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Backing It In

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I know that the rear tire needs to spin slower then the front for the rear tire to slide around a corner. The methods I know on doing this are 1 using the clutch and 2 using the rear brake. When first learning to do this and practicing it at slower speeds which way is a better way to start out?

 

Another technique I know is to purposely let air in the rear brake line so you have to stand on the rear brake harder which makes it less likely for the rear wheel to lock up because with the air in the line it wont have the same braking power. My only issue I see with that is you can't modulate the pressure as easily since you have to apply so much pressure.

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Much better would be to simply lower the point where the brake pedal engage the pads. Now you will find that you may run out of movement of your foot before the wheel locks up, while the modulation is still unaffected by spoingy air.

 

 

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Rear brake should not be used on the racetrack. PERIOD. (unless it rains but i'm not sure exactly).

 

"Backing it in" can be induced by locking up the rear, true. You can use rear brake, or drop the clutch abruptly on downshift. But this is not what you are seeing in MotoGP or moto2.

 

To prove it, go watch a few moto2 races and you can see that even on right hand turns, they back it in and don't use rear brake. It's obvious because now that almost all riders let their inside leg hang during braking, you can see the rear end of the bike "come around" while their right leg is dangling in the air.

 

"Backing it in" is a result of "threshold braking" combined with "trail braking".

 

If you and your bike weigh 500lbs, lets say when you sit on the bike on a constant speed there is 250lb on the front and 250lb on the rear.

 

During very hard braking, you would want 490lb on the front and 10lb on the rear. Just enough weight on the rear so it still sort of "follows" the front.

At times, you will see the rear tire skipping.

 

So once the rider start to turn the bike, the front end is gripping and turns, while the rear with 10lb of weight on it continues straight ahead. There you go - you are crossed up... Don't release the brakes enough, and you'll get more and more crossed up until you crash.

 

To sum it up, backing it in is not a stunt that is induced by rear brake like on your BMX bike, it's a result of going very fast into a corner with extremely aggressive trail braking technique.

 

Hope this helps.

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Rear brake should not be used on the racetrack. PERIOD. (unless it rains but i'm not sure exactly).

 

"Backing it in" can be induced by locking up the rear, true. You can use rear brake, or drop the clutch abruptly on downshift. But this is not what you are seeing in MotoGP or moto2.

 

To prove it, go watch a few moto2 races and you can see that even on right hand turns, they back it in and don't use rear brake. It's obvious because now that almost all riders let their inside leg hang during braking, you can see the rear end of the bike "come around" while their right leg is dangling in the air.

 

"Backing it in" is a result of "threshold braking" combined with "trail braking".

 

If you and your bike weigh 500lbs, lets say when you sit on the bike on a constant speed there is 250lb on the front and 250lb on the rear.

 

During very hard braking, you would want 490lb on the front and 10lb on the rear. Just enough weight on the rear so it still sort of "follows" the front.

At times, you will see the rear tire skipping.

 

So once the rider start to turn the bike, the front end is gripping and turns, while the rear with 10lb of weight on it continues straight ahead. There you go - you are crossed up... Don't release the brakes enough, and you'll get more and more crossed up until you crash.

 

To sum it up, backing it in is not a stunt that is induced by rear brake like on your BMX bike, it's a result of going very fast into a corner with extremely aggressive trail braking technique.

 

Hope this helps.

 

Don't forget about Newton's 3rd law of motion. Every action has an equal and opposite reaction. When you try to turn the handlebars in one direction, the handlebars try to turn you in the other direction. Since your lower body should be locked onto the frame with your knees this twisting force is transfered to the frame making the rear end step out.

 

Of course if the rear tire has traction then everything stays in line. But when the rear tire has almost no traction there is very little keeping it from stepping out of line. So the result when you turn the handlebars is you end up turning the frame too.

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I believe most racers use the rear brake, albeit probably not (much) to back it in. If for nothing else, applying the rear brake a split second before the front brake will squat the bike and allow you to brake harder before the rear wheel leaves the ground.

 

Here's an interesting discussion about rear brake useage

http://motomatters.com/forum/viewtopic.php?f=2&t=58

 

Here's one article claiming that to get faster, you need to use the rear brake more, like Stoner:

http://www.motorcyclenews.com/MCN/RidingEvents/ridingeventsresults/Riding-skills/2010/march/mar1910-how-to-ride-like-casey-stoner/

 

 

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As I recall, last year when I trained with another school (it was provided free or I wouldn't have gone), the instructors were backing it in using engine braking and clutch modulation.

