27 replies to this topic

[Roger39]

I was wondering what the most effective way of warming slick tyres is. I heard, I think it was Martin Brundle say a while back that weaving side to side didn't do much in the way of warming the tyres up. I know when I raced karts I used to go into the corners quite slow and then increase the power gradually and really try and load the outside tyres up. Seemed to work quite well but if there is anyone with some data to prove the effectiveness I would be keen to see it...

[DaveW]

An interesting question that I (for one) can't answer from detailed knowledge.

Not letting that get in the way, simple-minded logic would suggest that heat will be generated within the tyre by anything that works the the tyre structure without damaging the compound. I guess the latter is not essential, provided some compound is left and you are not interested in using the tyre after it has reached operating temperature.

With that logic, all the following would be expected to increase tyre temperature to a greater or less extent:

- rolling the tyre with an applied mean vertical load
- applying varying vertical loads (road & driver inputs)
- applying lateral loads (weaving/turning)
- applying longitudinal loads (accelerating/braking)
- running tyres at camber
- "toeing" the tyres.

The problem with weaving & turning is that the process is not necessarily stable, because loads are applied to both front and rear tyres in a more-or-less balanced way. It follows (again logically) that a "weak" tyre will heat quickly, whilst a "strong" tyre will heat slowly. I suspect that is why weaving is often not helpful. However, you may recall that Alonso, in his first stint at Renault, developed a unique method of loading his front tyres without over-loading his rears. Curious that I haven't noticed him using the manoeuvre recently.

Running a "toed" set-up is possible in theory, but it can cause other issues when it is used explicitly for heating tyres.

Tyre pressures are a variable, within reason & depending on construction.

Tyre damping varies with temperature. This would suggest that a good set of tyres is one that is matched to the target vehicle & its performance so that the tyres increase temperature quickly and evenly when cold & reach a stable condition such that heat lost equals heat gained at the compound operating temperature.

Now lets hope that somebody with better knowledge than I have will add to (or contradict) the above.

Edited by DaveW, 28 July 2009 - 05:46.

[DaveW]

Sticking my neck out still further, I would add the following to my initial post:

When rig-testing vehicles (on non-rotating cold tyres) I consistently estimate lower tyre damping "coefficients" when tyres have been "used". This suggests that, just like road tyres, slicks "run in" when they are first used. The characteristic provides a rational explanation (in part, perhaps) why new tyres are good for qualifying (they heat up more quickly than used tyres). Incidentally, tyre damping appears to be mainly hysteretic with only a small viscous component, which may be part of the reason that accurate tyre models remain elusive.

Vehicle suspension "set-up" can affect significantly the rate at which heat is input to tyres. Thus, for example, aggressive damper settings and stiff bars are often used for qualifying on slicks (when tyres are required to heat up quickly), whilst linear damper settings and soft (or no) bars are used to keep wet tyre temperatures low.

Finally, as you suggested in your post (& I hinted in my initial reply), a driver can (& does) affect the rate at which heat is input into tyres, and hence the average values of tyre temperature during a stint. This can become very obvious when tyres are not matched well to a vehicle, as is the case for current F1 tyres (I would contend).

[rolf123]

Weaving side to side in 2nd gear is indeed useless. But in 4th or higher it does work very well.

[DaveW]

Down force, I guess... What vehicle, Rolf?

[OfficeLinebacker]

I think the weaving is more for cleaning off the tyres

[primer]

I think the weaving is more for cleaning off the tyres

Weaving appears to be for the benefit of the driver. To get a feel for the amount of grip available from the tire.

[Petervl]

In my experience weaving works, as soon as there is some temperature (grip) in the tire; the heat is created by increasing the normal load and by creating lateral load. With cold tires there is no grip -> no lateral load -> no load transfer, thus reduced effect of weaving. Furthermore weaving without some grip leads to sliding on the tires which only creates surface temperature but no core temperature.

Longitudinal load transfer (braking, accelerating) can be used, but the difficulty is the uneven heating of the front and rear tires due to the additional energy put into the tires at the driven side, which can overheat the rears before the fronts are at working temperature.

Weaving to clean the tires seems unlikely to me, as normally the track is rather dirty off the rubber line.

regards
Peter

[Ross Stonefeld]

Weaving appears to be for the benefit of the driver. To get a feel for the amount of grip available from the tire.

Which might be useful if you went through the corners at the same speed you do on the recon lap, sawing at the wheel as you did so.

[Ben]

One example from a couple of weeks back (GT car (Dave will know which one...) so only moderate downforce effect with speed) One driver went down the backstraight at 200km/h in a straightline on his out lap, the other went about 120 km/h and weaved a lot.

Who's tyres got hotter faster? (we had IR sensors)

Ben

Edited by Ben, 28 July 2009 - 14:21.

[Petervl]

Ben, I would guess the faster car, given the way you pose the question . Interesting, as on open wheelers surface temperature tends to drop with increasing speed... so I find it difficult to make a conclusion on the actual heating of the core of the tire? But no doubt a GT car at speed over bumps generates quite some heat and could be more efficient than driving slow & weaving.

[Ross Stonefeld]

One example from a couple of weeks back (GT car (Dave will know which one...) so only moderate downforce effect with speed) One driver went down the backstraight at 200km/h in a straightline on his out lap, the other went about 120 km/h and weaved a lot.

