gibsonjv Report post Posted August 24, 2010 I have a 1999 Discovery 36T, 5.9L Cummins, Allison 6 sp, It has 5 Michelin XRV 235/80R22.5 and one XZE (same size inside rear)of various ages from 3903 to 2407. I was given this RV by my parents and I need to replace 2 tires minimum, maybe three. I plan on changing tire size to 245/75R22.5 and going with Toyo. At minimum I will replace both fronts. If needed would it hurt keep the 2 newest Mich's on the inside of rear duals and put 2 new Toyo's on the outside. Load specs are the same as the Michelins but the revs/mile are 556 for the Mich and 561 for the Toyo. Does this matter? What damage can be done? Should I wait and replace in pairs the rear as sugested by tbutler in another post? Thanks in advance for answers. Vic Gibson Share this post Link to post Share on other sites
tireman9 Report post Posted August 24, 2010 I have a 1999 Discovery 36T, 5.9L Cummins, Allison 6 sp, It has 5 Michelin XRV 235/80R22.5 and one XZE (same size inside rear)of various ages from 3903 to 2407. I was given this RV by my parents and I need to replace 2 tires minimum, maybe three. I plan on changing tire size to 245/75R22.5 and going with Toyo. At minimum I will replace both fronts. If needed would it hurt keep the 2 newest Mich's on the inside of rear duals and put 2 new Toyo's on the outside. Load specs are the same as the Michelins but the revs/mile are 556 for the Mich and 561 for the Toyo. Does this matter? What damage can be done? Should I wait and replace in pairs the rear as sugested by tbutler in another post?Thanks in advance for answers. Vic Gibson I would suggest you NOT mix different brands or different type tires from same brand as a pair of duals. You need to keep the Outside Circumference (more accurate measure than Outside Diameter) as close as possible to the same. The reason for this is that the larger tire of the pair will be forced to carry greater load (probably by multiple hundreds of pounds). Different brands and in many cases even tires of the same brand but different designs will have different dimensions. In general it is also desirable to have all tires on any axle all the same brand & type and should always be of the same size. Only exception would be a VERY temporary slow speed drive if you had suffered a tire failure and were running a spare to get to the tire store to get a replacement tire. Sorry if this makes your situation more complex. Share this post Link to post Share on other sites
StellersJay Report post Posted August 24, 2010 If you change tire sizes on the duals, keep in mind the spacing between the duals. You do not want to create a situation where the dual's sidewalls make contact. Most, if not all, the tire spec. tables will indicate the dual spacing for various tire sizes. Sam Share this post Link to post Share on other sites
Guest BillAdams Report post Posted August 24, 2010 I would be perfectly fine to put 2 tires of the same size on the same set of duals assuming they have about the same amount of wear as well. So 2 Toyo's on one set of duals and 2 Michelin's on the other would be OK while one new Michelin and one old Toyo would not be a good combination. I would prefer to have 4 of the same type/mileage on my drives if possible but sometimes the road disagrees with my preferences. If I lose one of my duals however, I will replace both on that side at that time. Share this post Link to post Share on other sites
wolfe10 Report post Posted August 24, 2010 Bill, Totally agree as long as the two brands (on other side of dual application) are roughly the same size so the differential doesn't have to work too hard. Said another way, if up-sizing tire size, I would not combine old/smaller tires on one side of the back and new/larger tires on the other. Look at tire "Revolutions per Mile" on the tire manufacturer's website for information on how different your two selections are. Brett Share this post Link to post Share on other sites
gibsonjv Report post Posted August 24, 2010 Thanks for the info. I believe I am going to put 2 on the front and replaced a pair over the next 6-10 months that will get me in a good rotation cycle. I am not a full timer (yet) but plan on using it alot on weekends within 3-4 hrs from home. This will make it easy to maintain tires and other maintenance for now. Thank you guys alot for the info. Vic Share this post Link to post Share on other sites
Guest BillAdams Report post Posted August 25, 2010 Bill,Totally agree as long as the two brands (on other side of dual application) are roughly the same size so the differential doesn't have to work too hard. Said another way, if up-sizing tire size, I would not combine old/smaller tires on one side of the back and new/larger tires on the other. Look at tire "Revolutions per Mile" on the tire manufacturer's website for information on how different your two selections are. Brett I completely agree. Thanks for making that clarification. Share this post Link to post Share on other sites
