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Trek 7.2 FX - braking noise

stfc1stfc1 Posts: 505
edited March 2010 in Workshop
First of all, apologies for the fact this is a hybrid rather than a true road bike query, but I posted in the commuting workshop forum and it seems a bit of a ghost town. I'm happier in the road forums and there is so much bike knowledge in here that I hope there might be some crossover. So...

Does anyone know if the 2009/10 model of this bike is notorious for being especially noisy when braking? I'm starting to think there is something wrong with it.

Mrs stfc1 had a 2007/08 model until it was crushed by a dump truck late last summer (fortunately she wasn't but it was close). The shop she bought the (largely silent!) original from replaced the damaged one with a new one, and ever since she has had to endure a ridiculously noisy front brake.

Remedies I have tried:
Cleaning the rims
Toeing in the pads
Replacing the pads with Kool Stop Salmons
Replacing the Salmons with cartridge pads
Tightening all connecting bolts
Sanding the surface of the brake pads
Fitting old-school MTB brake booster

Some of these things have worked in the very short term, but the noise soon returns. Could it be that the wheel is out of true, would this be a cause of noise?

I'm starting to get concerned now that there might even be a safety issue, although the stopping capabilities of the brakes are decent, because we're talking loud, loud screeching here, not just the odd squeak. Could there be something wrong with the forks or frame that means slight braking vibrations are being amplified to such a ridiculous degree? Mrs stfc1 is reluctant to ride her bike it's so bad, and I'm at my wit's end trying to sort it for her. Even a very good LBS couldn't do much on a quick inspection, though I'm on the verge of taking it to them and asking them to do whatever it takes.

Thanks for any light anyone can shed on this issue...

Posts

  • keef66keef66 Posts: 13,286
    I'm not familiar with the bike; what kind of brakes does it have? V's, cantis, single / dual pivot calipers? And what make
  • stfc1stfc1 Posts: 505
    keef66 wrote:
    I'm not familiar with the bike; what kind of brakes does it have? V's, cantis, single / dual pivot calipers? And what make

    Tektro V-brakes, so I would have expected them to be okay...
  • keef66keef66 Posts: 13,286
    Just had a squint at the current spec on Evans' website. that says Tektro V brakes, no model number, so I'm guessing they are one of the cheaper components that allow them to sell a bike for that price.

    I've always found that cheap V and cantilever brakes squeal, and assume it's because the sloppier manufacturing tolerances allow the arms to vibrate on the pivots.

    Can you borrow some Shimano XT or similar V's to see if that makes a difference? If so, it would be a quick and relatively cheap upgrade.
  • keef66keef66 Posts: 13,286
    http://www.chainreactioncycles.com/Mode ... elID=20678

    front XT brake for £20. ( LX is the same price, so why not have XT?)
  • alfabluealfablue Posts: 8,497
    I think it may be a combination of poor tolerances of the brakes along with the steel fork, in combination they resonate and "sing". I had this problem with a 2000 XT v brake, resolved with XTR (I think they have been improved now).
  • stfc1stfc1 Posts: 505
    The idea of fitting a new brake was about all I had left, just a bit concerned about throwing good money after bad if the fork was the problem. That CRC price for the XT is good though so, assuming the current version is way ahead of the 10-year-iold version alfablue mentions, perhaps it is worth a punt...
  • alfabluealfablue Posts: 8,497
    the 10 year old version was an early "parallel push" type, teething troubles with the design I think, they were infamous at the time.
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