Maintaining tire temps

[captainmorgan]

In terms of thinking about what factors increase and decrease tire temps over a race, is it safe to assume that convection to air is the main, if not only factor that decreases temperature?

If that's the case, could teams control tire temperatures by a fairing covering a portion of the anterior surface of the front tires?

[Jersey Tom]

Definitely not. Two things:

1. Tire wear has a HUGE impact on undertread temperature.

2. HEAT IS NOT NECESSARILY GOOD.

[DaveKillens]

x

[The_Man]

Yes, it is interesting. There has been so much talk about the tyres being responsible for a thirds of the drag generated. if there is something in front of the tyres they can control the airflow. However, in that case the point of open wheeled racing may go under question. I'm sure some rules prevent the something in front of the tyres for temperature or aero control.

Can anyone confirm this?

[DaveW]

In terms of thinking about what factors increase and decrease tire temps over a race, is it safe to assume that convection to air is the main, if not only factor that decreases temperature?

If that's the case, could teams control tire temperatures by a fairing covering a portion of the anterior surface of the front tires?

I think your logic is sound. I believe NASCAR's use a driver-controlled "blower" in the front right wheel arch. If that is correct, then it is used when required to reduce "push" (understeer) by cooling the most loaded tyre if/when its temperature becomes too high.

I suspect that creative interpretation of existing regulations would ensure that devices intended explicity to control tyre temperatures would be excluded from F1 (e.g. the ubiquitous "movable aerodynamic device").

[DaveW]

In terms of thinking about what factors increase and decrease tire temps over a race, is it safe to assume that convection to air is the main, if not only factor that decreases temperature?

If that's the case, could teams control tire temperatures by a fairing covering a portion of the anterior surface of the front tires?

In fact, your post could be very significant.... Perhaps recent aero regulation changes and the constant search to improve the aerodynamics of F1 vehicles has affected tyre heat dissipation significantly. This could be one reason for wildly fluctuating performance this year (e.g. Button's broadcast complaints about uncontrollable oversteer).

[Roger the knife]

Surely the governing factor is still how much heat you're generating, not how fast it's dissipating. All F1 cars are very similar regarding the amount of tyre in the airstream, so rather than the Brawn losing tyre temp, it surely isn't generating enough, and relies on track temp too much to help.
Ross is a pretty smart cookie, so for them to be this stumped by something that is apparently so simple, indicates that generating the correct tyre temp for any given conditions is a lot more complicated than it appears...
I always imagined it was fairly simple, normal load, camber, tyre pressure, camber gain, steering geom, but there are obviously other factors involved in generating temp, so can any of the boffins come up with a more informed solution.

[DaveW]

Surely the governing factor is still how much heat you're generating, not how fast it's dissipating.

I agree with your sentiments, but stable (average) tyre temperatures will be reached when heat generated equals heat dissipated. I agree that the controls used to affect heat generation are reasonably well-known. Heat dissipation would presumably be affected by, amongst other things, the airflow around the tyres. I was merely suggesting that this fact may have been overlooked in the constant search for improved downforce & aero efficiency (L/D), especially given the aero regulation changes this year (tyres, I suspect, will not have changed).

[Jersey Tom]

Guarantee you these teams don't know what the "optimal" temperature is.

(Because there is none.)

[DaveW]

Guarantee you these teams don't know what the "optimal" temperature is.

(Because there is none.)

JT, you can't leave it at that! You make what appears to be a controversial post with no explanation. I see you hail from Akron, so you must know what you are talking about.

As one who doesn't pretend to understand the complexities of tyres & their properties, I'd be grateful for more insight, specifically about your introduction of the (apparently mythical) concept of an "optimal" tyre temperature.

[Jersey Tom]

Guarantee you these teams don't know what the "optimal" temperature is.

(Because there is none.)

JT, you can't leave it at that! You make what appears to be a controversial post with no explanation. I see you hail from Akron, so you must know what you are talking about.

