Tyres

[Birkin S3 ZA.]

Your neck muscles will look like David Coulthard and your eyes will pop out when you brake

[Harry No Sheds Flatters]

Why 🤔

[GaryT]

Quoting Capt Sensible: 

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To be honest I fancy a change. Plus running two sets of wheels means being able to cater for a wider variety of conditions. I had also considered running Avon ZZR's alongside Avon CR28 Sports.

[OliverSedlacek]

I know they really need to be properly hot to generate grip.

[Rampmonkey]

I've been strongly advised to give them a wide berth due to my wet sump vx! Dry sump however.... 😬

[ECR]

Because you will generate a lot more g's in cornering and braking, oil surge can be a problem if the car is not dry sumped. if you want to minimise setups between road and track tyres, then make sure both sets are the same construction (radial/crossply). 20 psi hot is a reasonable starting point on pressures. The slicks will undoubtedly be wider than your road setup so watch carefully for clearance issues on your first runs.

[oldbutnotslow]

I run slicks on a wet K but I have a Hellier baffle. I also have an SPA digital temp and pressure gauge so I know what pressure I have on track. I also use a full synthetic ester based 5/40 oil. I regularly get 100+ on the temp but still maintain 70 psi when giving it full beans.

 

One thing to remember is that you will change the handling of your car if don't maintain (ish) the overall diameter of the two sets of tyres .

Quoting Michelin

A 16/53/13 S310 slick has an overall diameter of 529mm and a tread with of 178mm

A 175/55/13 avon CR500 had an overall diameter of 527mm so 1/2 the difference is 1mm or the square root of bugger all. The tread width is 184mm

 

The 205/55/13 normally fitted to the rear on 8" rims has an overall diameter of 554mm.

A 22/54 13 slick has an overall diameter of 540mm so 1/2 the difference = 7mm

 

This means that you will lose almost 1/2 the CC recommended rake of 15mm so if you intend to use your car primarily on track then its worth getting it set up (flat floor) for the slicks with may be a little more rear rake (3 to 5mm) than play around on this basis. I generally like around 10 to 12 mm rake but an errant tyre pressure will alter this considerably. The last track day at Cadwell I started off at 14 psi cold going to 16 hot

 

Too little rake will tend toward understeer. Too much rake tends to oversteer

 

Its true to say that slicks work better when they are warm. However they dont need to be blisteringly hot to achieve tremendous grip.

 

Slicks are much cheaper if you buy them as part worn A fresh set should run you £25 to £35 a corner including posting to you.

Once you have run them you wont go back to using normal road tyres on track.

I like Yoko A021 for wet days but I do have a set of full wets that I have used almost exclusively at Spa where it seems to pee down quite a bit!

 

Good luck

Grant

 

 

 

Edited by - oldbutnotslow on 15 Jul 2013 15:02:42

[GaryT]

Thanks for all the responses, I'm glad I asked as I'd not even considered rake and different tyre diameters!

Cheers, Gary

 

Edited by - GaryT on 16 Jul 2013 22:35:10

[neilg]

Don't worry about minute differences in rake here , camber there, blah blah. just bolt em on and go like hell. Unless you're at and over the limit all the time steering on the throttle and generally pretty good all round on a circuit you're unlikely to need to bugger around too much. Ive got all sorts of tyres and wheel combinations and never bother too much faffing around for a track day.

The biggest difference is that slicks are:

1. Cheap....i've got a second hand set that cost £50-00 for four and have done over eight trackdays with them.

2. Progressive once warm....so you can slide them with more confidence.

3. Very good on a damp track....once heat into them.

4. Braking is far better .

5. Look cooler...and that's important 😬 😬

 

Obviously if you're racing all of the above out of the window in the search for a few tenths here and there but for a trackday just bolt them on and go play. You'll love them.

 

 

[Jaseb]

What Neil said

[Iain A]

I have been running second hand slicks for dry trackdays for years. I also use AO21 for wet days.

I use michelin radial slicks - same size front & rear. They are fronts from a Formula Renault. The advantage of using the radial slicks is you don't need to change camber settings.. Having said that crossply slicks work pretty well without changes (I tried Avon ACB0).

On track I do a couple of slow laps to warm things up and then start to build speed on the 3rd lap.

On the limit I find the slicks quite progressive, but when you reach the limit you are generally going quite quickly. Take care!

As for set up I find slicks need a couple of psi more than road tyres or wets. I also fine tune the balance of the car with the rear ARB.

The best bit about using slicks is the cost.. they last ages and used ones are cheap. Go well and have fun

[GaryT]

Thanks for all the posts. Clearly a few people enjoying slicks. I have decided to give Avon ZZRs a go on the back of a lot of positive feedback.

[Smithy7]

Slicks will put a lot more stresses on everything and if you use them regularly your maintenance costs will rise dramatically. Been there, done it, however, they are blxxdy good fun and you must try them or at least do half the track day on them, probably better in the afternoon when you've learnt the track again.

 

Dave