Slick Tyre Wear -

[oldbutnotslow]

One evening and one full TD and the rears are showing significant wear on the inside edges of the tyres (inner 2") on both tyres after some 300 miles

Im running 0.25 degree rear ears with a pressure cold of 20psi. and a ZF dif.

 

Its the wear pattern that has me confused

 

Inner edge wear would normally indicate a significant neg camber setting but this is not the case. Admittedly we were pushing on at Cadwell but I would not have expecetd to see this sort of wear.

 

I have a TD at Oulton shortly but on this wear rate they will be through the wear markers well before the days end

 

Any thoughts would be welcome.

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here

 

[Alex Wong1697456877]

TADTS.

 

Never worked out why though. Also, it doesn't take long for the tyre to wear itself into what is effectively neutral camber if not negative camber.

 

Even with the 0.25deg ears, they wear out on the inside first.

 

Edited by - Alex Wong on 7 Jun 2006 09:11:59

[oldbutnotslow]

Whats the view of having them swapped around on the rims so that the worn bits are on the outside of the rims?

Currently set up as per Avon; spec number on the inside on the N/S rear and spec number on the outside on the O/S Rear. They could be swapped N/s to O/s and still have the spec numbers on the correct place.

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here

 

 

Edited by - oldbutnotslow on 7 Jun 2006 10:13:52

[Mark Durrant]

Why not give Avon a call as I have found them to be very helpfull

 

Mark D

Comp Sec

 

[Unclefester]

Is that 0.25° toe out? I'm surprised they wear that quickly, but if they are toing out you would expect some inner edge wear.

 

I'd check the toe out, it sounds like it could be more than it should be.

 

 

NICE PLATE!!!

😬 😬here *eek*

[fatcat]

sadly slicks do that ! I can usually kill a soft set in under an hour 😳

 

You should be fine swapping rims (retain rotational direction) but get a tyre fitter who knows what he's doing - they don't usually worry about removing tyres and they can get damaged.

 

Probably not related to the wear you describe but keep an eye of the pressures. 20 cold might be a bit high, most slicks like to run at around 21-22 hot.

 

If these are Avons, then talk to them for more info, they are very helpful, 01225 703 101

[oldbutnotslow]

Well Ive spoken to Avon and there are a couple of things that came out of the conversation that was interesting. Given the sort of use that I am putting the car to:-

The tyre direction indicators being on the car the right way around (spec number) is only really important on the first use of a set of slicks. After this you can move them around!

There is another 2 mm under the wear indicators

The expected life of medium compound slicks will be between 200 ans 300 miles depending on how hard you use them

They suggest starting with 15 to 16 lbs/sq in cold to run at 20 hot so as Fatcat says perhaps Ive been running them at too high a pressure thus getting them too hot.

Running them at this psi will mean that the tyres will need 2 or 3 laps to warm them up otherwise they will feel very squirmy.

A1/4 of a degree neg on the rear is good but better would be bolt upright.

 

He accepted that the CR500's dont perform all that well on X ply settings but that they will be acceptable using 1/2 degree neg at the front and 1/4 at the rear.

 

Ive met Brian Davies at a couple of meets and have spoken to their race dept 3 or 4 times mainly about compounds and they are really very helpful.

 

So, perhaps the main factor was the too high pressure and my expectations of wear life. 😳

 

 

Grant Taylor

OBNS Motorsport

 

😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here