Generating Heat into Tires

GTO · Post 01 Mar 2007, 21:03

After reading news about preseason team testing, the most common issue seems to be cars adjusting to the new Bridgestone hard compound tires specifically generating heat into them.

I'm wondering

... since lack of heat in tires is such a problem & there's huge heat source (namely brakes & exhaust) so close, why can't heat normally vented from these sources be diverted & used to resolve cold tire problem? Perhaps a controlled shot of hot air directed onto tread area whenever it is needed? Perhaps some other transfer device or method?

tomislavp4 · Post 01 Mar 2007, 22:19

If FIA alows it why not, but I don´t think nthey will...

dumrick · Post 01 Mar 2007, 23:18

Also, i guess that the area around the wheels is heavily regulated and has to be kept free from devices. This historically was enforced to keep the formulas as open-wheelers, as opposed to sports cars.
The heat transfer that exists is mainly made trough the rims by heat conduction to the tyre walls and to the air inside and by convection by the side, but most of it is wasted, anyway.
What about placing a source of infrared radiation in an allowed area, directed at the rolling surface? The radiation would heat the tyres...

DaveKillens · Post 02 Mar 2007, 11:09

Ahh, this touches on one of my favorite pet theories. If there could somehow be some form of heatpipe from the brake disks to the tire carcass, things could be interesting. A driver blasts down a straight, and during this period the tires cool. Then the brakes are applied, and the heat is quickly transferred to the tire. On turn-in the tires are already nice and hot, giving maximum grip.

But back to the topic, one day we may see a laser mounted low on the sidepods (one firing forward to the front tires, and one rearward to the rear tires) to heat up the tires.........?

joseff · Post 02 Mar 2007, 18:21

Lasers? How big? The tyres need a whole lap to heat up with up to 550kW going through them. Maybe 300kW average? Let's say 5% is lost as friction, heating up the tyres. That means 15kW for a pair of tyres. 30kW total for a radiated heat system to warm up the tyres during the warm-up lap. And for the next 305km, the laser system will only be used for 3 more sets of tyres? so that means carrying paperweight for 290km.

Mikey_s · Post 02 Mar 2007, 18:59

It's a good question. I think the main reason that these two sources are not used to any great degree relates to practical aspects.

The temperature of the exhaust gases is extremely high and could lead to meltdown if incorrectly controlled.

As for heat from brakes; undoubtedly it does heat up the wheels, but the main problem I think is that when the brakes are in use the amount of heat generated is enormous and the main objective is to dissipate it asap away from the brakes rather than to put it elsewhere. Furthermore, the main problem as I see it is that you want the heat on the tread of the tyre and air is a pretty good insulator... so then you have to get the hot stuff from where it is generated to where you want it... complicated, but so are most good ideas. On the other side, i guess you would like the heat from the brakes to be on the tyres, BEFORE is is actually generated... hmmm that's a bit more difficult!

ginsu · Post 03 Mar 2007, 03:07

Yeah, one of the main problems is that rubber is not a good conductor of heat and neither is the air or nitrogen that they fill the tires with. Maybe they could inflate the tires with a gas that is a good/better heat conductor (not sure if one exists).

Also, one of the better tire models out there accounts for heat generation (Hallum Racing Enterprises). And much of the heat generated by the tire is done under braking, and also the amount of tread has a lot to do with this (i.e. more tread, more heat). This is due to generating greater deformation in the tread with greater tread depth.

DaveKillens · Post 03 Mar 2007, 06:50

I recall reading in a book by Paul Van Valkenburgh that they found out through some of the earliest instrumentation was that a tire started to reach optimum temperature cornering, but it took a small amount of time before the temperatures climbed up to this level. So in the earlist phases of cornering, the tires did not offer maximum grip. Wouldn't it be nice so that as soon as the driver started the turn-in, the tires were truly at 100%?
Not to mention when on new tires, where the first few laps have to be utilized in building up the temperature and pressures. Those are the obstacles. I think it's against the rules, but why not construct the tire with an additional layer (0.05 mm) of incredibly soft rubber that heated up like crazy, and scrubbed off after one or two corners?

persovik · Post 03 Mar 2007, 12:18

A good device for putting heat into the tires would probably be a microwave device, but any device to do so would be a band-aid.
Far better to address the actual problem, which is changes in car balance.
A car that is good to drive on cold tires will be able to generate the heat, a car that is bad on cold tires will have to be driven so slow that not enough heat is generated.
Putting extra heat into the tire before turn-in cuold of course have some benefit in corners that are quickly dealt with, but would be counter-productive in long corners where you need to start off slightly cold not to overheat the tire through the corner.