GlennSullivan

I’ve just run into a strange situation that I’m wondering if anyone can help with. Like many of us C6Z owners, I swapped out my original Goodyear RunCrap Tires for something better. At the time, I installed Michelin Pilot Super Sport non run flats, 285/35/ZR18 in front and 345/30/ZR20s in the Rear. They are a tight fit but the traction improvement was exceptional.

Fast forward to last weekend, wife and I out for a ride and I hit a rock in the road that cut the sidewall open on the RF tire. AAA brought the car home and I got on tire rack and ordered 2 new Pilot SS 285/35/ZR18s. They show up 2 days later and as soon as I see them, I’m thinking they look really wide and sure enough they are over 1” wider than the current 285’s.

I check the sidewalls of existing and new tires and all the key information matches, however there are a few numbers that are different. I expect different brands and models of the same brands to size differently, but the same make model and size with such a MAJOR size difference?

Does anyone one have a reason of why this is and if it is possible to obtain the “same size” Michelin PSS 285 replacements?

Creatre

Can you post pictures of your sidewalls? There is no way those are the same size tires.

Cap'n Pete

WTF?! They look like rears compared to the fronts!?!

racerx3317

No way those are the same size, different aspect ratio or something. Also, were you on stock wheels? 18 fronts and 20 rears or did you mean 19s?

BoostedNoMore

You cant compare mounted tires to unmounted tires. Once they are mounted on the wheel it will pull them in a bit.

2k Cobra

Even the tread looks different!

GlennSullivan

Sorry, typo on the current rear tires / they are 345/30/ZR19s on Stock Z06 Wheels Below I have posted sidewall pictures, the ones on wheels are the current and the ones off wheels are the recent arrivals. I've also provided a side by side, note the HUGE DIFFERENCE in the groove difference!

acrace

I don't have the answer for you, but note that the M01 designation means that it is a version specially designed for Mercedes. Michelin oftentimes has specific versions for different OEMs as the OEM engineers may want to make tweaks for noise, ride harshness, etc. It may be possible that the "standard" 285/35-18 size got discontinued, since you got your set (noted the 2013 build date).

passagemaker43

Have you thought about returning them to Tire Rack and swapping them out for a pair of Michelin 4S's? If you think the extra inch or so will cause interference issues the 4S's are just over an inch narrower and a pound lighter with the same diameter. Always a potential issue when you run different tire construction front and back but since they are both Michelins and the 4S was designed to replace the Super Sports I wouldn't expect a problem. I will say the very wide grooves in the super sports and the actual rubber part on the road seems smaller on the wider tires which would give me pause. I like wider but I want more tire contact for the extra width. I just switched to 295 19 inch Toyo's up front which are an inch wider than the 285's you just got. Haven't mounted them yet but don't expect a fitment issue. My track Z runs 315 Hoosier's up front without an issue.
Keith

GlennSullivan

What I did short term just so I can get the car back on wheels and out of the way in the garage is swap the 285 super sports for 275s, they arrived today and will mount them tomorrow. The sidewall / diameter is quite a bit smaller. Next I’m going to speak to Michelin and see if they can ID the 285s I have and maybe locate a pair. If not I’m going to change to 4s all the way around.