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  1. #1
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    Interesting observation. Roundagon vs Cleansweep G2

    I had my bike on a trail that went 35 miles with a 7,000 foot drop and got to really try the brakes out for the first time.

    I have BB7s front and rear with a 203mm roundagon up front and a 185mm cleansweep in the rear. I have to admit I was wrong on my theory.

    First test, I got up to 30mph and braked somewhat gently and steadily until stopped on a 13% grade. I stopped in a marked off distance every time. My observations were the cleensweep although smaller didn't get as hot as the roundagon but it was close. I was stopping by dragging the brakes the whole time. These stops were at the limit of being able to touch them without burning myself instantly.


    Then I tried going faster but applying the brakes, letting off, applying again, letting off, until I was stopped. I did the same number of applications for each brake and this is where the real difference was. The cleansweep was pretty warm. The roundagon burned me pretty bad.

    I've always assumed that since the roundagon had more mass, it would take longer to heat up. This may still be true but the cleansweep cools so much quicker, in the real world it's going to run cooler under any normal condition.

    Regardless, they stopped me at 250lbs over and over from 30+mph without fail.

  2. #2
    meh....
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    Not really a fair/valid test. The rear brake doesn't do as much "work" as the front because of weight shift on the bike as you're going downhill, and that your weight shifts forward when you're stopping anyway.

  3. #3
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    Quote Originally Posted by Monte
    Not really a fair/valid test. The rear brake doesn't do as much "work" as the front because of weight shift on the bike as you're going downhill, and that your weight shifts forward when you're stopping anyway.

    Re-read the test. I stopped in the same distance every time. Weight and traction makes no difference because I never approached the limits of traction. Each brake does the same work stopping the same weight from the same speed in the same distance.

  4. #4
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    My opinion: too many variables in the test. Front vs rear brake, rotors of different sizes. But that's beside the point. I think if you accounted for those and tested a roundagon vs a clean sweep of the same size under the same conditions, you would get the same result. My understanding is that clean sweep rotors come with hydraulic systems precisely because they're designed to cool faster and not overheat the brake fluid; mechanicals do not suffer that problem, hence being able to keep costs down with a less intricately machined rotor.
    Quote Originally Posted by JonathanGennick View Post
    I am a poser. But forums.poser.com doesn't seem to exist, so I come here instead.

  5. #5
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    Quote Originally Posted by Slow Eddie
    My opinion: too many variables in the test. Front vs rear brake, rotors of different sizes. But that's beside the point. I think if you accounted for those and tested a roundagon vs a clean sweep of the same size under the same conditions, you would get the same result. My understanding is that clean sweep rotors come with hydraulic systems precisely because they're designed to cool faster and not overheat the brake fluid; mechanicals do not suffer that problem, hence being able to keep costs down with a less intricately machined rotor.
    Don't forget that Avid also sells the BB7 for about half the price of their cheapest hydraulic brake (Juicy 3). Even if the Cleansweep did help the BB7 perform better as well, Avid probably doesn't want to raise the price of the BB7 more to include the better rotor. People will only pay so much for a mechanical disc brake

    Actually, didn't the BB7 used to come with Cleansweep rotors a few years ago? EDIT: yep, they did

  6. #6
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    You need ABS on your brakes.

  7. #7
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    Quote Originally Posted by Slow Eddie
    My opinion: too many variables in the test. Front vs rear brake, rotors of different sizes. But that's beside the point. I think if you accounted for those and tested a roundagon vs a clean sweep of the same size under the same conditions, you would get the same result. My understanding is that clean sweep rotors come with hydraulic systems precisely because they're designed to cool faster and not overheat the brake fluid; mechanicals do not suffer that problem, hence being able to keep costs down with a less intricately machined rotor.

    Don't forget, I was testing a smaller cleansweep against a larger roundagon and the cleansweep still stayed cooler. I think that's pretty conclusive being that the cleansweep was at a disadvantage but came out on top.

    I wish you guys would get off the front vs rear. I was stopping in the same measured distance for both brakes. Same g-force. Front vs rear does not matter in this case.

  8. #8
    squish is good
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    Most scientific test ever.

    JK it really isn't.
    Bike good, work bad.

  9. #9
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    Quote Originally Posted by Clutchman83
    Most scientific test ever.

