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Rear Brake & Gas


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I am not a racer, nor one of the "fast guys."

I have a question for those guys though...

 

In slow-speed maneuvers, it is a basic thing to "pull" with the motor while lightly dragging the rear brake.

The bike lifts from chain tension.

 

In theory (or my limited understanding of it), this seems like it would have really great turn-in and mid-turn applications.

 

It seems it would lift the bike and provide stability.

(and no, we are not worried about locking the rear tire if the engine is pulling...)

 

For example, think of being at a stand-still, waiting to pull away at a light.

Rear-brake on, a little bit of clutch and throttle, the bike lifts noticeably, without actually applying any forward torque to the rear tire.

 

So here is a specific question:

If a little bit of maintenance throttle is good, might a little bit more be better, then cancel out the forward effect on the tire by rear-braking.

Wouldn't this be a really good dynamic in a turn?

 

(let the flames begin...)

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I am not a racer, nor one of the "fast guys."

I have a question for those guys though...

 

In slow-speed maneuvers, it is a basic thing to "pull" with the motor while lightly dragging the rear brake.

The bike lifts from chain tension.

 

In theory (or my limited understanding of it), this seems like it would have really great turn-in and mid-turn applications.

 

It seems it would lift the bike and provide stability.

(and no, we are not worried about locking the rear tire if the engine is pulling...)

 

For example, think of being at a stand-still, waiting to pull away at a light.

Rear-brake on, a little bit of clutch and throttle, the bike lifts noticeably, without actually applying any forward torque to the rear tire.

 

So here is a specific question:

If a little bit of maintenance throttle is good, might a little bit more be better, then cancel out the forward effect on the tire by rear-braking.

Wouldn't this be a really good dynamic in a turn?

 

(let the flames begin...)

 

Hey Crosby,

There are only a few times I use the rear brake

1.) I accidently hit it with my foot

2.) I run off the track and need to stop

3.) I am on the throttle and start to wheelie

4.) I am going into a corner way to hot

5.) My front brakes fail

6.) I am sitting on my bike in the garage drinking beer and decide to work out my right calve muscle

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Fossil cracks me up with his reasons for rear brake use (I wouldn't personally do #4, don't like to move my feet, and got a better sense of my finger pressure). I hadn't thought of #5 at all, silly me!

 

Now Crosby, what is to be gained by using the rear while also on the gas...and when exactly are you talking about using it, parking lot speeds, or in real turns?

 

CF

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Fossil cracks me up with his reasons for rear brake use (I wouldn't personally do #4, don't like to move my feet, and got a better sense of my finger pressure). I hadn't thought of #5 at all, silly me!

 

Now Crosby, what is to be gained by using the rear while also on the gas...and when exactly are you talking about using it, parking lot speeds, or in real turns?

 

CF

 

#4)Is only to be used in H..y S..t mode. Isn't that one of the modes on the new BMW? And this is when one recognizes very early in the turn like coming down the straight approaching the turn screaming like a little girl...I hope this clears things up Cobie..

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It's funny how some people seem so determined to make riding their motorcycle so much more complicated than it has to be - pushing on pegs, twisting the body, modulate multiple controls simultaneously when 1 would work perfectly fine. :D It's really simple, use the throttle to speed up, the front brake to slow down, and countersteer to steer. You know, brake, gas, steering wheel, not much different than a car, except more fun. It really doesn't need to be any more complicated than that for public road riding, although I guess you gotta deal with that shifting business.

 

On a less cynical note, I'm not following your logic on how this rear brake plus throttle thing is going to add stability. But one definite plus side is you'll get a lot of practice installing rear brake pads.

 

No mean spirit intended here... just some friendly sarcasm. :D

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Using the rear brake to control power or wheelspin wasn't all that unusual, but with more and more electronics probably just about gone from pro racing these days. But I know many who use the rear brake to tighten their line a little, helping the bike turn. For really slow work, like balance type of riding, it's also good to use the rear brake.

 

I would also recommend using the rear brake on longer bikes, particularly riding two-up. You will typically need 10-30 % less distance to come to a stop with the addition of the rear brake on most bikes that aren't of the sporty type (tall and short) since the rear wheel will always be weighted significantly. Sportier bikes, which I presume most of you own, can do a front wheel mono even two-up, and then there is no use with the rear brake.

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Motorcycles have rear brakes?

I find the rear brake quite handy .... but mostly on the road.

