Going to go with some 18x9.5(f) and 19x10(r) on my 01' C5. I was told that the rear diameter needs to be at least an inch larger than front. I was then told that diameters need to be as close as possible...can someone shed some light on which is which? Thanks

 

Like 8VETTE7 said, rears should be larger in overall diameter than the fronts. That being said, you can still run the same size diameter rims. I ran 18" front and rear rims on my 98 but had different size tires to compensate the difference in overall diameter. Therefore, I had no TC issues.

 

Thanks guys...yes I'm referring to diameter of tires not wheels sorry. So at least 1/2" bigger diameter on rear and I'm good to go? Thanks for the knowledge.

 

So here's my setup...I have a 01' Coupe. Gonna buy the C6 styles wheels in staggered 18x9.5 / 19x10. Right now I'm looking at going with 275/40/18 and 275/30/19 tires. Diameter seems to be right on these. I believe offset is 58 for wheels. My car is 58(f) and 65(r). Any suggestions on tire sizes with these wheels? Will I need spacers for rear? Thanks again!

 

that combo is 26.7 dia front tire, 25.5 dia rear tire approximately depending on brand, exactly the opposite of what you need to avoid a tcs problem. the rears need to be taller than the front

 

Sorry, I listed the wrong tires. I was looking at some Achilles ATR Sport 2 tires and this is what saw:

255/35/18 - 25 diameter
275/30/19 - 25.5 diameter

Should diameter be larger? You guys are super helpful? Thanks

 

.5 larger in the rear should work just fine for the tcs

 

So with my anticipated wheel setup, I'm torn between these tire sizes....what do you guys think and why? I really appreciate it!

245/40/18 (f - 25.70 diameter)
275/35/19 (r - 26.60 diameter)
or
255/35/18 (f - 25 diameter)
275/30/19 (r - 25.5 diameter)

 

We see a lot of vettes down at the shop and a 1/2 inch difference
wont cut it for some vettes. I guess it's the factory tolerance
each day is a little different. To be safe give yourself a inch
difference.
Good luck.

 

I currently run 26.7 & 26 without issue.

 

I have run 18" front and rear wheels with 265/35-18 and 295/35-18 tires respectively. Those sizes are pretty much the same diameters as the stock tires f & r. I never had a code problem. I am switching to 19" wheels f & r. I will run 265/30-19 fronts and 305/30-19 rear tires which will essentially give me the same diameters again with no problems. As other have written, it is the overall diameter that makes all the difference.

 

Along the lines of what others have said, the factory standard tire size (245/45x17; 275/40x18) on the base C5 made the rear tire 1” higher than the front. This actually works out to a ratio of ~1.04 (properly 1.038910506 - now you see why they say 1.04 ) with the rear tire being this much taller which allows the ABS and TC systems to work properly. Other tire sizes maintaining this same ~1.04 ratio should not interfere with these systems.
Of you suggestions, above, I like the 245/40-18 and 275/35-19. This would put you at 1.035 (rounded up to 1.04) versus the 255/35-18 & 275/30-19 which is a ratio of 1.02. (As road pilot stated, this ratio is not working for some of the Vettes coming in to their shop).
Remember, too, that the C6 base set up is 245/40-18 & 285/35-19 - surprisingly an ~1.04 ratio.

 

245/40/18
275/35/19

I would go with these because I like the thicker sidewall

 

I think the topic of tire size choice has been one of the most popular ones I’ve ‘enjoyed’ since joining the C5 family. It also seems like one that has had less contentious interchanges than certain others that seem to raise the emotional levels. I won’t bore you with details as to why I have stock sizes on my coupe, since my first c5 was a Z06. If I had it to do over again, I would have gone to Z06 sizes for everything.
Here’s the rub: it’s VERY difficult to find a matched set of the stock C5Z tires anymore. When I, like my friend Striper replaced our tires, we went with 275/17 in front and the “Z-proper” 295 in the rear. I also believe profiles were 45/40, respectively. In my case the stagger difference was .4”, which I was concerned about but worked out fine.
I may be mistaken but I read a long time ago that the GM specified stagger difference was .5”-1.4”. There have been many people who’ve not adhered to that standard and have had no problem.
For me, I don’t like the front tire to appear larger than the rear. After talking to Striper about his wheel change I did some research and found a lot of possibilities to maintain stagger and in my preference have a wider tire in the rear, while using a variety of wheel sizes. Ride is most important to me because I drive my car and a low profile (let’s say below 30) would be too harsh for daily driving even tho’ handling would likely be great.
My only question is why no one seems to be interested in a C5Z-like setup with 295’s in the rear?

 

I have found in many cases when people run different diameter wheels front and rear, with the fronts 1" smaller in diameter than whatever the rears are, they tend to use a smaller tire but with a taller sidewall than the rear tire. This looks odd to me, with the front tire looking fatter than the rear tire from the side view. That's why I prefer same diameter wheels all around, using a lower profile tire in the front. With the CCW Classics I had, I had 18" wheels all around with 265's in the front and 295/35-18's in the rear. I am going to 9" x 19" front wheels with 265/30 tires and 11" x 19" rear wheels with 305/30-19's in the rear. This way the car will have the correct rake and stagger.

 

Yep, even the factory tires on the Z sidewall = 4.17" front, 4.06" rear looks off to me.