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Tire rim size

Purchased vehicle with 17" rims. Found spare is a 16". Will I cause damage if I use 16" in an emergency?

Make?
Model?
Model year?
FWD/RWD/4WD/AWD?

How Do The Overall Diameters Or Heights Of The Two Different Tires Compare?

Some vehicles have standard 16" rims and tires and optional 17" rims and tires available with possibly almost the same overall tire diameters.

CSA

Mercedes Benz, SL300, 1991, RWD

What are the two tire sizes? Are the 17s factory?

Tires on vehicle 245/45R17 95H CH95
Spare tire 205/55 ZR16
Bought used do not know tire history

17s: 80.7" circumference
16: 78.2" circumference
So it’s close, wouldn’t be a too much of a problem on the front for short distance (except for the handling difference between the tires), but I’d worry a bit if you have a limited-slip differential on the back. Match would be closer it the spare was a 215/55x16. Find out more here: http://www.miata.net/garage/tirecalc.html

And I was asking if the 17" rims were factory, not the tires, sorry for not being clear.

I can’t see it being a problem on any rwd or fwd vehicle. The donut spair that comes with many vehicles is a lot smaller then the tires on the car. Just have to limit your driving speed and distance and get the flat repaired or replaced as soon as possible.

Found a similar situation with BMw’s X5 spare by design (I dont know if it was a 17",16" difference but they were different by design. I found out because the lid covering the hole that the spare fit in would only close with the spare in it not a running tire/wheel.

If you have a limited slip differential(LSD) and install a different size rim on the driving axle you will burn out or shorten the life of the differential. This is true of any LSD whether FWD or RWD or AWD.