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Rear Suspension And Gas


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The rear brake is used as an advanced skill in several types of situations in road racing. Can you be more specific about how using the rear brake will redistribute weight "for beter traction/drive"?

 

Thanks,

racer

 

G'day Racer

 

I've given this some thought and decided that this is what happens...

 

By applying the rear brake with the throttle on means something has to give. If the motor is unable to turn the rear wheel or has resistance, then it would want to spin itself around the rear wheel thus biasing weight towards the rear which in turn creates more friction between the the tyre and surface which enables more traction.

 

Does this sound plausible?

 

Willy

 

Applying the rear brake adds more weight to the front, not the rear. And, in any case, adding more weight and braking force together to the same wheel, front or rear, increases the load and stress on the contact patch which typically reduces the amount of available traction. If the front wheel is light to begin with, for instance when you are cresting a hill, dragging the rear brake can add weight to the front and help create more traction at the front. But, even if you are accelerating, dragging the rear brake counter-acts the acceleration and weight transfer to the rear, hence, why you can control a wheelie with the rear brake or bring the front down with it.

 

You're an argumentative sod Racer

 

Of course, applying rear brake in a deceleration mode will add more weight to the front as evidenced by nose dive, but we're talking applying rear brake under power.

To simplify, if you had a piece of rubber in your hand or sandpaper or timber and your ubbed them across a concrete surface, would friction be greater if you applied more weight to these? Same applies to tyres. Would you have any grip on the rear tyre when it is skipping across the tarmac because you are heavy on the front brakes?

 

I agree that braking into a corner can place extra stress on available front wheel traction as evidenced many times watching GP's. That is not to say that there is not more traction available due to weight transfer, more a case of simply overbraking/locking front wheel or just going beyond the limit of available traction.

 

You are correct when you say that the rear brake will bring the front down cresting a hill, as would deceleration. The point I'm making is to apply the rear brake WHILE accelerating.

 

Just finished work, had a few beers, will get back asap

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Applying the rear brake decreases acceleration, on or off the gas, and adds more weight to the front. Period.

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Wheelbase lengthening really doesn't come into it but yes, wheelbase will lengthen. So what? It's not as though there is any resistance to lengthening the wheelbase after all there is no wall in front of you same as there isn't when you are racing/riding.

 

Right. Only the mass of the machine and rolling friction to resist forward acceleration...which you don't have with the rear brake on. Not sure how good of a test this is either. Only one cuppa so far and I gotta leave for work. I'll think more about it.

 

As for video, I don't think so. How 'bout you sit on your bike in your garage, start it up, put it in first, apply the back brake, let out the clutch and you tell me what happens. It'll take about a minute. I've just done it.

 

What kind of bike do you have?

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I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

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Wheelbase lengthening really doesn't come into it but yes, wheelbase will lengthen. So what? It's not as though there is any resistance to lengthening the wheelbase after all there is no wall in front of you same as there isn't when you are racing/riding.

 

Right. Only the mass of the machine and rolling friction to resist forward acceleration...which you don't have with the rear brake on. Not sure how good of a test this is either. Only one cuppa so far and I gotta leave for work. I'll think more about it.

 

As for video, I don't think so. How 'bout you sit on your bike in your garage, start it up, put it in first, apply the back brake, let out the clutch and you tell me what happens. It'll take about a minute. I've just done it.

 

What kind of bike do you have?

G'day Racer

 

The bike's rear wheel offers the most resistance to forward movement as this is the one that has to do all the driving. What I'm saying is that most resistance comes from the rear wheel whereas the front wheel is "happy" to roll. Evidence?...Which one would wear the most in a 1/4 mile drag?

 

To understand better why the rear rises and forgetting all about chain pull, I thought this might help...

Picture the chain as merely the drive, it is rotating the rear wheel.

The rear wheel transfers that drive through the axle alone.

The axle transfers that drive via the swingarm to the swingarm pivot shaft which transfers it to the bike frame

That rear axle is below the swingarm pivot shaft.

Provided the suspension can keep the rear axle below the swingarm pivot shaft, then it will continue to try to push "under" the swingarm pivot point.

 

I have an 02 ZX636.

 

BTW, thanks for the interesting discussion.

