Interesting comparison test VIDEO about flexion Extralite/KCNC levers- Mtbr.com
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  1. #1
    El Toro
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    Interesting comparison test VIDEO about flexion Extralite/KCNC levers

    hi, a Spanish guy has made a flexion test using a measurement instrument (I don't know how do you say in English). This is NOT an Scientist test , but youŽll want to see these videos . He measured 0.15 mm. of flexion with EL:

    http://www.youtube.com/watch?v=AH8iid5hxkg

    and 0.60 mm. with KCNC

    http://www.youtube.com/watch?v=83O79OJiiWk

    Regards

  2. #2
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    That doesn't prove much... Who knows how much pressure was applied to each lever?

  3. #3
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    He must be a lefty

  4. #4
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    Well, obviously not very much force was being applied, as the guy was only using one finger (probably less than 20lbs of force). Also, you have to take into account that the lever blades only have like a 2:1 leverage ratio, so there's probably like <40lbs of force at the cable stop. I would never use those levers with a mechanical disc brake.

    Personally, I really really like my Dangerboy Mechanical Levers, they are pretty heavy but they are so solid that I don't feel any flex at all with a serious two finger pull (which can be in excess of 50lbs in panic mode).

    Mechanically, especially with parts designed for braking, there is a reason why stiffness is sooo important, mainly because the efficiency of the design is destroyed by any flex. All the energy goes into flexing the part when it should go into making you stop. Your fingers feel the flex and grip harder, but it only flexes more and the braking doesn't improve. At that point, your brain is not confident about your ability to control your speed. Personally, I really hate crappy braking systems, they add fear to my ride when I need it least.

    If you've ever had the pleasure to step on a Porsche brake pedal, you will know how wonderful a nicely setup braking system can be (really confidence inspiring, too).

  5. #5
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    Which is the weight of the levers DANGEROY?

  6. #6
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    Quote Originally Posted by ginsu2k
    Well, obviously not very much force was being applied, as the guy was only using one finger (probably less than 20lbs of force). Also, you have to take into account that the lever blades only have like a 2:1 leverage ratio, so there's probably like <40lbs of force at the cable stop. I would never use those levers with a mechanical disc brake.

    Personally, I really really like my Dangerboy Mechanical Levers, they are pretty heavy but they are so solid that I don't feel any flex at all with a serious two finger pull (which can be in excess of 50lbs in panic mode).

    Mechanically, especially with parts designed for braking, there is a reason why stiffness is sooo important, mainly because the efficiency of the design is destroyed by any flex. All the energy goes into flexing the part when it should go into making you stop. Your fingers feel the flex and grip harder, but it only flexes more and the braking doesn't improve. At that point, your brain is not confident about your ability to control your speed. Personally, I really hate crappy braking systems, they add fear to my ride when I need it least.

    If you've ever had the pleasure to step on a Porsche brake pedal, you will know how wonderful a nicely setup braking system can be (really confidence inspiring, too).
    all your speech about lost energy and i read you are using mechanical discbrakes???????

    c'mon guy - that's where you have lost eenergy in 1st place: friction within the cable

  7. #7
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    well...

    Quote Originally Posted by palmix
    hi, a Spanish guy has made a flexion test using a measurement instrument (I don't know how do you say in English). This is NOT an Scientist test , but youŽll want to see these videos . He measured 0.15 mm. of flexion with EL:

    http://www.youtube.com/watch?v=AH8iid5hxkg

    and 0.60 mm. with KCNC

    http://www.youtube.com/watch?v=83O79OJiiWk

    Regards
    flex on the KCNC is greatly affected by the amount of torque you apply on the main clamping bolt when mounting them. the extralites have seperate clamping bolts just for the clamping, on the KCNC these are also holding the lever blades. by thightening that bolt harder the levers sit much more secure on the handlebar. so if that main bolt isn't torqued hard enough it results in flex...pretty basic and easy to understand.
    if your brake is working well you will already laying in front of your bike before you would notice any flex anyway
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  8. #8
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    Quote Originally Posted by froniuss
    Which is the weight of the levers DANGEROY?
    I believe the entire Dangerboy brake w/lever weighs 125g a piece.


    all your speech about lost energy and i read you are using mechanical discbrakes???????

    c'mon guy - that's where you have lost eenergy in 1st place: friction within the cable
    Actually, the first place you are going to lose out is in the design of the brake lever as it converts your finger force into cable force, so technically, even with friction, the design of the brake lever should be as robust as possible. Deflections of nearly 1mm with less than ~20lbs of force is abysmal. Where I bike I can descend for nearly half an hour, so brakes are mission critical components.

    I think the main point is that those levers should only be paired with rim brakes. I know, Nino would never make this mistake.

    Also, I have three bikes and two of them are with mechanical disk brakes, mainly out of cost. One bike I already had the Dangerboy levers, so I needed a mechanical disk brake, and the other I already had some Shimano Dual Control levers so I was also stuck with mechanicals.

    BTW, MTBing is not the only thing I blow my money on.

  9. #9
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    Quote Originally Posted by ginsu2k
    Well, obviously not very much force was being applied, as the guy was only using one finger (probably less than 20lbs of force). Also, you have to take into account that the lever blades only have like a 2:1 leverage ratio, so there's probably like <40lbs of force at the cable stop. I would never use those levers with a mechanical disc brake.

    Personally, I really really like my Dangerboy Mechanical Levers, they are pretty heavy but they are so solid that I don't feel any flex at all with a serious two finger pull (which can be in excess of 50lbs in panic mode).

    Mechanically, especially with parts designed for braking, there is a reason why stiffness is sooo important, mainly because the efficiency of the design is destroyed by any flex. All the energy goes into flexing the part when it should go into making you stop. Your fingers feel the flex and grip harder, but it only flexes more and the braking doesn't improve. At that point, your brain is not confident about your ability to control your speed. Personally, I really hate crappy braking systems, they add fear to my ride when I need it least.

    If you've ever had the pleasure to step on a Porsche brake pedal, you will know how wonderful a nicely setup braking system can be (really confidence inspiring, too).
    It doesn't work that way. If you hand a weight from a rubber band and a steel rod that wieghs 2lbs, and lift the weight off the ground, the 2lbs for force you are lifting the weight with is still transferred to the mass equally. The only differnce is you need to lift your hand a lot higher with the rubber band as it stretches to get the mass off the ground. Equate this to modulation. A too rigid brake setup = poor modulation. Flex is designed into systems for this reason. Too much you get a spongy feel, too little, brakes act like an on/off switch.

    Have you ever seen the difference between racing/peformance clutch disks vs. street use clutch disks? Street clutch disks have a wave spring looking thing sandwiched in the middle of the friction pads to give it some deflection when the pressure plate makes contact. That and there are springs in the hub to soften engagement ever more. This gives you good modulation and helps you take off from a stop smoothly w/o stalling or spinning out. I ran a race clutch for a while in my muscle car from my high school days. It was a bear to drive. The car would shudder and shake when taking off from lights, but it engages more than positively in a race.

    I don't know which is better, or if this flex even matters. His test is far from scientific. If you want an apples to apples test, you'd need to place a load cell in between your brake pads and pull the levers until you get equal squeezing force on the rim. A lower leverage ratio lever will require you to pull on the lever hard, adding more force to making it flex. Then, you need a broader test sample, like som Avid, Shimano, Pauls, etc... levers to find out how much flex matters at all in the first place.


    BM
    "I've come to believe that common sense is not that common" - Matt Timmerman

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