Why new tires don't look as the original tires on my IS350?

Sep 20, 2008 4 Replies

I changed 2 front tires on my IS350. Bridgestone 225/40R18 88Y changed for Michelin 225/50ZR18 88Y



Same type but they look different. The original tire was kinda thinning towards the outer edge of the wheel. The new one is like all other ones.



Why tire shapes are so different?


The Bridgestone tires are a different size (lower profile) than the Michelins, which have a slightly taller sidewall. Tread patterns differ from manufacturer to manufacturer.

Why would you put a different size tire on the front? The Michelins are NOT the same size as your old Bridgestones -- 50R18 instead of

40R18. Good thing you don't have all wheel drive, or you would be in a bit of trouble.

Also, your speedometer/odometer readings will also be off by a considerable amount with this change. If you change the width/diameter ration, you have to also change the diameter to keep the same tire circumpherence.

Unless your 50R18 is just a typo. :-)

Why would you put a different size tire on the front? The Michelins are NOT the same size as your old Bridgestones -- 50R18 instead of

40R18. Good thing you don't have all wheel drive, or you would be in a bit of trouble.

Also, your speedometer/odometer readings will also be off by a considerable amount with this change. If you change the width/diameter ration, you have to also change the diameter to keep the same tire circumpherence.

Unless your 50R18 is just a typo. :-)

First of all, Michelins are much better tires than the Bridgestones you replaced. Like others said, these are taller profile (50) tires than the typical 40 you replaced.

According to the Michelin website, the "standard" is the 225/40R18 (88Y front / 95Y rear). Your specific model year may allow the 225/50 if the manual says so; otherwise you have the wrong tires on there. I'd use only the specified geometry but others may differ.

Who put those tires on there?

formatting link

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required