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I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

 

I agree we may be missing each other but now I'm missing you as well.

 

Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

I don't think the position of the caliper has any bearing on this but I will stand corrected

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I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

 

I agree we may be missing each other but now I'm missing you as well.

 

Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

I don't think the position of the caliper has any bearing on this but I will stand corrected

It's one of the reasons why rear brake calipers have been moved over recent years.

Now regarding that chain pull thing: I'd have to reread it, however one thing that often gets overlooked is Newton's 1st law. F1=F2, for every action there's an equal and opposite reaction. Don't overlook opposing forces which often is not what we observe (ex. centripetal vs centrifugal force)

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Wheelbase lengthening really doesn't come into it but yes, wheelbase will lengthen. So what? It's not as though there is any resistance to lengthening the wheelbase after all there is no wall in front of you same as there isn't when you are racing/riding.

 

Right. Only the mass of the machine and rolling friction to resist forward acceleration...which you don't have with the rear brake on. Not sure how good of a test this is either. Only one cuppa so far and I gotta leave for work. I'll think more about it.

 

As for video, I don't think so. How 'bout you sit on your bike in your garage, start it up, put it in first, apply the back brake, let out the clutch and you tell me what happens. It'll take about a minute. I've just done it.

 

What kind of bike do you have?

G'day Racer

 

The bike's rear wheel offers the most resistance to forward movement as this is the one that has to do all the driving. What I'm saying is that most resistance comes from the rear wheel whereas the front wheel is "happy" to roll. Evidence?...Which one would wear the most in a 1/4 mile drag?

 

To understand better why the rear rises and forgetting all about chain pull, I thought this might help...

Picture the chain as merely the drive, it is rotating the rear wheel.

The rear wheel transfers that drive through the axle alone.

The axle transfers that drive via the swingarm to the swingarm pivot shaft which transfers it to the bike frame

That rear axle is below the swingarm pivot shaft.

Provided the suspension can keep the rear axle below the swingarm pivot shaft, then it will continue to try to push "under" the swingarm pivot point.

 

I have an 02 ZX636.

 

BTW, thanks for the interesting discussion.

 

Dear sir,

Pointing to tire wear does not prove your point. You cannot compare rolling resistance with the rearward force being applied from the engine through the rear tire. The rear tire must overcome the inertia of the bike AND continue powering thru just to maintain 0 (zero) acceleration.

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Ok, now we're getting somewhere.

 

TWIMC:

 

I grabbed my favorite technician at lunch today and we performed the rear brake test on several different motorcycles including a shaft drive cruiser, an old cage frame swingarm standard and a 2003 CBR600RR. (A big thank you to the anonymous service customers who unknowingly donated their bikes to unwittingly participate in this international forum test program :) ).

 

The results on the cruiser bike and near vintage standard were indeterminant at best. The shaft drive and cage frame swingarm had no perceptible motion.

 

The CBR600RR squatted like a b!t@h in heat.

 

That said... I need to eat before I throw a wobbly.

 

BRB

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Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

Why? Acceleration (or lack of it) is the single defining parameter for weight bias (and the most common condition that any motorcyclist might find oneself in when seeking more traction from the rear wheel).

 

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

More acceleration equals more weight on the rear wheel. Any brake equals less acceleration.

 

Less acceleration equals less weight on the rear wheel. Period. (Have you read A Twist of the Wrist?)

 

Or do you think you can pop a wheelie by applying the rear brake? (I think a world full of stunt riders would disagree.)

 

Here's my rear brake test:

 

Go pop a wheelie and apply the rear brake. What happens?

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I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

 

I agree we may be missing each other but now I'm missing you as well.

 

Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

I don't think the position of the caliper has any bearing on this but I will stand corrected

It's one of the reasons why rear brake calipers have been moved over recent years.

Now regarding that chain pull thing: I'd have to reread it, however one thing that often gets overlooked is Newton's 1st law. F1=F2, for every action there's an equal and opposite reaction. Don't overlook opposing forces which often is not what we observe (ex. centripetal vs centrifugal force)

 

Sorry, but that doesn't sound right to me. I will abstain from asking you for proof as I hope common sense will prevail.

