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Desisuperman
02-15-2004, 11:42 PM
Looking at tires for my Bmw Style 71 rims (17" 7.5) but i dunno how to read these specs on tires or what exactly i should be looking for

here are a few exmpales of what i found

255/40-17 KUMHO

205/40R17 KUMHO

225/45YR17 Pirelli

What exactly does these specs mean and what should i be lookin for?

:confused:

Mystikal
02-15-2004, 11:58 PM
Here is a good guide: http://www.tirerack.com/tires/tiretech/general/size_information.html

Also, the proper size for 17's on an E36 would be 225/45/17 or 235/40/17. :)

3-Series
02-16-2004, 02:04 AM
First set of numbers is width, second set is sidewall height, and the third is the diameter.

225 is your best bet. 235 can cause rubbing issues and may require you to roll the fenders.

Desisuperman
02-16-2004, 04:04 AM
Originally posted by 3-Series
First set of numbers is width, second set is sidewall height, and the third is the diameter.

225 is your best bet. 235 can cause rubbing issues and may require you to roll the fenders.

Kewl, thanks man! Should i go with 40 or 45?

Desisuperman
02-16-2004, 04:11 AM
also, what does it mean when they say a tire is "Z Rated"

3-Series
02-16-2004, 04:30 AM
H, V, Z rated deal with tire speeds and performance. A Z rated tire yeilds maxium performance and it rated at 155mph+, whereas an H rated is 125mph tops. V rated is in the middle of those.

As for 40 or 45, it depends on you. 40s will give a stiffer ride and yeild slightly better handling, but 45s will give you a less harsh ride and a little more sidewall flex.

thinair
02-16-2004, 07:07 AM
For a 7.5" rim I wouldn't go wider then 225. The second number (40 or 45) is the % of the width of the tire for the height, or the aspect ratio.

As mentioned, go for 225/45/17 so you don't screw up your speedometer accuracy too much.

Desisuperman
02-17-2004, 05:42 PM
thanks for the help man

Desisuperman
02-20-2004, 04:47 PM
i was hoping to go with 40's instead of 45 but it's next to impossible to find 225/40/17.... so, it looks liek i'll have to go with the 235/40/17 whichi are common tires to find. Am i pushing it with 235's? Spoke to a guy who runs a a tire shop and he said it shouldn't be a problem with a 328, anyone want to onfirm this before i go out and buy these?

thinair
02-20-2004, 07:17 PM
Originally posted by Desisuperman
i was hoping to go with 40's instead of 45 but it's next to impossible to find 225/40/17.... so, it looks liek i'll have to go with the 235/40/17 whichi are common tires to find. Am i pushing it with 235's? Spoke to a guy who runs a a tire shop and he said it shouldn't be a problem with a 328, anyone want to onfirm this before i go out and buy these?

Sorta, for a 235 it is pushing it a little.

The actual proper rim size for a 235 is a 8.5". I have 235's on an 8" rim and I don't bulge too much.

I guess it depends on the tire you're buying, they usually have a minimum rim width.

MP328
02-20-2004, 08:08 PM
mine are 235/45-17 and it's 2" lowered and it rubbed in the beginning. 4 months after i put them on i rolled the fenders and i can again stick a finger between the tire and the fender. (couldn't do it until then)

if ur car is not lowered yet!!! i dont think it will rub. if ur planning to lower it u might have to roll the fenders.