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  1. #1
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    Hope Mono adjustments

    I was testing my calipers-hope mono m4's before installation. i inserted the disc into the caliper, and pulled the brake lever. the clearance is extremely small, and i'm worried that when i finally install them, there will be brake drag and very bad disc rotor rub. i know clearance is usually small with dual sided calipers, but is there any way to enlarge the pad distance?

    also, the front lever depresses closer to the bar than the rear lever. how do i make them depress the same?
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  2. #2
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    Install the brakes first, if you have problems after that - come back.. There is no way you can test the Hope brakes without installing them.

    The Hope Mono M4 is "self adjusting". Before the install, use some flat object the push all the pistons to the bottom. Then make sure that you use shims to center the caliber to the disk.

    They should be just fine after that. You can fine tune the levers with the screw in the levers.

  3. #3
    pj.
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    Misctwo, I wouldn't worry about the clearance. Once they are in use, they'll sit just clear of the rotor - only a couple of thou at most.

    As for the levers being uneven - the engagement point is adjustable (lever reach). Use a ruler to measure between the bars, and the levers. If they start off the same, but compress to different position, then it's likely to be either air in the system, a rotor out of true, or worn pads.

    I wouldn't recommend doing anything just now. Stick them on the bike, align the calipers (with the pads out), true the rotors, adjust the lever reach, zip tie the levers to the bars overnight, ride, and go from there.

  4. #4
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    Quote Originally Posted by pj.
    Misctwo, I wouldn't worry about the clearance. Once they are in use, they'll sit just clear of the rotor - only a couple of thou at most.

    As for the levers being uneven - the engagement point is adjustable (lever reach). Use a ruler to measure between the bars, and the levers. If they start off the same, but compress to different position, then it's likely to be either air in the system, a rotor out of true, or worn pads.

    I wouldn't recommend doing anything just now. Stick them on the bike, align the calipers (with the pads out), true the rotors, adjust the lever reach, zip tie the levers to the bars overnight, ride, and go from there.

    thanks PJ. question again though, what does ziptying the levers to the bars overnight do? does that adjust engagement point? if it means there is air in the system, would I have to bleed it?
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  5. #5
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    Any air bubbles in the lines are compressed when you pull the lever in. This makes it easier for the bubbles to overcome the viscosity of the brake fluid and lets them float to the top of the line and out into the reservoir.

  6. #6
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    Quote Originally Posted by Furrner
    Any air bubbles in the lines are compressed when you pull the lever in. This makes it easier for the bubbles to overcome the viscosity of the brake fluid and lets them float to the top of the line and out into the reservoir.

    y'all just rocked my world. now, kickoff time!
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  7. #7
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    Not correct.

    If you check stokes law.

    For low reynolds number - Drag is proportional to r the radius of the bubble.
    Fd = 3*mu*PI*V*(2r)

    But boyancy is proportional to the volume or r^3.

    Think about a series of bubbles rising to the surface in a diving video. Small bubbles = slow, big bubbles = fast.



    Quote Originally Posted by Furrner
    Any air bubbles in the lines are compressed when you pull the lever in. This makes it easier for the bubbles to overcome the viscosity of the brake fluid and lets them float to the top of the line and out into the reservoir.

  8. #8
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    Quote Originally Posted by heatstroke
    If you check stokes law.

    For low reynolds number - Drag is proportional to r the radius of the bubble.
    Fd = 3*mu*PI*V*(2r)

    But boyancy is proportional to the volume or r^3.

    Think about a series of bubbles rising to the surface in a diving video. Small bubbles = slow, big bubbles = fast.
    ok so, if he is not correct, what does it do to depress the levers overnight?
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  9. #9
    pj.
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    Itís a quick fix to spongy levers

    Quote Originally Posted by misctwo
    ok so, if he is not correct, what does it do to depress the levers overnight?
    Itís a time-tried method Ė do a search.


    [Heatstroke Ė I believe the effects of boundary layer, and surface tension outweigh dynamic drag]

  10. #10
    pj.
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    if 'aint broke, don't fix it

    Seriously though, I wouldn't do anything right now. Definitely donít open the bleed nipples. Fit the brakes, and then see if you have any problems.

  11. #11
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    Agreed,

    its surface tension not drag.

    I was just correcting the earlier statement about small bubbles and viscous forces.

    Quote Originally Posted by pj.
    Itís a time-tried method Ė do a search.