The position of the caliper is only relevant to weight distribution i.e. if it is on the top of the swingarm, then this obviously alters the COG. If it is on top of the swingarm, then it is less likely to pick up debris from the road. If it is on top of the swingarm, then a pushing force is applied to the stay as opposed to a pulling force on the stay should it be under the rear axle. The way the rear caliper is set up on my bike i.e.with the stay an integral part of the swingarm where the caliper holder slots into lugs on the swingarm, wouldn't really matter much if the caliper was above or below the disc.

Are you the same Jaybird from BITOG btw?

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Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

Why? Acceleration (or lack of it) is the single defining parameter for weight bias (and the most common condition that any motorcyclist might find oneself in when seeking more traction from the rear wheel).

 

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

More acceleration equals more weight on the rear wheel. Any brake equals less acceleration.

 

Less acceleration equals less weight on the rear wheel. Period. (Have you read A Twist of the Wrist?)

 

Or do you think you can pop a wheelie by applying the rear brake? (I think a world full of stunt riders would disagree.)

 

Here's my rear brake test:

 

Go pop a wheelie and apply the rear brake. What happens?

I see your point.

But acceleration is only possible should the rear wheel have traction. A rear wheel spinning faster but not gripping does not equal acceleration and no further weight transfer is happening.

My point once again is that you can accelerate while applying rear brake creating drag which causes the rear spring to load, transferring weight to the rear wheel creating more traction. I don't know if I can put it any clearer than that. It's probably more an issue with dirt bikes so let's forget it.

Wheelies have never been my forte unfortunately.

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I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

 

I agree we may be missing each other but now I'm missing you as well.

 

Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

I don't think the position of the caliper has any bearing on this but I will stand corrected

It's one of the reasons why rear brake calipers have been moved over recent years.

Now regarding that chain pull thing: I'd have to reread it, however one thing that often gets overlooked is Newton's 1st law. F1=F2, for every action there's an equal and opposite reaction. Don't overlook opposing forces which often is not what we observe (ex. centripetal vs centrifugal force)

 

Sorry, but that doesn't sound right to me. I will abstain from asking you for proof as I hope common sense will prevail.

The position of the caliper is only relevant to weight distribution i.e. if it is on the top of the swingarm, then this obviously alters the COG. If it is on top of the swingarm, then it is less likely to pick up debris from the road. If it is on top of the swingarm, then a pushing force is applied to the stay as opposed to a pulling force on the stay should it be under the rear axle. The way the rear caliper is set up on my bike i.e.with the stay an integral part of the swingarm where the caliper holder slots into lugs on the swingarm, wouldn't really matter much if the caliper was above or below the disc.

Are you the same Jaybird from BITOG btw?

No I am not from BITOG

Common Sense is not a Common Virtue

Position of caliper does more than just COG and debris protection. Motorcycles have evolved and placement of componentry is not as arbitrary as "let's put it there because it fits" anymore.

Anywho, I think I'm getting "stupider" by the minute. Peace.

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Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

Why? Acceleration (or lack of it) is the single defining parameter for weight bias (and the most common condition that any motorcyclist might find oneself in when seeking more traction from the rear wheel).

 

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

More acceleration equals more weight on the rear wheel. Any brake equals less acceleration.

 

Less acceleration equals less weight on the rear wheel. Period. (Have you read A Twist of the Wrist?)

 

Or do you think you can pop a wheelie by applying the rear brake? (I think a world full of stunt riders would disagree.)

 

Here's my rear brake test:

 

Go pop a wheelie and apply the rear brake. What happens?

I see your point.

But acceleration is only possible should the rear wheel have traction. A rear wheel spinning faster but not gripping does not equal acceleration and no further weight transfer is happening.

 

Let's try to apply your "theory" to a real world situation then.

 

If I was stationary stuck in the mud or snow, applying the rear brake would do nothing as I am not moving. However, I could slide my fat butt back and (compressing the rear suspension in the process) transfer a bit of weight to gain some traction. But that is due to my butt moving, not the suspension compressing. And, in that scenario, dragging the rear brake if the rear wheel was spinning, might compress the rear and cause the bike to slope rearward which might alter the static weight balance toward the rear to help the spinning wheel bite (but not very much).

