Anyone Use Slicks?

[Shakey_Jake 3 1 Cars]

Hi all,

 

I've got a 205 gti6 track car and I'm after a decent set of track tyres, I was looking into the likes of Toyo R888s and Yokohama A048s but they are very expensive, even used ones with very little tread left. I don't really need road legal tires as I am happy to take a spare set of wheels to the track.

 

So, I've been looking at used slicks on eBay mainly 19/57/15 michelin s9c. They are a good price used and have generally have decent tread left across the tyre. The problem is I have no experience with these or any other slick tyre for that matter.

 

The question is, does anyone on here use slicks on there trackcar? If so which type/make of tyre do you use and what problems have people experienced with using them as they will obviously give a lot more grip than e-marked road tires so have yous had any breakages because of using them? And finally is the size I mentioned the correct size for 205 gti 15" alloys?

 

Appreciate any help,

Jakey

 

 

[Baz 421]

Slicks aren't aloud at some trackdays.

 

To get the best out of them and not roll your car you need to have the correct suspension setup.

 

They're much more succeptable to temperatures and heat cycling.

[allanallen 528 2 Cars]

As Baz says they need to be warmed up and cooled down correctly. Ideally you want to be running a reasonably stiff setup and plenty of negative camber to get the best from them. I do know of plenty of people who run slicks on basically 'fast road' cars with no probs whatsoever though.

You just need to be respectful of them, they don't 'let go' progressively like a road tyre.

That size youre looking at is ideal really

 

[parry 23 1 Cars]

I run slicks on my 205. They are useless when cold! The rears dont heat up easily on my 700kg 205 and it causes problems on cold days. If you can make sure you get a very soft compond to ensure you get heat in quickly especially the rears. In qual I have been known to run 888s on the rear and slicks on the front on very cold days. Not the best but at least I stay on the grey stuff.

 

Also I had to go upto 400lb springs at the front to get the slicks to operate correctly.

 

In saying that I am now getting 1.3g which is up there some dedicated race cars with aero.

[omega 82]

intresting thread

i would have thought the reason you are useing slicks is to get more grip

if you getting more grip/force through useing them then it would follow that you are putting more strain/stress on other parts so more likely to get breakages of shafts/cvs etc

or am i wrong? and the standard parts are up to the job.

[parry 23 1 Cars]

So far with the 8v on TBs all is good. Next season sees double the power with the 16v, that will test a few things! At the moment I have 106hp atw, 16 valves I am hoping for 190 to 200hp atw.

[Shakey_Jake 3 1 Cars]

Thanks for the replies.

 

It's good to here they won't cause big breakages as I was thinking they would cause snapped driveshafts at every opportunity as my local tracks croft and knockhill have slow hairpins but as someone mentioned it depends on throttle control and not just planting it out of a hairpin, also I was thinking along the lines of fuel starvation which is a problem with even road tyres so with slicks would the next problem of oil starvation not come into it? Or am I just being paranoid about all this?

 

I've already got a few mods on the car to increase negative camber but how much would be needed as I may need adjustable top mounts too, can anyone give me a figure of how much camber would be a good starting point?

 

[parry 23 1 Cars]

2.5deg for slicks and then adjust for there to sut track

[EdCherry 34 1 Cars]

There are different types of construction.

 

Crossply will give a much more progressive break away than Radial tyres will.

 

Crossply are very sensitive to camber control and heat, not so suited for a 205's original geometry.

 

Radial is much more forgiving tyre in terms of bad geometry and heat, although has a rather more snap type break away usually.

 

Usually a tyre company, Dunlop in your case, will happily advise you on temperatures the would expect to see at the core and maximum camber. The camber you will want to run will vary due to the target temperature spread/tyre wear and characteristics it will give.

 

You can use slicks on your car fine, and you will gain a slight advantage grip wise off the bat. To gain the full advantage though you will need to change some of the geometry and dynamic conditions of your car.

[Cameron 16]

Jakey, you get what you pay for I'm afraid; and if you think new 888's are expensive, try getting some quotes for new slicks!

 

If you don't want to spend any money then just fit decent (i.e. a good tyre model) part-worn road tyres, otherwise get your wallet out.

Edited December 28, 2012 by Cameron

[Normski 1]

I bought a set of Dunlop slicks a while back £150 a corner!!! but they do last a long time if you rotate them and turn them on the rim to even out the wear. I've also used part worn Michelins which were ok but not as good as the Dunlops, you don't know what your getting second hand, the racers have taken the best out of the tyres.

For track day use you don't ​need ​ to do anything to the suspension set-up, you won't be getting the maximum out of the tyres but they will still be out performing any road legal tyres.

I've not had any reliability issues with using slicks, they are the best way for the money to cut your lap time.

[pier_bruce 0 1 Cars]

I bought a set of the michelin s9c off of eBay to test as I can't afford to destroy the avons and I was disappointed, as norm said the racers took the best out of them and they were hard and shiny which I came to a conclusion they had been stood around for a long period of time. I had to do some serious tyre warming to get a bit of heat into the fronts but the rears didn't even work.