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Rear brake should not be used on the racetrack. PERIOD.

 

 

I have heard this piece of advice a lot, normally geared towards riders new to the track that are using the rear brake without realizing how light the rear wheel gets under hard braking, and thus are in danger of highsiding the bike.

 

Once a rider understands the dynamics of the rear wheel and weight transfer, it certainly seems possible that a rider could use the rear brake judiciously to break the rear tire loose and let it come around, and I have in fact heard of riders that do this - even one that had a hand lever installed to control the rear brake more accurately.

 

A few years ago I went to a race school that uses dirtbikes to each roadracers how to 'back it in' and it was all done with the rear brake. It was enlightening and really a lot of fun.

 

I do not recommend using the rear brake on a sportbike on the track (or backing it in, for that matter) because it is too easy to slide the rear tire and potentially highside, but I imagine there are experienced riders that can and do use the rear brake on the track... so I would not be so bold as to say "never"!

 

One of the cool things about motorcycles is there is always something new to learn. :)

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Doohan used a thumb-operated rear brake all of his championship winning years, due to the Assen accident that left him with little movement in his right ancle.

 

Kai

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He also said that he couldn't understand why anybody with the full range of movement in their foot would consider a thumb operated brake as he saw it as a handicap, but it was the only way he could use a rear brake - a brake he considered vital. I don't think you'll find many world champions that didn't/doesn't use the rear brake. A racer will use every means available to them to gain a tenth.

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I am sorry but I don't agree with not using the rear break period on the track, some schools even teach learning to use the rear brake in conjunction with the front because if you can use the rear but not abuse it you can brake that much harder over another rider that only uses the front.

 

A tip I know is to allow some air in the rear brake line so the rear wheel has a less chance of locking up because it wont have it's full braking force. I have a trackday coming up on Monday, not sure if I am going to try this or not but I may play around with modulating the clutch instead of using the rear brake.

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I'm with hotfoot on this one. Sure there will be a certain percentage of elite riders who can benefit from using the rear brake to rotate the bike into a corner, and that style seems to go in and out of fashion among the best racers. But your typical track day guy (and, I would guess, a very large percentage of amateur racers) would be better off confining rear brake use for those times when they run off onto the grass!

 

Me, never. No rear brake ever ever ever. Causes nothing but trouble and distraction (except, as mentioned, when I unintentionally go "farming" - then it's quite useful).

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Well after my trackday yesterday I didn't try backing it in. I was too focused on line building and establishing better reference points. Although I did use the rear brake.....once I rode off into the grass when hitting a false neutral and didn't have enough time to fix it before the corner came lol.

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Rear brake should not be used on the racetrack. PERIOD.

 

 

I have heard this piece of advice a lot, normally geared towards riders new to the track that are using the rear brake without realizing how light the rear wheel gets under hard braking, and thus are in danger of highsiding the bike.

 

Once a rider understands the dynamics of the rear wheel and weight transfer, it certainly seems possible that a rider could use the rear brake judiciously to break the rear tire loose and let it come around, and I have in fact heard of riders that do this - even one that had a hand lever installed to control the rear brake more accurately.

 

A few years ago I went to a race school that uses dirtbikes to each roadracers how to 'back it in' and it was all done with the rear brake. It was enlightening and really a lot of fun.

 

I do not recommend using the rear brake on a sportbike on the track (or backing it in, for that matter) because it is too easy to slide the rear tire and potentially highside, but I imagine there are experienced riders that can and do use the rear brake on the track... so I would not be so bold as to say "never"!

 

I'd agree witrh this! Sliding the rear on a dirtbike at 30mph on mud is easy and great fun. Trying to transfer those new found riding/sliding god skills onto tarmac at 5x the speed is much, much harder!

 

and I use the rear brake on my racebike all the time in the pits going to and from the track! :D

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Got a chance to watch some GP's this weekend, and when the right foot is off, for sure not using it then to back in.

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Funny this, the rear stepping out under hard braking/downshifting is why I'm working on an air bleed system and a better slipper clutch at the moment. I never use the rear brake, but have a few corners where the rear steps out as I tip in, it very much feels like I'm twisting it out with the steering input.

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