Brawn tyre temperature

[brierleys]

I was just thinking about the Brawn tyre temps after we saw the drivers struggling to generate heat on Sunday. I just don't understand enough about it and wondered if anyone could explain it. Why do different cars generate different tyre temperatures when they appear to be extracting similar performance from the tyres? Surely the effort being put into the tyres by two different cars travelling at the same speed round the same corner is the same?

[Get Karter]

I remember the mention of different weight distribution in the Brawn, with less over the front.

[The Wookie]

Good question, weight distribution is a good suggestion as they seemed to struggle with the rears over the weekend.

I theorised that they'd produced a mechanical grip (rather than Aero) oriented design that allowed suspension geometry and kinematics that produce less tyre scrub than others. I must admit I couldn't imagine scrub making that much difference to tyre wear with the amount of grip they generate

[telecat]

The Brawn is essentially designed to make the maximum use of it's tyres by not putting as much mechanical load through them as others. In this they can run softer tyres better than other teams on the grid. Normally this is an advantage, note the performance drop off of the Red Bull's at Monaco. Where the tempearture is lower than expected the tyres are not "worked" as hard so do not heat up as much as the other teams. As races in Europe will get hotter from now on the Brawn's "advantage" will return.

[brierleys]

telecat said:

The Brawn is essentially designed to make the maximum use of it's tyres by not putting as much mechanical load through them as others.

How can the load be reduced without reducing the performance? Do they have a more efficient suspension setup that allows them to use less downforce (I assume this is where most of the load comes from)?

[scoobydude]

The car doesn't work it's front tyres particularly hard because it generates lots of it's downforce with it's diffuser not with bodywork aero.

[35secToNuvolari]

Not really helpful with the topic, and it's an old article, but it's interesting, and it mentions tyres. ha. http://www.grandprix.com/ft/ft00263.html

[navier_stokes]

scoobydude said:

The car doesn't work it's front tyres particularly hard because it generates lots of it's downforce with it's diffuser not with bodywork aero.

I don't think anyone on this board is in a position to make that statement :P

Besides, you want an aerodynamically neutral car, otherwise you get a pig handling car which the Brawn is clearly not. The aerodynamic centre is equally as important as the centre of mass (weight distribution) on the car.

[Alfie Noakes]

I had a good think about this.

I don't know!

[Nick M]

Alfie Noakes said:

I had a good think about this.

I don't know!

I saved myself the effort and went straight to 'I don't know!'

[scoobydude]

Let me put it a different way. The Brawn Diffuser creates a lot of downforce, but is tucked away beneath the car so it doesn't mess up the airflow over the car. The effect is you get a lot of downforce without suffering the undue amount of excess drag you would suffer by generating the downforce with body shell design and wings. the downside to this is the front of the car isn't pushed down and worked as hard as it would be if you were generating the downforce with the wings and limited body areo available. Therefore the Brawn relies on mechanical grip from the tyres to create front end grip and therefore a balanced car. In order for this to work the track temperature has to be higher than most of the cars on the grid need it.Brawn have a problem generating heat in their front tyres on cool tracks, just about all the other teams have a problem keeping their tyres from overheating on warm tracks. Adrian Newey designed the RB5 with pull rods in the rear suspension because he originaly didn't think the diffuser would be deemed legal and therefore had to think lateraly about how to keep the rear of the car "aero tidy" with the required downforce producing body aero in place. Now he has the diffuser in place, the RB5 will stick like st to a blanket but the front tyres will still have the problem with overheating unless a new front section has been designed in tandem with the new diffuser to reduce this effect.

[heebeegeetee]

Very good question by the OP, may i say, and i wish i knew the answer.

I thought it amazing to have to watch two racing cars constantly weaving along the straights to generate heat in their tyres. In 30 years i've never seen the like.

Also, did you see how the Brawns can run much closer to the car in front with less of a loss of performance? It certainly is one hell of a design.

And yup, hotter GPs beckon and i think we'll see the brawns at the front again.

[DrTre]

Surely things like aggression of getting into and out of a turn are factors, as are oversteering/understeering balance behaviour?

Two cars/drivers can go round a given corner in the same overall speed but at any point within that corner might be doing different speeds relative to one another. Total supposition but might the one with the least mean deviation from the overall speed be "working" the tyre less? If that's the way the inherently behaves then it's difficult to drive around that.

Like everything in F1 I imagine that what are similar time/speed differences translate to massive effective differences in keeping a tyre in it's optimum operating range.

[stevesingo]

scoobydude said:

the car isn't pushed down and worked as hard as it would be if you were generating the downforce with the wings and limited body areo available. Therefore the Brawn relies on mechanical grip from the tyres to create front end grip and therefore a balanced car.

If that is the case wouldn't the balance change with speed. The Diffuser will generate down force in proportion to speed, so at high speed there will be a lot of rear grip but at lower speed there will be less. The mechanical grip will not be as sensitive to speed changes. If your theory is true, the car would oversteer at low speed and understeer at high speed.

