Tyre evolution

[marmer]

simple question might be a complicated answer.

as f1 tyres loose rubber and flick it all around the track does this affect the wheel diameter and ride height of the car surely it should with how precise f1 cars are made. if you loose 5 mill in ride height over a tyres life this would affect performance

[cramr]

I think the possible tyre change in radius is irrelevant compared with the weight reduction of the fuel they are burning, 105kg per race, around 2 or so per lap.

This weight change surely create a bigger effect on the car that the possible 5mm over 30 laps

[ChrisDanger]

Well a 5mm change in radius is about 1.5% difference. For a given torque the available propulsion force would change by this amount (smaller radius = greater force) and for one rotation of the wheel you would travel less distance the more wear there is by the same percentage. You can think of it like affecting the final drive ratio. So more wear, or a smaller wheel, would mean higher acceleration with a lower top speed. Also the larger the diameter the larger the contact patch (for vertical sidewalls), so you'd have more grip from a new tyre all else being equal (which it's not).

[hollus]

I once made the same question, thinking of top speeds in the days of rev limiters enforced in the rules. I was told that tire wear will account for 1 mm tops.

[marmer]

thanks

[Jersey Tom]

The total depth of tread rubber on a racing tire tends to only be 2-3, maybe 4mm. Wear will be somewhere less than that.

Lot of things are going on as a tire is raced. Wear absolutely will affect both loaded and effective radii. If inflation pressure changes as tire temperature goes up or down, that will also affect things. Likewise, you can have carcass degradation as well.

[marmer]

would have thought there was more depth than that based on the amount of marbles left

[ChrisDanger]

Yeah, I also thought there'd be more wear, thinking about the amount of marbles.

With a two stop race and an average of 1.75 mm wear, a total of 0.25 m³ of rubber would be generated, which is quite a lot. It's about a litre of rubber shed per tyre.