM

Ahhhh you are correct Mr.D. I don't know why I had it in my head the measurement was to the ground. I should have remembered from last year when I changed all the air bags and leveling valves. Old age???

I appreciate hearing good reports on Michelin tires!

Thanks everyone.

wilco1 · 06-06-2013, 12:49 AM

Quote:

Originally Posted by Graniteman

So I am researching tires since my XZA2's are aged out. I have a few questions.

I read where some are increasing to a taller size ie; going from 215s to 315s so that they can run lower tire pressures. I realize that you would need to check clearances from undercarriage and suspension parts. And that putting them on the rear would throw the speedo and odometer off. I am wondering, would the ride height need to be reset? If so wouldn't that create a spongier ride?

2) Is there anyone who likes Michelin tires? I have been happy with My A2's but it seems like many have had more bad experiences than good.

Graniteman,

Depending on what size tires you have now, it may be possible to do what you want to do without a lot of drama or extra expense.

Check the various tire manufacturers and see if they have have a suitable tire one "load range" higher than you have now (i.e.. if you have load range G, look for a load range H) that is similar in diameter to what you have now. That resolves the axle ratio/odometer issues and potentially gives you more carrying capacity or the same at less pressure.

On my last coach went from Mich XRV 255/80 22.5 G to Goodyear G670 275/70 22.5 H. More carrying capacity at less pressure. No issues with buying new wheels, dual spacing or changing odo calibration.

As for brands, I think any of the "brand names" will probably work fine if properly maintained. With respect to tire reviews/complaints on the forums, you need to understand that a vast majority of new RV's have either Michelin or Goodyear tires installed, that those having had tire problems therefore will have had either Michelin or Goodyear tires, and that the (presumably) vast majority who have had a good experience with their tires haven't posted a "wow..I love my tires" message on the forum.

I've had Michelins, Goodyears and now Continentals. I have the coaches weighed, aligned and I know what the pressures should be and check regularly. Happily, I haven't had any tire problems with any of them thus far.

My thoughts FWIW.

tfw