Very stiff Front derailleur shifter - why? What possible replacement?

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Laowai_1
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Joined: 29 May 2018, 11:46am

Very stiff Front derailleur shifter - why? What possible replacement?

Postby Laowai_1 » 29 May 2018, 12:32pm

I'm doing detailed planning on refurbishing my 28 year old Raleigh Dynatech MTB. One issue is the Front Dérailleur shifter: it has become so stiff on changing to a larger chain-ring as to be too difficult to use. The objective of this forum post is to get some guesses as to why, to request a remedy if such is possible and to comment on a replacement shifter.

The derailleur itself is the original bottom pull 1990 3 position Deore LX component. I have taken this off the bike, cleaned and examined it. Nothing seems to be worn; the spring is just really strong (not surprising, judging by the gauge of metal used in the spring) and I can just about operate it when holding the device in my hand. The operation is smooth. The cable guide under the bottom bracket has no real wear to it - it is not fouling the cable.

The shifter is a Deore XT integrated shift/brake device, replacing the original LX device about 10 years ago, as an incidental to upgrading the brake levers (before I realised that all that was required was to set the geometry of the canti brakes correctly!). I am concerned that even though the shifter is an XT model (which was top of the line 30 years ago), it still contains a large amount of plastic, so is not going to survive in the long term with the amount of pressure I need to put on the lever to change up a chain-ring. I have not risked opening the shifter housing in case it all goes 'boing'. Are there any opinions of why it is so stiff and what can I do about it?

An approach to managing the problem is to replace the shifter. I cannot identify a current model Shimano integrated 3 position shifter/brake for an MTB (Hmm - that seems strange), but my LBS has suggested using a Shimano Altus SL-M310 shifter. I think this is designed for use on a 3x9 or 3x10 system. Is this going to work on an old 3x7 set-up where the chain rings are probably further apart? Even allowing for the continual upgrading within a Shimano model name, is an Altus sifter going to be man enough to overcome that industrial strength spring in the Deore LX derailluer?

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foxyrider
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby foxyrider » 29 May 2018, 1:02pm

Replace the cables - inner and outer - will almost certainly save changing anything else.
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

peetee
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby peetee » 29 May 2018, 2:03pm

Disconnect the cable at the mech, lightly hold the cable end and operate the shifter. Note the amount of effort required. Now create some slack in the cable and release the first bit of gear outer at its far end ( down tube braze on, probably). Create a few inches of bare inner cable adjacent to the shifter then, holding it as tight as you did before, operate the shifter again. If it is much easier to shift the problem is the cable.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

gregoryoftours
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby gregoryoftours » 29 May 2018, 6:45pm

Some of the old higher end front mechs used to have a spring tension adjustment, usually a little allen fitting on a sort of cam barrel. Not sure if LX models did though. How does the resistance feel if you pull the cable away from the down tube a bit by hand?

esuhl
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby esuhl » 29 May 2018, 11:44pm

My painfully stiff gear shifter was caused by a combination of a kink in the gear cable, and gunked up cable casing.

Laowai_1
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Laowai_1 » 30 May 2018, 6:21pm

foxyrider wrote:Replace the cables - inner and outer - will almost certainly save changing anything else.


These are new cables -Jagwire - inner and outer

Laowai_1
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Laowai_1 » 30 May 2018, 6:40pm

peetee wrote:Disconnect the cable at the mech, lightly hold the cable end and operate the shifter. Note the amount of effort required. Now create some slack in the cable and release the first bit of gear outer at its far end ( down tube braze on, probably). Create a few inches of bare inner cable adjacent to the shifter then, holding it as tight as you did before, operate the shifter again. If it is much easier to shift the problem is the cable.


Sorry, being Laowai, I'm far too old and stupid to follow these instructions. The cables, inner and outer, are new, Jagwire with about 5 miles and 5 months of use on them.

Having now stripped the frame and removed the inner from the shifter, I find that the shifter is very free and easy to use. The mech, off the bike, appears (according to a technician at my LBS, who was a pro in the period when my bike was new) to be virtually 'as new' with no detectable wear or corrosion in the pantograph mechanism. But the spring is so 'industrial' that it requires some force to operate it.

I see that I might have clamped the inner at the mech in the wrong orientation. It is a bottom pull mech so I clamped the inner so that it was straight and vertical after passing through the guide under the BB. But there appears to be a groove in the clamp which, if I were to use it, would cause the inner cable to turn through 90 degrees (from vertical to horizontal) at the clamp bolt. Could this make a significant difference to the effort required to operate the shift on a change-up?

(I can't test this theory because I have shipped the frame off to Argos for repainting).

Laowai_1
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Laowai_1 » 30 May 2018, 6:43pm

gregoryoftours wrote:Some of the old higher end front mechs used to have a spring tension adjustment, usually a little allen fitting on a sort of cam barrel. Not sure if LX models did though. How does the resistance feel if you pull the cable away from the down tube a bit by hand?