Why is the rear brake handy?

  1. Using the rear brake doesn't change the weight distribution as much as when using the front brake
  2. Using the rear brake doesn't affect the steering geometry as much as using the front brake
  3. It's much easier to just ease off a bit of speed than when using the front brake (useful when you're getting a whee bit too close for comfort to the guy in front, you just want to back off a bit, not brake hard)
  4. Applying the rear brake a split second before the front brake will make the rear of the bike quat a bit, lowering the centre of gravity, allowing you to brake harder before the rear end comes up (this is primarily for emergency braking on the road, where you want to come to a halt as quickly as possible - something you very very rarely need on the track)
  5. If you get hit by a car from the rear, when you're stationary, using the rear brake will reduce the risk of the bike getting thrown around the steering head pivot point (hard to describe, but easy to demonstrate: sit on your bike and apply the front brake alone - have a friend push the bike from behind. Now try the same with just the rear brake applied. Huge difference in how the bike reacts).

Except for #5, the rear brake is just a "helper", not the primary brake.

 

Kai

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Motorcycles have rear brakes?

I find the rear brake quite handy .... but mostly on the road.

Why is the rear brake handy?

 

 

3. It's much easier to just ease off a bit of speed than when using the front brake (useful when you're getting a whee bit too close for comfort to the guy in front, you just want to back off a bit, not brake hard)

 

Kai

 

we can still use the throttle and the FRONT brake at the same time (without revving the engine). it helps to keep the suspension at its mid range. i did try it, it works perfectly. it's also very handy when approach to a stop sign or red light.

 

rear brake could be handy if we pop up a wheellie.

 

i've heard that the rear brake on ducatis (not sure if on all ducatis) does not even slow down the bike.

 

 

 

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Doohan depended greatly enough on the rear brake to fab a thumb operated unit when his foot became inoperable. A faulty rear brake was partially reason for Dovi's fall today - it forced him to rely on the front too much.

 

Until you can stay with the top riders of the world, of which virtually everyone use the rear brake to some extent, you should perhaps look at the rear brake with a bit more open mindednesswink.gif

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In theory (or my limited understanding of it), this seems like it would have really great turn-in and mid-turn applications.

 

It seems it would lift the bike and provide stability.

(and no, we are not worried about locking the rear tire if the engine is pulling...)

 

For example, think of being at a stand-still, waiting to pull away at a light.

Rear-brake on, a little bit of clutch and throttle, the bike lifts noticeably, without actually applying any forward torque to the rear tire.

 

So here is a specific question:

If a little bit of maintenance throttle is good, might a little bit more be better, then cancel out the forward effect on the tire by rear-braking.

Wouldn't this be a really good dynamic in a turn?

 

(let the flames begin...)

 

Getting the rear end to stay up a little higher mid corner would be easily solved with a different spring rate, pre-load, or damping settings. Using the rear brake for that just seems kind of complicated when all you need to do it put a little more pre-load on the suspension.

 

There might be 0.03 seconds a lap that can be gained if you use the rear brake correctly but even then you wont be using it while on the throttle when the right suspension setup will fix the issue. For people at our level there would be MUCH easier ways to make faster lap times :).

 

I did learn the rear brake + throttle techique for low speed manuvering but I found you can get the same results without using the brake. If the tight U-turn is up hill then you don't need the rear brake. If the turn is down hill then you can just drag the rear brake with no throttle. Its its level you should be able to do it either way.

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Until you can stay with the top riders of the world, of which virtually everyone use the rear brake to some extent, you should perhaps look at the rear brake with a bit more open mindednesswink.gif

 

Because we're all going to be like these guys? The local riders in the area who are very good don't touch their rear brake. Trackdays or racing. Why? Because our skill level will never be that of Doohan and Dovizioso.

 

I just do trackdays, and will never push enough for the need to make small enough adjustments to require the use of the rear brake. The only time I even remember they're on the bike is when I leave the pavement. I have better things to work on that will help me improve my times. Lots of other things.

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Jasonzilla, my point was simply that there is nothing wrong with using the rear brake and that it will - if applied correctly - be a benefit. It's much like the clutchless shifting; for some, it is simply absorbing brain power better diverted towards more pressing issues, for others it's second nature. The rear brake is similar in that it will be natural to use for some, whereas others will find it confusing.

