What are the hazards of driving with 2 differant size rims? I want to buy a set of 16" rims for my 90 300E, but would like to keep the 15" rim for a spare? Is this a bad idea? Should I order 5 16" rims and tires instead of 4?

Bad idea! I would only do that in a extreme emergency. If you can do it get 5 wheels same reason you don't want to do that on a 4WD what if the spare go's flat you would be left with a size that is really wrong

Does'nt matter if you run 15, 16, or 17" rims, as long as the overall size of the tires ( diameter/circumference ) is the same.

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2007 C 230 Sport.

So what will happen if I run differant diameter tires? Will the car go around in cirlcles like Curly from the Three Stooges? I dont want to buy 5 tires, seeing If I use my existing spare it would only be for a few miles till I can get a new rim and tire. In my 20 years of driving I never had a flat belireve it or not. knock on wood. Plus the spare tire compartment will be to small for a bigger tire

driving with different size circumference will make your car pull hard one way in an emergency braking situation..
so just put the tire on the way you want to go!

seriously.. just check a tire size calculator from someplace to figure it out.

OK thanks, so if I run 225 55 16s for the four, I should get 225 55 r15s for the spare with the 15" excisting rim?

negative there ghostrider..
225/55/16 = 225/60/15, +/- couple tenths of an inch
but dunno if you can even fit that under there on a 124
maybe 225/50/16 = 225/55/15.. dig?
http://http://www.miata.net/garage/tirecalc.html

What about weenie wheels? They seem smaller than the regular tires. I've never thought to measure the diameter of one to see if it matches the regular tires.

I've never have a car with a weenie wheel for a spare, but they do seem smaller that the others when you see them going down the road. Does MB use those in any of their newer cars?

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OBK #55

1998 Lincoln Continental - Sold
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weenie wheels.. highlarious.
definitely do not trust those little bastards.
in an emergency, doesn't really matter to get you to where you need to go.
but dangerouso' to mismatch circumference for any prolonged period of time. (don't ask how i know)

those weenie wheels are not for real driving. they are just to get you to the next shop or home late at night.

real world driving if using different size rear wheels and tires can result in boiled diff lube and toasted gears. you dont want that.

otherwise same overall diameter is what matters, rim size is as noted above not important for a spare. but not recommended for more than emergency situations as the handling will be different with different size rims and could cause some instablilty in hard cornering.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

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