Rear brake usage?

[All]

Recently, I've seen quite a few people saying they don't even bother with the rear brake--the argument being that, under hard braking, most of the weight will be on the front wheel, thus rendering the rear brake almost useless. Do you agree with this?

The dude that taught me to ride said that you get more stopping power using both.

Out of interest, does anyone know what the general racing practice is regarding the use of the rear brake?

[dipshit]

Recently, I've seen quite a few people saying they don't even bother with the rear brake--the argument being that, under hard braking, most of the weight will be on the front wheel, thus rendering the rear brake almost useless. Do you agree with this?

Nope.





The dude that taught me to ride said that you get more stopping power using both.

And he would be right.

[R6_kid]

Depending on the circumstances (how hard you are braking) and the bike you are riding (i.e bike configuration) it can sometimes be rendered 'useless'.

At the RRRS course we show the difference between using only the front, and only the rear, and that when applied correctly using both is the most efficient. It's all about contact patch (tyre) and weight transfer.

Some say that on a sportsbike you're braking is distrubuted as much as 90% front and 10% rear, and given the orientation of a sportsbike under hard braking you may find the rear wheel is a few mm or even a few centimetres or more off the ground (so yes, it's useless for now).

'correct' theory would have you initiate the rear brake momentarily before (practically the same time as) the front, and you are basically applying pressure to the levers exponentially until the point just before loss of grip/lockup (which can only be learnt through experience). And the main thing is that you dont let the wheel lock up of course!

Best thing to do is to get out and practice, and find what works for you... our bikes may all be 'the same', but one thing that works for one person may not work so well for you.

[toebug]

I use both but tend to use the rear the most. I use the front to stop in a hurry and use both at the same time, but on the open road tend to mainly use the rear and I often just trail the rear in the corners too.

[GaZBur]

Recently, I've seen quite a few people saying they don't even bother with the rear brake--the argument being that, under hard braking, most of the weight will be on the front wheel, thus rendering the rear brake almost useless. Do you agree with this?

The dude that taught me to ride said that you get more stopping power using both.

Out of interest, does anyone know what the general racing practice is regarding the use of the rear brake?

Seen this question before Do I Need My Rear brake (http://www.kiwibiker.co.nz/forums/showthread.php?t=51067&highlight=rear+brake)- so check that out for wide and varied opinions there.
If someone says you don't need them then smile and nod like you are agreeing - and pass them under brakes on a track day. Its the only way they will accept the fact that while the rear only may increase breaking by 10-15% it increases contol immeasurably. And how much would we pay for a 10-15% improvement in power or handling????

[All]

Depending on the circumstances (how hard you are braking) and the bike you are riding (i.e bike configuration) it can sometimes be rendered 'useless'.

At the RRRS course we show the difference between using only the front, and only the rear, and that when applied correctly using both is the most efficient. It's all about contact patch (tyre) and weight transfer.

Some say that on a sportsbike you're braking is distrubuted as much as 90% front and 10% rear, and given the orientation of a sportsbike under hard braking you may find the rear wheel is a few mm or even a few centimetres or more off the ground (so yes, it's useless for now).

'correct' theory would have you initiate the rear brake momentarily before (practically the same time as) the front, and you are basically applying pressure to the levers exponentially until the point just before loss of grip/lockup (which can only be learnt through experience). And the main thing is that you dont let the wheel lock up of course!

Best thing to do is to get out and practice, and find what works for you... our bikes may all be 'the same', but one thing that works for one person may not work so well for you.Does it follow that, if your rear tyre breaks contact with the road, you're using too much front brake?

[All]

Seen this question before Do I Need My Rear brake (http://www.kiwibiker.co.nz/forums/showthread.php?t=51067&highlight=rear+brake)- so check that out for wide and varied opinions there.
If someone says you don't need them then smile and nod like you are agreeing - and pass them under brakes on a track day. Its the only way they will accept the fact that while the rear only may increase breaking by 10-15% it increases contol immeasurably. And how much would we pay for a 10-15% improvement in power or handling????Geez, I've done it again! I even ran a search to check if this topic had been covered, but didn't see that thread. Cheers for the link.

[All]

I use both but tend to use the rear the most. Wow, that's the first time I've ever heard of anyone doing that.

[kickingzebra]

I didn't think I used the rear much until mine malfunctioned on one bike at paeroa....

Yes, both are very useful for control, and funnily enough, keeping the rear on the ground under hard braking is a function of a well modulated rear brake.

They are there for a damn good reason.

[discotex]

Recently, I've seen quite a few people saying they don't even bother with the rear brake--the argument being that, under hard braking, most of the weight will be on the front wheel, thus rendering the rear brake almost useless. Do you agree with this?

Yes. You said "almost useless" and that is correct on sporty bikes.



The dude that taught me to ride said that you get more stopping power using both.

If you're getting stopping power out of the rear on a sports bike then you probably have more front stopping power left.



Out of interest, does anyone know what the general racing practice is regarding the use of the rear brake?

Don't think there is one. Personally I use my front for stopping power and my rear for low speed manoeuvring. You hear of racers using both and racers using front only.

On the track I'm front only. Rear locks up instantly under heavy braking. I figure engine braking gives me as much a I can expect from the rear.

If I have to stop in an emergency the last thing I want to worry about is modulating my rear and I'm willing to give up 5% of my potential max stopping power to get the 95% done right. Why get 80% out of the front while you worry about the rear locking up.

That said, if you're in a perfect world and you're a perfect person you can probably stop slightly quicker using all the rubber you have on the road. Likewise if you're on a cruiser your rear will help heaps.

Can see the 2-finger vs 4-finger debate on the horizon now :jerry:

[R6_kid]

Does it follow that, if your rear tyre breaks contact with the road, you're using too much front brake?

