| Author |
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Jim_sb
| | Posted on Thursday, February 16, 2006 - 12:27 pm: | 
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Hello Thunderbox,
You are correct, we are in complete agreement.
I like your "pushing harder with less apparent effort" wording. That is exactly on point.
Best,
Jim in Santa Barbara |
Bomber
| | Posted on Thursday, February 16, 2006 - 12:32 pm: |
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this is one area in which I've never agreed with the factory and many of the buell faithful --
while it is certainly true that locking up the rear brake is bad, I maintain the same attitude toward brake power as I do engine power -- while it is certainly possible to have too much (absolute horsepower corrupts absolutely?), I'd rather decide how much brake to use, rather than having the facotry decide how much brake I use
I use the rear brake very often -- for very low speed steering (parking lots), settling the bike just in advance of, and sometimes through, thurn in for a corner, certainly whenever I go "off road" (gravel on shoulders) -- I was very dissatisfied with my tuber's rear brake when I bought it, but managed to get it performing to a point where I felt it was acceptable
luckily, the two other people on the planet who think like I do can always call Al at American Sport Bike and fix the problem ;-} |
Blake
| | Posted on Thursday, February 16, 2006 - 01:43 pm: |
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Buell rear brake calipers are not dual piston, they are single piston floating calipers.
Is anyone disagreeing with the following?:
"On clean pavement, all/100% of available emergency braking power resides entirely in the front brake."
I guess I should clarify that the above applies to sporting bikes, not big heavy cruisers or touring bikes that will skid the front tire before the rear begins to lift. And of course the front tire needs to be something with adequate grip, like a sport-touring tire or better. |
Lowflyer
| | Posted on Thursday, February 16, 2006 - 01:56 pm: |
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I have skidded the front and rear tires simultaneously on the Uly on clean pavement. I think the EBP resides almost entirely in the front. As long as the back tire maintains contact with the road while the rear brake is applied, I disagree with the 100% number. |
Bomber
| | Posted on Thursday, February 16, 2006 - 01:59 pm: |
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blake -- you are absolutely correct --
not every use of a brake involves emergency braking, of course, which makes the discussion a little more involved, and much more interesting |
Josh_
| | Posted on Thursday, February 16, 2006 - 02:09 pm: |
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I haven't seen this posted here yet so...
Remember it is for all intents and purposes impossible to lock up the rear brake ... unless you pull the clutch in. |
Jim_sb
| | Posted on Thursday, February 16, 2006 - 02:13 pm: |
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Blake,
No disagreement here.
I suspect more accidents have been caused by inadvertent rear brake lockup on the street than by having a rear brake that is not as effective as desired.
Regards,
Jim in Santa Barbara |
Henrik
| | Posted on Thursday, February 16, 2006 - 02:53 pm: |
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Jim, I see one downside to your solution of adjusting the rear brake lever: I think, that with the lever adjusted down, you will bring your ankle joint into further extension, at which point you may have less dexterity/fine control, thus making it more difficult to finely modulate the rear brake?
Just a thought.
For that reason I've installed a smaller rear disk on the SV, and since that wasn't enough, I'll have the disk drilled as well. If that's still not enough, I'll go searching for a bigger bore master cylinder - and most likely screw all the previous work up 
Henrik |
Blake
| | Posted on Thursday, February 16, 2006 - 02:55 pm: |
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"I have skidded the front and rear tires simultaneously on the Uly on clean pavement."
You may have thought the road surface was clean and dry, it obviously was not. If the rear tire is not floating/skipping over the road surface, you are not using 100% of the available braking power. Period. |
Blake
| | Posted on Thursday, February 16, 2006 - 02:56 pm: |
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Again, on a clean dry road surface. |
Blake
| | Posted on Thursday, February 16, 2006 - 02:58 pm: |
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What Jim said. If you use the rear brake in a panic/emergency stop scenario on dry, clean pavement, you are asking for trouble, or you are not getting close to using 100% of the available braking power on a sport bike. |
Thunderbox
| | Posted on Thursday, February 16, 2006 - 03:02 pm: |
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Henrik you would need a smaller bore on the master cylinder to increase pressure. |
Jim_sb
| | Posted on Thursday, February 16, 2006 - 03:15 pm: |
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Hi Henrik,
Agreed.
I will explain my motivations.
I high-sided a GS500E once - panic stop on the street - doing 45mph. There was a dense grove of trees on the right side of the road I was on. No driveways or vehicles in sight.
