Technology used to detect tyre wear

[kaustubr]

hello friends,
I was curious to know about the technology that the pit wall uses to detect the tyre wear on the car. Is it plain naked eye that judges the tyre wear or is there some technology that suggests the amount of tyre wear and the amount of rubber loss from the tyre?
thank you!

[Tim.Wright]

I've wondered this as well. Wear could perhaps be measured with a laser distance sensor given the amount of rubber which flies off them.

Degradation would be a bit harder... I assume they usea mix of temperature, optical slip sensors and accelerometers to create a "photo" of the tyre's operating point. And from this they asses the level of degradation.

It might be even simpler though. Perhaps they average the slip angle during each corner to see the rate at which it increases.

[riff_raff]

In reality, I don't think teams have an accurate method of measuring tire wear. More likely, they simply watch for changes in lap times, sector times, cornering speeds, etc.

[bhall]

http://www.f1technical.net/forum/viewto ... =6&t=12524

[Jersey Tom]

I was curious to know about the technology that the pit wall uses to detect the tyre wear on the car.

Radio technology.. when the driver is screaming that his tires are junk and lap times have gone to crap.

[MOWOG]

I think we would all be astonished at the volume and scope of telemetry these cars send back to the teams. Every aspect of the car's performance is monitored constantly in real time. IIRC, the teams have hundreds of engineers back at the factory analyzing every bit and byte of information as it is received.

I do recall one team - Lotus I think - that fitted some cameras and spotlights to the undertray of their car during free practice at a race last year trying to see just what it was the tires were doing out there.

But yeah, the driver screaming over the radio about how there is no front grip - and no rear grip either! - is probably a big part of it too.

[Dragonfly]

They definitely have IR/Laser temperature sensors for each tyre. Front are more obscure but the rear tyre sensors can be seen as small bulges on the car's floor in front of the tyres.

[Jersey Tom]

I think we would all be astonished at the volume and scope of telemetry these cars send back to the teams.

I think most here would be astonished at how limited some aspects of data collection are.

Are there IR sensors for tires? Sure, for measuring surface temperature. Some swear by it, some swear against it. But using a laser to try to measure tread wear? Exercise in frustration and futility IMO.

Not to mention, how relevant is the tread depth in and of itself? You can have tires with full tread on them and be junk.

Bottom line - just because it's F1 doesn't mean everything needs to be over-complicated and over-engineered. Lap times are the most direct measurement of performance fall-off.

[Tim.Wright]

Lap times are the most direct measurement of performance fall-off.

If they are driving to a target laptime, its a bit harder to assess.

I'm sure they are (at least attempting to) quantify tyre deg looking at the axle force/slip relationship for each lap. Easy enough to calculate with a gyro, accelerometer and a slip sensor. You do a long run on friday and correlate the laptime drop-off to your force/slip measurements and then try to use this in the race to help your strategy.

Obviously some corrections will need to be included, but since the tyres are so unpredictable, there is a lot of time to be potentially gained if you know the degradation condition.

[langwadt]

Lap times are the most direct measurement of performance fall-off.

If they are driving to a target laptime, its a bit harder to assess.

I'm sure they are (at least attempting to) quantify tyre deg looking at the axle force/slip relationship for each lap. Easy enough to calculate with a gyro, accelerometer and a slip sensor. You do a long run on friday and correlate the laptime drop-off to your force/slip measurements and then try to use this in the race to help your strategy.

Obviously some corrections will need to be included, but since the tyres are so unpredictable, there is a lot of time to be potentially gained if you know the degradation condition.

I imagine you could estimate the diameter of a tire by using a laser/camera combo like in an optical mouse looking at the thread to measure actual speed vs. rpm of the wheel

how the diameter changes with speed would probably tell something too

[Jersey Tom]

I imagine you could estimate the diameter of a tire by using a laser/camera combo like in an optical mouse looking at the thread to measure actual speed vs. rpm of the wheel

I just don't see any way you'd have the resolution to measure this well with a laser. For one, tread depth on these tires I'd estimate at.. 3mm at the most? Wearing off less than that over a tire run. You'll have whatever crap is stuck to the face of the tires as it's running.. being picked up, being thrown off. Between suspension travel, steer, suspension compliance, tire compliance under lateral longitudinal and vertical loads, velocity change.. how would you ever be able to get any sort of good measurement?

Just seems impractical. And like I say, even if you were to get a number somehow.. of what use is it? I'd rather have that engineer looking at something more directly meaningful.

[marcush.]

I don´t think it´s impossible:
There are tread depth indicators and you could measure to the ground of these with a laser beam .as the reference distance then you just read out the difference betwen the normal distance and when measuring down to the ground of the indicator.
and only count the steps falling into the predicted threshold eg you start with the measured tread depth and allow for the 3 mm to be worn away.A very cool thing would be to actually put a indicating paint on the ground of the wear indicator as soon as it´s not visisble to the beam it would stop reading out .
The challenge is of course the pickup as is the tread being not only shifted under sideloads but also the change in diameter under centrifugal and vertical load changes .You need not only a god sampling rate but also a good means of dressing up your measured data .....I´d say possible ,but not worth the hassle:
The tyre degradation -falling of the cliff may not be indicated by tyre physical mass loss....so the aim is to predict grip fade and that could be better investigated by tyre slip vs input ..a tyre losing grip will pull less gs at the same slip angles and speeds so you will see the drop off .Add to this your knowledge of live tyre temps it should be well possible to understand if your tyre is losing grip because of overworking (high temps) ,or not pushing hard enough ...or being worn off completely and losing temp because there is not much rubber on there anymore...

[turbof1]

Don't forget tyre wear is NOT even across the tyre surface. Just look at tyres from the chinese gp: at a particular strip of the tyre there were big chunks missing, while adjacent to that the tyre was brand new. Shoulders also have a very different wear pattern.

The best way to get a sence of tyre wear is to use the tyre. Combine laptimes, video images, final state of the tyres and feedback from the drivers, and you have a good idea of how the tyres behave.

[Jersey Tom]

There are tread depth indicators and you could measure to the ground of these with a laser beam .as the reference distance then you just read out the difference betwen the normal distance and when measuring down to the ground of the indicator

... I just don't see this happening.

[thisisatest]

For actual circumferential wear, there seems to be an easier way. just compare the wheel speeds with the GPS actual speeds to determine the tire diameter. you could run some fancy algorithm to factor in corner load, downforce, tire growth at speed, if you really wanted to. or you could just look for the relative changes.
as far as degradation "wear", I agree with Tom. just look at the lap times and listen to the screaming driver.