A question for the racers

[marcmcm]

After having heard some of you racers say that you don't use your rear brake when racing, I was just wondering why the MotoGP guys rear tires slides out when they are entering a turn.  I wouldn't think it would be from downshifting since they are blipping the throttle to match road speed to revs.  What gives?  Thanks fellas

[cpchillin]

I think that the rear tire is sliding due to the rapid deceleration. Most of those guys run a single pot rear brake so that the rear brake can't lock-up on them. It's loading the front tire alot therefore it wouldn't take much for the back tire to slide.

[Hi-Side]

Some of them are quite adept at using the rear brake. They also have slipper clutches, which if you've never had one is one of the sweetest things a bike can have.

Rear braking, however is a much more advanced skill to be able to rear brake while leaned over. It can be very distracting and the margin of error is very small. Just one less thing to worry about when you're racing... and when the rear end is off the ground anyway, you get no rear braking. The guys that I know that can do it and do it well have swiss-cheesed the rear rotor so that there is actually minimal braking, unless you're applying alot of pressure, then you still get marginal braking, just enough to slow the tire.

Mine generally only slides due to engine braking...

[cbrf4 269]

Actually, road racers, or the professionsal, don't use the rear brake to slide the rear tire (or known as backing it in).  This is a dirt track style of racing but I can assure you that although they do use the rear brake, they don't slide the rear with it.  They actually use to clutch.

[Hi-Side]

Uh no... most club racers use the clutch to back it in, but all of the gp guys use rear braking as well as both bostroms, all 3 haydens and yates. A clutch slide is very different from a rear brake slide... when you see rossi, yates or bostrom at the last race at barber, backing it in sideways... thats all rear brake.

[RacerChic]

Like Hi-Side said, those guys have slippers cluthes, when they're braking, down shifting and ready to turn it in....the front end gets heavy...the clutch causes the tire to step out.....they're feathering the clutch at it's "catch point".

Sam

[cbrf4 269]

Uh no... most club racers use the clutch to back it in, but all of the gp guys use rear braking as well as both bostroms, all 3 haydens and yates. A clutch slide is very different from a rear brake slide... when you see rossi, yates or bostrom at the last race at barber, backing it in sideways... thats all rear brake.

Actually, no.  If you look at it again the rear tire is still spinning, if the rear brake is locked, then why is the rear tire spinning.  I have actually had the priveledge of a profession AMA racer show me and do it, so yes indeed, they are using the clutch.

[Hi-Side]

What kind of idiot are you ? Of course the wheel is still spinning. Does your front wheel quit spinning when you hit the front brakes ?

On a full superbike and on the Kawasaki 600 supersport bikes (ZX-6R) they have slipper clutches. You don't have to feather shit. You down-shift 3 times and dump it... thats the beauty of  the slipper clutch... and why its called a slipper clutch.

I'm not sure who you're talking to, but I used to be a professional level racer, and am still a front running club and regional racer. Alot of my friends are still what you'd consider AMA Pro's, which just means they race nationals. And we (Hi-Side Racing) also help sponsor several "Pro" level racers.

None of my friends and very few of the privateers can afford a slipper clutch, so they're careful downshifting going into a turn hot, which does tend to get you a little sideways.... thats a little sideways.

Ben Bostrom, Rossi, Yates, Hayden sideways or backing it in is caused by rear brake.

All of those mentioned, except for Rossi were exceptional dirt trackers,which is where they perfected that. Rossi came up through the GP's.

125 & 250 GP bikes have no engine braking at all, so you have to use the rear brake to settle the bike, the same way we use engine braking to settle the rear, except he's more aggressive, and it is very clear when he gets off the rear brake and it straightens out in a corner.

[marcmcm]

So if I understand correctly a slipper clutch won't let the back tire lock up when you dump the clutch?

[Hi-Side]

That is correct. We have one at the superbike school. Its one of the instructor bikes. You can downshift 3 gears and let it go, you don't pop the rev limiter like you would on a regular bike and the rear doesn't lock up, you just get a nice little slide... but not the complete sideways rear-braking stuff that you see rossi and bostrom doing.

Its the only time I've gotten to use one and it is definitely one of the nicest things Kawi has done. That and the radial mounted brakes. If the damn Kawi 600 had more power, I would have ended up on one of them this year.

[marcmcm]

Do they travel with that bike?  I was at the school a few weeks ago at Pocono; loved it...bets money I ever spent.  Try and get out to Pocono next year Terry, I'll be going again.  Thanks for the education.

[Hi-Side]

Yes its the only newer looking bike that the instructors use. All the rest are 2002 model ZX-6's and 2 ZX-9's. All of the student bikes are the new ZX-6 RR's (636). There is also one 636 set up for the mechanic, that is just smoking fast, with the same kind of suspension as on my race bike. You really have to keep the 600 wound up though - really high in the rpm range.

Supposedly next year, all of the instructor bikes will be replaced with the 636's.

I've been to Pocono once 2 years ago, but its all the way across the country for me and I end up taking 2 days of vacation just to do a weekend school, or a whole week if its a Mon-Thurs., but I do like VIR and Barber.

[Marsh]

What kind of idiot are you ? Of course the wheel is still spinning. Does your front wheel quit spinning when you hit the front brakes ?

The Flaming never stops  

The rear tire doesnt have to lock to slide all it has to do is loose enough grip and speed from using the rear brake or very slopy downshifting(helped by a weight distribution of about >90% to the front) you can slide the wheel in either cases most of the slides you have seen are caused by the rear brake.

Here is a Screensaver (sorry its the best footage i found to show how the master does it)------->   http://www.mysimplelife.com/misc/RossiSaverInstaller.exe

you will notice his right foot move off the brake and he stops sliding

it takes more effort to flame than it does to help imo

[cpchillin]

Hey Terry could you teach me how to slide the rear into a turn? I'd pay you at least minimum wage to help me out!

[Hi-Side]

It wasn't meant as a flame at all. He said, " If you look at it again the rear tire is still spinning, if the rear brake is locked, then why is the rear tire spinning." I merely responded to that.

And to slide, the rear tire just has to be spinning at a slower speed than the bike is traveling. This can be caused by clutch or brake. Clutch is alot less dramatic and doesn't get the bike completely sideways, as the slide stops as the tire catches up to the speed of the biks. Intentional slide with rear brake is way more dramatic (read sideways), as it helps to square off a corner.

And I'd  be more than happy to show you how to slide the rear in a corner, but my riding backround does not come from dirt-track or GP, so you'll only see the clutch slide with me, but I'd be happy to show you the aaron yates style of lighting up the rear tire on the exit.