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Crosby,

 

I think you are on to something. If you are leaned over and have some throttle on to stabilize the bike, but still feel you are going too fast, you could roll off the throttle, use the front brake or use the rear brake. Rolling completely off the throttle can be abrupt on many bikes--mine included--although, you could trying rolling off as gently as possible. The problem is that at low throttle openings many fuel injected bike are On or Off. I wouldn't normally want to use the front brake IN a corner (I've seen too many experts tuck the front tire and fall down, and I'm nowhere near their level). So, that leaves rear brake and--at the same time--maintenance throttle. You wouldn't need to do it often, or use much rear brake but a gentle toe touch on purpose is much better than lighting up an SR and chopping the throttle, manhandling the bars or freezing up.

 

Even when I'm braking hard, I still squeeze on a little rear brake first before really working the front brake. I've found using the rear brake just before the front brake acts like a sort of manual anti-dive control and helps stabilize the bike. I also use the rear brake to give the bike "something to pull against" at parking lot speeds or when pulling out (creeping forward) and turning into heavy traffic. I use the rear brake a LOT in gravel because the front locks up so fast. I use my rear brake for normal stopping chores. You can also abuse the rear brake on purpose and have a bit of fun sliding around. So, I guess I use the rear brake to:

 


  1.  
  2. Finesse corner speed
  3. Reduce front end dive
  4. Stabilize the bike at very low speeds
  5. Stop in gravel, sand or dirt
  6. Stop under normal conditions
  7. Slide on purpose

 

I know lots of people hate the rear brake, but I use it a lot.

 

Best wishes,

Crash106

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Me personally on the track dont use the rear brake but I do use it when riding around town. I think of the the brakes this way Front brake for big braking when travelling at speed (obviuously big brakes big stopping power) and rear brake for slow speed manouvering tight turns less than 10 km/h etc.

 

Yes I know that Rossi uses his rear brake to turn in and trail brakes but for me i'm not at that level plus I work off the principle of KISS (Keep it simple stupid).

 

On track I guess if your are as fast or are your local fast guy then maybe you may use your rear brake but if your a D grader or novice and your talking about using rear brake and trailing it in then I would suggest to learn how to walk before learning to run. But if your not into the track or just regurgitate something off the net then book into a track day and see why the school teaches the way it does.

 

If you can stay with the top riders of the world I would suggest maybe opening a school of your own

 

Cheers

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I think we ran CROSBY off? COME BACK Crosby! It's ok. This is what happens when you ask questions on this forum!

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I dont use the rear brake much when on a decent run out of town, but anything below 35mph then thats when i use the rear brake, it works imo much better than using the front. I did an advanced riding class and used the front brake all the time, when i was getting debriefed the instructor mentioned this very thing as he seen the front of the bike dipping whenever i applied the brake. Its much smoother to use the rear in low mph.

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I crashed when I used my front brake after i went off the track on loose gravel and grass. Why should we use the rear brakes only once we leave the pavement? Please shed some light on the issue.

 

Its kind of hard to explain. Think of it this way, when you use the front brake all of the motorcycles weight is being pushed onto the front tire. Just like if your trying to push a pencil across a desk by the eraser it can try to turn on its own (which would be washing out the front tire on a motorcycle). If you use the rear brake its pulling the bike to a stop and all of the weight is hanging from the rear tire keeping the bike stable even if the rear tire locks up.

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I crashed when I used my front brake after i went off the track on loose gravel and grass. Why should we use the rear brakes only once we leave the pavement? Please shed some light on the issue.

 

Its kind of hard to explain. Think of it this way, when you use the front brake all of the motorcycles weight is being pushed onto the front tire. Just like if your trying to push a pencil across a desk by the eraser it can try to turn on its own (which would be washing out the front tire on a motorcycle). If you use the rear brake its pulling the bike to a stop and all of the weight is hanging from the rear tire keeping the bike stable even if the rear tire locks up.

Another way to look at this is to recognize that off track surfaces typically do not offer the same amount of grip that asphalt does so when you use the front brake off track, there isn't enought friction available for the tire to take the entire weight of the bike (and you) pushing the smaller contact patch beyond its limits. Once the front contact patch is overwhelmed and it loses traction the bike becomes unstable almost immediately. The rear as Fajita Dave points out is acting more like an anchor holding back (again with limited friction) the gross combined weight but the front can hold traction (if you don't try to turn very much) so the bike is more stable as a result.

