linober Report post Posted September 25, 2014 Because there are no replacement tires available (per Michelin) of the original (oem) that came my w/ 32' FRED on a Freightliner chassis, my local supplier recommended the R255/70R/22.5 in its place. I Will be replacing all six (6) tires at the same time. GOOD IDEA OR NOT??? Share this post Link to post Share on other sites
kaypsmith Report post Posted September 25, 2014 As long as you have side to side clearance, should be ok. 255 vs 235 = 20 mm, or in inches about 8/10 of an inch wider. The height overall is 2.25 mm in radius, or 4.5 in diameter about 1/10 of an inch. I have replaced 235/75X22.5 with 245/70X22.5 and the circumference is almost identical, which is what affects the speedometer calibration. Probably not enough to worry about. Share this post Link to post Share on other sites
tbutler Report post Posted September 26, 2014 The side to side clearance is a very important factor with the rear duals. There must be sufficient space between the two tires for cooling and also to prevent "kissing" at the point where the tires are on the pavement and bulging at their greatest. Kissing can destroy tires in a short period of time. Poor cooling will destroy the tires over a longer period of time. Share this post Link to post Share on other sites
tireman9 Report post Posted October 1, 2014 linober You didn't specify which Michelin design tire you are replacing. I will assume it is the XRV which according to the Michelin RV tire Brochure requires a minimum "dual spacing" of 10.3". The 255/70R22.5 XZE specifies a min dual spacing of 11.6 Dual tire spacing is controlled by your wheel design so the only way to know for sure if you will be able to change the size as suggested is to get the wheel part number and confirm with the wheel mfg the design spec for dual spacing. In addition to dual spacing you need to worry about clearance to the frame, suspension and exhaust on the inside and to the body on the outside. Even if you were to buy new wheels that meet the dual spacing requirement that might create other clearance issues. Maybe you need to check other tire suppliers such as Goodyear, Bridgestone/Firestone or Toyo for replacement in your original size and Load Range if Michelin is not able to provide tires. You might also ask the tire dealer that suggested the larger tires if he was willing to be responsible for the dual spacing mis-match. Sometimes I think dealers are more interested in just making the sale than in providing the service their customers need. You might also spend a few minutes reviewing the topic of dual tires on my blog. I have 9 posts with "dual" as a label. Share this post Link to post Share on other sites
