Drag Radial Sizing
 

Will Nitto NT05R 315/35R17 fit on a 2014 GT brembo that has a 1.5" drop?

I'd be very interested in learning how to determine the answer to #2. I know the total height will be just shy of 21.1" but I have some questions:

1) Will 17" wheels clear stock brakes?
2) Will 21.1" tall tire cause any issues?
3) Am I completely off thinking I can run 315? I will not mod to make it fit.

I'm sure I'll have more questions tomorrow. Thanks for any input!

120 views and no responses. It that because noone knows or because I'm asking the wrong questions?

Ok. I'll play.

1) 17" wheels will work on the backs, but the clearance issue isn't in the wheel diameter, but rather the backspacing of the wheels that allows the thicker calipers to clear. Front can fit SOME 17", but 18" would be best for cost.
2) Where the hell did you get a 21.1" tire diameter? That is WAY too small for your car. If you actually run a 315/35R17 then that diameter is 25.7" which is about 1.3" shorter than your stock 255/40R19. For track use this would be OK as it would be like reducing the gearing in your rear. Everyday driving would be messed up because speedo would be off. Maybe someone else could tell you what gear it would be similar to.
3) If offset and backspacing is correct then you can fit a 315. I think correct offset should be +40.

I'm no expert, but maybe this gets the conversation started.

I don't need an expert! I appreciate your response. Here we go!

1) These will only be mounted on the rears for track days (1/4mi) only. Granted I will most likely drive to and from the track that day.
2) You're right - my midnight math is lacking. 25.7" it is.
3) I need to read up on offset.

Maybe the easy answer is to go with 18's instead.

I have Sve drift wheels 18x9 front and 18x10 back , they have a 43 mm off set i believe with a 2inch drop on h&r springs 275x35 bfg rivals on the back. the drifts wheel can fit the big breaks and are 21 lb front and 23 lb in the back. A guy i autocross with has 295s on the rear with an 1/8 inch clear of his strango sway bar. This is his autocross set up but i know he is cutting it close. don't know the offset on his rims sorry.

I'll warn you here what i warned you there: No drag radials on an MT car. It is asking to break stuff. 3.55 is fine on a tire that tall. I run a 28" setup on my 3.73 car and it just kisses the factory limiter right at the stripe in 4th, perfect.

15" wheels will clear the brakes and you are way better off dropping some rim size and gaining some sidewall flex. I'm using 28X10X16 Hoosier slicks on '00 Mustang stock wheels.

If I can find a way to get em to the track I'll get slicks for sure why would DR break stuff and slicks not?

Radials have a relatively stiff carcass and rely more on compound than construction to hook. Radials tend to slip then grip and the shock loads on the driveline are huge. A bias slick just hooks, wrinkles and goes.

Just drive them out there if you don't want to mess with changing them at the track. I've done it lots and lots of times. Just go slow and be mindful to avoid potholes, road trash and such. It really isn't a big deal. They will fit in the trunk with the seats down, easy, if you want to go that way.

My setup will dead hook a 6000 rpm clutch drop launch, on a reasonable surface. I dropped down to 4500 because it didn't 60 any faster going out higher. The cars like to eat a little in first gear.

P, you're a lifesaver. Time to start looking into slick sizing. Thanks for all the help!

Yer welcome. I've been down this road a few times in 30 years in the hobby.

I like Hoosier because they are wider for height than Mickey. I've used both and each is good. Don't bother with tubes either. I just wipe dish soap undluted inside the tire and they don't leak. Balancing is also optional on a slick. I do it but the tire changes shape so much and is so light, it's not really relevant.

Oh and, your track officials may want a driveshaft loop for a slick car. I recommend Stiffler's. 1/2 hour bolt on, completely removable, strong design. I'd do this even if it wasn't mandated; I've seen the party a busted driveshaft has under a car and I value what's left of my legs at more than ~$100-150.