Tires Help......I know......Not Again.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Tires Help......I know......Not Again.
I'm sure that the topic has been discussed ad nauseum but I was wondering what size tire to run on 18x9.5" & 18x11" Rims? I imagine that the fronts would be 285/35/18 or 295/35/18 but I'm not sure what size for the rear. Would I be looking at a 315/30/18? What combo would work well together and what brand of tire would work for a car driven 99.9% on the street? Keep in mind that even though I drive the car year round, I only take her out in nice weather. Also I know that the 285/35 is a very hard size to find and choice may be limited to Nitto. Thanks for the replies
Pro
Joined: Jun 2004
Posts: 618
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From: Houston TX
You want your wheel to be 80-90% of the tire width. So for a 305 that'd be around a 10-11" wide wheel for example. I know there are some that go even wider on the wheel like the Viper which is around 95% the size of the tire, but thats typically about the right range. Since one is in mm and the other in inches, divide by 25.4. You can bump up the width, but try to bump them the same on both ends to maintain the same balance. To help in keeping the same overall tire circumference, search google for "miata tire size calculator". Enter the stock #s and then mix and match figures until you find something within a few percent. You'll have to play around a bit because wide tire selection sucks. It'll tell you how many MPH that equates to at speed. To find opinions and ratings on tires, I'd checkout www.tirerack.com (you can limit your search to ultra-high performance and max performance IMO). Find what fits and then there should be hundreds of reviews to find a consensus on everything from noise, tread life, to wet and dry traction.
Last edited by Ducman69; May 13, 2006 at 03:41 AM.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
I currently run a 255/40/17 up front and a 285/35/18 out back on factory 17x8.5's and 18x9.5's. I'm thinking that a 285/35/18 up front would work with a 315/30/18 out back with the 18x9.5 and 18x11 setup?
Pro
Joined: Jun 2004
Posts: 618
Likes: 0
From: Houston TX
I'm guessing you picked 315/30/18 due to tire selection, as thats a bit shorter than stock.
Were you also going to try and match front and rear tires?
Smaller rather than bigger should be ok (not quite sure how active handling works with the speed sensors), but it will be affecting your speedo, gearing, and you'd have a little over half an inch more fender gap.
Unfortunately, I don't recall the offset on my AM wheels, but the 275s up front seem to fill it pretty tight up front, so I'd search teh forum to see if anyone has mounted your wheel + that tire up front. Wheel widths should be ok. If I don't find a set of nice larger used wheels soon, going to reuse my 18s but go a little narrower this time w/ 265/35 and 295/35 18s wrapped in KDW2s w/ for $845 is a pretty good deal IMO. Thats still plenty of tire on the road and they don't look dinky driving behind Z06s.
Were you also going to try and match front and rear tires?
Smaller rather than bigger should be ok (not quite sure how active handling works with the speed sensors), but it will be affecting your speedo, gearing, and you'd have a little over half an inch more fender gap.
Unfortunately, I don't recall the offset on my AM wheels, but the 275s up front seem to fill it pretty tight up front, so I'd search teh forum to see if anyone has mounted your wheel + that tire up front. Wheel widths should be ok. If I don't find a set of nice larger used wheels soon, going to reuse my 18s but go a little narrower this time w/ 265/35 and 295/35 18s wrapped in KDW2s w/ for $845 is a pretty good deal IMO. Thats still plenty of tire on the road and they don't look dinky driving behind Z06s.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Originally Posted by Ducman69
I'm guessing you picked 315/30/18 due to tire selection, as thats a bit shorter than stock.
Were you also going to try and match front and rear tires?
Smaller rather than bigger should be ok (not quite sure how active handling works with the speed sensors), but it will be affecting your speedo, gearing, and you'd have a little over half an inch more fender gap.
Unfortunately, I don't recall the offset on my AM wheels, but the 275s up front seem to fill it pretty tight up front, so I'd search teh forum to see if anyone has mounted your wheel + that tire up front. Wheel widths should be ok. If I don't find a set of nice larger used wheels soon, going to reuse my 18s but go a little narrower this time w/ 265/35 and 295/35 18s wrapped in KDW2s w/ for $845 is a pretty good deal IMO. Thats still plenty of tire on the road and they don't look dinky driving behind Z06s.
Were you also going to try and match front and rear tires?
Smaller rather than bigger should be ok (not quite sure how active handling works with the speed sensors), but it will be affecting your speedo, gearing, and you'd have a little over half an inch more fender gap.
Unfortunately, I don't recall the offset on my AM wheels, but the 275s up front seem to fill it pretty tight up front, so I'd search teh forum to see if anyone has mounted your wheel + that tire up front. Wheel widths should be ok. If I don't find a set of nice larger used wheels soon, going to reuse my 18s but go a little narrower this time w/ 265/35 and 295/35 18s wrapped in KDW2s w/ for $845 is a pretty good deal IMO. Thats still plenty of tire on the road and they don't look dinky driving behind Z06s.
Pro
Joined: Jun 2004
Posts: 618
Likes: 0
From: Houston TX
Well its a hypothetical price... the rears are on backorder: Tirerack.com. I hope they'd work, Those are the Z06 OEM sizes. Well, the rear is, technically the fronts on Z06s were 17s, but thats the calculated "plus" size going with an 18" wheel. I really don't know what happens with the active handling if you go crazy w/ the sizes. *shrugs*
PS, ur thread = teh not popular
Well, the rear is, technically the fronts on Z06s were 17s, but thats the calculated "plus" size going with an 18" wheel. I really don't know what happens with the active handling if you go crazy w/ the sizes. *shrugs*PS, ur thread = teh not popular
