Track Wheels: 16s vs 18s

[Roger 911]

I'm looking for some inexpensive track wheels for a '86 951. They will be used for both Autocross and DE. My ideal would be a set of four 16 x 8 early offset Phone Dials which I could run 245/45s on. In my quest to find these, I have come across two interesting alternatives. Both are late offset and would require spacers/adapters, but I'm fine with that (I have run them on a '72 911 DE car for 14 years).

Option 1 - Late offset 951 Phone Dials, 7s and 8s. I'd have to run 225/50s on front.
Pros: light wheels, cheaper tires. Cons: smaller front tires.

Option 2 - 18 x 8 Cayenne wheels. I'd run 245/35s all around.
Pros: 245 "square" tire set up. Cons: Heavier wheel (+10 lbs, I think), more expensive tires.

I can get the Phone Dials for $100 and the Cayenne wheels for $150. So the real question comes down to which one will perform better. Smaller and lighter, or bigger and heavier? Better response versus better grip?

Thoughts anyone?

Thanks.
Roger

[DannoXYZ]

Not much tyre selection in 245/45-16 size nowadays. However, a variety of DOT-R track tyres can still be had in that size.

Both sets of wheels in square set-up 8" front/rear with same model 245mm tyres will perform similarly. The 18" will have slightly crisper turn-in, but max-grip will be about the same. Even better if they're on 10" wheels, in which case, the difference between 16" vs 18" wil be even less.

On bumpy courses, the lighter 16" wheels with more sidewall flex will be faster. On all courses, the acceleration-penalty of +50lbs of unsprung weight can add up. I saw a recent test on motorcycles with carbon-fibre wheels that were just 1-lb lighter than stock improved times at Willow Springs significantly.

[Roger 911]

With respect to 16" size availability, yes, if we were using these as street wheels it would be limited, but as you note, for the track, there are still quite a few good options. We have Mille Miglia Cup 1s 17" on the car now with 205 front and 255 rear tires (previous owner's choice). I did a couple DEs and the car was definitely lacking front grip. We'll be switching to 225s on the front with these wheels, but we (we refers to my son and I) will use them for the street (really prefer OE wheels over these for track use).

Roger

[DannoXYZ]

Easiest option at the moment with what you would be 2x 16x8" wheels to get 16x8" all around. Then 245/45-16 all around in a track compound would reduce understeer and quick turn-in.

Keep an eye out on here and RL classifieds for used track wheels. Some 17x10" all around would be perfect with 255/40-17 tyres.

Being able to rotate tyres with a square set-up really makes using track easier. Otherwise you may end up throwing out a tyre that's only 25% worn.

[Roger 911]

I bought the 16s yesterday.



Yes, a square set up would be ideal. I'll keep my eyes open and see if some additional 951 8s show up.

Roger