Brakes, I can't work this out .....

canaryv
canaryv Posts: 37
edited June 2010 in Road beginners
The rear brake on my road bike works supebly - it's almost literally a stop on a sixpence job. My front brake on the other hand won't stop me at all, completely useless.

I've gor Ultegra so they should be good and I've changed the pads, checked the cables, cleaned the wheel rims, taken it into two different bike shops to check over but still I'm no further forward - First shop said it was contaminated brake pads and changed them again, second said the front was simply at the worse end of 'working properly' but the rear was at the top end. Can't fault wither shop as both gave it their best shot but this can't be right, surely they should have similar stopping power.

Any ideas would be really appreciated as it is hitting my confidence when I'm riding - It's even got to the stage where I'm looking forward to uphill bits more than down and that's just not right !

Comments

  • Hals1967
    Hals1967 Posts: 231
    Sounds daft, but is the quick release on the front brake open or opening when you're riding ?

    1967 Engine
  • canaryv
    canaryv Posts: 37
    thanks Hals but no, I've tried having the brake in all sorts of positions though; dead close to the wheel so it's almost rubbing or loosened so its well away and has some distance to travel and I need to give the lever a good tug. Makes no difference. I'm stumped.
  • canaryv
    canaryv Posts: 37
    PS Hals - Just read your post on your first century, what a great effort, completed my first a few weeks ago too in about the same time. Didn't hit 48 mph though but with potential for speeds like that you can understand why I want TWO reliable brakes.
  • plankton_brain
    plankton_brain Posts: 99
    have you tried swaping the calipers over? that would show if its calipers or levers that are the weak link.
    If its calipers leave the good ones on the front, thats where you need the power
  • desweller
    desweller Posts: 5,175
    I usually notice a reduction in braking performance if the pads are contaminated with aluminium bits from the rim, or if the rims are dirty. Since you've changed the pads, if I were you I'd give the rims a good scrub with some hot water. You might also want to scrub the brake pads at the same time as, if it is down to oily rims (fnar fnar), the pads might have been contaminated again.
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  • Hals1967
    Hals1967 Posts: 231
    plankton_brain wrote:
    have you tried swaping the calipers over? that would show if its calipers or levers that are the weak link.
    If its calipers leave the good ones on the front, thats where you need the power

    I wish I had Plankton for brains - that's a great idea !

    1967 Engine
  • sub55
    sub55 Posts: 1,025
    Hals1967 wrote:
    plankton_brain wrote:
    have you tried swaping the calipers over? that would show if its calipers or levers that are the weak link.
    If its calipers leave the good ones on the front, thats where you need the power

    I wish I had Plankton for brains - that's a great idea !

    won`t fit :roll:
    constantly reavalueating the situation and altering the perceived parameters accordingly
  • Hals1967
    Hals1967 Posts: 231
    That's why he's got Plankton for brains :lol:

    1967 Engine
  • neeb
    neeb Posts: 4,473
    What did you try cleaning the rims and brake blocks with? Try acetone, that should definitely remove any oily contamination. Try also realigning the brake pads, is it possible that they could be "toeing in" or out, or otherwise not making uniform contact with the rims? Also check they are nicely in the middle of the rims and in the same position on each side. If you loosen the bolts that hold the pads on just enough so that they can move around easily but not flop around, and then pull hard on the brake lever, you should be able to get them to align perfectly with the rims. Then re-tighten the bolts.

    It's certainly not a good situation to be in - if anything you want the front brake to be more powerful to avoid the risk of locking up the back wheel, that's why campagnolo brakes use double pivot at the front and single at the rear.
  • curium
    curium Posts: 815
    neeb wrote:
    What did you try cleaning the rims and brake blocks with? Try acetone, that should definitely remove any oily contamination. Try also realigning the brake pads, is it possible that they could be "toeing in" or out, or otherwise not making uniform contact with the rims? Also check they are nicely in the middle of the rims and in the same position on each side. If you loosen the bolts that hold the pads on just enough so that they can move around easily but not flop around, and then pull hard on the brake lever, you should be able to get them to align perfectly with the rims. Then re-tighten the bolts.

    It's certainly not a good situation to be in - if anything you want the front brake to be more powerful to avoid the risk of locking up the back wheel, that's why campagnolo brakes use double pivot at the front and single at the rear.
    Toeing in is good, no? My Tricross demands regular toeing to minimise brake shudder.
  • neeb
    neeb Posts: 4,473
    Toeing in is good, no? My Tricross demands regular toeing to minimise brake shudder.
    Shouldn't be necessary with a good set of stiff road brakes. The tricross has cantilver brakes, right? I used to get all sorts of trouble with cantis and V brakes re: squealing and shudder on MTBs and cross bikes, but have never had any issues at all with high quality road bike brakes (campagnolo ones at least).

    With any rim brakes, once the blocks have worn a little the surfaces will be parallel to the rims in any case. I think the toeing in thing just helps a bit when initially setting up wobbly cross/MTB brakes... :wink:

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