Abrupt harsh gearing

jmttdr
jmttdr Posts: 5
edited August 2017 in Workshop
Looked in search to no avail, so please divert me to an answer if found, thanks.

I have a 30 day old (new) bike with an Ultergra 11s groupset.

I've covered circa 500km on the bike and suffered a front chaindrop which has slightly bent my chainring/spider, roughly 2mm at it's worse.

Anyway, I have installed a new chainset to diagnose the issue which is a fix, so the frame and BB are fine...

At first, even when the chain was not running true, my gears were shifting fine for approx 80km.

However, on both chainsets, the rear derailleur gear changes have become super abrupt. It's as if the gears are almost slipping into one and other both up and down. Each change is really loud and quick like chain slap to the cogs.

The only way I get smooth gearing is if I change under 90-100+ cadence. Otherwise they are as described above.

I have changed cable tension and indexed a few times with the same result.

In the bike's short time the gears/chain have been cleaned with de-greaser and re-lubed religiously.

Is there any suspect causes people may have had for this? Cures I can try? I've ridden fixed up until this point so don't so i'm still learning about gear mechs so please go easy on me :)

Thanks in advance

J

Comments

  • fenix
    fenix Posts: 5,437
    I really doubt you've bent anything. The teeth are different to allow better shifting.

    You are meant to ease the pressure on the pedals slightly whilst shifting - are you doing this ?

    I think your gears sound fine ?
  • k-dog
    k-dog Posts: 1,652
    It's common for gears to need adjusted after a short time - commonly called cable stretch but it's really caused by the outers and ferrules squishing together.

    Adjusting the cable tension should fix it. Most shops offer a tune-up within the first few months to remedy this too.
    I'm left handed, if that matters.
  • svetty
    svetty Posts: 1,904
    jmttdr wrote:
    I've ridden fixed up until this point so don't so i'm still learning about gear mechs so please go easy on me :)J

    I think this is the issue. Practice will improve the slickness of gear-changing. It is best to avoid shifting under full load - a transient easing of power - and hence chain-tension - is preferable.
    FFS! Harden up and grow a pair :D
  • on-yer-bike
    on-yer-bike Posts: 2,974
    Could be the B screw adjustment. The top jockey is not close enough to the largest cog.
    Pegoretti
    Colnago
    Cervelo
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  • dj58
    dj58 Posts: 2,223
    If you have experienced a chain drop, overshift, you need to check and adjust the limit screws on the front derailleur.
  • jmttdr
    jmttdr Posts: 5
    Fenix wrote:
    I really doubt you've bent anything. The teeth are different to allow better shifting.

    You are meant to ease the pressure on the pedals slightly whilst shifting - are you doing this ?

    I think your gears sound fine ?

    I wish this was true but there's about 2mm play. The front derailleur shows it up. New chainset runs fine but gearing still harsh...
  • jmttdr
    jmttdr Posts: 5
    on-yer-bike wrote:
    Could be the B screw adjustment. The top jockey is not close enough to the largest cog.

    I will try this thanks
  • jmttdr
    jmttdr Posts: 5
    Svetty wrote:
    jmttdr wrote:
    I've ridden fixed up until this point so don't so i'm still learning about gear mechs so please go easy on me :)J

    I think this is the issue. Practice will improve the slickness of gear-changing. It is best to avoid shifting under full load - a transient easing of power - and hence chain-tension - is preferable.

    I will definitely ensure I ease off when shifting. Even when travelling at 10kmh and under no real load the chain just seems to slam so quickly.

    My legs jolt as it's so quick, must be slipping or something.

    Thanks.

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