On my 2001 I currently have installed - GY-EMTs P245-45ZR17s on front and P275-40ZR18s on rear (which I believe is stock from factory).

I just priced some Michelin A/S ZPs - 245-45ZR17s front and 275-40ZR18s rear.

I have seen posts on the forum about how the Michelins are "rounded" more when mounted (not looking quite as cool as Goodyear EMTs) - which I understand, but I have also seen posts which claim that they "Look MUCH Narrower" than the GY-EMT on the car.

My question is this: If these are the same specification tire size (as they appear to be), is this just an "illusion" or is it true that less tire tread is in contact with the road. The reason I ask is because unless I am reading something wrong off the Goodyear and Michelin sites, these appear to have the same tread witdth?

 

They look like the same tread width to me although I've seen that comment.

When the Michelins are mounted the bead protrudes by a small amount outside the rim. I'm told it's to protect against rim scrapes but that could be myth.

And the Michelins are not the best lookers but a big improvement all round.

 

The Michelin and the Firestone run flats are rounded on the edges. They do not affect the cool look. The Firestone may look quite a bit narrower at first since I know it has rim protector ridge built into the sidewall. The width of a tire in the P Metric system is not the width of the tread but the width of the tire body. Both of those tires will far outcorner a regular GY EMT. So much for extra tread. In fact the rolled over corners may actually help their cornering ability.

Bill

 

Here are the widths from Tire Rack:
The OEM Goodyear runflats are EXTREMELY WIDE for their size. The tread width is even wider than the 295 Z06 tires, here are the specs (tread width)
-Goodyear F1 GS EMT (275) 10.3 inches
-Goodyear Z06 (295) 10.2 inches
-Firestone (275) 8.6 inches
-Goodyear F1 GS D3 (275) 9.4 inches
-Goodyear F1 GS-2 EMT (285, 19 inch diameter) 9.2 inches

Michelin does not publish their tread widths.

With all due respect to Bill Dearborn, I don't know how he knows that the Michelin and Firestone will out handle the OEM Tires? The Goodyear Run Flats were designed for the C5, and Corvette Enthusiast Magazine (March 2006 Issue) tested the Goodyear Run Flats to out handle the Goodyear GS D3 tires, which are the best non-runflat tires tested by several magazines. I know a lot of people bash the Goodyear Runflats, but they are good handling tires.

 

I have no personal problem with the performance of Goodyear RFs - in fact my first replacement set were also Goodyear RFs. I am just looking for something a little less noisy (getting old I guess). It is not just the "noise" but the "type of noise". I would not mind exhaust noise that feeds my ego, but just tire-drone isn't all that cool to me.

I remember when I first picked up my new C5 in Dallas (having owned several Corvettes in the past) and I remember the first thing I noticed was the noise coming from the rear tires (thought it was the differential at first). Not that big a deal (still score the C5 99 out of 100), but it was my first and one of only two "negative" impressions in regards to the car. I don't expect a Mercedes quiet ride, but if I can reduce the tire noise and at the same time save a couple hundred bucks and get equivalent or better street handling - why not? It is not like I am going racing anytime soon.

 

IMHO, the comments about the Michelin tires looking skinny is overstated. I cannot tell the difference when looking at the car from any angle. If you stick your nose to the tire's shoulder you may notice the Michelin is rounded between the sidewall and tread, but it's a small radius. FYI, some more stats:

Michelin Pilot Sport AS ZP Section Width:

245/45-ZR17 = 9.6" (GY OEM = 9.6")
275/40-ZR18 = 11" (GY OEM = 10.8")

Section Width = is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point.

Tread Width = the distance between the outer edge and the inner edge of the tread of a new tire. However today's radial tires often feature tread designs that incorporate rounded shoulders and there is no industry standard pertaining to "how much" of the rounded shoulders should be included in the tread width measurement. Because of this, it is difficult to accurately compare the tread width differences of one tire brand to another.

I love my Michelins compared to the OEMs, but I wanted an all around performing tire with better all weather handling, longer tread life and quieter.

 

I have the Pilot Sport AS ZP tires and just ordered my second pair for the rear

The foot print is narrower then the stock EMT tires. This became evident the first time I drove the car in the garage after washing it with the Michelin tires installed. The wet tread pattern is about an inch narrower.

However, the tires bite like crazy and and much quieter.

 

[QUOTE=AJay;1558079255]I have the Pilot Sport AS ZP tires and just ordered my second pair for the rear

I am considering the Michelins. I can find Pilot Sport AS on Michelin's website but no mention of ZP. Are they ZP?

 

[QUOTE=bscottb;1558080343]I was unable to find the ZPs on the Michelin site as well, but Discount Tire showed them in their local computer - so they do exist. The Michelin site also showed no suggestions for a 2001 C5 last time I checked?

 

I ran by Discount Tire locally today and they actually had the ZPs for the front in stock. So I measured the approximate ground contact portion of the ZP compared to the GY-RFs on the front of my car and it looks like at least on the front that the GYs are about 1/2" wider in surface contact area. Don't know about the rears?

 

I didn't start tracking my car until the EMT's were already worn down quite a bit. I replaced them with the GSD3's and the improvement in the ride and quietness was immediately noticed. My track times were immediately improved but I wore them out in about 4 weekends. I replaced with the Firestone wide ovals and added a couple of seconds back onto my laptimes. And treadwidth is definitely significantly narrower than the EMT's. I have Z06 size Firestones and the tread is still narrower than my original base coupe size EMT's.

So take it for what it's worth.

 

Regardless of the discrepancy in tire dimensions, the Michelins are such better tires in every way, there is no contest.

 

I can state that for the Firestone Run Flats it is based on personal experience. I am able to compare autocross times from one set of new tires to another set of new tires since I do a lot of autocrossing on a Go Kart track where the layout is always the same. The only variable is the weather. I have been running on that track since 1993 and ran my 97 there when it was first new and also ran it a couple of years later when I replaced the EMTs with the Firestone Run Flats. Most of the time I run DOT R tires but when I do not have a set to run I use my street tires.

At that track the Firestone's were so much better it was amazing. The average on course time for Corvettes with street tires is about 132 seconds. In the dry with the EMTs I always turned times around the average. With the Firestones I was turning times of 128 in the wet and around 127 in the dry. On DOT R tires I could turn times around 124 in the dry.

I am pretty sure from talking to people who are running the Michelins they get better performane in the dry than the Firestones. That leaves the EMT sucking wind. The reason for the difference. The EMT is stiffer and does not roll over sufficiently and because of the sidewall stiffness the EMT has a tendency to wrinkle its tread so not all of it is on the ground in hard corneirig situations. This wrinkle is usually about 2 inches in from the outside edge of the tire and people who push the tires on autocross courses or roadcourses will see quite a bit of wear just to the outside of the center rib of the tire. Another reason is the rubber itself. The Firestone tires use a stickier compound.

Bill

 

The other big difference besides tread width, the the repairability and run flat ability between the two brands. If to believe as stated:
Goodyear R/F, can run 200 miles flat.
Goodyear R/F can run 100 miles flat and be repaired
Michelin can Run Flat 50 miles and can/should not be repaired.
If reports are true. Michelin is going to be on the Vette in 2008.

All in all it seems that GoodYear or Michelin it is what ever you want to live with, no matter what they are both very expensive.