Which front Shimano shifter?

[Twizit]

Strange question for a first post (sorry I will intro myself elsewhere shortly!)...

Am currently riding Trek 7.5FX with Deore trigger shifters and can't get a decent range of gears using the middle chain ring without some element of chain rub.

I can probably live with it by limiting the range of gears used, but I miss being able to trim the front shifter. I understand some of the Shimano range have a sort of "half click" adjustment - can anyone tell me which? Shimano website isn't much help.

Many thanks in advance

 

[Mr Pig]

How many gears do you want to use with the middle chain ring?

The Deore shifters do have barrel adjusters on them. It's more likely that the front dérailleur is either not set up very well or you're trying to access too many gears on the cassette from the middle chain ring.

 

[Steve Austin]

from experience, you can set it up to not rub on about 5/6 of the 9 gears. Ie it will rub on the top or bottom 3 gears.

but then them 3 gears that it will rub on, are possibly where you should have shifted up a ring anyway....

I've never used a MTB trigger shifter that you can trim, road shifters? yes. Mtb Shifters? no.

 

[fossyant]

You can trim shifters, but it's a compromise on triples.. - You have to make sure the mech is happy on smallest chain ring (front) and biggest sprocket (back at wheel) and biggest chain ring (front) and smallest sprocket (back at wheel).. that sets the limits.....

You can trim slightly, but don't expect a full range without trimming .

I know loads of folk expect this, but not even pro level stuff will work like that - it's just pushing the chain/mechanics too far.... if it rubs shift chain ring and sprockets.... the important bit is setting the limits above....

Think of it like this...

Inside Front (little) might work with 1-6 (biggest is 1) of 9....rears
Middle front might work with 2-7 of 9....rears
Outer front (big) might work with 3-9 ( i.e. smaller ones) of 9....rears

You don't want the full range in the middle as MTB/Triple gears overlap loads, and if you run with a bad chain line - i.e. bending the chain too much, it wears it out fast.

 

[Alembicbassman]

Manufacturers advise against using small chain ring with smallest sprocket and large chainring with largest sprocket on a triple. It causes a lot of lateral stress on the chain.

Best thing is to work out all the ratios on all chainrings and see where there is crossover so you know what alternative gearings to use if you get rubbing.

 

[Twizit]

Many thanks for all the replies. Don't worry, I'm aware that I shouldn't be using extremes chain line angles on the gearing, so I'm not expecting to be able to use all 9 gears on the middle front ring - appreciated being my first post you have no idea of my (lack of) techinical knowledge!

The middle ring trimming is currently set up so it works best in gears 3-7. However I tend to find this means I do a lot of jumping between the big and middle front rings, at times when gears 8-9 would work best on the middle ring. I guess my question was born out of being used to have ultimate adjustment on the front shifter (old twist grips!), and I thought some front shifters had a sort of "half click" trimming ability - maybe not, and maybe that's just on the road components?

Anyway, obvious solution is for me to adjust the front so it works best on gears 4-9 on the middle chainring. I'll just have to suffer the indignity of using the grannie ring more often rather than just getting away with gears 1-3 on the middle ring...

Many thanks for the advice and replies though.