 

Once I start moving out of the mudhole, continuing to drag the rear brake might help to the degree that the rear wheel continues to spin, but, the more traction I get, the more it will transfer potential weight forward, ie. without the brake, I could accelerate harder and transfer more weight rearward than applying the rear brake might, if it could. Remember the wheelie example. It's primary effect would be to slow me down now that I am making progress out of the mudhole. Once in motion (accelerating), the only practical use I can think of would be to slow or stop the spinning wheel (to help gain traction)... like it was designed to do. But, that is about slowing the spinning wheel more than weight transfer. Which is why advanced roadracers (and I imagine dirtbikers) on especially powerful machinery use it when exiting corners to control rear wheelspin under acceleration, not to transfer weight to the rear for more traction. They are already transfering exponentially more weight under acceleration than dragging the rear brake ever would if it could.

 

My point once again is that you can accelerate while applying rear brake creating drag which causes the rear spring to load, transferring weight to the rear wheel creating more traction.

 

No. Loading of the rear spring in that scenario is not due to weight transfer, it is due to force from the motor being transmitted to the spring via the rear suspension geometry.

 

I don't know if I can put it any clearer than that. It's probably more an issue with dirt bikes so let's forget it.

Wheelies have never been my forte unfortunately.

 

Blah blah blah. PUSSY. You're really quite a whiney little sod aren't you? Typical bully that runs away when he can't win or gets his nose bloodied a bit.

 

(ETA: This last was meant as an in kind jestful poke for continued and unneccesary name calling by you here in this thread, Willy. We've been able to avoid the flaming and other sorts of personal attacks found on other forums here and I think it would be nice if we could continue to do so. Thanks.)

 

That said... dirtbikes have never been my forte. In any case, any acceleration will do more to transfer weight to the rear than the rear brake ever could... if it could at all once you begin to accelerate. Once you are moving, the "weight transfer" created by the brake goes forward no matter the slope of the bike rearward.

 

Look, I see the picture of mechanical forces you are trying to paint. But, just like the effect of chain pull compressing the rear suspension is far outweighed by the effect of the accelerating rear wheel which overhwelms it, the potential for weight transfer you imagine is far outweighed by the weight transfer of acceleration. I fail to see any practical value beyond controlling wheelspin... like it was designed to do. Which is more about the wheel than the weight.

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No I am not from BITOG

Common Sense is not a Common Virtue

Position of caliper does more than just COG and debris protection. Motorcycles have evolved and placement of componentry is not as arbitrary as "let's put it there because it fits" anymore.

Anywho, I think I'm getting "stupider" by the minute. Peace.

 

Apologies. I didn't mean to infer that you lacked commonsense. Peace

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I don't know if I can put it any clearer than that. It's probably more an issue with dirt bikes so let's forget it.

Wheelies have never been my forte unfortunately.

 

Blah blah blah. PUSSY. You're really quite a whiney little sod aren't you? Typical bully that runs away when he can't win or gets his nose bloodied a bit.

 

 

 

 

 

That's not nice.

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Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake.

 

Why? Acceleration (or lack of it) is the single defining parameter for weight bias (and the most common condition that any motorcyclist might find oneself in when seeking more traction from the rear wheel).

 

 

It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction.

 

More acceleration equals more weight on the rear wheel. Any brake equals less acceleration.

 

Less acceleration equals less weight on the rear wheel. Period. (Have you read A Twist of the Wrist?)

 

Or do you think you can pop a wheelie by applying the rear brake? (I think a world full of stunt riders would disagree.)

 

Here's my rear brake test:

 

Go pop a wheelie and apply the rear brake. What happens?

I see your point.

But acceleration is only possible should the rear wheel have traction. A rear wheel spinning faster but not gripping does not equal acceleration and no further weight transfer is happening.

 

Let's try to apply your "theory" to a real world situation then.

 

If I was stationary stuck in the mud or snow, applying the rear brake would do nothing as I am not moving. However, I could slide my fat butt back and (compressing the rear suspension in the process) transfer a bit of weight to gain some traction. But that is due to my butt moving, not the suspension compressing. And, in that scenario, dragging the rear brake if the rear wheel was spinning, might compress the rear and cause the bike to slope rearward which might alter the static weight balance toward the rear to help the spinning wheel bite (but not very much).