No. It could also be too much rear brake.

I tend to say its better be near max of front braking potential, and only be using say 3/4 rear brake than, near max of rear and only enough front to keep the rear at full.

Physics (and practice) says that the front brake is generally* the most efficient out of the two when only one is used.

This is for straight line emergency braking where wiping off as much speed is your main goal.


*will vary dependant on bike type and braking equipment.

[Ixion]

I use both but tend to use the rear the most. I use the front to stop in a hurry and use both at the same time, but on the open road tend to mainly use the rear and I often just trail the rear in the corners too.

Agreed. I don't use brakes much. Front is for when I NEED to stop , like , NOW. With the rear added to help keep things steady. The argument that the rear has less effect than the front ignores the fact that the front brake destabilises, whereas the rear stablises.

Normal riding I just use the brakes to adjust speed on entry a wee bit, or to steady the bike through the corner (exspecially the old style hinged frame bikes, by now the hinge is usually well worn). And for that the rear brake is much better.

And the "ignore the rear" argument 'may' be valid on sprots bikes, in the dry. But the wet is another matter. Especially wet and oil in town. So I think it wise to get in the habit of using the front and rear for serious stopping, and the rear for fine adjustment.

[toebug]

Wow, that's the first time I've ever heard of anyone doing that.

My bike has fairly heavy engine braking so can wash off speed just by backing off the throttle. I also have a dirt bike back ground so tend to ride my bike that way to a degree. I do find though that late model litre bikes need the front brake alot more than my bike.

[discotex]

And the "ignore the rear" argument 'may' be valid on sprots bikes, in the dry. But the wet is another matter. Especially wet and oil in town. So I think it wise to get in the habit of using the front and rear for serious stopping, and the rear for fine adjustment.

Totally agree. Kinda forget about riding in the wet with such lovely weather.

Low speed, downhill corners, wet riding all benefit from judicious use of the rear brake.

[Paul in NZ]

Siiigghhh!

Answer = It depends....

If you are riding a modern sports bike - the rear is no more than a parking lot brake because an any velocity above walking speed the weight trasfer would lock up the rear IF it had a decent brake. (modern technology allows bikes to carry the weight higher so that weight transfer is encourage mainly so the rear tyre does not cut loose under acceleration)

Go back to pre WW2 and most makers did the opposite - had a deliberately weak front brake so it would never lock up on the crap roads they enjoyed... The rear was your main stopper and the weight was carried low as most bikes were slim singles or V twins..

So - on a cruiser - your rear brake is VITAL to fast stops BUT don't try in on a modern sports bike steaming into a down hill hairpin beacuse your rear wheel will have left terra firma about a half clenched buttock before you event thought of slowing down

[Ixion]

Oh, and with BMWs all bets are off, whole different ball game.

[homer]

Does it follow that, if your rear tyre breaks contact with the road, you're using too much front brake?

um no

having done this yesterday
i suggest you go try it .

yes both breaks will work ,thats why there there

but if you have to stop in a hurry , i mean from 100km in like 30 meters backs are a waste of time .

Yes i use both ,i cant not do , i learnt to ride dirt bikes .
but i know exactly when the rear starts to lock up , i feel it

think about it , if your hard on the front then what weights on the rear to even get grip .

exactly ......fuck all
you only need touch the rear break a little and it near locks up

[Mikkel]

Depending on the circumstances (how hard you are braking) and the bike you are riding (i.e bike configuration) it can sometimes be rendered 'useless'.

Indeed, as with just about everything else, it depends on the circumstance.

If you are braking *hard* on a sportsbike you won't gain anything by using your rear. The only thing you achieve is to risk locking up the rear and loosing stability...

Trying to brake too hard can also cause an accident... Trust me, you don't want to lock your front up if you can avoid it!
Better to hit that stationary truck at 10 km/h than "dismounting" your bike because you come too hard onto the brakes.
Stoppies might be the fastest way to stop - but most people can't maneuver in a desirable fashion if their rear wheel is in the air.

[homer]

Indeed, as with just about everything else, it depends on the circumstance.

If you are braking *hard* on a sportsbike you won't gain anything by using your rear. The only thing you achieve is to risk locking up the rear and loosing stability...

Trying to brake too hard can also cause an accident... Trust me, you don't want to lock your front up if you can avoid it!
Better to hit that stationary truck at 10 km/h than "dismounting" your bike because you come too hard onto the brakes.
Stoppies might be the fastest way to stop - but most people can't maneuver in a desirable fashion if their rear wheel is in the air.

Hows you today mate
hope you not to sore

[Mikkel]

Hows you today mate
hope you not to sore

Slightly off-topic. The HTFU pills (Voltaren 25 mg) works to some degree. But I have had better days for sure. The whiskey also helped a bit...

[sugilite]

Agreed. I don't use brakes much. Front is for when I NEED to stop , like , NOW. With the rear added to help keep things steady. The argument that the rear has less effect than the front ignores the fact that the front brake destabilises, whereas the rear stablises.

Normal riding I just use the brakes to adjust speed on entry a wee bit, or to steady the bike through the corner (exspecially the old style hinged frame bikes, by now the hinge is usually well worn). And for that the rear brake is much better.

And the "ignore the rear" argument 'may' be valid on sprots bikes, in the dry. But the wet is another matter. Especially wet and oil in town. So I think it wise to get in the habit of using the front and rear for serious stopping, and the rear for fine adjustment.

+1. Perfect :yes:

[All]

No. It could also be too much rear brake.

I tend to say its better be near max of front braking potential, and only be using say 3/4 rear brake than, near max of rear and only enough front to keep the rear at full.

Physics (and practice) says that the front brake is generally* the most efficient out of the two when only one is used.

