Reduce tires pressure by increasing wheel temperatures?

[Chuckjr]

Why not monitor the internal tire temp and pressures at all times while the car is driving on track? Seems that would be the fairest solution.

[Nickel]

Why not just let the teams run whatever tire pressure they want?

[Sevach]

Somewhat ironic that at least in FP we are seeing more tire failures than ever after Pirelli decided to enforce something to protect them.

[Edax]

You should link the article in question, because it sounds pretty much like a mixed up journalist.

Yeah pressure increases with an increase in temp

I was wondering if some teams found a way to increase the volume of the air in the tyre. The only way to do that would be get the rim to expand and for that you would want to heat the wheel up. I just don't know if it would be possible to build a wheel that can expand enough to increase the internal volume to an extent that the increase in volume provides a sufficient decrease in tyre pressure.

I think it would be difficult to do with thermal expansion alone. you basically only have the rim to work with. Any higher expanding material than magnesium alloys would impose a severe weight or strength penalty.

One thing I could envision is to span a membrane inside the circumference of the rim. This would create a cavity, which interfaces with the main volume by a flexible membrane. By keeping this cavity under reduced pressure you could theoretically control the amount of flex of the tire under loading by the ratio between the two volumes, the pressure differential and the elacticity of the membrane.

I guess that would give a similar advantage as lowering the tire pressure, without actually lowering the tire pressure.

[rjsa]

Aren't the tyres assembled on the wheels by Pirelli? Because until the last time I did a pit walk the tyre providers would have a box dedicated to them where they would to the assembly and balancing for the teams.

[Edax]

Aren't the tyres assembled on the wheels by Pirelli? Because until the last time I did a pit walk the tyre providers would have a box dedicated to them where they would to the assembly and balancing for the teams.

I would guess so. I remember that Ferrari in the past had some problems with the tires spinning on the rims which was told to be caused by them delivering the rims to Bridgestone extremely late and not having enough time to get the lubricant to settle.

[bill shoe]

Why not just let the teams run whatever tire pressure they want?

Within limits, if you reduce pressure you get larger contact patch which gives more overall grip. However, reduced pressure reduces the load capacity of the tire which means you could overheat it and/or overstress it easier. Tire failures are safety risks, and they make Pirelli look bad as if they can't make competent tires.

[bill shoe]

Maybe use wheels with hollow spokes and fill the spokes with some kind of closed-cell foam. Somehow arrange the foam so it has a non-linear compression response, i.e. you want it to suddenly collapse right after it gets a little over the min tire pressure, this keeps tire pressure close to min as the tire and air heats up. Yea easy to say hard to do. Just slowly trying to zero in on the tricks that could be in play here.

[Nickel]

Why not just let the teams run whatever tire pressure they want?

Within limits, if you reduce pressure you get larger contact patch which gives more overall grip. However, reduced pressure reduces the load capacity of the tire which means you could overheat it and/or overstress it easier. Tire failures are safety risks, and they make Pirelli look bad as if they can't make competent tires.

Solution: pirelli recommend a tire pressure and record each team's chosen tire pressure setting. If failure occurs, point finger and say "we told you so". Teams will not deliberately choose a pressure that leads to tire failure as this leads to zero points on race day. To suggest the teams will deliberately set themselves up for failure is madness.

[Paul]

Red Bull design chief Adrian Newey spent the Belgian Grand Prix worrying about the safety of drivers Sebastian Vettel and Mark Webber because of tyre problems. Remember this?

[Nickel]

Red Bull design chief Adrian Newey spent the Belgian Grand Prix worrying about the safety of drivers Sebastian Vettel and Mark Webber because of tyre problems. Remember this?

Yes, I'm not sure what it proves... If anything, it somewhat proves my point. They ran a less than optimal first stint to get around their problem, combined with raising tire pressure to reduce the risk of a blowout.

They made a decision. If they didn't think the tire would survive, they could've changed the camber settings and started from the pit lane. Instead they finished 1-2. Gamble and win. Had one or both cars suffered a failure, I bet they wouldn't have exceeded camber recommendations again, and pirelli could've said " told you so "

[mrluke]

Red Bull design chief Adrian Newey spent the Belgian Grand Prix worrying about the safety of drivers Sebastian Vettel and Mark Webber because of tyre problems. Remember this?

Yes, I'm not sure what it proves... If anything, it somewhat proves my point. They ran a less than optimal first stint to get around their problem, combined with raising tire pressure to reduce the risk of a blowout.

They made a decision. If they didn't think the tire would survive, they could've changed the camber settings and started from the pit lane. Instead they finished 1-2. Gamble and win. Had one or both cars suffered a failure, I bet they wouldn't have exceeded camber recommendations again, and pirelli could've said " told you so "

If the tyres failed it would have been a big news story about crap exploding pirelli tyres and RBR would do exactly the same at the next race.

[1158]

I think it would be difficult to do with thermal expansion alone. you basically only have the rim to work with. Any higher expanding material than magnesium alloys would impose a severe weight or strength penalty.

One thing I could envision is to span a membrane inside the circumference of the rim. This would create a cavity, which interfaces with the main volume by a flexible membrane. By keeping this cavity under reduced pressure you could theoretically control the amount of flex of the tire under loading by the ratio between the two volumes, the pressure differential and the elacticity of the membrane.

I guess that would give a similar advantage as lowering the tire pressure, without actually lowering the tire pressure.

I was thinking about something like that also but 2 things made me pause.

First it cannot be something that is easily noticed, Pirelli would see it when mounting the tyres and get the FIA to stop it right away.

Second the regs forbid it. 12.8.3 A complete wheel must contain a single fixed internal gas volume. No valves, bleeds or permeable membranes are permitted other than to inflate or deflate the tyre whilst the car is stationary.

That was why I was thinking it has to be something with the wheel expanding. The more I think about it though the more I think we are getting a little too cute. As was suggested earlier the teams are probably heating the hell out of the wheels before they put them on the cars to keep the pressures high. Once the tyre warmers are gone and the cars are rolling the wheel temps probably start coming down pretty quick, dropping the pressures.

[bill shoe]

But all the teams are doing that, yet the rumor claims that once all the cars all settle into race pace, two teams have lower running tire pressures.

[hardingfv32]

Assuming appropriate load capacity.... Does lowering the tire pressure decrease tire temps ? Why/How?

Brian