Should I go to 13's?
 

Ok I wanted to get some other RX7 auto-x'ers opinions on this one. I currently have 15x8 Sportmaxxes (heavy) with 215/50-15 R-Comps on my 13BT GSL-SE SSM car. I have come across a set of 13" R comps for a good price and started debating on whether I should stick to the 15s I have or sell them and pick up the 13" R Comps and some Aero or Diamond Racing wheels. My main thoughts are lowering the car and reducing unsprung weight.

Side note: Can you even clear GSL-SE brakes with 13" wheels?

Thanks in advance,
Nate

Pic of car in current setup for reference:

https://farm3.static.flickr.com/2690...262757d347.jpg

I am running 13x7 panasport wheels on my sa with 20x9.5-13 goodyear slicks in FP, I like that set up it lower the center of gravity for better cornering, and lower rotational mass for better acceleration. as far as 13's fitting over se brake I am not sure about that.

Yeah that is a concern since most people running 13's appear to be running standard diameter 12a brakes. I also wonder if the added diameter of the 15s helps a little reducing wheelspin with ~250hp.

Donno if 13s will fit. Might be pretty snug. You can find some very light 15s, especially among the forged wheels. 11-12 lbs easily.

if you do a hub swap to a GSL SE brakes and stuff the new bolt pattern will open a ton of wheels for you but you will have to get the axle shafts from RE Speed so in all its a simple thing.

^He has an -Se....

But From what I've read, 13's wont fit over the -Se's brakes. I can test that for you later on today, My friend has some 13 inch steelies for has AE86. I can throw them on there real quick and see what happens.

i didnt look at that my bad but you should be able to get a ton of options, with the SE set up

That would be great man.


And yeah I know I could just get Diamonds in 15's or something but it still will sit higher and it seems like most really competitive FBs run 13x8's or something for auto-x.

I was thinking about going 13's also on my SE for next season untill i found out they did not fit. . I had some 15 inch diamond racing wheels on my last 7 i autocrossed and i was pleased with them


http://img155.imageshack.us/img155/6...3306146952.jpg

How heavy are your XXR's? I just bought a set of Rota RB's 15X8 and they are 15 lbs each.

16.5lbs per corner which I guess isnt horrible but FBs dont like too much unsprung weight from what I have seen.

16.5 lbs is a bit heavy for a 15x8, but not too bad. If you shop around you might be able to find lighter 15s, even cast ones. If you go forged, you could shave off a few pounds off each wheel. Also consider the tire weight. Not all tires weigh the same, and since they're further from the center of whe wheel, they contribute more to the wheel's inertia than the rims.

Yeah, 13's wont work bud.

Thanks for the info guys. Glad I asked before ordering new wheels lol.

I like the 13's for lower ride height and lower gearing. On most autocross courses, I'll only redline right at the end of the longest straight.

But I guess it doesn't matter to you now since you know that they won't fit anyway. :)

Maybe some 14x8 Revolutions?







.

14's are always an option but it seems like race tire choices are more limited for 14s these days than 13s or 15s

Oh here's a pic for reference, I just set a GSL-SE rotor in the wheel. there's on like at most a centimeter between the rotor and the inside of the wheel. The caliper wont clear it

http://i2.photobucket.com/albums/y18...1008101941.jpg