Front gears skipping middle ring on downshift

laurenceliu

Hi,

I recently bought a B'Twin 500SE (less than two months ago) and it was completely fine. A couple of weeks ago the chain started rubbing on the front derailleur, and I sorted that out by adjusting the tension in the cable, however now I have a new problem... When I downshift from the large ring, it skips the middle ring straight to the smallest ring, with a violent/aggressive move and sound. Again, I tried adjusting the tension and eventually gave up so I took it to a bike mechanic, and he couldn't figure it out why it was skipping it... (there's good reviews about this shop and being in Cambridge I imagine your cycling business wouldn't last if you were crap).

Has anyone got any suggestions of how to fix this problem? Am I missing something really obvious?

Thanks,

Laurence Liu

OnTheRopes

Why not take it back to Decathlon, assuming you bought it new then it must surely still be under warranty?

laurenceliu

OnTheRopes wrote:

Why not take it back to Decathlon, assuming you bought it new then it must surely still be under warranty?

I am going to now (50min train ride away. Bit of a pain to send it back...) Apparently there's a fault with my bike according to the second bike mechanic I gave it to...

zanelad

Couldn''t the bike mechanics sort the problem?

Might be cheaper, more convenient to have them sort it than go to the expense and hassle of returning it to the shop if it's a bit of a schlep.

shimanobottombracket

Is it possible you have set the cable tension with the shifter in the incorrect gear? For example if you increased the tension when the front mech is only supposed to be on gear 2, so that it moves the chain to gear 3? In this case any further upshifts would be prevented by the limit screw. But changing down could manifest in the symptoms you describe. Its a long shot but worth checking.