Are front mechs by design meant to do 'half a shift' ?

[mikeyw]

Had my Trek 1.2 for a couple of mnoths now and really enjoying it but always felt the front mech was cr@p anything higher than 3rd gear on the smaller ring and the chain starts catching....same applies on the lower gears on the big ring. Today however I seemed to have stumbled across a fix.....i'm wondering if this is by design or not !

I tried moving form the small ring to large but i did'nt seem to push the shifter hard enough however the front mech still moved slightly, enough so I could use the lower gears on the small ring without ant rubbing chain noise .....i tried this a few times and it seems to work.....so I can reposition the front mech by 'half shifting' thus removing annoying chain drag.

Is this meant to happen ?

 

[TheDoctor]

Evenings! And welcome...

You're exactly right - this is meant to happen. It's known as 'trimming' the front mech, and I think all STI / Ergo type levers have an arrangement for it.
The instructions for your levers should mention it - if you don't have them, check the Shimano site to download them. The instructions, that is, not the levers!!!

 

[spandex]

It is and I think it is a nice touch.

 

[mikeyw]

You live and learn - never knew this....bike came with.........nowt from the shop.

 

[Mike Rudkin]

Didn't realise it was a 'feature' lol.I just expected it to work like that,bit like the 'old days' when you changed gear by feel!! Mike.

 

[Headgardener]

Had my Trek 1.2 for a couple of mnoths now and really enjoying it but always felt the front mech was cr@p anything higher than 3rd gear on the smaller ring and the chain starts catching....same applies on the lower gears on the big ring. Today however I seemed to have stumbled across a fix.....i'm wondering if this is by design or not !

I tried moving form the small ring to large but i did'nt seem to push the shifter hard enough however the front mech still moved slightly, enough so I could use the lower gears on the small ring without ant rubbing chain noise .....i tried this a few times and it seems to work.....so I can reposition the front mech by 'half shifting' thus removing annoying chain drag.

Is this meant to happen ?

It sounds like you are running the chain at to sharp an angle through the front mech cage. It is not a good idea to run the chain from the big ring to the largest sprocket and small ring to small sprocket as this puts to much strain on the chain which would mean replacing it sooner than nessacary. I'm sure someone will explain better than I can in a bit.

 

[LondonCommuter]

I'm still learning about STI shifters, having a bought a new bike with them a few weeks ago. I have Tiagra and they do trim in this way. I think the cheaper ones do not.

 

[alecstilleyedye]

I'm still learning about STI shifters, having a bought a new bike with them a few weeks ago. I have Tiagra and they do trim in this way. I think the cheaper ones do not.

oddly my tiagras don't, but my cheaper sora ones do.

 

[jayce]

I have ultegra they do it ,