throttle blip - on a motorbike

[woodyracing]

Im not a biker or anything but i keep hearing motorbikes blipping the throttle on the downchange, is this for the same reason as heal and toe in a car ? (ie matching engine revs with the lower gear).

[Dave Brand]

Originally posted by woodyracing
Im not a biker or anything but i keep hearing motorbikes blipping the throttle on the downchange, is this for the same reason as heal and toe in a car ? (ie matching engine revs with the lower gear).

That's the reason I do it.

[woodyracing]

ah ok,
I dont hear many road cars doing it though, which is suprising with all the boy racers about

[sunbeam73]

thats because their bass tube subwoofer sub drivers 1300W quad nad sub amplifiers prevent you from hearing it.

[woodyracing]

heh, true

[Chris Griffin]

It's also a lot easier to blip on the downchange on a bike than it is to heal n toe a car. I reckon you'd see a lot of panel damage if the Johnny cum Latelys started to practice it!!!

[woodyracing]

>>Johnny cum Latelys

who ?

[Chris Griffin]

aka Boy Racers, Nova drivers, or indeed anyone that feels the need to wear a baseball cap while driving! Oops...I can get a bit carried away with this subject...."Nurse... Nurse"!

[woodyracing]

ok at least you didnt say XR2i's

i thought it might be easier to blip on a bike.

[DAVID PATERSON]

I suggest one reason why the baseball caps don't do it is because they know so little about cars and driving that they aren't even aware of such a practice.

An alternative reason is that the only motorsport these people expose themselves to is drag racing, where it isn't done, so they don't feel the need to do it either. They just concentrate on warming up the tyres on the driven wheels, getting the holeshot when the lights change and roaring up through the gears on a dead straight track.

Finally, perhaps the reason baseball caps don't heel and toe downchange is simply becuase it is a difficult thing to master which takes plenty of experience and skill, thereby precluding "the boys."

[Onlooker]

It also has a lot to do with the fact that a bike has a dog box and no syncro rings making it nessesary for smoth down changes

[Dave Brand]

Originally posted by Onlooker
It also has a lot to do with the fact that a bike has a dog box and no syncro rings making it nessesary for smoth down changes

It's done to match engine revs to speed. Changing down without increasing revs can lock the rear wheel.

Smooth changes are very easy on bike boxes. Most riders will change up without using the clutch - just put a bit of load on the gear pedal & momentarily close the throttle. Clutchless down-changes are also possible, but because of the need to get the engine revs up, it's only really an option at very low speeds on dry roads. Racers use quick-shifters, which sense movement of the gear pedal & cut the ignition for a few milliseconds - this allows clutchless gearchanges with the throttle held wide open.

[woodyracing]

Originally posted by Dave Brand

Changing down without increasing revs can lock the rear wheel.

They say that about cars, but i dont understand it.
I would have thought it just makes the engine rev a bit.

can anyone explain how it can lock the rear wheels ?
cheers

[Onlooker]

As a bike decelerates the weight is transfered to the front wheels( as is demonsrated when the race bikes lift the rear wheel) and as the force holding the rubber to the road deminises the likelyhood of locking inceases.Go change down in your car at a say 100kph into 2nd (in a manual)and it will lock no fear.

[Dave Brand]

Originally posted by woodyracing


They say that about cars, but i dont understand it.
I would have thought it just makes the engine rev a bit.

can anyone explain how it can lock the rear wheels ?
cheers

'Lock' is maybe overstating it, but it will break traction. It's all down to basic Newtonian physics. If the engine is turning slower than required for the gear selected, it's got to be accelerated. To do this requires a certain force; if this force exceeds the frictional force available at the tyre/road interface, the tyre will slip.

[woodyracing]

ok thanks i can understand that.

[a_richardson99]

I always blipped on down changes on my bike - partly because it made the bike much more stable on hard downshifts - but also because it sounded so cool...

It's much easier than with a car - on my bike I got it within 5 minutes in the car I still bunny-hop around when I try it.

Learned loads about it from watching a couple of Japanese car magazine VCDs where they track test (hard) the cars each month and show in car video including inset of the drivers feet.

[Teletubby]

I wear a baseball cap when driving my car!!!

True it's an Elise and the cap is to compensate for the fact that am follicularly challenged and my head gets sunburn!

And I don't have a Mega sub-woofer tweeter graphic amplifier! (the battery is feeble enough already!!)

[woodyracing]

Originally posted by a_richardson99
Learned loads about it from watching a couple of Japanese car magazine VCDs where they track test (hard) the cars each month and show in car video including inset of the drivers feet.

cool, which magazines are these ?

[a_richardson99]

I'll have a look tonight - something like TopsCar I think.

I bought a couple of them in Singapore for about £5 each - one has a flat out 10 lap race between 360/911turbo/Skyline/Evo/RX7 etc etc another one has a fantastic race between 911RS 2.7, Dino, Europa(!), Countach and a couple more Ferraris that I can't remember.

They do standing start tests of tuned and standard cars (blowing up an Impreza in the course of it) and in typically Japanese style after hooning about in the cars for 30 minutes they spend 20 minutes talking in detail about the relative merits of each car. Basically they make Clarkson and co look like amateurs. All very professionally done (bumper to bumper flat out racing and not a single touch) and although I don't recognise the drivers I get the feeling that there perhaps 2 journalists and 5 professional racers doing the driving.

[shiny side up!]

Y'all have more fun performance cars to play with than us in the US, so it may be a different story, but here any tranny you can get your hands on has synchros...which eliminate the need to rev-match on downshifting. (Actually, you can tear one up fast by trying). It is pretty hard to find a car in which you can heel-toe effectively on the street...

[a_richardson99]

Just checked - those VCD's were from 'Best Motoring' - based in Tokyo - all dubbed or subtitled in English.

[djb]

as David Brand stated,

"Lock' is maybe overstating it, but it will break traction"

exactly, and doing a sloppy downshift while straight up is one thing, but doing this while heeled over with your tires approaching traction limit and things dragging is another, and hence the hard earned habit of getting the right match up.

and unfortunately, I've never owned a car that had the pedals set up properly for heel and toe work, so I have never developed the talent.

[Red Dog]

What's that stuff about synchros avoiding the need to for heel and toeing? Sure, if you're just cruising around it means nothing but if you're doing a 'last of the late brakers' act into a corner and your car has rear drive, getting the downchange wrong can be like pulling the handbrake on

[woodyracing]

thanks for the magazine names a_richardson99.