105 Front shifting confusion

[bad boy]

Hello All,

Apologies if this seems a little silly but Ive sort of confused myself with trying to fully understand how the front shifting works using the 105 st-503 triple sti lever.

I'm used to indexed mtb shifters on my hybrid where its one click for a shift. I'm sort of thinking the same logic applies although when I sweep the lever going from any of the front rings until it clicks if I release the lever at that point it wont shift its not enough almost .

When reading the shimano tech docs it states "Operate lever a until gear shifting is complete". If I do this its fine no problems at all, so my question is,is this in fact how it works and I need to get used the fact its not just a click but more of a sweep until the shift has completed or not ?.

Its a new bike cable and the cable tension is fine no slack Ive checked all that, think I'm looking for a problem which isn't there

Thanks all

 

[PpPete]

IIRC Should be a little extra click for "trimming" the FD cage to just right place?
If it's not working for you I'd be happy to take those STIs off your hands

 

[Chris James]

To change to a larger chain ring to sweep the lever and hold it until the chain catches on the next ring - which is (I think) what you have described as working on your bike.

To change to smaller chain rings you just click the innner lever only.

There is also a trim function where you nudge the outer lever as if to make a change up and this partly moves the front derailleur to remove and chain rub you may be experiencing.

Basically, I think your shifters work ok!

 

[andy_wrx]

To move up from a smaller front ring to a bigger one, you sweep the two levers inwards : you're basically, via cogs, pulleys, levers pulling the cable tighter so that the derailleur cage is pulled across and nudges the chain onto the bigger ring.

To move down from a bigger front ring to a smaller one, you push the inner lever only inwards and it clicks : you're basically, via cogs and cams inside the shifter, allowing the shifter to release an amount of cable so that the spring in the derailleur pulls it back to the left and nudges the chain onto the smaller ring.

So it's more of an effort, a sweep, to tighten the cable and pull the chain onto the bigger ring; just a click to allow the shifter to release a bit of cable and the mech spring drop the chain onto the smaller ring.

You're describing that you sweep until the shifter clicks, but that's not quite enough to move to the bigger ring ?

You might find you sometimes need to sweep slightly further and hold momentarily, let the chain settle on the bigger ring and then release the shifter back to the click position.
This is normal, unless it's really excessive - if excessive it'll be that your cable is slightly slack, that you can improve this by tightening it a little by turninig the adjuster (usually on downtube or maybe inline on the cable itself)

But what you don't want is the chain moving too far and going off the other side of the ring (either shifting two rings or falling-off the outside/inside completely).

Depending where the chain is on the cassette at the rear (i.e. are you on big cog on left or little cog on right) then the chain is hitting the front rings at a different angle - if the front mech is set-up so that the sweep/click moves exactly thecorrect amount to move the chain onto the bigger ring when the chain is on the lefthand big cog at the rear, then when you're in the righthand little cog it could be too much and will push the chain too far. If set up so that it's the correct amount when you're in the righthand little cog, it's not enough when you're in the lefthand big cog and you need to coax it a little more.

 

[bad boy]

Thank you all for the replies have made a lot of sense.

I am familiar with the logic but in practise the results were slightly off and I didn't know if that was me getting used to the shifting or the shifting itself ?.

I was aware of the trim positions which I can use by nudging the lever which does not result in a click. When sweeping the leaver until it clicks was just wondering why that was not enough to fully shift up a ring, but if I sweep past the click slightly it shifts no problem.

On a test ride shifting up and down is fine but sometimes I don't apply enough pressure on the sweeping motion and it sort of tries but stutters, I suppose its a case of making sure I shift properly !?.

 

[Rob3rt]

Is it a triple, double, compact?

Because I had some confusion with my Tiagra (which is a compact), when shifting to the big ring, I was clicking the whole thing one click, this didnt shift up properly, turns out you need to sweep all the way across (2 clicks), which I THINK may not be the case if you are running a triple where one click should jump up one cog, full sweep jumps 2, like the rear shifter. Im not certain on this though.

I also found I needed to hold it at the maximum point of the sweep temporarily.

 

[bad boy]

Hi sorry it's a triple think it's just me getting used to it more
than anything else. I like to understand how it should work for the
future but think I have it sussed now !?.

 

[andy_wrx]

I was aware of the trim positions which I can use by nudging the lever which does not result in a click

Your trim should also be a click
- changing down : first click from lever should change from big ring to middle; second gentler click should just move cage over a bit to trim but stay in middle ring; third big click should change from middle ring to inner
- changing up, first click from lever should change from inner ring to middle; second click should change from middle ring to outer.
- but if in middle ring, gentle-click down to trim, gentle-click up should trim back the other way or push harder and get full click to change from middle ring to outer

When sweeping the leaver until it clicks was just wondering why that was not enough to fully shift up a ring, but if I sweep past the click slightly it shifts no problem.

On a test ride shifting up and down is fine but sometimes I don't apply enough pressure on the sweeping motion and it sort of tries but stutters, I suppose its a case of making sure I shift properly !?.

You could try just tightening the cable a little on the adjuster, just a quarter or half turn, see if it improves things.

As I say though, it does depend on what gear you're in at the back as to what chainline you have - this is obviously worse on a triple than a double/compact, as you have three rings rather than just two.