    JK it really isn't.
    ...but come on, we need posts like this so we could laugh at someone

  10. #10
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    This experiment is very scientific. Factors that make it very scientific and controlled are:
    1. Using very reliable gauge to measure temperature - hand
    2. Test sample is very comparable - 203mm vs 185mm
    3. Using precision equipment to apply same force - hand again - abeit different sides
    4. Test very similar conditions - both mount on a bike - only one in front where front wheel has practically unlimited traction
    5. Test bias - test was NOT blinded so tester conducted test w/ prejudices

    See? Very scientific experiment. Might I mention that there was an experiment by Sir Robert Bennett Bean that found 100% correspondence that black people's brains were smaller than white people's. Only when Franklin Mall in the US tried to duplicate results but using a blinded study found 0% correspondence whatsoever.

  11. #11
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    "1. Using very reliable gauge to measure temperature - hand"

    Level 1: Meh
    Level 2: Ow.
    Level 3: Oooow!
    Level 4: Owwa!!
    Level 5: !*%?!
    Level 6: Aaargh!!!

    Looks perfectly scientific to me.
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    What luck for rulers, that men do not think - Adolf Hitler

  12. #12
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    Quote Originally Posted by Clutchman83
    Most scientific test ever.

    JK it really isn't.
    No ****. I must've forgotten my heat sensor for my mountain bike ride.

    The plain and simple of it is the stopping distances were measured and kept consistant for every test. So was the speed. It was nohwere near the limit of traction even for the rear so front/rear bias plays no role. The only thing lacking are acutal temp measurements. There was enough difference in temp to feel it with my fingers which is all the proof I need.

    Really, I know it makes you feel good to try and pick others apart but besides your useless comment, explain to me why this is not valid.

  13. #13
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    Come on guys, just go through some of the OP's post history if you want to have some real laughs at boneheaded observations and theories.

  14. #14
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    Quote Originally Posted by vk45de
    This experiment is very scientific. Factors that make it very scientific and controlled are:
    1. Using very reliable gauge to measure temperature - hand
    2. Test sample is very comparable - 203mm vs 185mm
    3. Using precision equipment to apply same force - hand again - abeit different sides
    4. Test very similar conditions - both mount on a bike - only one in front where front wheel has practically unlimited traction
    5. Test bias - test was NOT blinded so tester conducted test w/ prejudices

    See? Very scientific experiment. Might I mention that there was an experiment by Sir Robert Bennett Bean that found 100% correspondence that black people's brains were smaller than white people's. Only when Franklin Mall in the US tried to duplicate results but using a blinded study found 0% correspondence whatsoever.
    Are you people too stupid to read my entire post?

    1. There was enough difference to feel by hand. When one burns you and the other will allow you to leave your hand on for a few seconds, that's a difference.

    2. Once again I'll repeat myself. The 185 (cleansweep) was at a size disadvantage yet still ran cooler so this is even more evidence to support the superiority of the cleansweeps.

    3. What does force matter when I'm applying just the right amount to stop in a pre-measured distance from the exact same speed?

    4. Once again, repeating myself, the measured distance vs the speed resulted in a slow steady stop. Traction of either tire played no role. I stopped just as slowly with the front as I did with the rear.

    5. Predjudices? I had no idea what was going to happen and I really didn't care. What I wanted was my front and rear rotors to look the same so I needed to figure out whether to buy another roundagon or another cleansweep.

    Seriously, everyone in this thread is so caught up in their superiority complex that they end up looking like the stupid ones.

  15. #15
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    Quote Originally Posted by Jerk_Chicken
    Come on guys, just go through some of the OP's post history if you want to have some real laughs at boneheaded observations and theories.
    Ah the peanut gallery is alive and well. Last I remember I tore you a new *******.

  16. #16
    i call it a kaiser blade
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    i find that since my fingers are calloused from bike maintenance, i use my tongue to test the "heat" of a brake.

    i burned myself on the front rotor after a ride, but the back didn't burn as bad.

    clearly meaning the front one was less efficient.

    i tried to run my finger over the rotor while i was riding once, too, but then i went over the front bars for some reason. clearly my brakes are to blame.

  17. #17
    squish is good
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    Quote Originally Posted by BuickGN
    Seriously, everyone in this thread is so caught up in their superiority complex that they end up looking like the stupid ones.
    HA!

    This one's gonna be fun.
    Bike good, work bad.

  18. #18
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    Quote Originally Posted by BuickGN
    Ah the peanut gallery is alive and well. Last I remember I tore you a new *******.
    Must have been the Pabst Blue Ribbon talking.