[Batfink 201]

What's your suspension and chassis setup. Quite frankly most people who fit slicks don't have a setup designed to get heat into the tyres. If I remember right touring cars tend to run toe in on the rear to generate heat. The slicks (if radial construction) will need around 2degrees of camber minimum.

If running Avon crossply I've been recommended by one distributor to run standard camber and for settings as they don't need the same camber like a radial but are lighter and more progressive. To then setup the car it's a case of taking tyre temperatures at the trackside

Edited April 9, 2013 by Batfink

[welshpug 1,657]

dunno about others, but the 306 touring cars ran rear toe out not in, so could be quite a handful and would turn in and step out like anything!

[EdCherry 34 1 Cars]

Lots of conflicting information here again, lots of here say!

 

Toe out not in

Camber is a measurement derived from Tyre Temperature and Width Used

 

and just to get people flaring up again

 

Lifting the rear inside wheels is a GOOD thing.

[Batfink 201]

Knew it was going to be the opposite to what I said but if you think about it it's pretty obvious it would be toe out :-/. Chris our engineer was telling us how complicated the trailing arm designs were to alter the geometry as the suspension moves on the Chevrolet wtcc cars

Edited April 9, 2013 by Batfink

[Shakey_Jake 3 1 Cars]

I bought a set of the michelin s9c off of eBay to test as I can't afford to destroy the avons and I was disappointed, as norm said the racers took the best out of them and they were hard and shiny which I came to a conclusion they had been stood around for a long period of time. I had to do some serious tyre warming to get a bit of heat into the fronts but the rears didn't even work.

S9c is a medium/hard compound so that may be part of the problem, I've got a set of these now and will give them ago at a trackday I'll be using Yokohama A048's for sprints due to the Michelins be too hard a compound so would never get heat into them.

 

Lots of conflicting information here again, lots of here say!

 

Toe out not in

Camber is a measurement derived from Tyre Temperature and Width Used

 

and just to get people flaring up again

 

Lifting the rear inside wheels is a GOOD thing.

Good thing? Could you explain that one please?

[EdCherry 34 1 Cars]

Most of the touring car designers since late 90's have been spending a lot of time on the rear geometry as your engineer says (whats his surname by the way?). The S2000 'Halfords' Civic was a particularly special example as are the 888 vectra's.

 

Unfortunately relating the thinking and geometry one would want into a 205 is a complicated matter, as well as having a driver than can indeed tame the beast once it is created.

[Batfink 201]

Defriez. Been working with RML on the wtcc program for years.

[allanallen 528 2 Cars]

Most of the touring car designers since late 90's have been spending a lot of time on the rear geometry as your engineer says (whats his surname by the way?). The S2000 'Halfords' Civic was a particularly special example as are the 888 vectra's.

 

Unfortunately relating the thinking and geometry one would want into a 205 is a complicated matter, as well as having a driver than can indeed tame the beast once it is created.

The vectras always looked broken from memory they ran about 9 degrees of negative camber on the rear at one stage?!

[EdCherry 34 1 Cars]

Not quite 9, Dunlop did issue technical bulletins concerning camber used and they're plea for everyone to stay below 5.

[allanallen 528 2 Cars]

It was getting close to that, in a straight line they were pretty much running on the side wall. Seemed to work though.

[Henry 1.9GTi 36]

I think 2.5 degrees is too little for a 205 front or rear. Lowered the wishbone geo wont add any -ve camber. It will probably roll off atleast 1.5 deg. As above tune with tyre temps across the tyre. Be wary that on the front you should see 10-20deg hotter on the inside edge due to braking and acc heat gen rather than lateral. Dont always aim for equal temps across the tyre. I run 3deg on the back, and even with that you can see just by inspecting the tyre that the inside edge isnt working as hard as the outside. Thats with reasonable roll stiffness 350lb front 25mm rear.

 

As with the chevvys seat also developed a passive rear steer which toed out the rear under load and had it para/toe in doing straight for braking performance and stability. Slicks NEED heat, just done a day in the wet on semi-slicks, the silverstone type RR. They are basically a slick with some tread cuts, super stiff sidewall etc.. car was pretty hairy to say the least, just couldn't build any rear temp.

[parry 23 1 Cars]

I think 2.5 degrees is too little for a 205 front or rear. Lowered the wishbone geo wont add any -ve camber. It will probably roll off atleast 1.5 deg. As above tune with tyre temps across the tyre. Be wary that on the front you should see 10-20deg hotter on the inside edge due to braking and acc heat gen rather than lateral. Dont always aim for equal temps across the tyre. I run 3deg on the back, and even with that you can see just by inspecting the tyre that the inside edge isnt working as hard as the outside. Thats with reasonable roll stiffness 350lb front 25mm rear.

 

As with the chevvys seat also developed a passive rear steer which toed out the rear under load and had it para/toe in doing straight for braking performance and stability. Slicks NEED heat, just done a day in the wet on semi-slicks, the silverstone type RR. They are basically a slick with some tread cuts, super stiff sidewall etc.. car was pretty hairy to say the least, just couldn't build any rear temp.

How did you achieve the camber in the rear?

[Rich_p 23]

Machined rear arms I suspect

 

http://www.306gti6.com/forum/showthread.php?id=144900