This is for straight line emergency braking where wiping off as much speed is your main goal.


*will vary dependant on bike type and braking equipment.


um no

having done this yesterday
i suggest you go try it .

yes both breaks will work ,thats why there there

but if you have to stop in a hurry , i mean from 100km in like 30 meters backs are a waste of time .

Yes i use both ,i cant not do , i learnt to ride dirt bikes .
but i know exactly when the rear starts to lock up , i feel it

think about it , if your hard on the front then what weights on the rear to even get grip .

exactly ......fuck all
you only need touch the rear break a little and it near locks upI should have been clearer, this is what I meant: if your rear wheel raises above the road due to heavy use of the front brake, does this automatically mean that you're not getting as much braking as if you relaxed the front a bit and utilised the rear, too? [I'm talking about on a sports bike here, obviously cruisers are a different story]

[All]

Trying to brake too hard can also cause an accident... Trust me, you don't want to lock your front up if you can avoid it!
Better to hit that stationary truck at 10 km/h than "dismounting" your bike because you come too hard onto the brakes.
Stoppies might be the fastest way to stop - but most people can't maneuver in a desirable fashion if their rear wheel is in the air.It's quite possible to recover from locking the front wheel (provided you're not turning at the time :)). I was encouraged to do just that at an advanced course. You just have to immediately relax the pressure as soon as you realize it's locked up.

[Mikkel]

I should have been clearer, this is what I meant: if your rear wheel raises above the road due to heavy use of the front brake, does this automatically mean that you're not getting as much braking as if you relaxed the front a bit and utilised the rear, too? [I'm talking about on a sports bike here, obviously cruisers are a different story]

It shouldn't affect your stopping distance whether you do a stoppie or manage to keep the rear down, but still utilising all of your weight to provide friction at the contact patch.

If your rear wheel is carrying any weight and you don't use the rear brake at all - then there is still an amount of braking potential untapped, no matter how small it is.


It's quite possible to recover from locking the front wheel (provided you're not turning at the time :)). I was encouraged to do just that at an advanced course. You just have to immediately relax the pressure as soon as you realize it's locked up.

I don't doubt that. But one might be tempted to look down at the non-rotating wheel and think "hmmm, isn't that supposed to go round and round and... OUCH!" Besides, you brake faster with a rotating wheel than one that is locked up (static vs. kinetic friction).

[All]

It shouldn't affect your stopping distance whether you do a stoppie or manage to keep the rear downThere seem to be many here that disagree with your contention.


I don't doubt that. But one might be tempted to look down at the non-rotating wheel and think "hmmm, isn't that supposed to go round and round and... OUCH!" You should feel it lock up. I don't recommend looking down at your wheels when you're braking. :)


Besides, you brake faster with a rotating wheel than one that is locked up (static vs. kinetic friction).Of course, locking the front wheel should always be avoided. My point was only that it is possible to recover from.

[R6_kid]

I don't doubt that. But one might be tempted to look down at the non-rotating wheel and think "hmmm, isn't that supposed to go round and round and... OUCH!" Besides, you brake faster with a rotating wheel than one that is locked up (static vs. kinetic friction).

according to HDTboy, and some others - hard on the gas can actually save a slipping/locked front - of course this is in a racing cirmustance, not stopping for an inanimate object.

[Duc]

All modern development for MCs has been in front brake systems eg MonoBloc. Bike reviewers constantly remark on the improvement and performance in these systems over previous ones. (Check out Ducati and Augusta latest reviews).

I do not know of any major developments in rear brake systems apart from maybe linked systems.

I am sure this development and the cost of it is because the manufacturerers have worked out on the track and road, which brake is the main brake to use if you want to stop effectively.

For the record . I use front mostly and a bit of rear trail brake (occassionaly and down hill) on my Ducati. On my '76 Honda CB550 Cafe Racer its mostly Back brake because the front brakes have always been crap on these ( ie.virtually ineffective !) . The back brakes on this are ver efective butr require a different riding caution. Namely ....space.

[Swoop]

The rear brake is also handy when you are stopped in traffic - on a hill...
At least you can have your hands free for carrying on with your knitting or whatever.


Nobody has mentioned linked-brakes yet either. Bugger for trail braking though.

[All]

At least you can have your hands free for carrying on with your knitting or whatever.Or texting! [Apparently there are some clowns that actually do this...]

[Hitcher]

The dude that taught me to ride said that you get more stopping power using both.

The dude that taught you to ride was 100% correct.

[Hitcher]

Nobody has mentioned linked-brakes yet either. Bugger for trail braking though.

I had linked brakes on my ST1300. Indeed trail-braking is not an option. Despite what the "purists" may contend, linked brakes are lovely things. I prefer them to bike I have ridden with ABS, which I do not much care for. Riders just need to be aware of how they work compared to how unlinked brakes work and figure out the relative commitments required between right hand and right foot.

[All]

Why can't you trail brake with linked brakes?

[Hitcher]

Why can't you trail brake with linked brakes?

Because the braking is split between both controls: i.e. hand lever only = 66% front, 33% rear; foot lever only = 66% rear, 33% front. So the ability to "finesse" your rear brake with just a touch, also applies some braking force to the front. The effect is just not the same. I tried trail braking a few times with my ST, but could never get it to do what I wanted. FJR1300 with no linked brakes, different story.

[scumdog]

About 400+km since I last touched the rear brake pedal.

[onearmedbandit]

Using the rear brake, even on a sportsbike, will in effect lower the bikes cog giving more grip. It's not just a 'stamp on the brake pedal' thing, but controlled use of the back brakes.