 

Once I start moving out of the mudhole, continuing to drag the rear brake might help to the degree that the rear wheel continues to spin, but, the more traction I get, the more it will transfer potential weight forward, ie. without the brake, I could accelerate harder and transfer more weight rearward than applying the rear brake might, if it could. Remember the wheelie example. It's primary effect would be to slow me down now that I am making progress out of the mudhole. Once in motion (accelerating), the only practical use I can think of would be to slow or stop the spinning wheel (to help gain traction)... like it was designed to do. But, that is about slowing the spinning wheel more than weight transfer. Which is why advanced roadracers (and I imagine dirtbikers) on especially powerful machinery use it when exiting corners to control rear wheelspin under acceleration, not to transfer weight to the rear for more traction. They are already transfering exponentially more weight under acceleration than dragging the rear brake ever would if it could.

 

My point once again is that you can accelerate while applying rear brake creating drag which causes the rear spring to load, transferring weight to the rear wheel creating more traction.

 

No. Loading of the rear spring in that scenario is not due to weight transfer, it is due to force from the motor being transmitted to the spring via the rear suspension geometry.

 

I don't know if I can put it any clearer than that. It's probably more an issue with dirt bikes so let's forget it.

Wheelies have never been my forte unfortunately.

 

Blah blah blah. PUSSY. You're really quite a whiney little sod aren't you? Typical bully that runs away when he can't win or gets his nose bloodied a bit.

 

(ETA: This last was meant as an in kind jestful poke for continued and unneccesary name calling by you here in this thread, Willy. We've been able to avoid the flaming and other sorts of personal attacks found on other forums here and I think it would be nice if we could continue to do so. Thanks.)

 

That said... dirtbikes have never been my forte. In any case, any acceleration will do more to transfer weight to the rear than the rear brake ever could... if it could at all once you begin to accelerate. Once you are moving, the "weight transfer" created by the brake goes forward no matter the slope of the bike rearward.

 

Look, I see the picture of mechanical forces you are trying to paint. But, just like the effect of chain pull compressing the rear suspension is far outweighed by the effect of the accelerating rear wheel which overhwelms it, the potential for weight transfer you imagine is far outweighed by the weight transfer of acceleration. I fail to see any practical value beyond controlling wheelspin... like it was designed to do. Which is more about the wheel than the weight.

G'day Racer,

"argumentative sod" is something my dad always used to say to me and there was no malice intended. That's always been the trouble with forums, facial expressions/body language don't exist and well...you know what I mean. If I could sort out how to post those icons below, I'd use one and there'd be no misunderstanding. Anyway, I'm sorry if I upset anyone, wasn't my intention.

 

Onto other things...

 

What you said about using the rear brake is complete bullshit

 

(joking).

 

It's true, it is used to control wheelspin. Dirt riding, I find it much easier to control what the rear wheel is doing coming out of a corner using the rear brake.

Strange though isn't it? You'd think you would have more sensitive control through the use of your hand in backing off the throttle rather than using a foot in a sock in a boot to control things. Maybe there is more to the rear wheel braking than this. It may be about controlling the suspension. I'm just putting it out there. Nothing wrong with thinkin' (insert smiley icon).

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Here are a few. I'll post more later when I have more time. You just need to remove the extra space before the last character to activate.

 

 

:lol : = :lol:

 

: ) = :)

 

; ) = ;)

 

: P = :P

 

 

I can't make the smiley board here work so I use the ones I've collected over the years. Some work here, a few of my favorites don't.

 

later

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  • 3 months later...
To whom it may concern:

 

Once you accept or grok that chain pull is always working to extend the suspension, raise the rear of the bike and/or pull the swingarm down, the next realization is that the forward motion of the rear wheel is also trying to push itself under the bike (ultimately lifting the front wheel) which also works to extend the suspension, raise the rear and/or pull the swingarm down.

 

So, there are actually two "component force vectors" being applied to the swingarm to create one "composite" force vector. At that point, the question becomes, which component is dominant or stronger, ie. which is more responsible for the fact that the rear of the bike raises up under acceleration? Chain pull acting to pull the swingarm down? Or the forward force of the rear wheel trying to push itself under the bike?