 

Rainman

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There are only a few times I use the rear brake

1.) I accidently hit it with my foot

2.) I run off the track and need to stop

3.) I am on the throttle and start to wheelie

4.) I am going into a corner way to hot

5.) My front brakes fail

6.) I am sitting on my bike in the garage drinking beer and decide to work out my right calve muscle

I really like your answer.

Let me write some more in addition wink.gif :

 

7.) To dag surprisingly. Watching scaried sleepyheads jumping around, during morning rides is priceless.

8.) Hit the binders making a fast turn back when you're watched by nice girls (works better if they're accompanied by bald, strong boyfriends).

9.) Like your #3 but being on the throttle and stop nice wheelie.

10.) Jumping across the wide ditch to move your front wheel up a bit. Be carefull, use with a clutch simultaneously to not off the engine.

 

Cheers,

-UFI-

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Pretty interesting thread, you guys have thought about some of this stuff obviously.

 

There are a few different parts to this: Street riding, track riding or racing, what happens when one gets in low traction conditions (gravel, etc.), what is good for the rider (keeping it more simple?) and hwat is best for the bike.

 

Let's start with what's possible from each of the brakes as a maximum. What percentage of the braking will the front brake do on modern sport bikes? We can also look at cruisers/touring bikes too, but for this, any modern sport bike built in the last 20 years, good tires, good working brakes. OK, tell me what the percentages are, front/rear.

 

CF

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I kind of answered that already, but a modern(ish) sportbike is capable of getting all its stopping power transferred to the front wheel by elevating the rear wheel clean off the ground.

 

Now, how often does this actually happen on the track? Is it even beneficial? Only very rarely do you see top level riders brake hard enough to get the rear wheel off the ground. However, as somebody mentioned, by applying the rear brake a split second before the front brake, you can lower the CoG of the bike and hence reduced the chance of a front wheel mono. And when the rear wheel is touching the ground, it can transfer anything from 0 to around 40% of the maximum braking force, depending on CoG, wheelbase, total vehicle weight, individual wheel load, tyres and more. A long cruiser riding two up with a fat rear and a skinny front tyre will depend heavily on the rear tyre for stopping.

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With a sportbike on a good surface 100% of the braking force can be handled by the front tire. I've never practiced trail braking on-road so I don't have any solid experience with that but your stopping power is reduced the lower the lean angles get. The front tire can only handle so much load for braking and cornering at the same time. Even though I never touch the rear brake on my sportbike unless traction is terrible I can see how the rear brake might help with trail braking on the track. While trail braking with front brake only the front tire has to handle two different forces that require grip at the same time so you need to balance the braking and cornering otherwise you over load the front tire and wreck. Mean while entering a corner the rear isn't doing a whole lot and has a lot more grip available to use. So if you balance the front brake, rear brake, and lean angle just right you should be able to use 100% of both tires available grip for trail braking and cornering instead of making the front tire do most of the work on its own. Letting you trail brake heavier and still have a decent amount of traction for cornering. Of course your still asking the tires to handle braking and cornering so you still wont be able to reach the bikes maximum lean angle.

 

For low traction surfaces or accidental off-road use on a street bike the rear brake can help you stop quicker in a straight line. When traction is low the front tire will lock up at some point. When the front tire locks up you no longer have control over which direction the motorcycle is going and will find yourself on the ground very fast. You can lock the rear tire if you want to and you can still maintain control of the motorcycle. So to get your max braking force you need to find the point just before the front tire locks up and use the rear brake for the rest. Keeping the rear tire rolling would be best but if it locks its not a big deal as long as your going in a straight line.

 

I do have lots of experience trail braking off-road on a dirtbike. I never really thought about it much until now but I did use the front and rear brake most of the time I was trail braking. The more I leaned the bike over the more I let off the front brake and the more I applied the rear. After I learned this (and didn't think much of it until now) I could brake much later and much deeper into the corner compared to using the front brake only. I was using the grip available from both tires for braking and cornering instead of only braking with the front. It really helped out with diving under someone to make a block pass :D. As always with off-road it depended HEAVILY on the surface. Sometimes with straight line braking I could lift the rear off the ground and use front brake only, other times I could barely pull the front brake before the front tire locked so I had to use the rear. For any surfaces in between you'd use both front and rear to get the shortest straight line braking distance. The margin for error off-road is so much larger then it is on-road so it didn't seem all that difficult to learn at the time. I would imagine that a sportbike on the track would throw you off quick if you got the braking balance wrong.

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