I finally ordered my Forgestars today, 18x10 +29 (wish they made a 10.5) and 18x12 +32. I'm at least going to try to fit 315/335 A6s because a local autocrosser has some spares I can play with. Pics coming once they arrive (8-10 weeks...?).

 

Your going to want at least an 11 on the front with that 315. I can sell you my take off 315's as I use them up if you want. I only make about 30-40 runs before selling them off.

 

Yeah, I debated on the 11s for a while. They would just require major fender work or enough gap to not rub with 315s, neither of which I want to do right now. With them squeezed on 10" wheels, I think I can get away with just a minor pull, and 335s shouldn't be much trouble in the rear. The 11" wheels fully sucked in to the suspension would still poke 5mm more than your setup in this pic:

I may take you up on those tires eventually. Did you get 315s to run at Dixie? I'll be watching the results closely, especially since I'll be running regionally with the other 3 BSP entries throughout the year.

 

Not yet, but I have some sticker 285's already. If I can't swap 'em with someone else, I will just buy the 315's outright. Hopefully b/w Dixie and D.C. I will have won 2 or 3 new hoos for the next batch prior to the NJ tour (assuming it doesn't get pushed back too far). I will probably have 18x11.5's or 18x12's by Toledo and Peru.

 

Hey guys I recently bought some some 18x8.5 and 18x10 +25 and I went a ahead and ordered tired but after looking through this thread idk if I chose the right sizes or not. The sizes I bought are 245/40/18 and a 285/40/18. I'm on stock ride height for now. Did I choose the right tire sizes lol?

 

Your front tires will look fine, but your rear is going to look like a monster truck

 

Regarding the REAR (front is perfect)...
You're gonna be fine..it's only .3" taller than stock and will read 1% slower on speedo. They won't be that much different than the *Ideal* size of 275/40, which has a slighly smaller sidewall and section width. I wouln't send em back for that.

In the future use this calculator:

http://www.1010tires.com/TireSizeCal...?action=submit

 

Read this entire thread:

https://my350z.com/forum/2003-2009-n...questions.html

This post within that thread will show you that you did fine:

https://my350z.com/forum/2487452-post8.html

 

Front 18" x 9.5" , Offset +25 to +30, Tires 255/40/18
Rear 18" x 10.5" , Offset +28 to +35, Tires 285/40/18 or 295/35/18


I would add that 245/40 on the fronts and 275/40 rear will also work, since they are within the *accepted* range for those wheel widths. In fact, I'm going with 275/40s on an 18X 11"..which is within the accepted range as well.

From Tire Rack:

275/40/18s..scroll down for 245/40/18
http://www.tirerack.com/tires/tires....=yes&tab=Specs

Rim width ranges explained:

http://www.tirerack.com/tires/tirete...jsp?techid=198

 

Way too small for an 18x11, that would have been correct for an 18x9.5

 

See my info from tire rack....

Also, there are many using 265/40/18 with 18X10.5s all around. There's a thread on this set up too. Apparently a lot of time attack cars use set up. That's really the *equivalent* of 275s on 11's as far as fit does.

 

I am not saying that it won't work, it's just really undersized (especially for this thread)

 

I'm running the same as your rear on the front with a 275/35-18 and an 18x11 +30 in the rear with 295/35-18.

I would say no you did not order the right sizes. 8.5 inch wide in the front is narrow. Definately to small to be posting in this thread anyway.

 

275 on an 11 inch wheel is very streched. I'm running a 295 on my 11 inch wide wheel and it is slightly streched.

 

It is "too" and cmon dude.. there are tons of people in this thread without 275+ on their fronts.

 

Thanks for the correction, I don't understand why you are trying to hate. Because I said 8.5 inch wide wheel is too small for this thread? Well it's true.

 

Technically, you only get *real* stretch when you go beyond the recommended ranges and 275s are within the range of an 11" wheel. *REAL* stretch occurs when the section width exceeds the rim width. So, an 11" rim is 279mm and a 275 is barely stretched (in the technical sense), so it's in the accepted application range. Same with 245s on 9.5s..although those are actually UNDER the 9.5" (241mm). As to 295s...ZERO stretch for sure.

If you're racing you really want the MINIMUM APPROVED tire size for a given wheel width..that insures no sidewall flex and maximum turn in response. As I indicated..Time Attack cars use 265s on 10.5 rims..pretty much the equivalent of a 275 on an 11" wheel.

 

He said *275s on the fronts*...nothing about 8.5s.

 

Yeah..for this thread..you're correct.

 

I'm running them on my car and I can tell you they are slightly small for the 11 inch wide wheel. A 275 will be small for that wheel in this thread. I'm not trying to argue with anyone, but a 265 on a 10.5 inch wheel and a 275 on an 11 are too streched for this thread.

BTW, good choice on those F14's Ron, gonna look good on your Z.