I see conspiracies everywhere - question regarding tyres wear and safety

[imdying]

you will literally see the tyres turning to rubber dust if you are pushing the limits if tyre performance.If you are going att lesser speeds the tryes wont disapear so fast but will likely wear faster than on road rates

That's a point; I've been assuming your going to the track to do track type riding (i.e. not a rider training day just doing emergency stops and crap like that).

I don't know enough about track construction, but somebody else might know; is the surface itself harder on tyres than your typical Kiwi road (or is it all the riding)?

[Bassmatt]

Piece of cake, I'm as slow as a wet week, so if I can shred a tyre out there, so can you.

It's the sustained abuse that kills them, your average road tyre just wasn't designed to do laps.

OK that makes sense.

[Bassmatt]

Most places would expect you to exercise some common sense I suppose.

Fair enough but i would be highly pissed to be told i wasnt being let on the track when its not stated in their rules.
Technically 1.9mm of tread could rule me out for the last couple of sessions at HD. Seems a little harsh, especially when Im sure i will have to sign a waiver absolving them of any responsibility.
Nanny Hampton Downs?

[imdying]

Fair enough but i would be highly pissed to be told i wasnt being let on the track when its not stated in their rules.
Technically 1.9mm of tread could rule me out for the last couple of sessions at HD. Seems a little harsh, especially when Im sure i will have to sign a waiver absolving them of any responsibility.
Nanny Hampton Downs?

Yeah I'd be a bit miffed to, but I'd not make the same mistake twice. It's not in the same league as not being told about wearing a back protector (just for example, no idea if that is a rule), but would still suck.

Enjoy your track day

[Mystic13]

So racers use slicks for maximum contact with the track which gives maximum grip (when dry)?
Does a worn, i dont mean completely worn out, treaded tyre have more, less or the same grip as a not so worn treaded tyre on a dry track?
The reason I ask is:

" All treaded tyres must be worn no more 2mm above the minimum tread-depth indicators at the beginning of the day (if subsequent inspection during the day shows the tyre to be on or below the tread-depth indicator, access to the track may be denied)."

This is for Hampton Downs track days.
Seems like a good way to sell some tyres.
Flame away!

I'm pretty happy with the rule. Personally I don't want you inside me on a corner with bald tyres or a lack of tyre tread. I don't mind going for a slide on my bike but I'd be disappointed to go for a slide, because you went for a slide, because your tyres were not too happy.

And don't they just check at the beginning of the day? I haven't had tyres delaminate but when I've pushed the use too far I endd up with a belt of steel showing for 3/4 of the tyre.

Yout tyre wear at the track will also be determined by track temperature.

[Bassmatt]

I'm pretty happy with the rule. Personally I don't want you inside me on a corner with bald tyres or a lack of tyre tread. I don't mind going for a slide on my bike but I'd be disappointed to go for a slide, because you went for a slide, because your tyres were not too happy.

And don't they just check at the beginning of the day? I haven't had tyres delaminate but when I've pushed the use too far I endd up with a belt of steel showing for 3/4 of the tyre.

Yout tyre wear at the track will also be determined by track temperature.

Its their track and they can make whatever rules they want, I am just trying to understand the reasoning behind them.
The rule is 2mm above the min tread indicator so we are not talking about bald tyres.
I understand that tyres wear faster on the track than the road which suggests to me that grip is also better on the track than the road. if they are deemed too dangerous for the track then why are they ok for the road?

[davebullet]

You go try taking a bald tyre to a track, do some laps. You'll probably get halfway through the first session before canvas starts showing through. The track is super hard on tyres.

What he said. My road tyres get nice and warm with just regular riding. Can't imagine how long a badly worn road tyre would handle track (ab)use before it would let go on you.

[Bassmatt]

What he said. My road tyres get nice and warm with just regular riding. Can't imagine how long a badly worn road tyre would handle track (ab)use before it would let go on you.

So at what stage do you guys replace your tyres? I was under the impression i coulkd safely wear them down to the min tread indicator.
Im talking for the road now not track
I still dont really understand why a worn treaded tyre has less grip. I can see that it MAY begin to wear through to the canvas or steel or begin to delaminate, but the tread itself does not provide any grip. Or does it?

[boman]

It has been 5 years or so, since I cut up a bike tyre to see what was left after it was non warrantafitnessable. From memory there was about 3mm of rubber over the cap ply nylon. That was from the top of the wear indicator to the tyre case IIRC.

I replace my bike tyres, as soon as the get down to the wear indicator, or if i have a deep cut in the tread. My ass is worth alot more to me, than a $350.00 tyre.

Thats just my opinion.

[RideLife]

I'ld be more interested in, if that guy trying to carve up the inside of "my corner" has his tyre pressure sorted, in a zone that allowes his tyres to work properly.
Who cares what his tread depth is.

I put a Brand new Bridgestone on the front of the GT before my last race day. It only had 2mm thread depth total through the wear zone from New. Would have been interesting to see what HD staff said about the 'saftey' of that 'new' tyre on their track!

[MaxCannon]

HD is very tough on tyres.
It also tears up knee sliders, gloves, toe sliders, boots and leathers.
The surface is very abrasive but offers a ton of grip.

I don't know how you ride but if you are pushing around the track the wear on the tyres is visible.
Big chunks of rubber start melting off the tyre.

They will wear even quicker if your pressures are not set correctly or your suspension isn't setup optimally.

I got 11000 km out of a rear which included 4 track days (3 at HD and 1 at Puke). It still had some life left in it but once down to the treadwear indicators it's wet grip had decreased noticably.

Also worth noticing. A worn tyre is likely to have flatened in profile (squared off). Handling willl be improved by new rubber that has a better shape to it.

If everything is working correctly tyres should be the only part of the bike touching the ground.
Given they keep my ass from sliding on the road I like to look after mine and use good ones.

[Wannabiker]

There is more than one rubber compound in a tyre...the tread rubber is laid around a pre-formed donut of rubber impregnated weave / belts. The rubber used in the carcas construction does not have the same grip as the tread rubber. The tread rubber goes on looking like a slick..it is smooth. The whole thing is put into a heated mould with the tread groves standing out as a positive into the inside of the mould.

An inner tube type device is inflated inside the tyre and pushes the carcas and tread rubber outwards to fill the mould and imprint the tread into the tyre..the mould is heated, th erubber vulcanises and hey presto, out pops a tyre.

The wear indicators serve to warn that:
1. You are approaching a different type of rubber, with different road holding characteristics. Those that manage to square off a rear tyre close to the canvas will notice the rubber in the centre is a different colour black...it has more carbon black in it....
2. You are running out of useable grooves to disperse road water....