    [Heatstroke Ė I believe the effects of boundary layer, and surface tension outweigh dynamic drag]

  12. #12
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    All of that is true only in a free suspension which you don't have in hydraulic lines. The bubble size that can form will completely obscure the line (and not allow fluid to pass therefore not allowing the bubble to rise), shrinking the bubble size allows the bubble to float upwards in the lines.

  13. #13
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    Quote Originally Posted by pj.
    Seriously though, I wouldn't do anything right now. Definitely donít open the bleed nipples. Fit the brakes, and then see if you have any problems.
    word. shouldn't be a problem....shimming looks to be a pain..
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    That is true, you cannot compare the two very different situations. Bubbles of air in the ocean are in a basically infinite environment in a realtively un-viscous liquid, and brake fluid is a vicsous fluid in a 2mm (?) brake line. The air bubble size is approaching the ID of the line, by compressing the bubble you put the bubbles in an environment where they are relatively small in comparison to the fluid they are in. As with most fluid dynamics formulae those will provide accurate predictions for fluid flow under 'perfect' conditions, but become very inaccutate when testing in less than ideal situations.

  15. #15
    pj.
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    Yeah, it is, but at least you only have to do it once

    Quote Originally Posted by misctwo
    word. shouldn't be a problem....shimming looks to be a pain..
    Donít know if you have considered facing the mounts. Supposedly it aligns the caliper better to the rotor, and gives a better feel. It might be an idea to ask your local bike shop how much they would charge.
    Last edited by pj.; 02-07-2005 at 09:12 AM.

  16. #16
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    Quote Originally Posted by pj.
    Seriously though, I wouldn't do anything right now. Definitely don?t open the bleed nipples. Fit the brakes, and then see if you have any problems.

    Hey...been a while...

    Anyway if you all remember, i had hope monom4 questions--i installed my monos, and the front brake is perfect. the rear brake, however, is spongy, and after some time, while depressed, the lever actually closes in toward the handlebar, finally touching it.

    obviously air in the line. i don't want to mess with rebleed right now, [SIZE=2]ain't got time.[/SIZE] gotta ride tunnel this w/e, and worry bout it later. still plenty of power.

    but is there any way to rid the air, other than rebleed, or does the ziptie on lever trick work great? there's a little stretch of cable that runs upwards and then back down, which can actually trap a bubble. should i mount the bike upright so the line allows the air to seep completely up the line into the resevoir?
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  17. #17
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    Quote Originally Posted by misctwo
    Hey...been a while...

    Anyway if you all remember, i had hope monom4 questions--i installed my monos, and the front brake is perfect. the rear brake, however, is spongy, and after some time, while depressed, the lever actually closes in toward the handlebar, finally touching it.

    obviously air in the line. i don't want to mess with rebleed right now, [SIZE=2]ain't got time.[/SIZE] gotta ride tunnel this w/e, and worry bout it later. still plenty of power.

    but is there any way to rid the air, other than rebleed, or does the ziptie on lever trick work great? there's a little stretch of cable that runs upwards and then back down, which can actually trap a bubble. should i mount the bike upright so the line allows the air to seep completely up the line into the resevoir?
    Yes that is the point, to get any bubbles to run back to the reservoir. Position the bike so the bubbles can run upwards in the line.

  18. #18
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    Quote Originally Posted by Grumpy
    Yes that is the point, to get any bubbles to run back to the reservoir. Position the bike so the bubbles can run upwards in the line.

    Yes it worked. Amazing. but still just a tad spongy. the pressure on the levers are almost equal now. going to leave the lever pressed for the day. i'm very easy to impress. thanks grumpy!
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  19. #19
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    Face The Fork and Frame Mounts

    if you dont have fun setting up hopes or magura's cause they are going to rub if you dont on 90% of bikes becuase the mounts are almost never straight.

  20. #20
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    Quote Originally Posted by scooterman
    Face The Fork and Frame Mounts

    if you dont have fun setting up hopes or magura's cause they are going to rub if you dont on 90% of bikes becuase the mounts are almost never straight.
    Absolutely! Even if they don't actually rub a slight angular misalignment can make the brakes perform poorly and be more likely to squeal (when the caliper pistons aren't completely square against the backs of the pads when they are on the disc)

  21. #21
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    I noticed that the mounts on my FL100RLT were off a bit. I ended up just using a different number/combination of shims and that seemed to do the trick. I guess it was a 'quick fix' option to facing the mount, but the caliper is centered and the brakes are golden!
    Bottoms up!
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