Track tyre wear limits

[S1000roo]

Evening all,
I have a question about how low can you run the rubber on track tyres before you hit the deck or they pop.
I’ve been riding track for a year now. Started on road tyres, moved to super corsas and now on slicks. I now have a pile of tyres that I’m reluctant to bin because I think they may all have a day or 2 left in them. But I’ve been putting new ones on for track days when they get towards the wear limits just in case they get to the stage of loosing traction before the day is out.
I don’t think I’ve experienced tyres ‘giving up’ whilst pushing hard. Have had a few moments but I’ve put them down to rider error. I’m running in fast group. Not the fastest out there but not slowest either.
I was out a couple of weeks back and a guy in front of me in pit lane before we went out had a super corsa on the rear that was totally slick on one side and I would say well past slick, really couldn’t have been much of the tyre left!
So, how low can tyres go?

 

[Gobert]

2 days from a new rear Conti slick - still looks fine but the grip has gone by then.

 

[bmwbadboy]

There is no magic formula and tire wear depends on your pace.

Rear is pretty simple, there are 2 things to look for, wear on treads/holes and shape. If treads are near flat or it looks triangular, bin it.

Front is more difficult. Bob from FWR says he changes front every 2 trackdays, he is a fast fella.

 

[TheGodfather]

Agreed it's all subjective and depends on many things. I used to buy a lot of scrubs or flip tyres but now I'm swapping tyres that are better condition than the scrubs I used to get.
I ignore tread pattern and dimples on slicks, I purely go on profile/shape to make my decision.

 

[S1000roo]

Clear as mud. Ha ha. Thanks though. I’ll bare that in mind and learning the shape vs traction equation.

 

[r25sti]

i change my front every 3 to 4 track days and the rear goes once i start to get more rear slides. i can normally tell when the rears going to slide as i get a slight shoulder about 25 to 30 mm in from the edge. everyones different though. i run dunlop kr or moto2 slicks.

 

[fast_ryan]

Track Tyre Wear Limits

The wear markers on slicks are a useful indicator but they won’t tell you the whole story. You also need to look at the profile and shape of the tyre and its general wear. Depending on what tyre brand and compound you are using, and how hard you push, will also impact on whether your tyres will last several trackdays or if they will be finished after just a couple of sessions.

 

[Monners]

Its heat cycles that makes the difference, not the amount of rubber. If you have done more than three days then they are past their best and start to get sketchy if you are running fast group pace. In lower groups it doesn't matter so much and scrubs are not so risky. If the tyres have squared off or worn on one side then they are still fine to use if they have not done the heat cycles other than not turning so well or whatever but some brands are better than others as they get worn down. Pirelli and Metzeller are soft so they warm up quickly to be safer out of the gate but as a result tend to go off quicker as they wear down. Dunlops on the other hand are hard and take a bit of warming up to be safe (in the uk particularly) but they will perform all the way down to the wire canvas.

 

[TheGodfather]

I believe Dunlop's aren't susceptible to heat cycles. I might be wrong but know it's the case with at least one brand.

 

[Monners]

All tyres are susceptible to heat cycles unless there's some secret tyres that have been kept from me?! A few years ago Pirelli / Metz were particularly bad for losing grip after a couple of heat cycles, probably because of their soft compounds, maybe thats what you read? They were updated around the beginning of 2018 so now they dont really drop off that much different to other brands but retain the soft construction. I couldn't use them on the Panigale R because it would collapse the tyre but I like them on the BMW.

 

[Corkgsxr]

My chat with the dunlop man he says heat cycles dont matter a toss. It's down to how well a tire deals with heat. Let's say you start with 10mm of tire, wear 1.5mm off it that might be 30% of the wearable amount of the tires but because the remaining has less to deal with same heat and flex it feels like a tire that's 70% worn.

If you get what I mean

 

[TheGodfather]

Exactly, I thought it was Dunlop. Its even in their literature somewhere.

 

[Monners]

Thats really interesting and not something I have heard before. I'd love to get a bit more information on why it is not an issue with Dunlop like it is with other tyres. The compound is certainly very different; much harder than most others and you have to be a bit careful on the first few corners but they have always been my favourite tyre to use when the conditions are decent.
https://www.dunlopracing.com/faq/

 

[TheGodfather]

That's what I'd read before. And from reading it again it would seem that it applies to all brands. Either way I agree And Dunlop are my tyre of choice. Though the Bridgestone VO2's are pretty good.