When is a track tyre 'past it'?
Discussion
Road tyres tend to wear quite uniformly and have those 'cool' little pegs in the grooves to tell you when they're getting low.
But what about road-legal slicks? How do you know when they've had enough?
These tyres have done about 80 miles on the road (sensibly driven) and one trackday - about 50-60 laps of Snetterton (7 x 20min sessions)
They are off the rear of an E36 BMW.
This is the outside edge. Clear signs of having been affected by heat (they're a bit 'bluer' in reality than the camera phone picks up) and starting to get pretty rough along the outer 2-3 inches of the tread.
Stranger, this is the inside edge. It is smooth, almost polished along the edge between the tread and the sidewall. As if it has been rubbing against something. I'm pretty sure that's impossible; these are 16" wheels, I use 17" wheels on the road and I think 18s would fit too. Any idea what's caused that 'polishing'?
So, how do I know when it's time to buy new tyres?
But what about road-legal slicks? How do you know when they've had enough?
These tyres have done about 80 miles on the road (sensibly driven) and one trackday - about 50-60 laps of Snetterton (7 x 20min sessions)
They are off the rear of an E36 BMW.
This is the outside edge. Clear signs of having been affected by heat (they're a bit 'bluer' in reality than the camera phone picks up) and starting to get pretty rough along the outer 2-3 inches of the tread.
Stranger, this is the inside edge. It is smooth, almost polished along the edge between the tread and the sidewall. As if it has been rubbing against something. I'm pretty sure that's impossible; these are 16" wheels, I use 17" wheels on the road and I think 18s would fit too. Any idea what's caused that 'polishing'?
So, how do I know when it's time to buy new tyres?
Unless you have an accumulated body of knowledge about a particular tyre on a particular car for a particular use, there is no hard-and-fast rule about whether a tyre has had enough. Instead, you go by how well it works: whether, relative to when the tyre was new, the car feels as planted, composed and controllable. If there is an obvious degradation, the tyre is either shot or getting there. You can still use such tyres - they're great for practising on a circuit and getting comfortable with a car that is not working well, they just won't be fast.
Re the tyre in the image, you still have pretty sharp edges along the tread pattern there, which usually indicates that the tyre is fine.
You can use up a tyre in a single, heavy, intense session, or you can use it up by putting it through a lot of heat cycles, even of short duration.
As for the "polishing", it's hard to tell from the image, but that doesn't look like typical burnishing through bodywork rubbing. It actually looks more like virgin tyre that has not yet made contact with an abrasive surface - it's obvious that the "hinge" (corner where sidewall meets tread) has itself been only very slightly used.
Re the tyre in the image, you still have pretty sharp edges along the tread pattern there, which usually indicates that the tyre is fine.
You can use up a tyre in a single, heavy, intense session, or you can use it up by putting it through a lot of heat cycles, even of short duration.
As for the "polishing", it's hard to tell from the image, but that doesn't look like typical burnishing through bodywork rubbing. It actually looks more like virgin tyre that has not yet made contact with an abrasive surface - it's obvious that the "hinge" (corner where sidewall meets tread) has itself been only very slightly used.
Those look like new compared to the last set of 888s I threw out!!
Once on track they (especially 888s) tend to go into meltdown pretty quick and look like cr*p after that, but just keep an eye on the grip, I found that after a while I could feel that they just didn't cut it any more.
Once on track they (especially 888s) tend to go into meltdown pretty quick and look like cr*p after that, but just keep an eye on the grip, I found that after a while I could feel that they just didn't cut it any more.
I agree with what flemke says, but would also add that the wear rate across the tyre isn't as even as it could be, hence hardly touching the rubber on the inner edge and beginning to roll onto the outer edge. Could be you need a little more negative camber on the rear (if you have the option to adjust it). Driving styles can also affect the way a tyre wears too.
The "white/silver" "rub" does look to me like it has rubbed against something. It's hard to tell how far round the tyre it goes from that photo, does it go all the way round? You would expect it to if it's rubbing on the wheel arch. But the white colour makes me wonder, have you dropped it on the wrong side of a kerb? If the "rub" is only for part of the circumference of the tyre that could be one explanation - the white being white paint from a kerb. Just a suggestion!
The "white/silver" "rub" does look to me like it has rubbed against something. It's hard to tell how far round the tyre it goes from that photo, does it go all the way round? You would expect it to if it's rubbing on the wheel arch. But the white colour makes me wonder, have you dropped it on the wrong side of a kerb? If the "rub" is only for part of the circumference of the tyre that could be one explanation - the white being white paint from a kerb. Just a suggestion!
Sorry - the bit that appears silvery/white is actually a reflection because it's so smooth. It's actually a very dark blue and does run all the way round. I'm just not sure what it could be rubbing against that would leave such a polished finish?
The problem with the inner edge is only on the NSR tyre.