 

And then, just how dominant is that component? Are they relatively close or is one WAY stronger than the other? And does that relationship remain consistent across the acceleration curve?

 

racer

 

 

I am from Belgium and very interested by this subject. I agree with racer. The dominant force who extend the suspension is the chain pull because it is +/- 4 time stronger than the driving force at the rear wheel. What you have to see is that the 2 forward forces vectors are applied (with their direction, sense and intensity) at the rear axel because there is only a bearing between the wheel and the swingarm, and then no torque can be transmitted between the wheel and the swingarm. That is not always easy to imagine but that's the reality. ;-)

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Of course, applying rear brake in a deceleration mode will add more weight to the front as evidenced by nose dive, but we're talking applying rear brake under power.

To simplify, if you had a piece of rubber in your hand or sandpaper or timber and your ubbed them across a concrete surface, would friction be greater if you applied more weight to these? Same applies to tyres. Would you have any grip on the rear tyre when it is skipping across the tarmac because you are heavy on the front brakes?

 

I agree that braking into a corner can place extra stress on available front wheel traction as evidenced many times watching GP's. That is not to say that there is not more traction available due to weight transfer, more a case of simply overbraking/locking front wheel or just going beyond the limit of available traction.

 

You are correct when you say that the rear brake will bring the front down cresting a hill, as would deceleration. The point I'm making is to apply the rear brake WHILE accelerating.

For that point, I agree with Willy. Yes, you can accelerate with your foot on the rear brake. Then, since the caliper is fixed on the swingarm (not only through a bearing like with the wheel), the rear caliper try, during braking, to lower the swingarm pivot and then compress the shock, even during a acceleration... You have then a little more rear grip due to the little squat rear weight transfer, but less driving force because the brake application. Then you can change for a moment your geometry with the rear brake application... :)
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For that point, I agree with Willy. Yes, you can accelerate with your foot on the rear brake. Then, since the caliper is fixed on the swingarm (not only through a bearing like with the wheel), the rear caliper try, during braking, to lower the swingarm pivot and then compress the shock, even during a acceleration... You have then a little more rear grip due to the little squat rear weight transfer, but less driving force because the brake application. Then you can change for a moment your geometry with the rear brake application... :)

 

What would be the use or application for this (using the rear brake during acceleration)?

 

CF

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For that point, I agree with Willy. Yes, you can accelerate with your foot on the rear brake. Then, since the caliper is fixed on the swingarm (not only through a bearing like with the wheel), the rear caliper try, during braking, to lower the swingarm pivot and then compress the shock, even during a acceleration... You have then a little more rear grip due to the little squat rear weight transfer, but less driving force because the brake application. Then you can change for a moment your geometry with the rear brake application... :)

 

What would be the use or application for this (using the rear brake during acceleration)?

 

CF

 

 

 

I don't do this with my CBR on the track but with my CRF on MX track to give more traction on the rear in certain corners...

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For that point, I agree with Willy. Yes, you can accelerate with your foot on the rear brake. Then, since the caliper is fixed on the swingarm (not only through a bearing like with the wheel), the rear caliper try, during braking, to lower the swingarm pivot and then compress the shock, even during a acceleration... You have then a little more rear grip due to the little squat rear weight transfer, but less driving force because the brake application. Then you can change for a moment your geometry with the rear brake application... :)

 

What would be the use or application for this (using the rear brake during acceleration)?

 

CF

 

 

 

I don't do this with my CBR on the track but with my CRF on MX track to give more traction on the rear in certain corners...

 

OK, I'll bite. What kind of turns/what situation would you use this for? I'm not expert in the dirt, and ride very rarely, but I like it.

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I'm not going to say I have ANY dirt track experience, but wouldn't applying the brake while accelerating decrease the dig the knobbies(?) would get from under acceleration? Or does applying the rear brake somewhat "load" the chassis for a boost to allow more dig when you release the rear brake? Like the compression we get from holding the front brake and spinning the rear tire? I'd still think it was the actual momentum from acceleration that would be the deciding factor. There's a whole other world out there. Who knew?

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