Gear Trimming?

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Homervanderlay
Posts: 25
Joined: 17 Aug 2020, 8:19pm

Gear Trimming?

Postby Homervanderlay » 16 Sep 2020, 11:47pm

Hi,

So I have the Shimano Claris 2000 8 Speed shift levers which allow for gear trimming.

This is the first time I have owned a bike that allows for gear trimming so was hoping to get some advice.

The trimming function works fine with both levers when in the largest chainring in the front.

However, when I click down to the smallest chainring in the front and use the smaller gear lever for trimming absolutely nothing happens. Is this normal?

I would have thought the smaller lever would allow for some gear trimming in the small front chainring?

Thanks for any input

Jdsk
Posts: 2349
Joined: 5 Mar 2019, 5:42pm

Re: Gear Trimming?

Postby Jdsk » 17 Sep 2020, 12:01am


pwa
Posts: 12724
Joined: 2 Oct 2011, 8:55pm

Re: Gear Trimming?

Postby pwa » 17 Sep 2020, 5:53am

Doesn't shifting from the big ring to the small ring involve going all the way with the left shifter, leaving no further trimming to the left possible? You are at the end of the range of movement with only a trim to the right possible (with the big lever). If you get chain rub while using the small ring and the biggest sprocket you need to adjust the limit screws on the rear mech.

ElCani
Posts: 273
Joined: 5 Mar 2015, 11:24am

Re: Gear Trimming?

Postby ElCani » 17 Sep 2020, 6:34am

pwa wrote:Doesn't shifting from the big ring to the small ring involve going all the way with the left shifter, leaving no further trimming to the left possible? You are at the end of the range of movement with only a trim to the right possible (with the big lever). If you get chain rub while using the small ring and the biggest sprocket you need to adjust the limit screws on the rear mech.


That’s right. Shifting down from the big ring puts the mech in the inner most position (as set by the limit screw) and from there you can trim the mech cage outwards with the brake/shift lever. From there you can trim inwards again with the small shift lever.

The logic behind this is that you are likely to already be in one of the inner (larger) rear sprockets at the point when you decide to shift down at the front.

Brucey
Posts: 40534
Joined: 4 Jan 2012, 6:25pm

Re: Gear Trimming?

Postby Brucey » 17 Sep 2020, 7:44am

Homervanderlay wrote:
However, when I click down to the smallest chainring in the front and use the smaller gear lever for trimming absolutely nothing happens. Is this normal?


Normal? Sort of.

As I explained in (one or each of) your previous thread(s), in bottom gear the FD position is solely determined by the L adjustment screw. Where a trim click is available this trims to the right. The trim click will only do anything useful if the cable is adjusted correctly.

If you want to resolve your problems you should probably stop making random adjustments and get the FD set up correctly as per the dealer manual. This will save you (not to mention everyone else) a lot of time in the long run.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Homervanderlay
Posts: 25
Joined: 17 Aug 2020, 8:19pm

Re: Gear Trimming?

Postby Homervanderlay » 17 Sep 2020, 7:58am

Thanks for the replies folks, a lot of useful information.

bgnukem
Posts: 440
Joined: 20 Dec 2010, 5:21pm

Re: Gear Trimming?

Postby bgnukem » 17 Sep 2020, 6:35pm

My guess is the front mech cable is completely slack in the small chainring position (as the mech rests on the stop screw) and the small trimming movement at the shifter is not taking up the slack/moving the mech. You may need to increase the cable tension.

rmurphy195
Posts: 1801
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Gear Trimming?

Postby rmurphy195 » 18 Sep 2020, 7:44pm

I have the 8 speed claris.

The small lever moves you onto the small chainring (releases the tension on the cable and the springs do the rest), the big lever pushes you onto the big chainring.

I've only ever found trimming necessary on the middle ring. This is when I'm on the smaller rear sprockets. In this instance, unless I change to the big ring then a small push of the big lever will move the front mech outwards slightly, you will hear a faint click from the lever, and the chain will stop touching the outer plate of the front mech.

EDIT: Never had a problem going onto the bigger rear sprockets, maybe cos my technique changing down involes only using the biggest couple of rear sprockets when on the smallest chaninring! When adjusting by the way, I've found that if the front mech is even slightly out of parralel with the chainrings then the change gets a bit unreliable.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !