Cold tyres.

[Adam43]

Warm tyres give more grip than cold tyres. However what opportunity is their to warm tyres on a Sprint or Hillclimb? Do sprinters chose tyres that work better cold or does everyone have tyre warmers(!). Or are there burn offs as in drag racing?

What is the form in Sprinting and Hill Climbing?

And then there is brake temperatures.

Is the cold tyre thing part of the fun?

[Steve Wilkinson]

Originally Posted by AdamAshmore

Warm tyres give more grip than cold tyres. However what opportunity is their to warm tyres on a Sprint or Hillclimb? Do sprinters chose tyres that work better cold or does everyone have tyre warmers(!). Or are there burn offs as in drag racing?

What is the form in Sprinting and Hill Climbing?

And then there is brake temperatures.

Is the cold tyre thing part of the fun?

Let me deal with this list of questions in order:

1. MOST venues allow tyre warming (i.e. spinning up the rears and then hard braking to put some heat into the front tyres and the brake pads) although where for instance the start for a sprint is actually on the race track then tyre warming is NOT allowed. There is always a designated area in which you can warm up the tyres; doing so outside of this area is frowned upon.
2. BMTR provide a full range of compounds for the Speed Event competitors.
3. Tyre Warmers are ILLEGAL.
4. Cold Tyres are not part of the fun, they are part of the challenge!
5. The application of tyre softening chemicals does occur but can reduce the life of said tyres.

Watching one of the big V8 single seaters warming up the tyres is certainly a crowd pleaser, although I am not quiet sure why they need to do it so many times. After all once they have spun up and put some heat into the rubber they then have to be lined up on the start and await the green light. During this time the tyres cool down at a rapid rate.

[Adam43]

Thank you.

Although challenge and fun are quite often interchangeable. The former producing the later

[Dennis.Doyle]

Originally Posted by Steve Wilkinson

...
5. The application of tyre softening chemicals does occur but can reduce the life of said tyres.

...

I thought the use of chemical tyre softeners was prohibited, or is that overridden somewhere else?

BTW Agree wholeheartedly that cold tyres are a challenge - the second lap of a 2-lapper is always more fun.

[b1ackcr0w]

Originally Posted by AdamAshmore

Warm tyres give more grip than cold tyres. However what opportunity is their to warm tyres on a Sprint or Hillclimb? Do sprinters chose tyres that work better cold or does everyone have tyre warmers(!). Or are there burn offs as in drag racing?

What is the form in Sprinting and Hill Climbing?

And then there is brake temperatures.

Is the cold tyre thing part of the fun?

q1. Driven Wheels, About 15 yards before the start. Other wheels, the first corner

q2. Tyre Warmers are banned - a very soft compound with low melt point is used instead.

q3. sort of.

q4. yes, traction is for wusses.

[b1ackcr0w]

BTW - I also thought compound softening adgent were banned. Can anybody shed light from the hallowed tome of Blue as to what is legal and what ain't?

[Hitech]

As far as I am aware tyre softener in speed events are allowed, but are of very dubious advantage. One of the front running single seater drivers in hillclimbing used it last year and had some phenominal start times around 1.6 seconds for the first 64ft, but the next few corners were 'interesting' until it had worn off, so it was swings and roundabouts really. And as has been said it will shorten the tyres useable life.

[DaveK]

Originally Posted by Hitech

As far as I am aware tyre softener in speed events are allowed, but are of very dubious advantage. One of the front running single seater drivers in hillclimbing used it last year and had some phenominal start times around 1.6 seconds for the first 64ft, but the next few corners were 'interesting' until it had worn off, so it was swings and roundabouts really. And as has been said it will shorten the tyres useable life.

Tyre softener was banned last year in the blue book pg68 common regs for competitors, article e12.9.5 'unless permitted under sporting regs the use of chemical tyre softners is not permitted'

It was used in 2005 on a certain car, but the near 70% rear weight distribution/ and start technique also helped.

As far as i'm aware non of the top10 used it last year.


Dave

[jonners]

Cleaning the tyres on the driven wheels with a practice start in the so call tyre warming area is worthwhile especially at muddy venues but I don't believe that the tyres really get that warm.

The top surface will get warm because of the friction etc but not to the extent that you'd think. Getting the air inside hot is what you need and that doesn't happen staight away.

And if tyre warming really worked god help you at the first corner if the fronts are still cold...

