Michelin XDN Tires

[Lin]

I have been offered some Michelin XDN 12R 22.5 take offs for my drive axle.  They are off a fire truck so they do not have too much wear or weathering.  I currently have 11R 22.5's on the bus and I understand that this will raise the rear axle about .5 inches which does not seem like a big deal.  The question is whether they are an appropriate tire.  My research seems to say that have an inclement weather traction tread.  Would I being giving up ride quality with these?

[tekebird]

liky not ride quality....but they will be noisy mothers.

[Stan]

The MC-5 originally had 12R22.5 tires so there is no problem going back to them. If your bus has a 3.36 rear axle ratio, the smaller tires were probably put on to reduce the top speed and give a little more power. IIRC there is 60 engine RPM difference.

I don't know anything about XDN tires except what I see on the tire sites. Grip tires tend to be noisy and wear a lot faster than highway tread. I don't see any indication of heavy sidewalls that would affect ride.

[TomC]

The unique thing of the Michelin XDN2 is that it is a high gripe bad weather and snow tire.  It won't produce as much noise as a heavy lug tire but will be a bit noisier than an all position tire.  Personally I like them because of the multiple sipings (1300 small cuts in the tire)  the tire can squirm without wearing prematurely.  Also, surprisingly, this translates into just about the best riding drive tire made (this applies to the XDN2).  If you do put the 12R on your drive, please notice the inflation guide suggestions.  For instance, if your drive axle weighs 20,000lb, then Michelin suggests 80psi.  The proper inflation for the weight and tire you use is the single most important aspect to getting both the best ride and tire life out of your tires.  Good Luck, TomC

[Lin]

Thanks for the info

Tom- They said it was Michelin XDN.  I see on their website that they make the XDN2 now and this one does not seem to be produced.  Just to be sure, I will call tomorrow to see if it is the newer version.  Any info on the plan old XDN though?

[HB of CJ]

My Crown Super Coach still has the stock 12RX22.5 tires and I was told by my mechanic friend that the two hole steel Budd type wheels are one-half inch wider than normal.  I do not know if running a 12R on an 11R rim would make any difference or not.  I'm also retired from an I.S.O. Class 1 fire department, sosss the idea of running ex-fire apparatus tires sounds cools to me.  Although be prepared for a "tire-memory" that includes full power starts, speeding, running stop signs, possibly red lights and other stuff.  Be warned. 

[TomC]

8.25 or 9.00 x 22.5 rim is acceptable for the 12R-22.5 according to Michelin.  Good Luck, TomC