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  1. #1
    S'Cruzer pierce's Avatar
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    rear v-brakes hitting leg

    until fairly recently, I'd not used v-brakes on anything... my old road bikes all had campy sidepulls, my vintage mountain bike had shimano deore cantis, and my newer mountain bike has disks... My old cruiser I've had for 30+ years had a sturmey-archer drum rear brake and a diacompe sidepull front, something I was never real happy with... So, I added V-brakes to the old cruiser bike via brazing on the posts, and they worked great. I was a convert.




    Then that old funky cruiser frame cracked at the too-thin seat tube, so I built up another pseudo-cruiser using a small hybrid frame,


    then decided it was too small and transplanted everything onto this larger hybrid frame


    on both these last two bikes, the noodle sticking out of the left side of the rear v-brake touches my thigh when that side is fully extended. rather annoying. if I lower the seat a little so my leg doesn't fully extend, it goes away but then I don't get full leg extension.

    now, this 2nd frame came with cheap shimano cantis, I suppose I could go back to them, but I really like the smooth easy power of linear pull aka 'v' brakes. is this just an issue with the frame geometry and the somewhat short seat stays on these two frames, and there's nothing I can do about it?
    Last edited by pierce; 07-20-10 at 11:32 AM. Reason: changed 'right side' to 'left side', I always get left right and right wrong. :-/

  2. #2
    Senior Member meanwhile's Avatar
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    You need to fit a cable guide to the seat tube:

    http://sheldonbrown.com/cables.html#routing

  3. #3
    S'Cruzer pierce's Avatar
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    Quote Originally Posted by meanwhile View Post
    You need to fit a cable guide to the seat tube:

    http://sheldonbrown.com/cables.html#routing
    not sure I follow, nor do I see any such on the article, other than the picture showing the sidepull install on a vintage lugged roadie and how long the cable should be. on this frame, the rear brake and both derailleur cables route under the top tube, held in place with three sets of three brazeons...

    if the cable is secured too close to the v-brake, then it doesn't have enough flex and the noodle-side of the vbrake will be constrained and not move freely.

    if you meant a cable guide for a canti, sure, I have that, I took it off the bike (it fit on the middle of the seat clamp QR shaft) when i removed the factory cantis.... I'm trying to figure out if there's any way I can make the v-brakes work without switching back to cantis.

  4. #4
    Senior Member meanwhile's Avatar
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    Quote Originally Posted by pierce View Post
    not sure I follow, nor do I see any such on the article, other than the picture showing the sidepull install on a vintage lugged roadie and how long the cable should be. on this frame, the rear brake and both derailleur cables route under the top tube, held in place with three sets of three brazeons...
    Your frame is lacking in braze-ons (or you haven't used them). That's why you need a seat post cable guide. Or you need a cable guide somewhere close to there and to take out the slack in the cable. A the moment you have an exaggerated version of "Too long" how-not-to photo. You've broken at least 3 of the 4 "commandments" that Brown gives on that page and getting things right requires some sort of cable guide near the seat post.

    If you can't make things right using Brown's guide... well, then you probably need to take the bike to a pro. Brown is as good it gets. But if you look again you shouldn't find things hard. Even a piece of tape around the top tube near the seat would help, together with shortening the cable.
    Last edited by meanwhile; 07-20-10 at 12:15 PM.

  5. #5
    coprolite fietsbob's Avatar
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    tighter noodle bend, there are many available bend shapes [QBP] and Zip tie the Housing to the seatpost.

    may come out above the rear stay U bend plate , but be closer in.

  6. #6
    S'Cruzer pierce's Avatar
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    I guess I need to take a closeup picture of the back brake install on this Crossroads. this frame came with cantis, and I refitted it with vbrakes.

    my point was, a V-brake needs a certain amount of flexibility in the last few inches of the cable, as the noodle itself moves from side to side when you apply the brakes. if those last few inches are too tightly constrained, or have too sharp of a bend, then the v-brake won't center properly.

    k, new pics...


    If make that cable _any_ shorter, the v-brake doesn't center properly.

  7. #7
    S'Cruzer pierce's Avatar
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    Quote Originally Posted by fietsbob View Post
    tighter noodle bend, there are many available bend shapes [QBP] and Zip tie the Housing to the seatpost.

    may come out above the rear stay U bend plate , but be closer in.
    actually, there aren't that many noodles. http://viewer.zmags.com/publication/...#/ec27acee/212

    I just realized I have a 135 deg. which I'd used on Cruiser v1.2 (the first bike in my opening post), but maybe that jagwire 135 has a narrower/sharper bend.

  8. #8
    coprolite fietsbob's Avatar
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    Then ... Consider the other V brake .. Cane Creek Direct Curve, No noodle at all.

    Or Magura's Hydrostop it doesn't even use a cable.

    Its >The < Hydraulic RimBrake. HS 22 or the somewhat more costly HS 33

    I happen to really like Mine.
    Last edited by fietsbob; 07-22-10 at 11:15 PM.

  9. #9
    S'Cruzer pierce's Avatar
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    Quote Originally Posted by fietsbob View Post
    Then ... Consider the other V brake .. Cane Creek Direct Curve, .
    oh.



    cool.

    no sheet. very cool.


    so... you unhook the cable from the top there? yeah, that looks simple and sweet. even easier to install right.

    I like simple solutions.

  10. #10
    Senior Member meanwhile's Avatar
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    Quote Originally Posted by pierce View Post
    I guess I need to take a closeup picture of the back brake install on this Crossroads. this frame came with cantis, and I refitted it with vbrakes.

    my point was, a V-brake needs a certain amount of flexibility in the last few inches of the cable, as the noodle itself moves from side to side when you apply the brakes. if those last few inches are too tightly constrained, or have too sharp of a bend, then the v-brake won't center properly.

    k, new pics...


    If make that cable _any_ shorter, the v-brake doesn't center properly.
    OK: you believe that a cable for v-brake needs lots of slack to work. Now go to your LBS and take a look a one done by a professional. See the (very large) difference?

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