Hmm, thanks for this comment. I must go and examine the shifter in more detail. My LBS technician commented that the 28 year old shifter was in better condition and far better made than those on bikes they have sold within the last year or two.

peetee
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby peetee » 30 May 2018, 8:03pm

Do you have a plastic guide under the bottom bracket? If so check that cable is routed correctly. If the guide has a bridge that the cable should pass under and the cable is on top this would give very heavy shifting.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

Manc33
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Manc33 » 30 May 2018, 11:05pm

Cable outer length too short?

It should go straight for about 2+ inches at least, before bending, at any point where there's housing going into anywhere.

On a road bike with the cable under the bottom bracket that narrows it down to the cable housing coming from the left shifter.

This is for a rear mech but the same applies anywhere for gears or brakes:

Image
When two cyclists get married, they should throw anodized cable crimps instead of confetti.

Laowai_1
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Laowai_1 » 31 May 2018, 1:36pm

Manc33 wrote:Cable outer length too short?

It should go straight for about 2+ inches at least, before bending, at any point where there's housing going into anywhere.

On a road bike with the cable under the bottom bracket that narrows it down to the cable housing coming from the left shifter.

This is for a rear mech but the same applies anywhere for gears or brakes:



I fully concur with this advice. One of the reasons I recently (in use terms) replaced the inner and outers for both mechs is the position, size and orientation of the 'first' cable stop after leaving the shifters. These stop are smaller than others on the bike, are mounted on the down tube no more than 1 cm away from the head tube and 'hide' slightly behind the head tube. This means that even though I made the first 'run' of new outer cable much longer than the original (to get that 'straight' run into the stop as shown in your diagram), the outer still has to adopt a sharp radius curve around the head tube. This is made worse by the fact that the cable stop inner diameter does not allow a standard ferrule to be used on the typical gear cable outer. Not only that, but the stop is only about 3 or 4 mm deep, compared to 7 to 10 mm on the other cable stops (e.g. for brake cable). So that end of the gear cable outer becomes quite deformed, quite quickly (I believe that Raleigh used a custom specification of gear cable outer diameter, with an integrated ferrule, provided by Shimano that is not longer available).

Having said all that I have no problem with the operation of the rear mech and the front mech cable is quite easy to run through its outers once disconnected from either the shifter or the clamp on the mech. So that isn't the cause of the problem.

I most favour the idea that I have clamped the cable in the wrong position and will check this in 2 months once the frame has been repainted.

In the meantime, thanks for all the suggestions.

gregoryoftours
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby gregoryoftours » 31 May 2018, 6:04pm

Generally if there is a little tab at the cable clamp point in the mech the cable needs to pass over it in order to get the correct cable pull. If it runs under then generally the mech will move too far for an indexed shifter and will also be harder to move.

gregoryoftours
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby gregoryoftours » 31 May 2018, 6:11pm

Are the cable stops on the head tube un-split? Quite often if the outer cable goes into these stops awkwardly it can introduce a surprising amount of friction. It can help to drill the cable sized hole in them a little larger, and also use a zip tie to try to keep the cable outer going into it at as straight an angle as possible. Sounds like that might be difficult in this case due to their position.

Manc33
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby Manc33 » 31 May 2018, 7:21pm

Laowai_1 wrote:These stop are smaller than others on the bike, are mounted on the down tube no more than 1 cm away from the head tube and 'hide' slightly behind the head tube. This means that even though I made the first 'run' of new outer cable much longer than the original (to get that 'straight' run into the stop as shown in your diagram), the outer still has to adopt a sharp radius curve around the head tube.


Not sure how it can be remedied in that case, maybe a cable tie as close to the head tube as possible, but that's just going to create a bend in the housing around the head tube, even though it would possibly fix it where the housing end goes into the frame.

If it was me I'd probably bypass the current erm... thing where the housing goes in (don't know the name) and just cable tie the housing as hard as possible to the frame, several inches past the head tub as opposed to being forced to have it one inch away. Then it looks a mess and has a risk of slipping but that's what I'd do, I'm stupid like that. :P
When two cyclists get married, they should throw anodized cable crimps instead of confetti.

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fausto copy
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Re: Very stiff Front derailleur shifter - why? What possible replacement?

Postby fausto copy » 31 May 2018, 9:10pm

I'm not sure if you've seen my posting on a similar matter, with my wife's bike with the stiff front shifter.

After swapping the original Shimano 105 (that had always worked fine with the bar end levers) to the Suntour Pro, we had the same problem with that too, using the new Shimano combined shifter/ brake levers on flat bars.

I was offered an XT derailleur and fitted it today and lo and behold all is fine and gear changing is now possible.

I tried operating the XT before fitting it and could easily move the arm over with moderate finger pressure.
I've just checked the spring tension on the 105 and the Suntour and cannot really move the arm at all.

I've got a new old stock LX changer and have just tried that and can move the arm on that one easily too.
Although it's 31.8, you are welcome to try it to see if that might solve your problems, as I reckon it could simply be down to the extreme spring tension.

fausto.