14" or 15" wheels for track car?

[Matt106]

Im currently looking for some new wheels for my track car (106 GTI). Im torn between a set of 14" or 15" Compomotives at the moment but whats best? Will I see a big improvement with that extra 1" oo err! or will the 14's be just as good?

The 14" wheels would have 185/55/14 tyres and the 15" wheels 195/45/15.

[ManOpener]

14's are likely to be lighter. If you have big brakes or intend on upgrading them, you may need 15s to clear the calipers.

[kambites]

I'd go for the 14s. The extra side-wall flex will make the car friendlier at the limit and they'll probably be lighter.

[varsas]

I'd choose on tyre choice, biggest reason for me to upgrade to 17's would be to get access to 'proper' performance tyres, like Pilot Sports, Pirelli Zero; that sort of thing.

If you are running R888's 15's will be easier/cheaper to get hold of?

[kambites]

Ah I was assuming that he'd already picked his tyres. Yes, that's probably more important.

[kit_kat]

ManOpener said:

14's are likely to be lighter. If you have big brakes or intend on upgrading them, you may need 15s to clear the calipers.

This.

I have 14's on mine at the moment as I only have standard brakes on it but I'm hoping to get some GTi 6 ones which would mean I need the bigger wheels. I also think there is a better tyre selection for the 15's.

[Matt106]

I'll be running a 266mm brake setup which fits snug under 14" wheels. I did have a 288mm setup but found it a bit heavy and slightly overkill on such a small car.

Over the winter I'll be running a normal tyre for a couple of track sessions. I'll then change these to a semi slick in the summer.

Ive looked into semi slicks and they're available in 185/55/14 at around £100 a corner which is pretty much the same as 195/15/15's.

[joe_90]

smaller the wheel, cheaper the R888's

[Matt106]

Semi slicks Ive looked into Toyo R888's and Yoko A048's I may have to run a 60 profile in these though.

Normal tyres I think Im going for the Toyo CF1's.

[Matt UK]

A lot of the MX5s now run 15's as the tyres in 195/50/15 size are pretty cheap

[Matt106]

So apart from tyre brand and choice, does the width of the tyres make much difference? For example will a 195/50/15 tyre hold the tarmac better than a 185/60/14?

[Chris71]

As mentioned above, definitely check availability.

I mistakenly thought the 13" tyres on the Caterham would be cheap. The bespoke size made for the car by Avon is worth every penny I'm sure, but it's twice the price of a moderately sporty 15" tyre!

[Matt106]

doogz said:

Yes.

The contact patch will be bigger.

But by a tiny amount. Also, as your 14's will likely be lighter, this will reduce unsprung mass and polar inertia, so the car will be a tiny bit quicker. Again though, tiny amount.

The rolling radii of the 2 different combo's are also very nearly identical, so tbh, it's whichever you think looks better/whichever you can gets tyres for cheapest.

Thanks for the info, I do prefer the look of the 14's! I think some more digging into tyre prices is needed!

[Cathar]

The contact patch will be wider, but shorter on the 15", the area will be more or less the same at identical pressures and vehicle weights!

[indigorallye]

You can get the A048 in a 185/55-14 which is a brilliant track tyre.
The R888 is only available in a 185/60-14.
This will give more sidewall flex obviously.
The 266mm brakes are more than adequate.

[thinfourth2]

Chris71 said:

As mentioned above, definitely check availability.

I mistakenly thought the 13" tyres on the Caterham would be cheap. The bespoke size made for the car by Avon is worth every penny I'm sure, but it's twice the price of a moderately sporty 15" tyre!

And at least twice as good

Don't try a moderately sporty tyre on a 7 as they don't work