[All]

Because the braking is split between both controls: i.e. hand lever only = 66% front, 33% rear; foot lever only = 66% rear, 33% front. So the ability to "finesse" your rear brake with just a touch, also applies some braking force to the front. The effect is just not the same. I tried trail braking a few times with my ST, but could never get it to do what I wanted. FJR1300 with no linked brakes, different story.I understand trail braking isn't just the rear brake; it refers to the gradual release of the brakes (front, rear, or both) up to the apex.

[Hitcher]

I understand trail braking isn't just the rear brake; it refers to the gradual release of the brakes (front, rear, or both) up to the apex.

Your definition is then different to mine. There is a big difference between what happens in a car and what happens on a bike.

[Ocean1]

Because the braking is split between both controls: i.e. hand lever only = 66% front, 33% rear; foot lever only = 66% rear, 33% front. So the ability to "finesse" your rear brake with just a touch, also applies some braking force to the front.

Interesting split ratios, is it adjustable? do you think you would have made much use of such an adjustment?

My use of brakes has traditionally been for more than just scrubbing speed, the back in particular is critical to changing the bike's attitude off road. I doubt I'll ever break the habit of at least covering the rear every time I use the front. The Buell's front brake is superb, the rear does lack feel though, and the engine braking can easily be enough to semi-lock the back wheel. That can be a good thing because while the back can step out a fair bit it's usually self-correcting and produces more effective braking than a total rear lock-up from a judicious stomp on the back brake. I’m still learning about the Buell, when to give it a nudge, and how much…

[Skyryder]

It's quite possible to recover from locking the front wheel (provided you're not turning at the time :)). I was encouraged to do just that at an advanced course. You just have to immediately relax the pressure as soon as you realize it's locked up.

This for most people is and automatic reflex to a locked up brake. Unfortunately sometimes the reflex is not fast enough.

Skyryder

[All]

This for most people is and automatic reflex to a locked up brake. Unfortunately sometimes the reflex is not fast enough.

SkyryderAlso, I think some people just freeze and/or grip the brake lever harder.

[Skyryder]

Recently, I've seen quite a few people saying they don't even bother with the rear brake--the argument being that, under hard braking, most of the weight will be on the front wheel, thus rendering the rear brake almost useless. Do you agree with this?

The dude that taught me to ride said that you get more stopping power using both.

Out of interest, does anyone know what the general racing practice is regarding the use of the rear brake?

The rear brake is usefull when braking if the bike is leaning over as in a turn. If applied with the correct amount of pressure the front will not lock as the pressure on the front brake need not be as severe due to the assist of the back brake. The secret here is having both work in tandem. The best way for this is to practice useing both when the bike is upright so that you get the 'feel' for the correct amount of pressure. Personaly if have to brake with the bike on a lean you have come in to hot. That's on the road. We've all done it so it's a usefull skill to learn useing both brakes in tandem. The real key is to do this under pressure and in an emergency so practice practice and more practice.

Skyryder

[Skyryder]

Also, I think some people just freeze and/or grip the brake lever harder.

I not about to disagree with you on this but I can only speak for myself. On the odd occasion I have had the front lock up I've released instantly and saved my arse. But if you are going down sometimes you are 'down before you know what happened. It's a bummer either way..........that's up or down.:bash:

Skyryder

[Hitcher]

Interesting split ratios, is it adjustable? do you think you would have made much use of such an adjustment?

Honda's "ratios" aren't adjustable. They use three-piston calipers front and rear. The hand lever works two calipers on the front and one on the rear. The foot pedal works two calipers on the rear and one on the front. Both levers = all calipers. Going like the clappers, stopping like the calipers!

[Ocean1]

Honda's "ratios" aren't adjustable. They use three-piston calipers front and rear. The hand lever works two calipers on the front and one on the rear. The foot pedal works two calipers on the rear and one on the front. Both levers = all calipers. Going like the clappers, stopping like the calipers!

Elegant simplicity, nice. Guess we can assume the pistons are all the same dia.

What was your issue with ABS? Was it fundamentally difficult to use or merely poor technical execution?

[Badjelly]

Elegant simplicity, nice. Guess we can assume the pistons are all the same dia.
Elegant simplicity is all very well, but I should have thought that on a bike there'd be some mechanism to limit the rear brake effort as the weight is transferred to the front. Like on my Ford Telstar SW.

[Ocean1]

Elegant simplicity is all very well, but I should have thought that on a bike there'd be some mechanism to limit the rear brake effort as the weight is transferred to the front. Like on my Ford Telstar SW.

Bike brake systems are generally way less sophistocated than a cars, perhaps one of the reasons is that independent control really is a desirable feature. I can see a GOOD independent ABS option being attractive though.

Also, that Telstar SW rear brake mechanism... you sure it's function isn't to increase bias to the back when there's a load in the back? Common feature on commercials.

[Badjelly]

Bike brake systems are generally way less sophisticated than a cars, perhaps one of the reasons is that independent control really is a desirable feature.

Yes, that's why I find it hard to believe that a manufacturer would discard independent control without including some mechanism to reduce the rear-brake contribution under hard braking.

There was a MotoGuzzi in the 70s that had a pedal that activated front & rear, plus a lever that activated only the front. So you could use the pedal for most braking, but add a bit of lever if you wanted to stop hard. Reviews suggested it worked quite well.


Also, that Telstar SW rear brake mechanism... you sure it's function isn't to increase bias to the back when there's a load in the back?

Er, yes.

[Mikkel]

There seem to be many here that disagree with your contention.

Wouldn't be the first time...

Anyway, if your bike and yourself constitute a total mass, M. Then the maximum amount of braking force you can achieve is equal to:

Ffriction = M*g*f

Where g is the gravitational acceleration (~9.8 m/s^2) and f is your static coefficient of friction. Unless there's a big difference between f for your front and rear tyre the magnitude of your braking force should remain unchanged regardless of the way weight is distributed between the two tyres.

