[Grok70]

Hi everyone,

Assuming perfect road conditions (dry, warm, no wind to speak of), what kind of braking is possible on a standard bike in various kinds of turns.

Eg.

1) A swerve. Like avoiding a minivan merging into your lane.
2) A turn like those of a highway changing it's direction from, say, east to south. Broad, mildly banked, high speed.
3) making a corner at a light in a 30mph zone on a 2 lane road when you have the right of way.
4) A series of switch backs, like on hilly roads.

If you noticed, I had wiped out recently swerving and braking Hard. My bad. But to what degree or how do you brake in other situations. The one I'm most worried about is if I'm coming around a reasonably broad curve on the highway at 60 or 70mph, what brake do I use, and how do I apply it safely, especially if changing traffic conditions make me have to stop in a hurry. How, I really want to know, do you stop in a hurry in a turn if you need to? Obviously it would be best if you can straighten out, but what if you can't?

One forum I read said to use the rear brake gently, to coax the bike deeper into the turn if you're going wide. This sounds like a recipe for a lowside...

One rider I spoke to said to almost always use ONLY the rear brake, and in a bad situation to jam the rear brake and start using the front. Then MSF says to jam on the rear brake so you can focus on staged braking the front in emergencies and to use both brakes all the time.

Another rider I spoke with who rode in LA for years said he almost always only used the front brake for everything.

Another rider who has ridden for 20 years almost without incident has his rear brake made really stiff, so he can only really activate it if he really jams on it, that way if he tenses up he won't accidentally lock his rear wheel, and basically never uses it.

When would I ONLY use the rear brake?
When would I ONLY use the front brake?

Honestly, in all the motorcycle information I've looked up, nobody has given much comprehensive information on braking, the physics of braking, or the practice of doing it on the road. There's so much variation in what I hear from experienced riders, it is very confusing. Like, for example, no one every told me that I can't swerve and brake, until I saw that Youtube video recently .

Best,


Thoughts etc.,?

 

[ninjaridaz]

The thing to do is not to put yourself in that situation. If I had to, I would use the front brake as little and as smoothly as possible. This will have the tendency to make you go wide. You will have to compensate.

 

[Misti]

Good question(s). Braking is a tough subject and as you pointed out there are many different opinions on how to do it correctly. I think the most important thing to do here is to really understand exactly what happens when you get on the brakes, either front or rear or both WHILE leaning over. This will really help to clarify what the best approach is to cornering while leaning.

FRONT BRAKE: Getting on the front brake while leaned over, even just a little bit, will transfer a lot of weight suddenly to the front tire (which is only designed to handle 30-40% of the total load) this pushes traction availability and is a huge reason why riders lowside in corners when riding the front brake or when they try to brake for an emergency.

This means that if you must get on the brakes mid corner or while leaned over the best thing to do is to begin bringing the bike upright at the same time by counter-steering it back up. The other thing to keep in mind is that you should be smooth and progressive with the brake lever and not jab at it suddenly. Smooth doesn't mean that you can't be quick with it (it is an emergency after all).

REAR BRAKE: The rear brake is a lot less powerful than the front and a common mistake of many riders is to lock up the rear by pressing too hard/too long on the brake lever. When leaned over, locking the rear can cause it to slide out from under you resulting in a lowside, or if it begins to slide and the rider panics and releases the brake completely it can cause a highside. If you must use the rear brake mid turn then the same thing applies, try to bring the bike as upright as possible while coming into the brakes quickly but smoothly. Remember that the rear brake has less stopping power so I wouldn't rely on the rear brake only to stop in an emergency situation EVER.

I tend to use front brake only when riding sportbikes UNLESS I end up off road in the gravel or sand or grass and then it is rear brake. On standard or cruiser type bikes then a combination of front and rear is best, 60-80% front brake 20-40% rear.

Practicing emergency braking is important and starting with braking in a straight line is a good start. Understanding how your bike will react and how hard you can get on the brakes is important. From there you could test a little bit what it feels like and what happens to the bike when you try to apply either some front or rear brake while cornering but I'd do this very cautiously and using only a tiny bit of brake at a time. This will give you an understanding of how quickly the bike dives when you being to apply some front brake or how easily it slips when adding some rear brake. I have done this many times just to get a sense for how my bike will react.

Best case is if you have to apply brakes mid turn then get the bike as upright as possible WHILE braking....

So, say you are going around a right hand turn and you suddenly encounter a car stopped in the middle of the road and you need to stop ASAP. How EXACTLY do you do it???

Misti

 

[ninjaridaz]

"...I tend to use front brake only when riding sportbikes UNLESS I end up off road in the gravel or sand or grass and then it is rear brake...." why?

