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Just curious
Macbeast - 26/3/09 at 12:17 PM

How do dragsters etc spin the rear wheels to burn off the tyres but yet hold the car without moving forward ?

Only academic question really - using a Pinto

blakep82 - 26/3/09 at 12:20 PM

they spin them up on a patch of oil or diesel don't they? seems a bit silly coz that would make them slippery, but i think thats what they do, and i think they do move forwards, but because its so slippery, they don't move much.
and maybe a line lock in the front wheels?

r1_pete - 26/3/09 at 12:21 PM

Mainly down to sheer torque to be able to break the tyres grip and then the power keep it spinning. They used to pump a bleach solution to hit the contact patch between the tyre and track, don't know whether they still do??

aka Keith - 26/3/09 at 12:21 PM

IIRC they use a line lock on the front wheels to hold them still.

blakep82 - 26/3/09 at 12:24 PM

The burnout

Example of a burn-out before staging at Hockenheimring, Germany. Note the amount of smokeWhen approaching the starting line (also known as the staging area), most racers will apply water (formerly thought to be bleach by spectators as it was dispensed from old bleach bottles) to the driven tires either by backing into a small puddle (the "bleach box" or "water box" or having it sprayed on. The car then exits the water and does a burnout to heat the tires, making them even stickier. Some cars have a mandatory "line-lock" which prevents the rear brakes from engaging when the brake pedal is depressed (which can be toggled on and off). This allows the car to remain stationary (with the brakes applied) without burning up the rear brake pads while doing a burnout. Cars in street classes (which must be street legal) are the only exception to this pre-race ritual, as the grooved tires tend to retain some of the water.

Gav - 26/3/09 at 12:57 PM

quote:
Originally posted by blakep82
Some cars have a mandatory "line-lock"


If i was going to be pedantic....

designer - 26/3/09 at 02:26 PM

They 'burn' on a patch of special detergent, to heat the tyres and make them sticky.

Macbeast - 26/3/09 at 05:33 PM

Very interesting - thank you.
As Mr Clarkson says - "There's no substitute for power "

clairetoo - 26/3/09 at 06:46 PM

quote:
Originally posted by designer
They 'burn' on a patch of special detergent, to heat the tyres and make them sticky.

Nope .......... just water
The technique on my drag bike was to roll past the water , then back into it . Select third gear , apply the front brake (just two fingers) and take all weight off the seat - at the same time placing ankles against the footrests
`Shock` the tyre loose with a quick dump of the clutch , then rock the bike slightly from side to side to warm the whole width of the 9" tyre .
As the bike starts to push forward , sit down and give it a lot more throttle , releasing the front brake at the same time , so as to finish of with a good rolling burnout (remembering to pull the clutch in without letting the revs die so as to avoid destroying the £2000 gearbox that self-destructs if driven , rather than driving )

Nothing to it , really

MK chippy - 26/3/09 at 06:55 PM

last time i was at santa pod one guy had a small lever that just locked the front brakes