Plus of course you may get clean 'click-click' changes or need to pause/hold the lever slightly depending on whether you change at the right part of the pedal stroke for the pins & ramps on the chainrings to just catch the chain.
Somet

 

[nickprior]

Your trim should also be a click
- changing down : first click from lever should change from big ring to middle; second gentler click should just move cage over a bit to trim but stay in middle ring; third big click should change from middle ring to inner

Maybe my 105 triple is set up wrong but changing down to the middle takes two clicks. First click moves the cage slightly to cater for trimming while still on the big ring, then click again to shift to the middle.

In real life when changing up I ignore the clicks and press the lever over until I get the result I want!

 

[bad boy]

Maybe my 105 triple is set up wrong but changing down to the middle takes two clicks. First click moves the cage slightly to cater for trimming while still on the big ring, then click again to shift to the middle.

In real life when changing up I ignore the clicks and press the lever over until I get the result I want!

Thanks for all the responses everyone.

Nick thats exactly the same as mine its 2 clicks from the big front ring to change down to the middle with the first click being a trim position for inner chain plate to not rub the rear low gears.

I downloaded the shimano tech doc and it has a sort of graph detailing all avaliable positions including the trim positions for a triple, I think there 6 in total.

If I nudge the leaver slightly say on the middle I can see it move slightly further out to avoid rub on the higher (smaller) rear gears which is how I presume it works.. this nudge does not result in an audible click as such however !!??.

I feel that everything is working as it should I reset the inner wire tension the other night and it seems fine no slack etc so am fairly content unless someone tells me thats not how its suppose to be ??.

 

[gwhite]

Maybe my 105 triple is set up wrong but changing down to the middle takes two clicks. First click moves the cage slightly to cater for trimming while still on the big ring, then click again to shift to the middle.

In real life when changing up I ignore the clicks and press the lever over until I get the result I want!

If this is happening then the tension of the cable is too high. The trim click should take place on the middle ring only. Change up from small to middle ring and set rear to the large, inner cog. In this position the chain should just miss the inner plate on the FD cage. Tension the cable to achieve this.This is the check for the correct tension. It's sometimes better to start the whole thing from the beginning with this problem and Parktool.com has a good explanation of this.

 

[bad boy]

If this is happening then the tension of the cable is too high. The trim click should take place on the middle ring only. Change up from small to middle ring and set rear to the large, inner cog. In this position the chain should just miss the inner plate on the FD cage. Tension the cable to achieve this.This is the check for the correct tension. It's sometimes better to start the whole thing from the beginning with this problem and Parktool.com has a good explanation of this.

well according to the all the lbs I have phoned and the shimano tech docs this is right for the setup in question. I did originally think the same as you, but after some research and speaking to another cc'er with the same bike/setup its a double shift down from the big ring to the middle with the first click being a trim position for the big front ring largest rear cog to prevent inner plate run on the FD.

I have had the cable out and started all over again but thats the way it is you can sort of click through to achieve a quick change but its definitely meant to be like that. I did read other people stating they played around with the H stop screw to eliminate one of the top positions but Ive not done this.

 

[gwhite]

well according to the all the lbs I have phoned and the shimano tech docs this is right for the setup in question. I did originally think the same as you, but after some research and speaking to another cc'er with the same bike/setup its a double shift down from the big ring to the middle with the first click being a trim position for the big front ring largest rear cog to prevent inner plate run on the FD.

I don't get this at all. You never run the largest ring with the largest rear sprocket. With a triple however all rear sprockets should be available with the middle chain ring and that's why the trim is on the middle position and why the cable tension is set on the middle ring.

"

1. Shift chain to middle chainring in the front and innermost rear sprocket.
2. View gap between inner cage plate and chain. Gap should be as small as possible without rubbing chain.
   
3. To reduce gap, increase inner wire tension by turning barrel adjuster counter-clockwise. Adjusting barrel may be on frame or on shift lever. Check gap again.
4. If chain is rubbing cage, turn barrel adjuster clockwise, or inward toward shifter body.

http://www.parktool.com/repair/

Perhaps you could post a link for the Shimano tech docs showing the trim adjustment for a triple FD.

 

[gwhite]

I've found a reply which does a better job of explaining the trim than I can.
quote:
You need to understand that with Shimano triples there are two shift positions for the middle chainring. These two positions place the front derailleur slightly to the left and slightly to the right of the middle chainring. Use the left position when the chain is on the larger cassette cogs and the right position when the chain is on the smaller cassette cogs. This should allow you to use all 9 cassette cogs. My wife is able to use all 9 cogs with her Ultegra triple even though the chain stays on her 47 cm bike are very short."
http://www.bikeforums.net/showthrea...105-Ultegra&highlight=front+der+trim+position

 

[bad boy]

I've found a reply which does a better job of explaining the trim than I can.
quote:
You need to understand that with Shimano triples there are two shift positions for the middle chainring. These two positions place the front derailleur slightly to the left and slightly to the right of the middle chainring. Use the left position when the chain is on the larger cassette cogs and the right position when the chain is on the smaller cassette cogs. This should allow you to use all 9 cassette cogs. My wife is able to use all 9 cogs with her Ultegra triple even though the chain stays on her 47 cm bike are very short."
http://www.bikeforums.net/showthrea...105-Ultegra&highlight=front+der+trim+position

Hi gwhite

Thanks for that yes I am following and you are right but there thats just for the middle ring, If I have understood and read correctly with the 105 ST-503 triple shifter and setup there are around 6 positions in total for the 3 rings.

As a result it requires 2 shifts down from the big ring to the middle.

Hope this makes sense !?.