 

[primalmu]

Probably because sport bike brakes are so effective that you can get by pretty well without the rear brakes. In contrast, cruisers usually have older technology, and while their geometry would make them more suitable for top of the line brakes (long and low = harder to stoppie), they are equipped with comparatively poor brakes, thus necessitating the need for using front and rear brakes at all times.

 

[ninjaridaz]

It sounds like that she would switch from front brake to rear brake only when going off road. I have never ridden dirt so I'm unfamiliar with the preference with the rear brake for loose surfaces.

 

[Grok70]

I tried out the rear brake today (had to get the bike home from the mechanic). The bike is much more happy with it at low speeds. The front brake is twitchy and makes the bike dive A LOT at low speed. I'm waiting to get into a parking lot to really practice and ride some more.

As far as Misti's question,

It sounds like if I'm in a long broad turn I need to adjust my speed to the vanishing point based on how fast my bike can safely stop while maintaining the turn, or else brake as much as possible hoping circumstances change and then lay it down or go off the road, (why don't they line the highways with pillows?!!

for being cutoff by a minivan I should have kept my bike straight or straightened it and then grabbed as much brake as I needed.

For winding turns, I have to use the vanishing point and be very cautious.

So to what extent at highways speeds, 55-90, do are you able to engine brake? I assume you can only do it if you are in the appropriate gear for the speed.

The skills I seem to need to practice are coordinating my right foot and the clutch. I'm pretty good at coordinating my right hand and the clutch. I watched myself, and I do not cover the front brake while riding unless I think I might have to stop. The rear brake definitely feels like a utility brake, though I suspect that once counter-steering is in full effect I should use the front for braking until I get down to 25 in non-emergency situations (that way if I jam up and forget to hit the front brake I won't start sliding). Thoughts?

 

[beginner]

When I accelerate the bike in a turn it tends to stand up, lean less, and go straighter. When I decelerate in a turn the bike tends to lean more and turn sharper. If I apply the brakes during a turn the bike tends to increase lean angle forcefully. After 3 years on the bike, if there is a way for me to use the brakes safely in a turn, I'm not skilled enough to do it. I assume that my braking is not going to be safe or effective unless the bike is standing up as straigth as possible and the bike is on a straight path.

Just being told that was not enough. I had to experience it, scare myself, meaning make the mistake, more than once. The way I learn those lessons, and live to tell the tale, is to make them in a parking lot, at low speed, where the chance of a life changing injury is lower. The most important thing I've learned in the parking lot is what a crappy rider I am. To be a little kinder to myself, I'm still a beginner.

I was challenged to ride a novel practice pattern yesterday. I did it and made a video. It demonstrates what I consider no better than beginner level skill.

 

[JBorg]

Maybe it's my bike geometry, but I find that if I brake in a turn the bike wants to decrease it's lean angle. There have been times that I've use rear brake in a turn and have felt like I had to push the bike down to keep the bike from straightening out. Not the best thing to do, I'm thinking! ..Better to enter at a safer speed.
What I guessing is that if there's enough traction to brake and turn, there's enough traction to maintain speed and turn.

 

[beginner]

Maybe it's my bike geometry, but I find that if I brake in a turn the bike wants to decrease it's lean angle. There have been times that I've use rear brake in a turn and have felt like I had to push the bike down to keep the bike from straightening out. Not the best thing to do, I'm thinking! ..Better to enter at a safer speed.
What I guessing is that if there's enough traction to brake and turn, there's enough traction to maintain speed and turn.

Is it possible that as you brake in a turn you also steer into the turn, which would tend to decrease lean angle?

 

[Misti]

"...I tend to use front brake only when riding sportbikes UNLESS I end up off road in the gravel or sand or grass and then it is rear brake...." why?

When you get on the front brake then you suddenly transfer weight to the front tire. During normal riding conditions on pavement the front tire of a sportbike is designed to carry 30-40% of the load so when you transfer weight to the front on pavement the tire can handle it. On dirt, sand, grass or mud the available traction is greatly diminished so transferring weight to the front tire via the front brake will push the limit and land you on your butt really fast. I found this out once when racing, went off track into the grass, hit the front brake and was on my head in an instant. Rear brake will help slow the bike down (though it takes longer to slow and can fishtail) but you won't get that drastic weight transfer and overload the front.

Make sense?

When I accelerate the bike in a turn it tends to stand up, lean less, and go straighter. When I decelerate in a turn the bike tends to lean more and turn sharper. If I apply the brakes during a turn the bike tends to increase lean angle forcefully. After 3 years on the bike, if there is a way for me to use the brakes safely in a turn, I'm not skilled enough to do it. I assume that my braking is not going to be safe or effective unless the bike is standing up as straigth as possible and the bike is on a straight path.