OR - having said all that - ask BMTR about crossply racing tyres - heating up radials quickly is difficult and some of the quick guys run extreme camber just to get the tyres warm. On the other hand crossplies - which will be ruined by lots of camber - heat up much more quickly because the way the plies run across the tyres mean that when the car rolls forward the plies rub against each other and generate heat.

Running crossplies sounds retrograde but it's the best kept secret in speed events

Question is - do the top ten guys use them??

[DaveK]

The top 10 pretty much use radials, i think alot of development has gone into the radials to make them suitable for the current carbon chassis cars. I don't think the charecteristics of the crossply tyres suit the ultra stiff chassis setup of the latest cars

Tyre warming/cleaning is also about getting the driver into a state of mind to prepare for the run as well

[kelvinjouhar]

Spinning the rear tyres obviously warms them a little, but whether it is enough to make any appreciable difference to your start time is debatable. When I drove the Pilbeam MP82, I would always spin them a few times before the start. For the last 2 seasons, driving the Gould GR37, I do not spin them any more ....Why ? Because the clutch is quite fierce, and the engine needs to be kept above 3500 rpm, and when I first drove the car and was spinning the wheels, I occasionally stalled it going to the line, and my co-driver Peter Smith was getting more exercise than he wanted, bringing the battery trolley to re-start the car !!

Anyway, my start times at Gurston are occasionally better than his, and always pretty close and he spins them up a few times - so I don't think it makes too much difference....Having said that, I agree with those drivers who sometimes say that they do it to get psyched up for the run - that is why I used to do it in the Pilbeam....each to his own !!

Regards
Kelvin

[Turby]

My thoughts on tyre warming extend to
a) hope for a red flag and a re-run
b) double enter the car and go second

[jonners]

Originally Posted by Turby

My thoughts on tyre warming extend to
a) hope for a red flag and a re-run
b) double enter the car and go second

As for b) I've deprived my Dad of a few runs due to damaged machinery so he now insists that I run second - so the plan worked out quite nicely...

[b1ackcr0w]

Startline marshals will tell you that on a warm, dry day, they get hot enough to make them too hot to touch.

[Dennis.Doyle]

Originally Posted by b1ackcr0w

Startline marshals will tell you that on a warm, dry day, they get hot enough to make them too hot to touch.

That sounds like a useful advantage as I guess you carry a higher average temperature most of the way to the finish.

Maybe another variable is over-heating the clutch? I see Alan Stanniforth’s book suggests allowing 20-30 minutes for heat dissipation, but perhaps that just applies to organic clutches?

Presumably, those with traction control, telemetry, pyrometers & data from test days have the definitive answer on this? I would love to know it though my clutch, gearbox, diff & driveshafts might disapprove.

I notice that Adam also asked about cold brakes. Since soft pad material gives more friction when cold I’d say it’s not a problem (I use Marina ones myself, but then I don’t ask a lot of them). However, I thought carbon brakes needed to be hot to work properly. Is this true?

[ben240z]

Warm the tyres to phsyc the driver up and please the spectators. I use carbon metalic pads and they work straight away even to the point of locking up all 4 wheels braking for the karousel. But then slowing 1000kg of car you would expect the pads to warm up quickly.

[Steve Wilkinson]

A few years back Patrick Wood persuaded the Bugatti Owner's Club to allow him to do some experiments during a Saturday Practice day at one of the hillclimb rounds at Prescott.

Firstly the tyre temperatures were taken in the Paddock.
Next Patrick drove down to the track and got ready for his run. The tyre temperature was again taken.
Patrick then did a series of 'burn-outs' and the tyre temperatures were again recorded.
Patrick and the MP58 were then pulled back down the track and he went through the tyre warming exercise, was lined up and when the green light came on rather than accelerate away the tyre temperatures were again taken.
This was repeated for all of Patrick's practice runs.

The findings of all this were that no matter how many tyre 'burn-outs' you did the tyre temperature would fall away dramatically during the wait for the green light.

After the exercise Patrick tended to do fewer 'burn-outs' however they were more extended. He also liked to get away as soon as the green light came on to maximise the temperature retention in the tyres.

In the final analysis it is what the individual driver believes is the best method that counts, after all it is the psychological advantage that matters.

[webbo]

Originally Posted by ben240z

But then slowing 1000kg of car you would expect the pads to warm up quickly.

Your car weighs 500 kilos Ben...............that makes you err heavy !

He he couldn't resist that one

[ben240z]

get back to your gardening

[webbo]

Originally Posted by ben240z

get back to your gardening

Getting bored gardening