Spare Tire Kit

[Slick Blackwings]

How can any spare work on these cars when the diameter of the front tire is different from the back tire? Doesn't that mean you would need two spare tires? The difference is .4 inches, so how many miles could you drive before you would damage the rear differential if you used a tire with the diameter of the front tire? Or wouldn't you damage it at all?

Enough to get you off the road

 

[KatyTxCT5V]

How can any spare work on these cars when the diameter of the front tire is different from the back tire? Doesn't that mean you would need two spare tires? The difference is .4 inches, so how many miles could you drive before you would damage the rear differential if you used a tire with the diameter of the front tire? Or wouldn't you damage it at all?

Unless someone has actually had to do this and has the experience, it can’t be answered. Way too many variables to take into consideration such as tire wear for example. Tires don’t wear equally.
Michelin shows a .3 difference and Continental shows .4 difference… etc.
As previously stated, rather than insert factory cheese wiz and even if the hole or damaged could be sealed, I rather take my chances partially if on a long trip, with possible little to no cell service, etc, etc.
if it gets me to a safe place, I’ll change the diff fluid again and move on.

 

[BimmerFan]

How can any spare work on these cars when the diameter of the front tire is different from the back tire? Doesn't that mean you would need two spare tires? The difference is .4 inches, so how many miles could you drive before you would damage the rear differential if you used a tire with the diameter of the front tire? Or wouldn't you damage it at all?

You could put the front on the rear, and the spare on the front.

PITA, true, but a possible solution.

 

[Jim2000]

You could put the front on the rear, and the spare on the front.

PITA, true, but a possible solution.

If you do that, then the diameter between the right rear and left rear is .4 inches different. Will that damage the differential? I don't want to give GM any opportunity not to pay on a warranty claim. Also, I want to prevent the hassle in obtaining a new differential. I wonder about the time in obtaining a new diff, plus my car is inoperable.

 

[KatyTxCT5V]

The Modern Spare Tire states the following below, so with factory Michelin rear being 26.3”, splitting hairs at 26.5” size or .2”, not .4”difference. Dealers always find ways to deny warranty if they really want to, thus always worth building relationships with their SM.

• Kumho T135/70/R19 Tire W/ A DOT Rating Of (104M) With A 26.5” Rolling Diameter