Wheel recommendation for track

[fuscobal]

Until now I've been on Nurburgring and Hungaroring with 235/35/19 and F1 asymmetric. As I felt there's too little grip for the power this car makes and the sidewall for this tire is too small for the track, I decided to go with 8x18" rims and semislicks. So the sidewall heights are as follows :

- 235/35/19 > 82.042mm > min 8" rim - current wheel
- 225/40/18 > 89.916mm > min 7.5" rim > R888 weight is 10.45kg
- 235/40/18 > 93.98mm > min 8" rim > R888 weight is 11.35kg

So, the question is, would I benefit more from the extra grip and sidewall from 235 or from the lower weight of 225 ?

[Hurdy]

The main thing is the tread width and with those two tyres you actually get an extra 20mm of width from the 235 section tyres over the 225 section (244mm v 224mm) and the tread width is actually less than on the 225 section 17" tyre (231mm). I know as it was one of my reasonings for going for 17" alloys over 18" 

On the 225 x 17's I had all the grip I needed at the 'Ring. I reckon dropping to a 8.5 x 17" alloy you could go balls out and fit 255 (265mm tread width  ) section tyres. The smaller rim would be lighter and make up for the heavier tyre (12kg). You may struggle with clearance though if you haven't got camber mounts

[fuscobal]

17" would be the cheapest option as I already got the OEM 17" so I'd only need tires. The problem is, with the S3 front brakes, the caliper sits only 2-3mm away from the rim and I'm afraid the brakes won't cool efficiently ! What rim and tire sizes would you put on my car after all Hurdy ?

[danishmkvgti]

17" would be the cheapest option as I already got the OEM 17" so I'd only need tires. The problem is, with the S3 front brakes, the caliper sits only 2-3mm away from the rim and I'm afraid the brakes won't cool efficiently ! What rim and tire sizes would you put on my car after all Hurdy ?

I don't think it would affect the cooling in a major way as the cooling comes from the hub side of the disc, meaning the center of the disc and then flows outwards. 

Look at F1 cars and other top racing cars they also drive 17" and max size brakes

[Hurdy]

17" would be the cheapest option as I already got the OEM 17" so I'd only need tires. The problem is, with the S3 front brakes, the caliper sits only 2-3mm away from the rim and I'm afraid the brakes won't cool efficiently ! What rim and tire sizes would you put on my car after all Hurdy ?

I don't think it would affect the cooling in a major way as the cooling comes from the hub side of the disc, meaning the center of the disc and then flows outwards. 

Look at F1 cars and other top racing cars they also drive 17" and max size brakes

^^^^This^^^^^

If you have coilovers already, then I'd go for camber mounts and run 8.5 x 17 wheels with 255x35x17 R888's on track.

For normal road use I'd stick with 8x17 or 8x18 and run normal 225 section tyres.

[fuscobal]

Isn't 255 too wide for this car ? If I stick with 17" I'd use the OEM rims wich are 7.5x17. This rim doesn't allow more than 235 unfortunately ! I have PSS10. What camber mont would mate with this coilover ?

[Hurdy]

Isn't 255 too wide for this car ? If I stick with 17" I'd use the OEM rims wich are 7.5x17. This rim doesn't allow more than 235 unfortunately ! I have PSS10. What camber mont would mate with this coilover ?

I have some camber mounts that I bought that would fit my PSS10's but haven't fitted them. They are KW spec and still fit the Bilsteins. I'll dig them out tomorrow and find out the exact kit number There are a couple of GTI's in the USA running 255 section tyres for track use and both say they have no scrub and use a coilover/top mount camber adjustment set-up.

Hmm, if you are wanting to use the OEM wheels then I recommend sticking with the 225 section rubber

[fuscobal]

Thanks Hurdy. Yes, OEm wheels are 7.5" so they don't take more than 225. Anyway, with the 235 I have now on my 19" the wheel is perfectly aligned with the fender/arch because I only have about -1 negative chamber. If I want to go 245 or 255 I will certainly need more negative chamber. How much camber do you aim at the track ?

[danishmkvgti]

Fuscobal, i have a set of KW camber top mounts that i won't need as i find i have enough negative camber with the T&T mk " lower control arms. Spring inner diameter for these is 61mm and outer diameter is 81mm. Smaller than the stock diameter springs. PM me if you are interested 

[fuscobal]

Danish, will they work with B16/PSS10 ? I will try to measure the springs when I get the chance. I've talked to Toyo and for the weigth of my car they've recommended going with 33 PSI cold pressure and max. 38 PSI while hot. The ideal thread temperature is between 71C and 105C with a recommended maximum difference between inside, middle and outside of the thread of 15C !

[danishmkvgti]

Danish, will they work with B16/PSS10 ? I will try to measure the springs when I get the chance. I've talked to Toyo and for the weigth of my car they've recommended going with 33 PSI cold pressure and max. 38 PSI while hot. The ideal thread temperature is between 71C and 105C with a recommended maximum difference between inside, middle and outside of the thread of 15C !

I have a friend with same coilovers as you, i'm trying to get him to measure his 

[fuscobal]

Ok, thanks Danish. I will measure the damaged front springs I've just replaced. After 3 years with PSS10, one spring was 3cm shorter (1.2") !!!!!! Roads are really bad here. With the new springs installed my PSS10 came to life again. What are the differences between the OEM camber plate and the aftermarket adjustable ones in terms of noise, comfort under normal road driving... ?

[fuscobal]

Inside diameter > 82mm
Outside diameter > 105mm

[danishmkvgti]

Inside diameter > 82mm
Outside diameter > 105mm

you will need to make new plates for the springs to rest on i'm afraid 
Looks like st. spring diameter to me

[fuscobal]

Well, if the B16 springs go on the OEM plates it would seem logical to me for them to have the same upper diameter as stock ! From what I see, there are several choices on the market like K-mac, H2sport and K-sport (these are made for their own coils but seem to also work with others). K-mac goes for about 500$ while H2sport are half that (i don't know why this big difference). TT lower arms in my country are about 750 Euro (1000$) including ball joints, bolts, bushings...  The 2 options :

1) Camber plates > will pull the upper part of the damper towards the interior of the car, creating more negative camber and more room for the wheel to go well under the fender/arch, especially if the wheel is much wider than stock. From what I've read the ride with those + coilovers is harsher than only coilovers
2) TT arms > will pull the lower part of the damper towards the exterior of the car, creating more negative camber and a wider track between the front wheels but will not help much with the wheel going under the fender/arch. The ride is same as with the OEm arms so these have an advantage on bad roads

Those said above represent my logic and may be innacurate. Can anyone comment on them ?