All of a sudden a vehicle came flying out of the trees, up the short embankment (trees were very close to the road) and into my lane. There was oncoming traffic, I had no other choice but to try and stop as rapidly as humanly possible at the moment. This was when I was riding on a learner's permit and prior to taking the MSF course. I've learned a LOT since then...
Anyway, I locked up the rear (way too easily I might add). The cager, realizing her error, stopped after consuming half of my lane.
My choices at this point were to:
A. Continue my skid straight ahead into her car. I could not have stopped in time.
B. Release rear brake, regain steering and perform an emergency swerve (just on my side of the yellow stripe - there was oncoming traffic) to avoid the cage.
I chose option B.
The GS500E snapped mightily back into line, shot my arse into the sky. I refused to let go of the bars and had a great view of my bike from the "blimp" perspective with my arse above my head.
I miraculously came down on the bike, regained control and swerved around the car (and remained on my side of the center line).
This all happened very fast. But in my judgement I could not have stopped (skidding) without hitting the car.
The end result was I have:
A. Tremendous respect for the ugliness that can be caused by a high-side.
B. Knowledge that if I ever do lock up the rear brake at speed I really don't want to release it.
C. Adjusted the rear brake pedal on all my bikes to make it very difficult to cause an inadvertent lockup.
There are times when the rear lockup is desirable, as already stated. There are times when it's fun, too.
WRT my Uly, I plan to go the other way and make the rear brake a little more usable by raising the pedal.
Best,
Jim in SB |
Henrik
| | Posted on Thursday, February 16, 2006 - 04:14 pm: |
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Dave; thanks. I didn't make that clear in my previous post, but on the SV I'm trying to go the other way. I have too much rear brake and need a lot less.
Jim; good points all.
Henrik |
Blake
| | Posted on Thursday, February 16, 2006 - 04:52 pm: |
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"I have too much rear... and need a lot less."
You really should quit obsessing about that. |
Lowflyer
| | Posted on Thursday, February 16, 2006 - 07:41 pm: |
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"You may have thought the road surface was clean and dry, it obviously was not."
It's apparently more obvious to you now than it was to me at the time. I reckon we differ in our definitions of braking power. For me it means any deceleration caused by actuating the brakes. That means anytime the tires are on the ground and both brakes are actuated, the braking force is divided regardless of the road surface conditions. 100% is a very definitive figure and that is at the heart of my disagreement.
(Message edited by lowflyer on February 16, 2006) |
Henrik
| | Posted on Thursday, February 16, 2006 - 09:49 pm: |
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Now, now Blake |
Windrider
| | Posted on Thursday, February 16, 2006 - 11:09 pm: |
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Wow, a lot of interesting and varied opinions about the rear brake and proper use of brakes on motorcycles.
Here is more of my 2 cents:
It is quite a complex task to complete a perfect stop on a motorcycle. During the course of a rapid stop the effectiveness of the rear brake changes as more weight is transferred to the front tire from the rear tire. Thus, to get the most effective performance from the rear brake the rider must quickly apply maximum braking force on the rear brake at the beginning of the stopping effort and then taper off on the rear brake as the bike slows down and nears a stop.
The key is to remember that the rear wheel is carrying 50% of the weight of the bike and rider at the beginning of the stop and therefore it can help to haul the bike down. Once the stopping force is applied weight is thrown to the front wheel and the then the rear wheel carries very little weight and thus can not provide much stopping force.
In order to stop a motorcycle in the shortest distance possible you must use both brakes. If you doubt this, go to a empty parking lot, pick a line to start from, cruise over this line at a fixed speed and stop the bike as fast as you can using the front brake. Mark the spot, then try it with only rear brake. Finally, try again using both brakes and using the rear as hard as possible at the beginning of the effort and then tapering off on rear brake force as the bike nears a stop. Using both brakes you will achieve your shortest possible stopping distance.
I practice stopping techniques every Spring and use both brakes at every stop so that my mind and body react automatically to get the quickest stop possible when a deer jumps out in front of me or a cell phone yacking cager suddenly swerves into my lane.
David Hough describes the physics involved in stopping a motorcycle better in his excellent book "Proficient Motorcycling" which should be in every motorcyclist's library.
Ride on. |
Dragon_slayer
| | Posted on Thursday, February 16, 2006 - 11:33 pm: |
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Hey, you forgot the best use of that rear brake. When I park my bike, I hang my helmet off the rear brake pedal and use it like a parking brake!
No seriously, low speed dirt and gravel: rear brake; high speed dry pavement: front brake; normal street riding: both brakes; ice, snow, or rain: any brake and pray! |
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