wheel size??

ok i want new wheels and tires on my car. i want bigger rims and lower profile tires without changing the overall size of the wheel so it will not mess up my speedometer.
my tires:
P215/60R16
if i put on 17's i will need wut??? is this right or not?
P215/30R17???? im just not sure about the aspect ratio...
30% of 215 is 64.5 but how many millimeters are in an inch???

What's the year, make and model of the car?

94 cutlass supreme sl 2 door but why would that matter? not tryin to be smart or anything, just wondering

I need the vehicle information to see what we've test fit for your car. The 17" tire choices that would be compatible would be:

225/50-17 25.9" diameter
225/55-17 26.7" diameter

Your 215/60-16's are 26.2" diameter. 1" = 25.4mm.


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just wondering.....how did u come up with 26.2????
ok i did 215mm x .6 = 129mm so 60% if 215mm is 129mm right???
ok so 16inches + 129mm = total wheel diameter
so 16inches x 25.4 = 406.4mm
so 406.4mm + 129mm = 535.4
so the total wheel diameter is 535.4mm
535.4 / 25.4 = 21.07"
i got 21.07" as the total wheel diameter and u got 26.2, how??

Re diameter -

you need to add the section height twice so 129mm + 129mm + 16" = 26.2"

Hope this helps.

o yea haha how could i forget that...DUH!

Give this a shot. It's a tire size calculator. Will tell you, and show you what different sizes will work. Include speedometer difference