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Knocking from front end?

Portland BillPortland Bill Posts: 378
edited September 2012 in Workshop
Morning people!

Got my new Felt Z85 last week and I tightened everything up (at least I think I did!) when I built it, but already there's a distinct knock coming from it when I go over rough bits of tarmac in the road.

At first I thought it might just be my co2 canisters knocking together, but I checked them and they're still well separated in my censored pouch.

It seems to happen when my front wheel judders over anything but only when I'm on the bike. I've tried giving the front wheel a little bounce when I'm off the bike and it sounds perfectly solid, but of course I appreciate there's a totally different force over it when I'm on the bike and pedalling.

Just wondered if anyone could suggest some things to check.

Cheers

Kristian

Posts

  • estampidaestampida Posts: 1,008
    edited August 2012
    could be a slipping star fangled nut

    headset loose?

    front hub / wheel loose?

    brake loose or summit?

    is it just a noisy carbon fork??
  • StefanPStefanP Posts: 429
    could be the gear/brake cables knocking perhaps?
  • deswellerdesweller Posts: 5,271
    You can check play in the headset by holding the front brake on and rocking the bike in the fore/aft direction. If there's any play you'll feel a clunking through the bars.
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  • Well I tried that but there's nothing, it seems sound enough.

    I tried gently pranging the front wheel off the floor with the brake on though and there's a definite rattle.

    I'm wondering if you could be onto something with the cables. They are very snug against the side of the headstock. Could be a noisy carbon fork I guess. I'm not used to carbon at all so it could be that. I might pop in to see my LBS owner later on and see if he thinks it's ok or not.
  • stokey1964stokey1964 Posts: 454
    what about the knurled retaining nut for the inner tube valve?

    you dont need it anyway so take it off
  • I had exactly the same on my new bike. It was just the headset was needing tightened.
    Once I'd sorted that, there was still a rattle ... one of the cables was close to the headtube and going over rougher roads caused it to rattle, badly.

    I'm sure there's other ways to resolve it, but I've ordered myself some Jagwire mini tube tops, as a couple of the other cables on the bike already use them to stop rattles, but not this particular cable ... grrr ...
  • Doesn't have them. :?
  • mercia_manmercia_man Posts: 1,365
    Sounds like a loose headset to me. Try tightening up the bearings a bit. I've also found it helps to put the front brake on and press down on the bars when you re-tighten the stem after adjusting the bearings. This avoids any play between the stem and head spacers - I've had this trouble in the past.

    I've also had noises due to cables knocking and rattling against carbon frame and carbon bars. I'd had success with try frame protectors, little rubber donuts, zip tieing cables together and taping them more firmly and re-routing slightly underneath bar tape.
  • Turns out it's the front hub.

    I was watching everything on my way home from work and on a descent with not a bad but pretty rough surface I looked down and it looked like the wheel was shaking from side to side so I stopped and had a look and there's a little play in the front hub so there's a start.

    How do I tighten that up? As far as I'm aware it's got sealed bearings or cartridge bearings in the hub and I've only worked with cone hubs before.
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