Help with tire selection

DByers · 01-24-2007, 03:12 PM

I am looking into new tires and budgeting for some 2007 items. Currently I am running Yokohama AVS100 205/60 on 15X7 on all four corners. I would like to shorten the sidewall to get less flex but I am thinking the 205/50 series on 15's would shorten the overall height to much, just about an inch. I know it would effectively shorten my gearing also, but to what extent? I was also thinking about finding some 16x7 fuchs or other wheel to run for my track events and then run 205/50 on 16's which would keep my height about where it is now, give me the lower sidewall but cost more and possible create more rotating mass. Since I am running stock brakes on my 71 I don't know if more mass is a good thing. Tire selection would be greater I think in the 16" wheel size also. I am leaning towards Toyo RA1's and if I had them on separate wheels I could extend their life.
Car is set up street/track with the following
20F T.B.'s
26R T.B.'s
21mm adjustable front sway
19mm rear sway
alignment by TRE with -1.5 deg in front & close to -3 deg rear, lowered to euro height. Weight is about 2150lb with a 1/2 tank of gas.
Car is used on weekends and will see about 12 DE/track days in 07.
Thoughts, recommendations or criticism is welcome.
TIA

rgrimm · rgrimm's Garage

I like this site for tire size comparison.

http://www.miata.net/garage/tirecalc.html

Beyond that, I'm not sure I can be of much help.

PatrickB · PatrickB's Garage

Hey Dan~

You're welcome to try my 6&7x16's for a day at the track... I've got Falken 451's mounted on them that should be fairly equal to the AVS100's...

They probably have a couple of track days left on them... They're just sitting as spares for now, as I'm lovin' my new 8&9's!!

sig_a · 01-24-2007, 07:16 PM

I have 15 inch Fuchs on my '87 Carrera 3.2. I bought a set of 4 Pirelli P6000 from Tire Rack. Front are 195x65x15; Rear are 215x60x15. $543.82 total delivered to Zionsville, IN - just outside of Indy. Although these tires are tall, I feel no squirm. Then again, I don't track the car.

Tyson Schmidt · 01-24-2007, 07:17 PM

Dan I'm running 205/55/15 front and 225/50/15 in back on 15X7" Fuchs on Tangerina.

They are the BFG G-Force Sport. But you can do better tire wise.

jim72911t · 01-24-2007, 07:40 PM

Tyson, (sorry for the hijack)

What sort of camber settings are you running on the rear to get 225/50's on 15x7's in the rear? I've seen this setup before and would like to try it on my '72T. As luck would have it, I have a stack of good 225/50 RA-1's left over from my E30 track days.

Thanks,
Jim

DByers · 01-25-2007, 06:13 AM

Thanks for the help guys.

Patrick, what series tire are those on the 6 and 7's? I might take you up on that.

Tyson, I feel to get a 225/50 under the rear I would need some "evil" done to the rear control arms like you explained in the other thread. The 205/60 actually pearls on the passenger side rear on hard lefts during track days. The 225 would give me a wider patch but would be also wider overall. Since Ingo is out of country, I may go by his place and "borrow " his 16's while hes not looking to play with.

Mike Bonkalski · 01-25-2007, 06:34 AM

I like the Toyo Proxies T1-R's. They come in a good range of sizes as well.

Take a look here - http://www.tires-easy.com/start.html

PatrickB · PatrickB's Garage

Quote:

Originally posted by DByers
Thanks for the help guys.

Patrick, what series tire are those on the 6 and 7's? I might take you up on that.

Tyson, I feel to get a 225/50 under the rear I would need some "evil" done to the rear control arms like you explained in the other thread. The 205/60 actually pearls on the passenger side rear on hard lefts during track days. The 225 would give me a wider patch but would be also wider overall. Since Ingo is out of country, I may go by his place and "borrow " his 16's while hes not looking to play with.

205/55/16 & 225/50/16...

Time to start getting EVIL!

You put those on, and I'll never keep up with you!!

Paulporsche · 01-25-2007, 02:01 PM

I used to have the same tires and sizes as sig_a. I switched to 205/50/16s on 7s all around for street use. The squirm a lot less yet have about the same ride quality. The tires are Fuzion ZRi. I am very happy with them.

BTW if you go from 205/60/15 to 205/50/16 your speed will read about 2.5% higher than before @ the same speed.

Tyson Schmidt · 01-25-2007, 05:38 PM

Quote:

Originally posted by jim72911t
Tyson, (sorry for the hijack)

What sort of camber settings are you running on the rear to get 225/50's on 15x7's in the rear? I've seen this setup before and would like to try it on my '72T. As luck would have it, I have a stack of good 225/50 RA-1's left over from my E30 track days.

Thanks,
Jim

I'm running -2.5 in back.

The fender lips are not rolled. The car is too original and still has the textured finish on the lips, so I don't want to disturb that.

I've had absolutely no rubbing issues with it. But then, tire sizes and dimensions vary greatly from brand and model, so sometimes the stated size isn't always on the money.

And every car is a little different too!