If you want me to I'm happy to expand upon the above.

The front/rear brake issue is more important in regards to staying in control, maintaining stability and having the ability to maneuver out of danger.
I've failed at this once recently. All other times I've used my brakes I've been successful...

[discotex]

I understand trail braking isn't just the rear brake; it refers to the gradual release of the brakes (front, rear, or both) up to the apex.


Your definition is then different to mine. There is a big difference between what happens in a car and what happens on a bike.

Lost count of the times I've read it means front then read it means back. Seems to depend on the context.

In a racing context I believe it's talking about the front (maybe even both).

I.e. loading the suspension under braking then rather than having the forks rebound as you tip in you gradually let the brake off as the cornering forces take over.

I never understood why you'd do this before riding round Taupo but makes a significant difference to how the bike handles. It was somewhat a eurika moment when I got it right the first time.

On the street/open road I try to get my braking done well clear of the corner though.

[All]

Wouldn't be the first time...

Anyway, if your bike and yourself constitute a total mass, M. Then the maximum amount of braking force you can achieve is equal to:

Ffriction = M*g*f

Where g is the gravitational acceleration (~9.8 m/s^2) and f is your static coefficient of friction. Unless there's a big difference between f for your front and rear tyre the magnitude of your braking force should remain unchanged regardless of the way weight is distributed between the two tyres.
If the rear tyre has lost contact with the ground (due to really yanking on the front), then, yeah, there's a big difference between f for the front and rear. That's what I'm getting at. Take these two situations--in which would you stop in the least amount of time?

1. Really haul on the front hard so that the rear is 5 cm above the ground during the whole maneuver.
2. Brake hard on the front but not hard enough for the rear to rise. Also use the rear brake as much as possible, but keep it short of locking.

The consensus seems to be that the latter would provide the most effective braking. I genuinely don't know.

[All]

Lost count of the times I've read it means front then read it means back. Seems to depend on the context.

In a racing context I believe it's talking about the front (maybe even both).

I.e. loading the suspension under braking then rather than having the forks rebound as you tip in you gradually let the brake off as the cornering forces take over.

I never understood why you'd do this before riding round Taupo but makes a significant difference to how the bike handles. It was somewhat a eurika moment when I got it right the first time.

On the street/open road I try to get my braking done well clear of the corner though.I ran a search on Google and most sources that I read say that it's just any braking past the turn in point.

[Mikkel]

If the rear tyre has lost contact with the ground (due to really yanking on the front), then, yeah, there's a big difference between f for the front and rear. That's what I'm getting at. Take these two situations--in which would you stop in the least amount of time?

1. Really haul on the front hard so that the rear is 5 cm above the ground during the whole maneuver.
2. Brake hard on the front but not hard enough for the rear to rise. Also use the rear brake as much as possible, but keep it short of locking.

The consensus seems to be that the latter would provide the most effective braking. I genuinely don't know.

No mate - f doesn't change with the weight distribution. f is a physical constant that tells you how well the tyre in question sticks to the road.
I won't sit here and type in an exhaustive explanation - I'm sure wikipedia (http://en.wikipedia.org/wiki/Coefficient_of_friction) can do it for me.

I'd agree that 2. is better - not because it'll make you stop faster, but because you have more control, more stability and more maneuverability.
If 1. reduces your stopping distance then it is only because you get to a point where you can not brake as hard without doing a cartwheel... 1. and 2. should give the same stopping distances if the wheel only just leaves the ground.

[All]

No mate - f doesn't change with the weight distribution. How can there be any friction if the wheel is not in contact with the road?

[All]

1. and 2. should give the same stopping distances if the wheel only just leaves the ground.I just wonder if, in a real world situation, this is the case.

[Mikkel]

How can there be any friction if the wheel is not in contact with the road?

f is the coefficient of friction not the friction force. If there's no normal force there's no friction either (i.e. if the bike and rider are weightless there's no gravitational force and consequently no normal force).

[All]

f is the coefficient of friction not the friction force. If there's no normal force there's no friction either (i.e. if the bike and rider are weightless there's no gravitational force and consequently no normal force).OK, I'm totally out of my depth with physics terms; I never studied it. :)

[Mikkel]

I just wonder if, in a real world situation, this is the case.

If you do two experiments there's good chance you'll see a difference. If you do 1000 thousand I think you'll find that the average stopping distance for 1. and 2. are within one standard deviation of each other.

If you're not used to lifting the rear, doing so may cause you to freak out a bit and do stupid stuff. (i.e. locking the front and doing a faceplant) That is one thing I know from experience.

[avrflr]

Anyway, if your bike and yourself constitute a total mass, M. Then the maximum amount of braking force you can achieve is equal to:

Ffriction = M*g*f

Where g is the gravitational acceleration (~9.8 m/s^2) and f is your static coefficient of friction. Unless there's a big difference between f for your front and rear tyre the magnitude of your braking force should remain unchanged regardless of the way weight is distributed between the two tyres.

If you want me to I'm happy to expand upon the above.
You can't achieve that maximum on a motorbike in the dry with warm sticky tyres because (since the braking force is applied at the ground and the c of g is above the ground) you will raise the rear wheel, at which point the braking force you can apply decreases. Using the rear brake can help the suspension squat, lowering the c of g, and therefore increasing the amount of braking force you can apply without raising the rear wheel.

[Skyryder]

There was a MotoGuzzi in the 70s that had a pedal that activated front & rear, plus a lever that activated only the front. So you could use the pedal for most braking, but add a bit of lever if you wanted to stop hard. Reviews suggested it worked quite well.
Er, yes.


They still link brakes on the cruisers. Front is independant. Once you hit the brake pedal both front and back link up. I only use the brake pedal on the twisties then only for minor adjustments. Most of my braking is engine braking with adjustments prior to leaning the bike over............to hot then it's both front and rear hardish.