The problem with the inner edge is only on the NSR tyre.
I had my last set of R888s down to zero tread showing whatsoever and still they performed great in the dry.....when I got them replaced, I asked the tyre fitter to get on hack saw on to them so see what amount of rubber was still left and to my amazement there was still a 1mm or two......
It could be rubbing lightly on the shock absorber, I've seen that happen before on some cars. You would be surprised how much everything distorts under high loads on race tracks, especially tyres. With most UK circuits being anti-clockwise the NSR will be subjected to more stress than the OSR.
V8mate said:
Sorry - the bit that appears silvery/white is actually a reflection because it's so smooth. It's actually a very dark blue and does run all the way round. I'm just not sure what it could be rubbing against that would leave such a polished finish?
The problem with the inner edge is only on the NSR tyre.
The simplest thing way to get a handle on what may be happening is to rub some chalk or bar soap on the area that concerns you, then drive a bit. Gradually ramp up the different loads that you put on the tyre, checking after each iteration as to whether the white mark has begun to wear away. You can also look for traces of the white mark on the damper or wheel well or wherever.The problem with the inner edge is only on the NSR tyre.
If it is only on NSR then it could be either lots of right hand bends on a clock wise circuit or the shocker is on its way out and allowing more compression in that corner and pushing the suspension down further and causing the rubbing.
I would make sure the shockers are OK, maybe an excuse to replace with some adjustables if you haven't got them already (that's what I did).
My A048 did a similar thing and the car was sliding all over the place, under steer, over steer really good fun and enjoyed it immensely but not quick, I recently changed the rears and now it just under steers.
I would say that as they go off you will feel the car move about a lot more and not be as quick in the corners. 2 choices replace them for new ones or play with the existing ones then replace.
I would make sure the shockers are OK, maybe an excuse to replace with some adjustables if you haven't got them already (that's what I did).
My A048 did a similar thing and the car was sliding all over the place, under steer, over steer really good fun and enjoyed it immensely but not quick, I recently changed the rears and now it just under steers.
I would say that as they go off you will feel the car move about a lot more and not be as quick in the corners. 2 choices replace them for new ones or play with the existing ones then replace.
V8mate said:
Nick J said:
2 choices replace them for new ones or play with the existing ones then replace.
Given they've only done c.200 miles, I really hope that I get a few more miles out of them yet!Just make sure nothing is wrong with the car as suggested above and use the tyres until they are worn out, then look at the price of replacing and weight up if it is worth the money. If not try something else. I found the A048 to be worth paying the extra as the cormering is now superb.
At the other end of the weight spectrum I have done 12 days; 8 sessions each day, on a set of 888s on my 530kg BEC and they are only just becoming illegal.
Once warm, they do feel absolutely fine and any problems I do have can be put down to driver error, poor throttle control – back-end breakaway, or missing braking points – locking-up.
They have been through so many heat cycles they are blue from the outside to the centre, but without an ability to do back-to-back, timed-testing, on the same circuit in the same conditions with new and old tyres, I guess that most trackdayers would be unable to detect the point when the tyres are shot.
Now its nearly September, I just worry a little about the next day being a wet one, but again, my guess is that unless it deluges, things will not be so bad. The tyre performance really is that much greater than a standard road tyre.
At the end of the day, it is controlling the car at its limits that makes trackdays so much more pleasurable than driving on the road. If that limit is 1 second a lap slower, does it really stop the enjoyment?
Once warm, they do feel absolutely fine and any problems I do have can be put down to driver error, poor throttle control – back-end breakaway, or missing braking points – locking-up.
They have been through so many heat cycles they are blue from the outside to the centre, but without an ability to do back-to-back, timed-testing, on the same circuit in the same conditions with new and old tyres, I guess that most trackdayers would be unable to detect the point when the tyres are shot.
Now its nearly September, I just worry a little about the next day being a wet one, but again, my guess is that unless it deluges, things will not be so bad. The tyre performance really is that much greater than a standard road tyre.
At the end of the day, it is controlling the car at its limits that makes trackdays so much more pleasurable than driving on the road. If that limit is 1 second a lap slower, does it really stop the enjoyment?
V8mate said:
Nick J said:
2 choices replace them for new ones or play with the existing ones then replace.
Given they've only done c.200 miles, I really hope that I get a few more miles out of them yet!
I bet you will get another 400 track miles out of them.I replace mine when they look like this
V8mate said:
teabagger said:
You mention the car is an e36 but the wheel looks like an e46 model wheel. You may have a wheel offset problem.
Correct and correct. Is there a simple cure?V8mate said:
teabagger said:
You mention the car is an e36 but the wheel looks like an e46 model wheel. You may have a wheel offset problem.
Correct and correct. Is there a simple cure?Dont go too thick on the wheel spacers or the tyres could rub on the wheel arch!
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