When is a tyre too worn to race on?

**David.Hicks** · 28 Aug 08, 08:44 PM

This thread made me wonder whether the tyres on my bike are OK are not? ... Tyres?

Anybody have any simple guidelines on tread depth etc.?

**998gsb** · 28 Aug 08, 08:45 PM

when you fall off at the first corner you come to....

**zimbo** · 28 Aug 08, 09:02 PM

It's got nothing to do with wear really David, it's all about heat cycles. Most of our tyres show little measurable wear to the tread when we change them. If your tyres are looking at all worn they'll be well past their best grip wise, the front runners are changing tyres every 9 - 12 heat cycles (one heat cycle being a single track session). having said that, as a novice you're unlikely to be pushing the tyres as hard as they do . . .

**David.Hicks** · 28 Aug 08, 09:27 PM

The tyres on my DD bike are clearly part-worn - I suspect they have been used just on the road.

Should I get new tyres now? Here's my plans for the coming few weeks:

Shakedown track day somewhere in the next 2 weeks
Friday 19th Sept ACU Test Day at Snetterton
Saturday 20th Sept DD day at Snetterton - 2 DD races + 2 all-comers races
Sunday 21st Sept DD day at Snetterton - 2 DD races + 2 all-comers races

**Rattler** · 28 Aug 08, 09:32 PM

Its a tricky one really, I'll use 4 sets this year, that's for races, qually, practice races and trackdays too.

Having raced on Diablos for almost 4 seasons now, I reckon that I can get 2 full race meetings out of a set and also cover practice etc on effectively one set during the period around these 2 race meetings. When they get worn they start to move around and slide a bit, but nothing silly and its all quite progressive and gradual.

But what I have been able to do this year is utilise a spare set of wheels and use my older Diablo tyres for practice and trackdays after I've stopped using them for the DD races.

For example, at Snett, I'll race on Saturday as well, but use old tyres then and save the decent ones (that have only done the long Donny race) for the Sunday qually and racing.

I've made the mistake in the past of using the best of the tyres for non-DD races and trackdays. And I know I don't push anywhere near the pace I would when racing. This way if I don't get any big slides from the tyres in practice, I know I can push harder during the proper DD race too.

I could probably get away with 4 rears and 3 fronts across the year at a push. Maybe others can get away with fewer? But I'd like to get to Cadwell knowing I've got decent grip on the race tyres.

**Rattler** · 28 Aug 08, 09:34 PM

Quote:

Originally Posted by David.Hicks

The tyres on my DD bike are clearly part-worn - I suspect they have been used just on the road.

Should I get new tyres now? Here's my plans for the coming few weeks:

Shakedown track day somewhere in the next 2 weeks
Friday 19th Sept ACU Test Day at Snetterton
Saturday 20th Sept DD day at Snetterton - 2 DD races + 2 all-comers races
Sunday 21st Sept DD day at Snetterton - 2 DD races + 2 all-comers races

It depends how worn they are really, but I'd probably stick with the ones you have for the trackday and ACU day. Then switch to new ones for the Saturday - scrub them in in Saturday qually and they'd be sorted for the races on Sat and Sun.

**Paul68** · 28 Aug 08, 09:35 PM

Good luck on finding any H-rated Diablos at the moment....

Word is that there may be some in time for Snet, but sod all use if you want to scrub them in before then.

Having said that, a 583 should get a couple of races out of cast offs from the Gucci class....

Wish I had a 583 still :-(

**zimbo** · 28 Aug 08, 09:40 PM

Quote:

Originally Posted by Rattler

It depends how worn they are really, but I'd probably stick with the ones you have for the trackday and ACU day. Then switch to new ones for the Saturday - scrub them in in Saturday qually and they'd be sorted for the races on Sat and Sun.

That's pretty sound advice actually! I'd go with that, provided you can get hold of a new set of Diablos for Snet. They only take about 3 laps to scrub in, so you can do that Sat in qually!

**Earkle** · 28 Aug 08, 10:02 PM

sorry to point out the obvious fella, but have you asked the guy you bought the bike off of about the tyres? the might have only done one cadwell trackday?!? or a couple mallory? also how old are the tyres??You have prob done it already, other than that, as it's your first day fella, i'd go with ratlers advice, BUT, only buy new tyres for snet if your not comfortable on them, not coz your worring about heat cycles, I.E. i don't think stoner would care, if he did a guest race, he's still be out in front, lol!!!

**Imola Duke** · 28 Aug 08, 10:25 PM

Quote:

Originally Posted by Paul68

Good luck on finding any H-rated Diablos at the moment....

Word is that there may be some in time for Snet, but sod all use if you want to scrub them in before then.

Having said that, a 583 should get a couple of races out of cast offs from the Gucci class....

Wish I had a 583 still :-(

Is it really that bad ? I need new tyres! or decent part worns.. any available ??

**Lin** · 28 Aug 08, 11:48 PM

If you have doubts - change them. Otherwise it will be in your mind when racing anyway.

**Carbon749** · 28 Aug 08, 11:58 PM

Slightly off topic, but, a mate of mine rides with slicks on the road in good weather. His view point is that as long as he keeps the wheels rolling then you can not tell if the tyres have tread or not

Just do not stop next to a police car

**Tasminracer** · 29 Aug 08, 12:28 AM

<LOL> im really not the person to ask that question... with a set of slicks for the tuscan coming in at around 1k and an ideal maximum life of about 3 hours I probably double that, apply lots of tyre softener and change them when the canvas starts to show!!!

Ideally you should change them when your lap times start to drop off. All tyres go through a cycle, warming up, ideal phase and then drop off.. If your a consistant rider and record all your lap time, you should notice that as the sessions progress the lap time in the ideal phase will start to creep up, and they will start to drop off earlier.. you may also find it takes longer to get in to the sweet spot as well.

obviously if your fairly new to racing, or learning a circuit your lap times may not be consistant enough to monitor it that well, but its always worth recording for each session

1) start tread depth & pressure
2) end tread depth & pressure
3) lap times
4) rider comments on the laps.
5) track and tyre temps ( across the tyre)are also helpfull to see whats going on.

If you just starting out, and running slicks, i'd change them before they get to the bottom of the tread depth markers..

G

edited to say Just noticed your probably talking treaded tyres..

As has been said tread depth isnt a good indicator on a treaded tyre... I've got sets of Kumho ( control tyre) of the other car that still have maybe 10mm tread, but are totally Fubared as they have gone hard through the heat cycles..

you need to go by feel and lap times.

**Matt-T28** · 29 Aug 08, 05:19 AM

I'm finding that a new set will do 2 race days and a trackday or two if i'm really lucky or they have been out in the rain in a race etc. Pembrey meeting gobbled a set of tyres in 2 x qually and 4 x races, they were absolutely knackered but the set i have in now have done brands (some wet use) meeting and donny and they have a trackday left in them.

hope this helps mate.

**Freak** · 29 Aug 08, 05:56 AM

Quote:

Originally Posted by Imola Duke

Is it really that bad ? I need new tyres! or decent part worns.. any available ??

Steve,

We've got some part worns from memory, I know I'll be swapping to a new set at Snett anyway so I'll have a pair on wheels there

Jon