MotoGP 2012

[DidJit]

No. Honda did try a fork lockdown...

Yeah, I was reading that bit last night. The Superbike fork had a mechanical push-button release, ...

*Raises hand* Excuse me sirs, could you explain the theory behind why you’d want to shorten the forks on launch? Is it to take advantage of aerodynamics to help keep the front down?

[roogazza]

*Raises hand* Excuse me sirs, could you explain the theory behind why you’d want to shorten the forks on launch? Is it to take advantage of aerodynamics to help keep the front down?

They strap drag bikes, maybe to stop fork movement and lift ?

[Badjelly]

*Raises hand* Excuse me sirs, could you explain the theory behind why you’d want to shorten the forks on launch? Is it to take advantage of aerodynamics to help keep the front down?

To maximise the acceleration you can support before the front wheel pops off the ground, you want the centre of gravity as low and/or as far forward as possible relative to the rear wheel contact patch. So, lower the bike and keep the wieght as low as possible. A light rider helps too.

[DidJit]

Grazie signori.

[Drew]

It means that 100% of the front wheel weight, is there holding the front down. With fork extension the front raises before that happens, and it wheelies worse.

[Robert Taylor]

Margaret Thatcher was a lesbian..

And good on her, so am I

[Robert Taylor]

To maximise the acceleration you can support before the front wheel pops off the ground, you want the centre of gravity as low and/or as far forward as possible relative to the rear wheel contact patch. So, lower the bike and keep the wieght as low as possible. A light rider helps too.

Not entirely true. Often the motor ( the heaviest lump of metal ) needs to be high in the frame to maximise weight transfer on acceleration to get the rear tyre to bite

[tbs]

Not entirely true. Often the motor ( the heaviest lump of metal ) needs to be high in the frame to maximise weight transfer on acceleration to get the rear tyre to bite

I theorize that in a dry start, a motogp rear tire will have enough grip to lift the front end off the ground even with a rider lying on the tank. The electronics will take care of any wheel-spin, but he'll get a better start by being able to use more power without lifting the front.

Heaps of mountain bike forks these days have a lock-down to lower the front for low gear climbing, as lowering the front end helps keep it on the ground.

Robert you're the Ohlins expert. Could they do it all electronically?

[Ivan]

I theorize that in a dry start, a motogp rear tire will have enough grip to lift the front end off the ground even with a rider lying on the tank. The electronics will take care of any wheel-spin, but he'll get a better start by being able to use more power without lifting the front.

Heaps of mountain bike forks these days have a lock-down to lower the front for low gear climbing, as lowering the front end helps keep it on the ground.

Robert you're the Ohlins expert. Could they do it all electronically?

Motocross bikes use them to i had one on my old 450 helped with launch really well as the 450's really wheelie out the gate standered but that helped cut the wheelstand out

[Badjelly]

Not entirely true. Often the motor ( the heaviest lump of metal ) needs to be high in the frame to maximise weight transfer on acceleration to get the rear tyre to bite

Ah, you're talking about the maximum acceleration you can support before the rear wheel loses traction. Also a factor.

[tail_end_charlie]

Yeah I was reading that bit last night. The Superbike fork had a mechanical push-button release, and the author had been looking for evidence of a fork shortening mechanism on the GP bikes. But, the book is now a couple of seasons out of date and I don't see why any lock-down (and even rear lock-out) couldn't be electronically controlled by the ECU launch control program. All Dani would need to do would be to press his launch control button while still rolling and then grab the front brake hard enough to compress the fork slightly. Hitting the front brake for the first corner could be the switch that turns it off.

Just speculating....

I gave that a little bit of thought after I posted that actually, and you could be right. Still, I've never really seen any evidence of this with the MotoGP bikes. I would think that there would be something like the DSS suspension that the new Multistrada and Panagali S have on them. If they have some sort of electro-magnetic launch lockdown or something like that, they would need to have some sort of wiring going to the fork internals. Best and easiest way to do that would be through the endcap of the forks at the top triple clamp, but there are plenty of pics of the area circulating, and none of them show anything like that.

I theorize that in a dry start, a motogp rear tire will have enough grip to lift the front end off the ground even with a rider lying on the tank. The electronics will take care of any wheel-spin, but he'll get a better start by being able to use more power without lifting the front.

Heaps of mountain bike forks these days have a lock-down to lower the front for low gear climbing, as lowering the front end helps keep it on the ground.

Robert you're the Ohlins expert. Could they do it all electronically?

Not entirely true. Often the motor ( the heaviest lump of metal ) needs to be high in the frame to maximise weight transfer on acceleration to get the rear tyre to bite

I'm sure that they could, considering all the other things they do....................the question is, do the rules allow for electronically controlled suspension? I have a feeling the rules specifically state that type of thing is not allowed. But I could be wrong.......hasn't happened before, but this could be a first time.

Ah, you're talking about the maximum acceleration you can support before the rear wheel loses traction. Also a factor.

I would speculate that with all the fiddling around they do with the ride height, engine placement and such that they have found as close to the ideal placement for the engine so that the forward to back pitching on acceleration and braking have the correct weight transfer to increase traction, but not too much to overload the front and rear respectively. So during starts they need to allow the bike to pitch back and compress the rear shock so that it literally drives the tire into the track (helped by the chain pull). If you locked the rear shock for starts, this weight transfer wouldn't happen and the TC would have to reduce the power so as to maintain traction (prevent wheelspin). So you would probably end up getting off the line slower. I could see some benifits to maybe firming things up, but you would then have to soften things back up for other parts of the track, which would require some sort of electronic trickery. And that brings us back to the rules, which I don't think allow it.

[Mental Trousers]

A fork lockdown system isn't needed when you've got 250+hp with traction control and anti-wheelie that works with inclinometers.

More importantly, locking the forks down will interfere with other systems as the nose down attitude will convince the system you're hard on the brakes, doing things to slow you smoothly rather than launch smoothly.

[tbs]

A fork lockdown system isn't needed when you've got 250+hp with traction control and anti-wheelie that works with inclinometers.

More importantly, locking the forks down will interfere with other systems as the nose down attitude will convince the system you're hard on the brakes, doing things to slow you smoothly rather than launch smoothly.

I dunno. The more mass you can put low and forward the more leverage it's going to take to lift the front, which means more power to the ground before the wheelie control has to do anything.

As for interfering with other systems.... that would merely be a matter of programing. Complicated? Absolutely, but what isn't on a GP prototype?

I'm not trying to labor the point. They probably don't use it in GP. It was just that Dani's little brake check about 5 meters out from his grid slot would have been perfect for initiating the system if it was there.

[imdying]

the nose down attitude will convince the system you're hard on the brakes

Can't be that simple; they'll probably be measuring the brake pressure to monitor that.

[Robert Taylor]

I theorize that in a dry start, a motogp rear tire will have enough grip to lift the front end off the ground even with a rider lying on the tank. The electronics will take care of any wheel-spin, but he'll get a better start by being able to use more power without lifting the front.

Heaps of mountain bike forks these days have a lock-down to lower the front for low gear climbing, as lowering the front end helps keep it on the ground.

Robert you're the Ohlins expert. Could they do it all electronically?

Anything is possible and a lot of the trickery is very jealously guarded. But I seriously doubt there is any ''lockdown'' activity going on. Irrespective of any electronic aids the basics are still of course very important, such as motor position, geometry etc.