I am thinking about purchasing R Compound tires to put on my car for the summer. I plan on driving street, a few x-cross events, road course and even drag race once or twice. I have another car so the street time would be limited. I am looking at the Nitto NT01's They have a treadwear of 100 so they aren't super soft and should give me some good life but I would like to know if anyone has used these and or what they thought of them. Secondly I have a touring and want to mount these tires on my stock rims. I have heard that a square design of tire sizes is the best for this car. The two sizes that would fit on my 18" rims are 245/40/18 or 275/40/18 and 275/35/18. I think the 245's are probably the best as they will prolly feel lighter but I have to wonder if the 275's would fit my stock rims and not rub? Would 275's look stupid on stock rims? I guess it might help me with traction while drag racing but I'm not sure if it would be that great say auto crossing. Does anyone have any pics of the 18" touring rims with 275's? Thanks in advance....

 

i would personally go 245's up front and 255's in the rear. 275 is too big on stock for my taste i have 275 on 9.5's and they fit near perfect def. too big for 8.5's just my opinion though.

 

I don't think the Nitto NT01's come in a 255. It seems like they jump from 245's right to 275's. I think 4 255's or 265's (max) would be perfect. So I guess if I want these tires I have to go with 245's or 275's

 

damn that sucks it will work just not optimal if your after a straight line time then you should be fine. But you will sacrifice some in the corners if your into that for fun like most of us .

 

 

I've run 275/17 RA-1's on my OE rims for track days - works perfectly!

*for autoX, the 275 might be too much rubber...if it's too wide & a hard R-compound, it might not heat up enough to really start sticking.

 

I think I am going to try and go with 245's in the front and 275's in the back. I checked with a tire calculator 245/40s and 275/40s should be perfect (I think you want to have the rear diameter a little bigger than the fronts but no more that a 6% difference, this setup the rears are about 4% of a difference) and Nitto offers these tire sizes in this Model of tire. Thank You ZTalker, your pic shows me that a 275 doesn't look too "bulgey" at all. I know that a 255 or a 265 would probably be a better rear size but I can't find these sizes in a R Compound tire. I can get these Nitto's right up the street and have them installed at Discount Tire. Here is a link for a tire size calculator where you enter the front and rear tire dimensions and it will calculate if they will work or not. If you enter in the stock tire sizes you can see that you want to keep that indifference or less between the front and rear as to not set off your slip warning light. http://www.miata.net/garage/tirecalc.html
You make a good point first350 hopefully the rears grip a little less on autoX as I have a feeling this setup will probably have a fair amount of under steer. I think for my overall needs and with my road course driving I'm going to need something a little harder as I want these tires to last all summer and the 275s should be good at the dragstrip but I wonder if the sidewalls are going to be too stiff for that. I guess I can always let air out of them.

 

I like the staggered widths for Track days - makes the car tend towards understeer (safer than having your rear end slide by you going 80+ MPH )

for autoX, it's gonna push...w/ patience, you can make it work --> slow in, fast out.

 

275/40/18 look much more aggressive from behind in the Z....comparable to the look of a late model 7series BMW,go check it out yourself. don't take my words for it.
make sure to double check the 275 width between brands and manufacterers. For instance, some Michelins and Bridgestone tires come small even though they are marked exactly the same size. i've had to go to the next size tire in order to match the oem tread width with Michelins before. Good luck.

 

ZTalker that is so weird that you mentioned the 7 series BMW as having an aggressive look from the back. I was at a light today behind a 740i and I was thinking to myself damm those look like wide wheels and I was thinking they must be some after market rims or something, but when he turned the corner they were def. stock rims. Do you have any pics from behind your car with your 275s?