from another source,

so it looks likes short term is not critical but obviously, like when turning, the diff is working.

on average a car is going straight and the diff gears dont turn. when turning the gears rotate. if tires are different size the gears are ALWAYS rotating and are not made to do that full time.

it looks like short trip should not hurt. those donuts prove that.

i guess those circle track cars give it a workout!!

500 miles of left turns

 

You can cause damage to the diff. May take while for you to find out, but it can. Really depends on the difference in diameter size.

Yes, the space saver tire is for limited use only, and I believe it is even stamped that way on the tire. For a limited time you can use a 32 and a 33, but I don't recommend it.

You might cause damage inside the diff that will not be evident for a while. You won't know this unless you disassemble the diff.

Why would a manual that is designed for servicing a vehicle have anything to say about using any parts but those recommended by the vehicle manuafacture? It's a service manual, not a design or owner's manual. An H3 comes with five identical size tires, there is a reason for this. The manual does not tell you what type of pistons to use, what types of rings. It is written for GM authorized repair, so the parts ordered via the parts department is supposed to be the corrrect part for the vehicle. THAT includes the tires.

If an H3 has tires replaced under warranty, the tires are ordered via the VIN number to make sure the correct size tires are ordered and installed.

However, the owner's manual does state:
Mixing tires could cause you to lose
control while driving. If you mix tires of
different sizes, brands, or types (radial and
bias-belted tires) the vehicle may not
handle properly, and you could have a
crash. Using tires of different sizes,
brands, or types may also cause damage to
your vehicle. Be sure to use the correct
size, brand, and type of tires on your
vehicle’s wheels.

 

yes it been an interesting topic for me, to see that a guy drives 10000 miles with 2 sizes, and some new vehicles being delivered with a smaller regular tire for spare. tundra

so its certainly not a good idea,obviously, buy not a disaster to drive to the tire store!

i also learned a little about that 60/40 torq split that i couldnt figger!

 

I will buy your spare tire from you. I will PM you

 

I'd get the spare and rotate it in. If you rotate frequently it will allow your set of five to last longer than just the four, so you are not wasting money.

 

If you rotate you spare tire in to the mix you will have to:
1. get a TPMS for the spare if it is not an 06
2. reset the TPM system after every rotation (the system only reads 4 tires at a time and the spare will not be read the rotated spare if it is not reset)

I leave my spare on the back so when I need new tires I nly have to buy 3 new tires and put the best of the old tires in the spare postition. With 315/75R16 MTZs that saved us $275!

 

TPMS sensor $30-50
Reseting the TPM system 10-15min manually / 2-5min with tool

Peace of mind knowing your tires are all wearing at the same rate and there is no chance of messing up your truck.

 

TPMS sensor $30-50 PLUS Tire R&R+install of TPMS+balance
Reseting the TPM system 10-15min manually / 2-5min with tool Just remember to tell the tech to do it EVERY time

I don't let my tires get below 50% tread (I sell them on craigslist and make some money back to spend on the new ones) so I don't worry about my spare having anything to do with messing up my truck.

 

Ok Tainter you got me.. add a few more bucks for the install.....unless your buddy owns a tire shop

but you should not have to remind the tech to reset the TPMS, they should do it anyway whether they do a 4 or 5 tire rotation. As soon as you move a tire position you need to reset TPMS.

regardless, I guess we all have are own technique, but I will alway stand by the rule that if you have a full size spare, put it in rotation.

 

Wish I had a buddy who owned a tire shop! That would have save me tons-O-cash in the past 4 years alone!