[dipshit]

OK, I'm totally out of my depth with physics terms; I never studied it. :)

Don't bother, he's talking engineering bollocks. What he is missing out on is the stability using the rear brake as well gives.

Have a look at these...

www.sportrider.com/ride/146_9510_motorcycle_braking_tips/index.html

www.sportrider.com/ride/146_0004_motorcycle_riding_skills/index.html

[Mikkel]

OK, I'm totally out of my depth with physics terms; I never studied it. :)

That's cool not a worry. I was just trying to illustrate the point that the stickiness of your tyres and how they grip the road in a given situation is the only thing that determines you "maximum stopping force". As said, this is pretty academic when considering some situations as there are other concerns that will prevent you from applying that force.


Don't bother, he's talking engineering bollocks. What he is missing out on is the stability using the rear break as well gives.

If you had bothered reading what was written you'd see that you are actually not correct with that statement...


You can't achieve that maximum on a motorbike in the dry with warm sticky tyres because (since the braking force is applied at the ground and the c of g is above the ground) you will raise the rear wheel, at which point the braking force you can apply decreases. Using the rear brake can help the suspension squat, lowering the c of g, and therefore increasing the amount of braking force you can apply without raising the rear wheel.

I take that what you mean is that there's a limit as to how much braking force you can apply without flipping the bike head over heels...
And true, the larger the vertical height from the centre of your front wheel to the centre of gravity the less force is takes to hoist the rear and flip it.
I see your point that using the rear at first will help to compress the fork without raising the centre of gravity. How much of an impact this has upon your actual stopping length I can't guess at.
Another way to prevent hoisting the rear would be to have a longer front fork and/or a higher degree of rake (increase the horisontal distance between the centre of the front wheel and the centre of mass).

[Ocean1]

Ffriction = M*g*f

Where g is the gravitational acceleration (~9.8 m/s^2) and f is your static coefficient of friction. Unless there's a big difference between f for your front and rear tyre the magnitude of your braking force should remain unchanged regardless of the way weight is distributed between the two tyres.

Can you demonstrate how static COF is related to dynamic friction?
Is the relationship between g and f linear wrt rubber/asphalt?

[Hitcher]

Gahhh! Here come the engineers and the physicists! Run, run to the hills!

[Swoop]

Throw them some pocket protectors to distract them!!!

[Mikkel]

Can you demonstrate how static COF is related to dynamic friction?
Is the relationship between g and f linear wrt rubber/asphalt?

Due to popular demand I'll flick you a PM if you're truly interested. Just let me know...

[Ocean1]

Due to popular demand I'll flick you a PM if you're truly interested. Just let me know...

Apparently we're not in that much demand. :scratch:

But don't bother dude, I've got some idea. :beer:

[sAsLEX]

If someone says you don't need them then smile and nod like you are agreeing
You are claiming you can beat some pretty handy racers then!


It's quite possible to recover from locking the front wheel

Try, on the gas at relatively low speed, locking the front. Most don't know what it feels lie and when it happens instead of relaxing will think something has gone wrong and do the completely wrong thing and squeeze harder!


About 400+km since I last touched the rear brake pedal.

I occasionally feather mine out and about, say once a week, to keep the surface rust away!


Using the rear brake, even on a sportsbike, will in effect lower the bikes cog giving more grip. It's not just a 'stamp on the brake pedal' thing, but controlled use of the back brakes.

Ah but do you need to use the brake to retard the rear wheel?


Due to popular demand I'll flick you a PM if you're truly interested. Just let me know...
Bugger it, lets have some mspaint physics!
<img src=http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=4699&d=1099893902>

[homer]

That's cool not a worry. I was just trying to illustrate the point that the stickiness of your tyres and how they grip the road in a given situation is the only thing that determines you "maximum stopping force". As said, this is pretty academic when considering some situations as there are other concerns that will prevent you from applying that force.



If you had bothered reading what was written you'd see that you are actually not correct with that statement...



I take that what you mean is that there's a limit as to how much braking force you can apply without flipping the bike head over heels...
And true, the larger the vertical height from the centre of your front wheel to the centre of gravity the less force is takes to hoist the rear and flip it.
I see your point that using the rear at first will help to compress the fork without raising the centre of gravity. How much of an impact this has upon your actual stopping length I can't guess at.
Another way to prevent hoisting the rear would be to have a longer front fork and/or a higher degree of rake (increase the horisontal distance between the centre of the front wheel and the centre of mass).

Maybe this was the actual point of safety of anit dive suspension

[Mikkel]

Apparently we're not in that much demand. :scratch:

But don't bother dude, I've got some idea. :beer:

Yeah, beers would be awesome. But I have had someone mentioning that combining drugs and alcohol is not necessarily a good idea ;)


Maybe this was the actual point of safety of anit dive suspension

I don't know. I guess you might loose some feeling with an anti-dive front suspension... That could be just a problematic, if not more so.

[terbang]

Don't bother, he's talking engineering bollocks. What he is missing out on is the stability using the rear break as well gives.
Yes there is a good arguement for stability, but what he fails to realise is that when you are doing a stoppie (intentional or not), the rear wheel, with its braking coefficient of "f" or not, is now just along for the ride.
I guess the manufacturers know a trick or two as well. Take a look at any sport bike and you will notice huge twin discs with multiple piston calipers on the front wheel and a token single disc (much smalller diameter) with only one or two pistons in the caliper on the rear. Its a pretty common theme across the spectrum of makers and sort of indicates where they think the braking should come from.. But hey, who are they and what would they know? They only build em eh...

[xwhatsit]

About 400+km since I last touched the rear brake pedal.