As one who doesn't pretend to understand the complexities of tyres & their properties, I'd be grateful for more insight, specifically about your introduction of the (apparently mythical) concept of an "optimal" tyre temperature.

viewtopic.php?f=6&t=6988&p=114262#p114262

In addition to that.. sometimes you don't even really know what you're after. Do you want to increase tire temp to get more traction? I can think of examples where increasing grip.. on a racecar.. SLOWS lap time.

I'm even wary of all the driver comments. Drivers don't know it all. Suppose they go out, run some laps.. then there's a caution. They run slow. On restart they complain there's no heat in the tires and no grip. What do they know? How do they know that's a heat issue and not pressure for example?

Biggest point of all is.. nothing is "optimum" or "optimized" in racing. Nothing.

[DaveW]

JT, thank you for your quick response. You make many points, most of which I accept.

Tyres are undoubtedly complex & little understood (certainly by me). However, I think you must agree that the thermal energy accumulated in a tyre does affect its performance, and its average temperature is one way of describing that energy state (whether it is possible to quantify it in an absolute sense is another topic entirely).

If you do agree, then a tyre on-track will ultimately reach a relatively stable condition where heat input is balanced by heat dissipated (perhaps with caveats). My point was to suggest that the energy state of the tyre in a condition of equilibrium (I would still prefer to call it temperature) is likely to change if the airflow around the tyre has changed significantly, and perhaps that is something that has affected Button's ability to drive his vehicle competitively. BGP appear to be mystified by his sudden lack of balance, & I suspect they will be very aware of the parameters that affect the heat input side of the equation (suspension characteristics, downforce, centre of pressure, engine, brakes, tyre pressures, driving style, track temperature, etc.)

[Jersey Tom]

You'd think you might have some affect on tire temps with changing airflow. But then how do you separate out tire effect from aero?

Plus, its REALLY hard to definitively say in advance if you want hotter or colder tires.

Point being, IMO tire performance maps are impossible to nail down to "optimum" (i hate the word) points or ranges. Much more difficult than say an engine or aero map I'd think. With tire testing... it's impossible to control a lot of things.

Button's performance can be anything. Could be purely mental for all we know.

[marcush.]

You'd think you might have some affect on tire temps with changing airflow. But then how do you separate out tire effect from aero?

Plus, its REALLY hard to definitively say in advance if you want hotter or colder tires.

Point being, IMO tire performance maps are impossible to nail down to "optimum" (i hate the word) points or ranges. Much more difficult than say an engine or aero map I'd think. With tire testing... it's impossible to control a lot of things.

Button's performance can be anything. Could be purely mental for all we know.

According to my personal experience and looking at Jensons face I´d say he has lost confidence .

As for higher or lower tyre temps I´d say I would always want to have even temps front and rear (assuming same tyre charcteristics front rear).

Hm as for the temp /pressure thing ,I have to conclude you will loose a lot of grip with improper pressures no question.So the tyre temp discussion will be hugely dependant on just wich cold pressure you are starting on and how you account for different behaviour with a sticker tyre or a scrubbed tyre in terms of pressure buildup.
If you assume a grossly wrong pressure rise in your tyres you will be lost. testing being limited ,we may watch their usual process of evaluation carried into the race weekend.This would also explain just why during a race the car gradually
transforms from beeing nowhere to fastest car in the finishing laps.
Sometimes little things do make big contributions.Just imagine some medium in the tyre /rimchanging from solid to gaseous state with temps rising above 100°C..
To my mind it is quite entertaining to see all these pros unable to get on top of this basic problem.
Please correct me but as far as I know the phenomenon of grip loss due to temps and pressure has not been properly separated with dedicated testing. Of course this would make for a very very nice test programme to quantify the influences.

[Jersey Tom]

Please correct me but as far as I know the phenomenon of grip loss due to temps and pressure has not been properly separated with dedicated testing. Of course this would make for a very very nice test programme to quantify the influences.

Very correct. But its VERY hard to test in any sort of controlled manner.

Edit - That's not entirely true I suppose. Michelin developed a kinda empiral, kinda physical tire model that includes temperature effectss. Accuracy is... subject to interpretation.