Spanner work ??

[Barracuda]

I have a new 105 compact on my Trek with Duraace 12 -27 up back.

Coming back to riding after 4 months off the bike from neck injury and I find that under load - standing on pegs or really trying to hammer the chain wants to slip and will also change cogs on me.... Also a slight "crunching" from bottom bracket area under load !

Stretched cables ???
Stretched chain???
******ed derailer ???

Bearings in new 105 screwed ??

Anyone???

 

[JayKosta]

1) Chain stretch: with bike on the ground & leaning against a wall, put a little 'forward' pressure on the crank and then pull on the frontmost section of chain to lift it from the ring.
A little movement is fine, but the chain shouldn't be above the sprocket teeth.

2) Crank bearings: try to push the crank axle left/right - there might be a tiny amount of movement felt, but too small to see.
Try to rock the ends of the crank arms in/out - tiny movement felt is ok, but too small to see.
If there is too much movement, have the bearings adjusted / serviced.

3) Jumping rear cogs: probably cable stretch. use the cable housing adjuster at the rear derail.

Jay Kosta
Endwell NY USA

 

[brianf7]

I have a new 105 compact on my Trek with Duraace 12 -27 up back.

Coming back to riding after 4 months off the bike from neck injury and I find that under load - standing on pegs or really trying to hammer the chain wants to slip and will also change cogs on me.... Also a slight "crunching" from bottom bracket area under load !

Stretched cables ???
Stretched chain???
******ed derailer ???

Bearings in new 105 screwed ??

Anyone???

Hang the bike on the clothes line by the saddle then put it in 3rd smallest cog then see where the rear mech is in relation to the cog and amount of daylight between the chain on either side adjust cables so it is in centre then run through all gears it should work smoothly if it is slow comming down slacken cables if it jumps a cog tighten untill it is perfect clean the chain.
Is the chain too long for compact???

 

[Barracuda]

1) Chain stretch: with bike on the ground & leaning against a wall, put a little 'forward' pressure on the crank and then pull on the frontmost section of chain to lift it from the ring.
A little movement is fine, but the chain shouldn't be above the sprocket teeth.

2) Crank bearings: try to push the crank axle left/right - there might be a tiny amount of movement felt, but too small to see.
Try to rock the ends of the crank arms in/out - tiny movement felt is ok, but too small to see.
If there is too much movement, have the bearings adjusted / serviced.

3) Jumping rear cogs: probably cable stretch. use the cable housing adjuster at the rear derail.

Jay Kosta
Endwell NY USA

And the winner is :-

1) ******ed chain and
2) Poorly adjusted Bottom bracket

Both now fixed and back on the beast tonight !!


P.S. Due to the overwhelming response I cannot possibly reply to everyone.