Morin all, Great spring day here in the midwest. I upgraded my tires to 35's except for the spare. Its a 33. Question,,, Will a smaller tire hurt my driveline if I get a flat ?? It would be short term till I could get the flat fixed.My service rep at the Hummer dealership said it wouldnt be a problem as long as I kept the speeds down and got the flat fixed ASAP..Getting ready for our yearly fishing trip and trying to decide if I need to spring for a new 35 for my spare. Really dont want to spend the 200$ for a spare, but messing up my drive train fer sure isnt a option. So any helpful input would be nice. Thanks..

 

On fulltime-FWD vehicles, it's advisable to have all five tires (includes the spare) the exact same size/construction/tread configuration. [sm=icon_cheers.gif]

 

...additionally, it's recomended that you include the spare with the scheduled tire rotations, so you will be extending the life of all your tires....better to buy one now than 4 later. Besides, it looks bad-a$$ having the 35" on the back of your H3. Trisha at Jordan Tire gave me a gooddeal on mine and it was shipped in 2 days- I had it mounted/balanced today for $29. Their Ph # is 866-492-1511 (if it helps)

 

The spare tire REALLY needs to be the same size if you ever put it in High Lock or low range, where there is no slip from front to rear. In high lock there is enough allowance for wheel speed variation from front to rear, and sisde to side to permit the oddball sized spare, but it is Highly advisable to get it matched ASAP. As mentioned by 07HummerH3, adding it to your rotations will make all of them last longer, and eliminate the worries if you get a flat.

 

i have seen many trannys(on front wheel drive cars)screwed up from having 2 different
sized tires on them
the rule of thumb is have the same size tires on the pulling wheels
so i would never use a 33 in sparew/ a set of 35
as far as changing out the spare when rotating tires
there are 2 theories
one is rotate the spare in and go alittle longer and buy 5 new tires
orleave it on the back and checkthe air init every so often and rotate the 4
and only buy 4 tireswhen they are shot
either way is fine just a personal perference

 

yeah, it's not a good idea to run two different sized tires on the same axle...But if you have to, take it slow until you can get to a shop to get the right sizes put on...It's the same thing as if one tire is low air pressure and the other is pumped up...hard on the diff, but it should survive for short distances..

I never put the spare on the road (unless needed)...4 tires are a cheaper than 5