The opposite is true actually as JBorg below describes. When you brake or roll off the gas in a turn the bike will tend to stand up and decrease lean angle a little bit. When you roll on the gas in the turn the bike will maintain its line. If anything different is happening then it is because you are STEERING the bike while doing so. If you notice that the bike is standing up while you are rolling on the gas you most likely have some input into the outside bar that is steering you upright and the same is true if you find the bike leaning over farther when you brake or roll off the gas. check to see what kind of pressure you have on the handlebars.

When you brake mid turn the bike as stated above will tend to stand up a bit but you still want to STEER it up as straight as possible if you trying to brake hard or make an emergency stop. If you are going around a right hand turn and need to brake mid corner then you would press on the left handlebar as you were braking to steer the bike upright and reduce lean angle.

Maybe it's my bike geometry, but I find that if I brake in a turn the bike wants to decrease it's lean angle. There have been times that I've use rear brake in a turn and have felt like I had to push the bike down to keep the bike from straightening out. Not the best thing to do, I'm thinking! ..Better to enter at a safer speed.
What I guessing is that if there's enough traction to brake and turn, there's enough traction to maintain speed and turn.

True, true and true.

Misti

 

[ninjaridaz]

Yup, it males sense now. Good to know, Misti. Thanks.

 

[gershon]

Anything about braking in a curve is highly dependent on the bike. My little Majesty will aggressively try to stand up and run wide with just a light touch on the front brake in a curve. It's controllable with counter-steering, but it was a little surprising. The Burgman 650 doesn't seem to care what I do with the brakes in a curve.

A little simplified math lesson. At the advisory speed, you are at .25 g's side force. MSF would tell you there are .75 g's available for braking. It's actually more as it's a fancy vector summation. At 50% over the advisory speed (at any advisory speed) you have about .6 g's side force. From experience using a g meter during braking practice, I know it's possible for either wheel to lose traction due to a road imperfection at about .65 g's. In other words, touching the brakes at 50% over the advisory speed MAY be dangerous. (Lots of hedging here.)

Stopping in your lane in a curve at speeds above the advisory speed by standing the bike up and stopping straight ahead is theoretically impossible for any curve where the advisory speed is based on the curve and not a hidden driveway or something. The good news is that if one is close to the advisory speed, counting reaction times and maneuvering times, one can stop in the same distance using about .4 g's of braking at the advisory speed.

Things get messy above the advisory speed and anything more than about 20% above the advisory speed makes stopping in the distance you can see difficult. The moral is, on a blind curve, staying near the advisory speed is prudent. On an open curve, once can make other choices based on their own assessment.

For the visual point, early recognition of movement allows for smooth throttle control t make adjustments unless you are going faster than I would. (Again, a lot of hedging for different opinions. I tend to be conservative.)

Racers will vehemently disagree with me and they should. They have more experience than the average rider and are probably more aware of what the bike is telling them. My thoughts are geared towards the average rider who may not be super proficient.

 

[gershon]

Rear Brake Effectiveness

The percentage of braking force available at maximum braking from the rear wheel is dependent on the height of the CG as a percentage of the wheel base and the distance of the CG from the rear tire as a percentage of the wheelbase. (Riding 2 up normally doesn't change this as there are compensating effects.)

Cruisers tend to have lower CG's and CG' that are further back. So about 25% of the braking will come from the rear brake at threshold braking. A sport tends to have a higher CG and a shorter wheelbase so very little rear brake is needed.

The following is for cruisers and other bikes with a low CG ONLY. I've never ridden a sport bike, so I won't express my thoughts.

In a parking lot, from 20 mph, practice stopping in 66 feet using rear brake only. This takes a very light touch. This is the maximum rear brake I use on the road in dry conditions. Then start walking the distance in using front brake to decrease the stopping distance. In a few reps, you should be at the minimum stopping distance.

On the road, I build a habit pattern by always using the amount of rear brake I would to stop in 66 feet using rear brake only, and then use the front brake to modulate the stopping distance. This leaves me with only one brake to worry about.

Whenever I suggest this technique, I get a lot of opposition. All I can say is it's harmless to go out to the parking lot and try it. For a bike with a low CG, the technique is sound. If you experience a rear wheel skid during the practice, reduce the amount of rear brake you use in the future.

In my opinion, many people use about equal pressure during normal stops and this sets them up with a habit pattern that will lock the rear wheel during hard braking. My opinion may be wrong as I haven't taken a survey or anything. I've just observed a number of riders lock their rear brake in what appeared to be normal stops that were a little harder than normal. (None resulted in a drop.)