I agree with what was stated earlier, the aero balance is most important.

As to why they struggle with tyre temps, I believe tat it is because the car is more mechanically efficient than aero efficient. It will play into Brawns hand next year when the cars have to run with full fuel from the start.

Steve

[scoobydude]

stevesingo said:

scoobydude said:

the car isn't pushed down and worked as hard as it would be if you were generating the downforce with the wings and limited body areo available. Therefore the Brawn relies on mechanical grip from the tyres to create front end grip and therefore a balanced car.

If that is the case wouldn't the balance change with speed. The Diffuser will generate down force in proportion to speed, so at high speed there will be a lot of rear grip but at lower speed there will be less. The mechanical grip will not be as sensitive to speed changes. If your theory is true, the car would oversteer at low speed and understeer at high speed.

I agree with what was stated earlier, the aero balance is most important.

As to why they struggle with tyre temps, I believe tat it is because the car is more mechanically efficient than aero efficient. It will play into Brawns hand next year when the cars have to run with full fuel from the start.

Steve

You're assuming the geometry of the diffuser remains constant at all speeds. "theory" I like that

Edited by scoobydude on Tuesday 14th July 23:17

[zac510]

I'm sure if they wanted more heat in the front tyres they could increase the front wing angle and thus downforce split. But this must compromise some other area of the car and hence stop them from doing it.
That is, cold front tyres is the least worst situation

[scoobydude]

zac510 said:

I'm sure if they wanted more heat in the front tyres they could increase the front wing angle and thus downforce split. But this must compromise some other area of the car and hence stop them from doing it.
That is, cold front tyres is the least worst situation

Correct. If they increased the front wing angle and therefore applied the conventional thinking, the clever trick diffuser would lose a critical amount of the air being fed from underneath the car, it would then cease to work as designed, lose too much of its downforce and an almost certainly cause the car to oversteer when you least want it to, ie during cornering. So scrabbling from the colder front tyres encountered on cool tracks is a least worst option.

[anonymous-user]

An efficient diffuser moves the centre of pressure forward, so the more efficient diffusers give more front end aero grip for free than rear, not the other way round.

I suspect the Brawn has it's weight distribution designed in such a way as to be light on the front tyres, relative to the other cars out there, we are talking about very small differences in the cars here. It can take just a few degrees change to switch the tyres on and off this year, and that situation is compounded by the two tyre compound gap Bridgestone has been supplying at all the tracks except Monaco so far this season. The rest of the season they are reverting to having compounds just one step apart as was the case last year, so Brawn should gain back a significant chunk of its pace from this alone.

A significant amount of the heat generated in the tyres comes from the brakes, which is why at Silverstone the Brawns struggled for front end grip, they dont use the brakes much there compared to the rest of the season. The cars has been designed with the whole season in mind, so we'll soon see if they have the capacity to keep up front, or they get overtaken in the development race, we don't really know where they are at right now but the other teams have made some significant improvements relative to them, that might not be enough for them though if Brawn can switch the tyres on at the remaining races.

[DSM2]

scoobydude said:

zac510 said:

I'm sure if they wanted more heat in the front tyres they could increase the front wing angle and thus downforce split. But this must compromise some other area of the car and hence stop them from doing it.
That is, cold front tyres is the least worst situation

Correct. If they increased the front wing angle and therefore applied the conventional thinking, the clever trick diffuser would lose a critical amount of the air being fed from underneath the car, it would then cease to work as designed, lose too much of its downforce and an almost certainly cause the car to oversteer when you least want it to, ie during cornering. So scrabbling from the colder front tyres encountered on cool tracks is a least worst option.

Some very simplistic views here.

Not to complicate things, beyond general understanding, but the Brawn suffers from rear grip when it's cool, just as much as front, hence the massive graining on sunday.

BTW when could you suffer from oversteer, other than during cornering?

[brierleys]

scoobydude said:

zac510 said:

I'm sure if they wanted more heat in the front tyres they could increase the front wing angle and thus downforce split. But this must compromise some other area of the car and hence stop them from doing it.
That is, cold front tyres is the least worst situation

Correct. If they increased the front wing angle and therefore applied the conventional thinking, the clever trick diffuser would lose a critical amount of the air being fed from underneath the car, it would then cease to work as designed, lose too much of its downforce and an almost certainly cause the car to oversteer when you least want it to, ie during cornering. So scrabbling from the colder front tyres encountered on cool tracks is a least worst option.

I like this theory of compromise because I had been wondering why they don't just put more front wing on and generate more load, more heat and more grip.

As someone said earlier, I don't recall anyone ever having this sort of problem before and it made me realise that although I think I'm an expert spectator, I really know very little about car dynamics and many of the behind the scenes technicallities of the sport. Perhaps those in charge of the sport could consider providing better information for those of us that want to learn more. The current 'F1 for dummies' approach taken by the media for mainstream viewers just scratches the surface.