Who's tyres got hotter faster? (we had IR sensors)

Ben

I think part of the problem is most people 'warm their tires' because they've seen it on TV or everyone else doing it, and just sort of aimlessly meander around the track. Maybe in an F1 car on a hot track and with tire warmers you can do things to maintain heat on the recon lap (they certainly give them the hurry up on the radio to do it) but in most underpowered single seaters on relatively mild days it doesn't seem to do much more than scrub any leftover junk on your tires. And even then it's not weaving, I alwyas found it better to turn the wheel a little more midcorner in one of the final bends for just a little bit of understeer. When Montoya was in CART and did it on a streetcourse late in the race, I think it was Long Beach, chunks of built up rubber were hitting the onboard camera from all the trash he'd accumulated behind the safety car

[Fat Boy]

I was wondering what the most effective way of warming slick tyres is.

Brakes do a good job of warming the tires. 1/2 of warming the tires is just to get them to operating pressures. If you use the brakes _a lot_ on the recon/warm-up lap(s) you can heat the wheel/tire assembly and get the pressures up to a reasonable value. You'll still be low, but maybe you won't be pounding off the ground like you would be otherwise. Loading the tires longitudinally probably doesn't hurt, either and getting the brakes to temp for the first corner is an added bonus.

Weaving side to side probably puts a little heat into the tires, but I agree that it's mostly a scrub thing. You have to be able to get the tire really loaded and deformed to really bring the temps up properly, and that's tough to do on a recon lap.

I used to love watching Alonso wrestle his car around on the recon lap. It was a pretty impressive display of car control.

[Ben]

Brakes do a good job of warming the tires. 1/2 of warming the tires is just to get them to operating pressures. If you use the brakes _a lot_ on the recon/warm-up lap(s) you can heat the wheel/tire assembly and get the pressures up to a reasonable value. You'll still be low, but maybe you won't be pounding off the ground like you would be otherwise. Loading the tires longitudinally probably doesn't hurt, either and getting the brakes to temp for the first corner is an added bonus.

Weaving side to side probably puts a little heat into the tires, but I agree that it's mostly a scrub thing. You have to be able to get the tire really loaded and deformed to really bring the temps up properly, and that's tough to do on a recon lap.

I used to love watching Alonso wrestle his car around on the recon lap. It was a pretty impressive display of car control.

But it can get him into trouble, like Nurburgring, when he spun on the recon lap.

Petervl yes the guy traveling faster in a straight line was putting more heat into the tyres. Having seen a bit more IR data it's clear that braking and a combination of vertical load and speed do the best job of heating the tyres.

Another area that can get you into trouble in this area is what the compound needs. If you have a soft compound on a single seater you can use the compound more before you get pressure in the tyre. This leads to strategies like running high cold pressures for qualifying to hit the hot pressure target earlier in a run when the compound's at its best. Unfortunately this isn't always the best approach with double stint endurance tyres for example because the compound itself needs more laps to heat up fully, so you're often better off waiting to build the pressure more progressively.

Ben

[DaveW]

Thanks, Ben. The use of high cold pressures for qualifying was something I have heard several times, but I didn't have a rational explanation for it.

[Fat Boy]

But it can get him into trouble, like Nurburgring, when he spun on the recon lap.

Details...Details....

[OfficeLinebacker]

I say that the weaving is for cleaning because I've heard NASCAR spotters say "clean the tires" when they mean for the driver to weave.

[gruntguru]

What are you guys on about? Please watch any episode of Top Gear for a demonstration of tyre warming technique.

[Tony Matthews]

What are you guys on about? Please watch any episode of Top Gear for a demonstration of tyre warming technique.

And heart-warming...

[Ben]

Details...Details....

Ben

[Jezztor]

In my opinion (no empirical data to support at the time of writing ;) the combination of weaving with longitudinal/vertical stimulation is important. The reason for this is that most races start from standing, and there's a wide misconception that it's just the SURFACE of the tyre that needs to be warm. Decent soak penetration through the carcass is important particularly for starts. This is analogous to the initial heat-cycle one puts a new performance brake disk through. My (potentially flawed) logic would suggest that heat generated in the sidewalls from weaving would conduct to the carcass and help with a more thorough heating process over the course of, say, a recon lap.

PS - Hi to all the oldbies, this is my first visit to "AtlasF1" in 4 or 5 years...

[gruntguru]

Hi to all the oldbies, this is my first visit to "AtlasF1" in 4 or 5 years...

They're all gone. Only us newbies here now.

[Jezztor]

They're all gone. Only us newbies here now.

Sorry I totally misphrased that; hi to EVERYONE

[jeremy durward]

Hi guys, any hints on warming tyres for hillclimbing?... or should i just give up try and clean the tyres with the burnout and just get on with driving

[gruntguru]

Sorry I totally misphrased that; hi to EVERYONE

Hi Jezztor. That wasn't a reproof just another poor attempt at humour.

[Tony Matthews]

That wasn't a reproof just another poor attempt at humour.

Made me smile...

[cheapracer]

Hi guys, any hints on warming tyres for hillclimbing?... or should i just give up try and clean the tyres with the burnout and just get on with driving

Hey Jeremy, long time no see.

You can do linelockers etc but don't you worry you have warm rears and cold fronts?

[jeremy durward]

Hey Jeremy, long time no see.

You can do linelockers etc but don't you worry you have warm rears and cold fronts?

yeah it has been a while... lack of my own internet connection:(

yeah i do worry about that a bit, i try and put some load through the fronts by being on the brake and turning back and forth but i don't think it does much beyond just cleaning the tyres.