Semi Slick Tyre on Radicals SR3 race wheels

[tracker11]

Does anyone of you use semi slick tyres on his SR3?
I have 3 set of wheels and I would like to have one set with semi slicks, to take part at the time attack series in Switzerland. They don't allow slicks.

So before buying a 4 set of SVA wheels I would like to ask first if I can use the racing wheels as well for semi slicks.

[radical78]

yes khumo

[Coldaswell]

I didn't think they allowed space frame chassis in the time attack series?

I looked a couple of years ago in the uk and that explained why the only "track day special" car was a KTM Xbow.

[tracker11]

radical78 said:

yes khumo

which dimension do you use?

[Coldaswell]

I use Toyos. 195/55 front and 245/45 rear. It would depend on your wheel size. Radical supply Dunlops which I've used with a rear 225/45.

There is conversion info on the internet to convert from slick to road sizes.

Which class in time attack are you entering?

[tracker11]

Coldaswell said:

Which class in time attack are you entering?

RWD pro class

2.2 Pro class

2.2.1 Engines & Exhausts
Open

2.2.2 Gearbox, Driveline & Brakes
Open

2.2.3 Interior & Exterior
Open

All convertible type vehicles must have a hard top, a full roll cage or maintain original rollover safety
devices.

2.2.4 Chassis & Suspension
Open

here you can find more information
http://www.speed-industries.ch/wordpress/wp-conten...

[dptdpt]

Coldaswell,do you have any issues with the Toyos catching the bodywork at the rear? I've tried Kumhos 265/45/16 but they catch from time to time at about ten o'clock looking at the wheel.

[Coldaswell]

Hi dptdpt,

No problems at all. The car came with one 235/605/R16 and one 265/605/R16 ( don't ask!). I may be wrong but I worked out the former as being equivalent to a 235/42.6/R16 road tyre. This means that my 245/45 s are a bit larger in diameter but still ok. A 265/45 would, I believe, be larger still.

I only have a 1299 engine so the 245 works well for me.
How have you found the Kumhos? I've been happy with the Toyos compared to the Dunlops. It may just be my perception but I think there is just as much grip when hot but more grip when cold with the Toyos. The largest rear Dunlop make is a 225 too.


Hi Tracker11, good news, they've seen the light
What else runs in that class?

[dptdpt]

Sorry for the long delay Coldaswell.
I calculate ( and am happy to told I am wrong) that 245/45/16 should be 627 dia. The Kumho 265/45/16 calculate to 645 although their sizing guide says 630 approx, so it could be that the Toyos are a better choice. They would fit OK if I raised the car a bit, but am reluctant to move away from factory settings.
I only drove on the Kumhos for two or three laps as they were borrowed, and catching the bodywork, so I can't say how good or bad they were. They were a lot better than my slicks on that cold and damp morning though. I did use Kumhos when I had a Caterham R400, and they were the brilliant, wet and dry, much better than Avon CR500's that came with the car.

[BioBa]

I use with great success Hankook soft semi slicks in 205/50/15 front and 245/45/16 rear.
Great price and perfect for sprints and hill climbs.