    There's always the NASCAR mullet as well:



    Anyhow, just like your old posts. You resort to calling everyone else a-holes, when your post history kind of shows either a bit of trolling, or an unhealthy obsession, coupled with lack of understanding, of the operation of brakes.

  19. #19
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    Quote Originally Posted by eat_dirt
    i find that since my fingers are calloused from bike maintenance, i use my tongue to test the "heat" of a brake.

    i burned myself on the front rotor after a ride, but the back didn't burn as bad.

    clearly meaning the front one was less efficient.

    i tried to run my finger over the rotor while i was riding once, too, but then i went over the front bars for some reason. clearly my brakes are to blame.
    That's very intelligent. You can't intelligently pick apart anything so you make smart ass comments. Another one that's too stupid to realize he's stupid.

  20. #20
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    Quote Originally Posted by Jerk_Chicken
    Must have been the Pabst Blue Ribbon talking.



    There's always the NASCAR mullet as well:



    Anyhow, just like your old posts. You resort to calling everyone else a-holes, when your post history kind of shows either a bit of trolling, or an unhealthy obsession, coupled with lack of understanding, of the operation of brakes.
    As usual, nothing to contribute. You follow me around like a little ***** looking for attention. One day you'll get off my nuts but I suppose negative attention is better than no attention for someone like yourself.

  21. #21
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    I won't take "you're stupid" from the likes of you.
    Quote Originally Posted by BuickGN
    3. What does force matter when I'm applying just the right amount to stop in a pre-measured distance from the exact same speed?
    Exemplary case - yes it does. Did you know that if you apply more force towards the beginning of the stop, your brakes will be cooler when you do stop?

  22. #22
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    "Another one that's too stupid to realize he's stupid."

    That should be another one who's too stupid...
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    What luck for rulers, that men do not think - Adolf Hitler

  23. #23
    i call it a kaiser blade
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    Quote Originally Posted by BuickGN
    That's very intelligent. You can't intelligently pick apart anything so you make smart ass comments. Another one that's too stupid to realize he's stupid.
    i just find your methodology hilarious.

    even if you took an IR temperature gun out there with you, i'd still laugh at you for comparing a front bb7 rotor with a back one, and of different size and specs for that matter--not even considering if you had the brakes adjusted properly.

    given the fact that i use a tiny rear bb7 brake rotor because anything bigger just tends to lock up the rear wheel (not a good thing), the cable slack, mechanical disadvantage, pad adjustment, pad wear, etc. are so random that if your funny little test were to mean anything, you'd have to try it under the same conditions with two similar FRONT rotors and use some kind of scientific (big word for book learnin) methodology to prove your ramblings.

    i use clean sweeps because i THINK they bite harder compared to roundagons.

    i have no proof for that.

    and neither do you in your assertions.

  24. #24
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    Quote Originally Posted by eat_dirt
    i just find your methodology hilarious.

    even if you took an IR temperature gun out there with you, i'd still laugh at you for comparing a front bb7 rotor with a back one, and of different size and specs for that matter--not even considering if you had the brakes adjusted properly.

    given the fact that i use a tiny rear bb7 brake rotor because anything bigger just tends to lock up the rear wheel (not a good thing), the cable slack, mechanical disadvantage, pad adjustment, pad wear, etc. are so random that if your funny little test were to mean anything, you'd have to try it under the same conditions with two similar FRONT rotors and use some kind of scientific (big word for book learnin) methodology to prove your ramblings.

    i use clean sweeps because i THINK they bite harder compared to roundagons.

    i have no proof for that.

    and neither do you in your assertions.
    But everything you cite doesn't matter. Explain to me why it matters if it's on the front or the rear when I'm no where close to the traction limits. I set a distance and speed that could be easily stopped with the rear brake with no locking.

    If I said the smaller rear is inferior because it gets hotter than the larger front, that would be dumb. But in fact the smaller rotor stayed cooler, that means something.

    And once again, get off this front vs rear thing. It makes no difference on these super easy stops. It only matters when the front braking exceeds the rear traction limits which did not happen in this case.

  25. #25
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    Quote Originally Posted by vk45de
    I won't take "you're stupid" from the likes of you.

    Exemplary case - yes it does. Did you know that if you apply more force towards the beginning of the stop, your brakes will be cooler when you do stop?
    Yes, and that's the first good argument in this thread. Thank you for that.

    I did my best to keep the stops linear. We're talking 10+ stops here, not just one and every time I had the same results.

    I understand this is not the most scientific test but I got the same results over and over again.

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