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Slicks to Treads
Twin40 - 11/1/13 at 02:57 PM

Hey people, need some racing tyre help!

I've recently signed up to the CSCC Mag 7's , and the reg's state i need to run 1A/1B treaded tyres. The MK currently has michelin slicks with the following sizes

Front: 24/54 13
Rear: 24/57/13

I'm not familiar with slick tyre sizes, so no idea what the metric equivalent would be, or which supplier can provide the correct size (yoko's?).

I think the tyres fitted are quite rounded (if that makes sense) so could probably get away with a narrower tread in metric size.

Any ideas? (have a look at my photo archive if it helps....)

Cheers

Clive.

snakebelly - 11/1/13 at 03:30 PM

have yopu tried giving camskil or George Polley Motorsports a call? they would be best to advise on what would be a suitable equivalent and both can supply lisat 1A/1B tyres in a variety of makes and sizes.
HTH

Twin40 - 11/1/13 at 03:37 PM

Thanks, hadn't thought of that! rely far too much on the internet these days.

Cheers

loggyboy - 11/1/13 at 03:39 PM

quote:
Originally posted by Twin40
Front: 24/54 13
Rear: 24/57/13

I'm not familiar with slick tyre sizes, so no idea what the metric equivalent would be, or which supplier can provide the correct size (yoko's?).


IIRC its fairly simple the 24 is the width in CMs (eqic to a 235/245 road type), albeit road cars usualy slight under this measurement and race tyres slight over)
The 54 is the overal diameter in cm.

so your tyres are approx 235 45 13. and 235 50 13
Which I doubt are tyre sizes avialable in road tyres.

[Edited on 11-1-13 by loggyboy]

Twin40 - 11/1/13 at 03:51 PM

Well thats a silmilar thought i'd had with the tyre size, but the rears are 10" wide and the fronts are 8" so i assume its something like

205/60/13
255/60/13

i should check the wheel rim width first, might help!

Thanks again

number-1 - 11/1/13 at 04:27 PM

Hi mate. Id be very interested to hear what you get told. Ive got a similar issue with the same size rims. The car came with slicks of the same size as yours. Im trying to work out what track tyres would fit.

If its of any use on the front ive got 230/535R13 on the front but in slicks

N1

number-1 - 11/1/13 at 04:36 PM

I forgot to mention that the car came with wets on.....160/515 13 front and 200/55 13 rears that were stretched to fit the rims

[Edited on 11/1/13 by number-1]

olimarler - 11/1/13 at 11:10 PM

What class are you entering?

Looks fun!

Oli

CNHSS1 - 12/1/13 at 12:40 PM

quote:
Originally posted by number-1
I forgot to mention that the car came with wets on.....160/515 13 front and 200/55 13 rears that were stretched to fit the rims

[Edited on 11/1/13 by number-1]


slicks, especially crossplies, are normally run with some stretch (ie 9" tyre on 10" rim), as this gives the sidewalls more mechanical stiffness, and you dont get an initial 'dullness' to steering inputs around the centre point as the load moves across the carcass.

as for OPs query, i suspect you will need to go slightly narrower on 1Bs than equivalent slicks. Most CSCC runners in other classes run R888s or yoko A048Rs on the classics.

it would be worth looking at Kumho V70 1Bs though as they do a 215 and 235/245 in 13". Soft compound will be too soft for circuit tacing 20mins plus for sure, but id ask tony at South Shore Tyres (Kumhos recommended Motorsport agent) for advice on mediums given the weight of the car.

all the above 1Bs have very stiff sidewalls and are a fair bit heavier per carcass than the equivalent slick though.

you could look at ACB10s from Avon as they are basically a slick crosspliy carcass with a moulded tread (some are E marked road legal, others not). Best advice there would be speak to BMTR in birmingham, they will give excellent advice on cambers, pressures etc etc.

Twin40 - 12/1/13 at 07:38 PM

quote:
Originally posted by CNHSS1
quote:
Originally posted by number-1
I forgot to mention that the car came with wets on.....160/515 13 front and 200/55 13 rears that were stretched to fit the rims

[Edited on 11/1/13 by number-1]


slicks, especially crossplies, are normally run with some stretch (ie 9" tyre on 10" rim), as this gives the sidewalls more mechanical stiffness, and you dont get an initial 'dullness' to steering inputs around the centre point as the load moves across the carcass.

as for OPs query, i suspect you will need to go slightly narrower on 1Bs than equivalent slicks. Most CSCC runners in other classes run R888s or yoko A048Rs on the classics.

it would be worth looking at Kumho V70 1Bs though as they do a 215 and 235/245 in 13". Soft compound will be too soft for circuit tacing 20mins plus for sure, but id ask tony at South Shore Tyres (Kumhos recommended Motorsport agent) for advice on mediums given the weight of the car.

all the above 1Bs have very stiff sidewalls and are a fair bit heavier per carcass than the equivalent slick though.

you could look at ACB10s from Avon as they are basically a slick crosspliy carcass with a moulded tread (some are E marked road legal, others not). Best advice there would be speak to BMTR in birmingham, they will give excellent advice on cambers, pressures etc etc.



Thanks for that mate, really helpful info. The kumho's might be a winner! I'll post up again once I get some fresh rubber. Cheers