Community Forums

dmason · 07-23-2013, 09:36 AM

Will I be causing myself problems if I run Michelin XZA2 Energy 315/80R22.5 tires on my steer tires (which will be new) and GY G670 295/80R22.5 (tires currently installed) on my drive and tag axles?

Our budget won't support new tires all around so I thought I'd change the steer tires for now and the drive/tag tires next April. Thanks.

Skip426 · 07-23-2013, 09:54 AM

A lot would depend on the tolerance of your anti-lock brake system to the tire size difference. You would have find out your brake system brand and the specs for allowable difference.
Another consideration before you go with a large tire, would be the spacing on the rear rims and if a larger tires would have enough space between them when mounted.

Haven't been to the GY, web site but Michelin requires a wider rim spacing.
13.2" on 295/80R22.5 vs 13.8 " on 315/80R22.5
GY web site doesn't list rim spacing spec's.

Triker56 · 07-23-2013, 11:11 AM

If it has antilock brakes (ABS), vehicle manufacturers advise buying new tires that are the same size as those installed at the factory.

The reason: the diameter of the tires affects how the wheel speed sensors read, which affects the operation of the ABS and traction control systems. Installing different-sized tires in the front and rear can also impact the operation of antilock brakes. (You’ll know that the ABS has been deactivated when the ABS warning light comes on.)

kketterling · 07-23-2013, 11:59 AM

A number of people have done this and hopefully they'll chime in concerning ABS. You might also do a search on this as there is quite a lot of info out there. Might add that at a minimum I plan to do the same thing this fall.

distaff · 07-23-2013, 02:34 PM

I've got 315s on the front, 295s on the drive and tag. Never thought about the ABS implications, but I have not had any symptoms of any problems. Mike Canter posts on this site frequently and I know he did it to because I followed his example.

We have both had them on for about 2 years and have not had any issues. We are both on the S-Series chassis from the same period.

boaterok · 07-23-2013, 05:31 PM

I have a 05 Exec Detroit 60 and also did this after talking to Mike Canter. I haven't had any problems and I pull 20' stacker trailer and I have had a few close animal encounters and never even felt or heard the ABS react. And have had them for a couple of years now

Mike Canter · 07-23-2013, 06:13 PM

I have 315's on the steer and 295's on the drive and tag and have had no problems. Some MHs have a problem on clearance with the air bags metal mounts that are behind the front tires but a little grinding helped.

Johnontheroad · 07-23-2013, 06:55 PM

My new coach had a serious out of alignment driver side duals, requiring an early tire change. Also, my GY670 had rivering, so I changed all tires except tags. I wanted 315's front and 295 rears.

But, both the alignment shop owner (himself a Executive owner) and the tire guy (who did all the warranty tire and wheel work for Monaco and Country Coach in Coburg) recommended staying one size all the way around.

They had several reasons, but the one that stuck with me was that after 4 or 5 years I may want to move the steers to the back and get new ones for steers. You can't do that if you mix sizes.

So I went 295 all the way around. But that was me, you may have other reasons to mix sizes. Just wanted to say what I learned when I was in this position.

== John

Mr_D · 07-23-2013, 07:06 PM

I put Michelin 305/70's on the front and kept the OEM size 275/70's on the rear. No problems with the ABS system after two years. But I did notice a loss of steering "precision" as it seems to wander more. Not excessive but noticeable to me.