Can I run a stock 17 as a spare to get my car home safely?

[karmannsport]

So one of the 18's got bent on the S4 i am buying and it is currently getting fixed. Would there be any harm in driving the car home with one of the factory 17's as a spare? The tires on the 18's are 235/40-18 and on the 17's they are 225/45-17 so theyre real close. I thought I remember my A4 having a space saver but I just wanna make sure this won't damage anything in the driveline if I drive it home like this. Thanks.

-Chris

[Yuckie]

It's probably fine, but why risk it? A veteran might have some more information on tolerances or something, but if I were you I'd wait it out. Doesn't sound like you have anything to gain.

[adr3naline fix]

How long do you have to go?

[flashovermac]

Your diameter difference is 1.722%... aka the 18's will be spinning at 60MPH and the 17 will be at 61MPH.

That's a 10.93mm (0.43in) difference in overall diameter (aka 14.1 extra revolutions per mile for the 17, vs the 18)

If it's a reasonably short distance, I say you're alright.

[cu52]

The avant has a donut in the boot, i don't believe it is the same diameter as the stock, I would check but I drove the sedan.

[Capt. Obvious]

You'll be fine. 1.7% is not a big deal. You can drive hundreds of miles if you need to without worry.

[MavSBM]

good to know...now I don't have to buy an 18 for a spare

[infinkc]

your fine. We are actually lucky that our spare in the sedan is an actual rim/tire compared to most that use a donut spare.

[bps4]

So one of the 18's got bent on the S4 i am buying and it is currently getting fixed. Would there be any harm in driving the car home with one of the factory 17's as a spare? The tires on the 18's are 235/40-18 and on the 17's they are 225/45-17 so theyre real close. I thought I remember my A4 having a space saver but I just wanna make sure this won't damage anything in the driveline if I drive it home like this. Thanks.

-Chris

if you are very concerned, call AAA, pay 60 bucks and they will flatbed it for you the same day, its free for like 3.5 miles and then the charge per mile after isn't too steep...

[Turbo1A4]

i drove for an hour like that when i got a flat in a small town who didnt carry my size tire so i had to drive all the way home