As I said in the previous post, a lot is dependent on the bike, so it pays to test for yourself.

 

[JBorg]

A little simplified math lesson. At the advisory speed, you are at .25 g's side force. MSF would tell you there are .75 g's available for braking. It's actually more as it's a fancy vector summation. At 50% over the advisory speed (at any advisory speed) you have about .6 g's side force. From experience using a g meter during braking practice, I know it's possible for either wheel to lose traction due to a road imperfection at about .65 g's. In other words, touching the brakes at 50% over the advisory speed MAY be dangerous. (Lots of hedging here.)

Stopping in your lane in a curve at speeds above the advisory speed by standing the bike up and stopping straight ahead is theoretically impossible for any curve where the advisory speed is based on the curve and not a hidden driveway or something. The good news is that if one is close to the advisory speed, counting reaction times and maneuvering times, one can stop in the same distance using about .4 g's of braking at the advisory speed.

Things get messy above the advisory speed and anything more than about 20% above the advisory speed makes stopping in the distance you can see difficult. The moral is, on a blind curve, staying near the advisory speed is prudent. On an open curve, once can make other choices based on their own assessment.

For the visual point, early recognition of movement allows for smooth throttle control t make adjustments unless you are going faster than I would. (Again, a lot of hedging for different opinions. I tend to be conservative.)

Given this, and the notion of available traction for turning vs. stopping, would you think that one's ability to negotiate an emergency stop in a turn would be better served by stopping straight, or attempting to stop while turning? (Assuming that the rider is thoroughly aware of his bike's traction limits)..

 

[CaptCrashIdaho]

Rear Brake Effectiveness

Whenever I suggest this technique, I get a lot of opposition. All I can say is it's harmless to go out to the parking lot and try it. For a bike with a low CG, the technique is sound. If you experience a rear wheel skid during the practice, reduce the amount of rear brake you use in the future.

Given this appears to be STRAIGHT line technique--how is it applied to braking in turns? Should one use the max STRAIGHT line rear wheel brake force while leaned over? OR do you have an equation to use for turns?

 

[gershon]

Given this, and the notion of available traction for turning vs. stopping, would you think that one's ability to negotiate an emergency stop in a turn would be better served by stopping straight, or attempting to stop while turning? (Assuming that the rider is thoroughly aware of his bike's traction limits)..

The answer is I don't know for sure. So much depends on the rider's ability, how the bike behaves and what speed you are as a percentage of advisory speed. I stick pretty close to advisory speeds because we do have a lot of critters here.

What I've found I do in real situations from videos I've taken while stopping for deer is brake at about .4 g's using both brakes while correcting to a line where I can stand the bike up and stop in a straight line. .4g's is just slightly more than what I observe people using when they stop for a stop sign. (I have a g meter so I can estimate this pretty well.) I've never had a situation on the road where I've had to come anywhere near threshold braking.

What I've done in a safe area and using a lot of caution is practice braking in a real curve on the road from about 45 mph. Nothing approaching threshold braking.

 

[gershon]

Given this appears to be STRAIGHT line technique--how is it applied to braking in turns? Should one use the max STRAIGHT line rear wheel brake force while leaned over? OR do you have an equation to use for turns?

To me a turn is like at an intersection. If for some reason I have to slow while in that turn, I don't mind using a little rear brake.

But I think you mean a curve. I'm unwilling to say. What I will say is a person should explore what effects braking LIGHTLY in a curve has on their bikes. Then if they want to carefully explore further, it's their call. I don't have experience on enough types of bikes to give a declarative answer on this.

 

[Misti]

What I will say is a person should explore what effects braking LIGHTLY in a curve has on their bikes. Then if they want to carefully explore further, it's their call. I don't have experience on enough types of bikes to give a declarative answer on this.

Agreed. People should definitely explore the effects that braking LIGHTLY in a curve has on their bike as it will be different depending on model etc and how well the person is able to modulate the brakes. It is always a good idea to know how your bike and you will react.

If you have to apply the brakes HARD while cornering (to avoid hitting something) then the very best option is to get the bike as upright as possible before doing so by counter-steering the bike back upright while getting on the brakes.
:biggrin:

Misti

 

[JBorg]

Something happened today that made me think about this thread.
I was riding around a crowded parking lot trying to get to an exit. I was in the middle on a sharp, slow (<5mph) turn and I gave it a little throttle. Instead of increasing the lean angle, the bike stood up and the turn widened (not my intention).
My feeling is that, since I was in a direct steering "mode", accelerating with the handle bars turned as they were made the bike behave as if I was countersteering and lean the bike in the opposite direction of the turn. This might be "Beginners" experience as he stated before.
Thoughts?