Forum home Road cycling forum Road beginners

Strange crank action

davesondrumsdavesondrums Posts: 3
edited January 2009 in Road beginners
Hello from sunny (well, cold, grey, bit wet) Brixton.

First post here, but I'm a long time reader.

Tried a search on this problem on the forum here (honest) but didn't find any results.

In short, my bike (Pinarello FP1) is working fine, but since yesterday I've noticed a strange 'delay' when applying pressure on both pedals before I actually move the chain ring.
It's minimal, but it's definately not right and I'm worried having had a previous bottom bracket fall apart that I'm heading down the same route.

It's doing this:

Once I apply pressure to either pedal, there's a split second, and a movement of a couple of millimeters on the ring before I actually apply pressure and move the wheel. It doesn't matter if I am stationary, or if I stop peddling then carry on, it keeps happening.

Does this ring any (hopefully simple easy to sort) bells, or is this the downward slope to another poxy bottom bracket?

Cheers,
Dave.

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    could be lose chain ring. or the freehub is on the way out. or even a lose cassette.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • nicklouse wrote:
    could be lose chain ring. or the freehub is on the way out. or even a lose cassette.

    Cheers nicklouse for the reply,


    I dunno, physically moving most of the external parts (rings, cassette, crank arms) doesn't give anything away, everything seems to be in place.
    I can only think either there's a 'slip' going on somewhere internally in the bracket, or there's something really simple I'm overlooking.

    Like I say, performance wise everything is fine - except this strange minimal movement of the crank arms/pedals with nothing in return.
  • SeanTSeanT Posts: 51
    Are you using carbon cranks?

    I had a similar experience the other day, it turned out that the aluminium insert of my Stronglight chainset had un-bonded from the carbon arm. It felt like the the cranks were loose on the bottom bracket splines.
  • Simon NotleySimon Notley Posts: 1,263
    I would agree with Nickouse that it sounds more like the cassette or freehub. After all, your cranks are directly connected to your chainrings*, whether or not your BB is in good condition, one will move when the other does. Your description sounds like the chain is turning the freehub a little further than usual before the pawls engage and you feel resistance, the chainring is turning, there's just no connection to the wheels!

    Do you have a different rear wheel you could try? That will confirm whether the problem is there or not. If it is then first check your cassette is fitted tightly to the freehub, if it is then it's probbaly time for a new freehub...

    My dad used to bring freehubs back to life with some kind of ritual involving leaving them in a jar of oil, but I'd probbaly just get a new one...

    *unless they're not attached tightly, check this first!
Sign In or Register to comment.