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My car is 568 RWHP and I have been running the 305/35/18 Mickey Thompson drag radials. Last two sets with a heavy foot and right at 1800 miles they are done. I need to also replace my fronts which are Bridgestones and 5 years old. I have read through every thread I can find and want to run the 888rs front and back. Yes I know I will loose some traction but want a tire that lasts longer and is easier on the budget. (To many toys). I have stock size wheels. Fronts I am thinking 275/40/17 and rears not sure to go 315/30/18 or 305/35/18. Does the extra .4 width really give any more traction? A 10.5 inch rim is marginal for the wider tire from what I understand and it will bulge a little. Height difference is almost an inch shorter on the 315/30. Don't really feel like I need a lower gear. Would love to get 4000-5000 miles from a set of tires.
Last edited by onanysunday; 04-20-2019 at 12:33 AM.
305/35 IMO. it's a 10.5 inch wheel, the extra 10mm probably won't equate to much if any extra rubber to the road.
305/35 has taller sidewall, helps with straight line traction
With 275/40/17 fronts, the 305s will keep the same front to back diameter difference in comparison to stock, while the 315s will be noticeably shorter. Could have TC issues at high speed...but probably would be fine.
I have 305/35/18 R888s on my OEM z06 rears and it already slightly bulges. I don't know if you'd see an actual increase in contact patch going up to 315, but I'm interested in your results. Going an inch shorter might be counterproductive as well...
I called Toyo for Grins and they were not much help. She did say on an 11" rim the width and diameter was 305/35 - 12.3" / 25.5" and 315/30 - 12.6 / 26.4. That is showing only .3 wider for the 315. Not a lot and I have to think the traction difference is negligible. If you think about a smaller diameter is going to ever so slightly reduce contact patch length wise. I guess no way to know unless trying both. Thinking I will stay with the 305s.
I called Toyo for Grins and they were not much help. She did say on an 11" rim the width and diameter was 305/35 - 12.3" / 25.5" and 315/30 - 12.6 / 26.4. That is showing only .3 wider for the 315. Not a lot and I have to think the traction difference is negligible. If you think about a smaller diameter is going to ever so slightly reduce contact patch length wise. I guess no way to know unless trying both. Thinking I will stay with the 305s.
I think some of those numbers are transposed...305/35/18 should be ~26.4" tall. I'm showing 305/35/18 = 12.01 wide, 26.41 tall and 315/30/18 = 12.4 wide, 25.44 tall.
That's what they "should" be anyway. Either way, 315/30 is going to be noticeably shorter and negligibly wider than the 305/35
I just realized you are looking at the R888R as well. You'd probably be better off with the regular R888. The R is supposed to have a stiffer sidewall, which won't help in the straight line traction department.
I got mine last year from tiresdirect.net. Under $900 to my door for the full set of 275/40/17 and 305/35/18
Well that is interesting. Here is a link to both https://www.toyotires.com/tire-finder/305/35/18 The 888r rates 1/2 point higher for dry performance. One is XL rated and one is SL rated. The 888r shows a speed rating of 105y and the 888 does not show one.
R888 -Ideal for road racing, track days and high performance driving schools, the Proxes R888 is the next-generation, street legal competition tire from Toyo Tires
$312 EACH
R888R - The Proxes R888R is an evolution of the race-winning Proxes R888, delivering even faster lap times and better dry handling. The credit goes to a new tread design and an improved contact patch that puts more rubber on the track. Racers will also appreciate the predictable handling and how quickly the Proxes R888R reaches optimal operating temperature.
Both are road racing tires, not drag racing tires. If you're looking for more traction and stability in the twisties, go with the R. If you're more concerned with off the line grip, and still want a perfectly capable tire for the twisties, I'd go with the regular R888. Totally up to you, I was just trying to help. I'm sure either would be a good choice.
Both are road racing tires, not drag racing tires. If you're looking for more traction and stability in the twisties, go with the R. If you're more concerned with off the line grip, and still want a perfectly capable tire for the twisties, I'd go with the regular R888. Totally up to you, I was just trying to help. I'm sure either would be a good choice.
I do appreciate it. I know there will be a trade off but would like the best straight line traction and mainly a tire that lasts a little longer than the Mickey Thompsons. If disappointed I can always go back. Sounds like the R888 is the tire I want then.
also consider that a shorter tire is gonna feel torquier than a taller one, so you'll have to be lighter on the launches to keep from spinning.
that & the ENORMOUS WHEEL GAP they'll cause!! the atrocity!!
Loved the R888 on my previous 535 WHP C6Z. Now have NT01 on my 623 WHP C5 & they are better than the R888 were. You're never gonna get full traction in 1st, but all other gears = greatly improved & I can still turn. I have them on base C6 rims in base OE C6 tire size
Last edited by BlackHellcat; 04-30-2019 at 03:44 PM.
Just talked to Toyo and the R888s no longer available. Only the R888r. Thought about trying to find some rears still out there but Tire rack is showing no longer available for the 305/35/18
04-20-2019, 12:26 AM
Which Toyo 888R for the rear? 02 Z06
Read all 24 reviewsThe Proxes R888R is an evolution of the race-winning Proxes R888, delivering even faster lap times and better dry handling. 
https://www.toyotires.com/tire/patte...petition-tires