Did it fall off?

I seem to have taken a leaf out of Motu's book, and give my rear brake an absolute hammering. I trail brake with it in all corners, probably too much. I even find myself using it with the throttle on, which seems pointless, but I suppose it's a way of smoothing out the forces in the rear end. On gravel I barely take my foot off the pedal. The brake drum is usually very, very hot after a ride -- at one stage I was worried I'd rooted the rear wheel bearings and that's why it was so hot, so I went for a ride without touching the rear brake at all. How strange and awkward that was! Hub remained quite cool, however.

I don't know how people can ride around town without touching the rear brake. Trying to slow and change down gears smoothly, especially when you're not travelling dead-straight, is very hard. I find it hard to blip the throttle whilst squeezing the front brake, so the rear wheel tends to lock and skip from engine braking and no blip anyway.

[DEATH_INC.]

I see your point that using the rear at first will help to compress the fork without raising the centre of gravity. How much of an impact this has upon your actual stopping length I can't guess at.
Nope, you've missed it. Using the rear first compresses the REAR suspension as well as the front thereby lowering the cog, where using just the front extends the rear and compresses the front, moving the cog up and forwards. It works, on my old beast I hammer the rear to the point of overheating it, as the rear is so high that it stoppies too much without it....

[GaZBur]

You are claiming you can beat some pretty handy racers then!

Shhhheeeit No! I got back into racing again last year after a big break but I am assuming that because ALL asked this question he can't either. If he was expert enough to completely unweight the back without it losing control he would not need to ask. We are not all expert racers sadly. I use the back brake a lot - but for the control it gives as the stopping power is as we all know minimal.
Can someone enlighten me please on one point. Someone here said doing stoppies were the fastest way to stop, I always assumed that once the point of balance is passsed and the rear wheel is off the ground you had to ease up on the front brake to prevent a face plant situation, therefor it's less efficient than keeping the rear wheel down. If you can enlighten me please keep it realtively simple as I don't get the physics equations.
Thanks.
GaZBur

[All]

If he was expert enough to completely unweight the back without it losing control he would not need to ask.I don't pretend to be a racing expert, but my only aim was to gauge opinion on what the fastest way to stop was. My ability to unweight the back without losing control is irrelevant.

[All]

Don't bother, he's talking engineering bollocks. What he is missing out on is the stability using the rear break as well gives.

Have a look at these...

www.sportrider.com/ride/146_9510_motorcycle_braking_tips/index.html
Interesting link. That certainly points to using both brakes being the best way to stop.

[Mikkel]

Nope, you've missed it. Using the rear first compresses the REAR suspension as well as the front thereby lowering the cog, where using just the front extends the rear and compresses the front, moving the cog up and forwards. It works, on my old beast I hammer the rear to the point of overheating it, as the rear is so high that it stoppies too much without it....

Could you please explain to me how you can compress the front fork without raising the centre of mass (in relation to the centre of the front wheel of course)?

You just did - indeed that isn't possible without the rear suspension being compressed. Bearing that in mind I think you didn't read what you quoted.

Or, have I missed the point again? :whistle:

[GaZBur]

OK I just had this seat of the pants experience after picking my bike up from the shop today in the rain. Got tyres changed from Knobs to Road tyres for Levels on Sat.
Tried stopping with just the front brakes - no drama.
Tried stopping with just the back brakes - no drame but not quite as positive.
A car pulled out on me - I hit both brakes simultaneously - no drama. Either of the first two options would probably have seen me on thier roof!
PS Riding with two tyres draped over your sholder is not the same as having air bags on a bike. In fact they ride up onto your neck under extreme braking.

[White trash]

I only use the rear for launching the bike off the start line.

Although I hope to bag the use of a friends datalogger on a test day and begin experimenting with a couple of different things so I will know conclusively what suits me best.

[All]

PS Riding with two tyres draped over your sholder is not the same as having air bags on a bike. In fact they ride up onto your neck under extreme braking.Haha, I'll take that under advisement! :)

[avrflr]

I guess the manufacturers know a trick or two as well. Take a look at any sport bike and you will notice huge twin discs with multiple piston calipers on the front wheel and a token single disc (much smalller diameter) with only one or two pistons in the caliper on the rear. Its a pretty common theme across the spectrum of makers and sort of indicates where they think the braking should come from.. But hey, who are they and what would they know? They only build em eh...
Racers that used the rear brake while winning world championships:

Wayne Rainey
Carl Fogarty
Mick Doohan
Valentino Rossi

But what would they know?

[Badjelly]

Racers that used the rear brake while winning world championships:

Wayne Rainey
Carl Fogarty
Mick Doohan
Valentino Rossi

But what would they know?

OK, but it might be interesting to have a list of riders that didn't use the rear brake while winning world championships.

[All]

OK, but it might be interesting to have a list of riders that didn't use the rear brake while winning world championships.That would be really interesting. I'd be quite surprised if there were any.

[Subike]

do we use rear brakes?
do we use front brakes?
each of us rides to our own style
and a vast majority of us survive, and survive having heaps of fun doing it too
I prefer to use all THREE braking systems
or have you all forgotten the amount of braking power the engine has.
Good controlled braking can begine with decelleration via the engine
and if you know your ride well,
planning your corners ahead,
Not racing on a track
Not going exsessively fast
Then your engine brake can do all that is needed..leaving your rubberbands to do their best job well....keeping you right side up and smooth.
Nothing worse that fanging into a corner, braking like a school boy puling his pud, just to fine FUCK wrong gear for the exit.
No matter how good your brakes are, front or rear, use all three and ride smooth on the road.
But then you may call me a nana for going slower than the bike can perform.
But hey 30 years riding, and no cage has stopped me yet!
Some have come close
but I ride to the conditions and my ability.
My ability?......still learning

[All]

do we use rear brakes?
do we use front brakes?
each of us rides to our own style
and a vast majority of us survive, and survive having heaps of fun doing it too
I prefer to use all THREE braking systemsFor sure. But this thread is about the fastest way to stop, not personal preference as such.

[Mikkel]

For sure. But this thread is about the fastest way to stop, not personal preference as such.

No, it's about how to use the rear brake if you want to brake in the shortest possible distance.

Stopping the fastest way possible is to hit a solid object that is coupled strongly to terra firma. Any experiments to confirm this hypothesis are undertaken at your own peril!

[Motu]

I hammer the rear to the point of overheating it, ....

My rear disc turns blue and smokes after a bit of a fang down the road....but the front is just warm to the touch,and yet the front brake is my main stopper.Like Ixion I seldom use the brakes hard,I set up the corner before entering....brakes are used for fine tuning,and obviously I trail brake to the extreme.My way may not be the fastest way around a corner,but I'm only riding to impress myself,not others.

[All]

No, it's about how to use the rear brake if you want to brake in the shortest possible distance.Well, as the title is Rear brake usage, I thought that using brakes was a given. Also, there's the fact that I started the thread (so presumably I know what it's about). ;)

[dipshit]

Could you please explain to me how you can compress the front fork without raising the centre of mass (in relation to the centre of the front wheel of course)?


Next time you are out riding, try using both brakes when doing a hard stop at a set of traffic lights. As you have come to a complete stop, keep both brakes applied for a few seconds... then release the rear brake *first* while still holding the front brake on - and you should feel the rear of the bike rising up.

Using rear brake as well has pulled your bike down.

When you use front brake only, you are lifting the rest of the bike up.

One way creates a more stable bike under brakes... while the other way creates a more twitchy and nervous bike under brakes.

[homer]

My rear disc turns blue and smokes after a bit of a fang down the road....but the front is just warm to the touch,and yet the front brake is my main stopper.Like Ixion I seldom use the brakes hard,I set up the corner before entering....brakes are used for fine tuning,and obviously I trail brake to the extreme.My way may not be the fastest way around a corner,but I'm only riding to impress myself,not others.

You should only be trailing the rear to help turn thru the corner
it shouldnt be hot at all.
You should only do this if you start to run a little wide and then just a touch of rear is often enought to slow and help turn the bike a little more.
Have you riden trail bikes?
thats where you learn this

[Motu]

Have you riden trail bikes?


You'd never get me to ride one of those ugly chook chasers!

[Ixion]

...
Have you riden trail bikes?
thats where you learn this



You'd never get me to ride one of those ugly chook chasers!

:rofl: :motu::killingme

That's got to go into the 'Quote of the year'. Or the "Putting your foot in it' award.

Should I tell him about the Ducati in your gargre?

[Mikkel]

Also, there's the fact that I started the thread (so presumably I know what it's about). ;)

Yeah, that's a mistaken assumption I also have made on several occassions ;)


Next time you are out riding, try using both brakes when doing a hard stop at a set of traffic lights. As you have come to a complete stop, keep both brakes applied for a few seconds... then release the rear brake *first* while still holding the front brake on - and you should feel the rear of the bike rising up.

Using rear brake as well has pulled your bike down.

When you use front brake only, you are lifting the rest of the bike up.

One way creates a more stable bike under brakes... while the other way creates a more twitchy and nervous bike under brakes.

The question you quoted was actually meant as a rethorical question.

However, I have indeed noticed this. Seeing as when you are stationary on a flat surface I always assumed that this movement was due to the fact that the wheelbase changes slightly when you compress your suspension. While the brakes are applied the wheels can not move the slightest and the tension will remain until either of the brakes are released.
I could be wrong though...

It is also pretty easy to acheive the same situation if you stop on a steep slope and try playing around with holding the bike on front, rear and both brakes and letting go of either in different combinations.

[howdamnhard]

What R6 said.:clap:

Depending on the circumstances (how hard you are braking) and the bike you are riding (i.e bike configuration) it can sometimes be rendered 'useless'.

At the RRRS course we show the difference between using only the front, and only the rear, and that when applied correctly using both is the most efficient. It's all about contact patch (tyre) and weight transfer.

Some say that on a sportsbike you're braking is distrubuted as much as 90% front and 10% rear, and given the orientation of a sportsbike under hard braking you may find the rear wheel is a few mm or even a few centimetres or more off the ground (so yes, it's useless for now).

'correct' theory would have you initiate the rear brake momentarily before (practically the same time as) the front, and you are basically applying pressure to the levers exponentially until the point just before loss of grip/lockup (which can only be learnt through experience). And the main thing is that you dont let the wheel lock up of course!

Best thing to do is to get out and practice, and find what works for you... our bikes may all be 'the same', but one thing that works for one person may not work so well for you.

[dipshit]

The question you quoted was actually meant as a rethorical question.


No, you were just talking bollocks again trying to confuse matters...

DEATH_INC:
"Nope, you've missed it. Using the rear first compresses the REAR suspension as well as the front thereby lowering the cog, where using just the front extends the rear and compresses the front, moving the cog up and forwards. It works, on my old beast I hammer the rear to the point of overheating it, as the rear is so high that it stoppies too much without it"

You:
"Could you please explain to me how you can compress the front fork without raising the centre of mass (in relation to the centre of the front wheel of course)?
You just did - indeed that isn't possible without the rear suspension being compressed. Bearing that in mind I think you didn't read what you quoted. Or, have I missed the point again?"


...What I described is a practical real world example of what death_inc was talking about.

[Mikkel]

No, you were just talking bollocks again trying to confuse matters...

I then bow in deference to your greater wisdom.

That's sarcasm if you were in doubt.