Problems with down-tube shifters

[slowster]

[It was due to the extra torque being put through the drivetrain causing the mech to move sideways.

How does torque through the drivetrain cause the mech to move?

[fastpedaller]

This can be demonstrated by loosening your friction shifter slightly (if you have one), so that it has just enough friction when the bike in being ridden with moderate effort. If the effort is then increased the mech may be able to move due to the cable being unable to hold it in position - the combined force through the chain and the spring of the mech overcoming the friction. Whatever, it wasn't the cable flexing, as the lever was moving!

[Bice]

This can be demonstrated by loosening your friction shifter slightly (if you have one), so that it has just enough friction when the bike in being ridden with moderate effort. If the effort is then increased the mech may be able to move due to the cable being unable to hold it in position - the combined force through the chain and the spring of the mech overcoming the friction. Whatever, it wasn't the cable flexing, as the lever was moving!

I vaguely remember this happening with one friction shifter I used on my Carlton mixte frame commuter years ago. But I use the Suntour ratchet friction shifters on both my ladies' step-through mixte frame commuter and my Diamant ladies tourer - which are both supposedly flexy - and I have never experienced it.

My mistake below re the front shifter FD-6503 being, in fact, a 9-speed. Sorry. It has shifted the 10-speed and 8-speed chains perfectly well (it looks remarkably similar to the 10-speed shifter on my Trek triple road bike although it is possible the latter dimensions differ a bit).

I am using cobbled together shifters and mechs from MTBs and road bikes on both the mixte and the Diamant, and they are working fine in extensive use: the mixte 7-speed as my daily commuter in London (MTB Altus front shifter; Miche road rear shifter); the Diamant 8-speed touring England and Wales (Ultegra FD-6503 9-speed front shifter; Altus X MTB 7-speed on the rear). I am considering using the Diamant for a 12-day, 1,000km tour in France with no concerns about the shifting.

The Ultegra FD-6503 should not even be used on 48,38,28 chainrings at all, but it works remarkably well - better than I expected, in fact - even though set high above the chain.

I do not know why the OP is getting 7 clicks on his supposedly 10 speed indexed shifter.

But friction downtube shifters are very forgiving and an improvised solution should be possible.

[ChrisF]

That thread started with me reporting slippage between the larger cogs.

I would very much suspect the derailleur hanger alignment in that case. I think misalignment is more likely to affect shifting when the derailleur arm is furthest away from the hanger, i.e. on the largest sprockets.
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Cheers Slowster. I do have a 'spare' wheel I can use as per the video (although it looks like it should be a non-servicable wheel - isn't there a good chance it will end up buckled?).
But this will have to wait until next week now -I'm away for a few days (on a different bike!)
Chris

[slowster]

it looks like it should be a non-servicable wheel - isn't there a good chance it will end up buckled?

I would have said that damage to the wheel would be very unlikely with the typical replaceable aluminium hanger, which is a relatively soft, sacrificial component. I don't know about a traditional steel derailleur hanger (although I think that was the example in the video).

I would take things one step at a time, and to begin with just use the wheel as a gauge to see if there is significant misalignment. Park Tool suggest 4mm as a benchmark - see https://www.parktool.com/en-int/blog/re ... -alignment, and I think with a 10 speed system that is the level of tolerance as well as accuracy/precision needed (I think the bike R J The Bike Guy was working on had fewer speeds).

The important thing is to determine whether or not it is the cause (or one of them) of your shifting problems. If it is, you will save yourself the frustration of trying everything else to see if it cures the problem. In my case fitting my spare derailleur hanger to see if that made a difference was the last thing I did after spending a lot of time trying other things. I learned from that experience that checking hanger alignment should often be the first thing to do, not the last.

Do you have a good bike shop/mechanic in your area? If you do and the alignment does need correcting, I would give them a call and ask how much they would charge (or maybe ask peetee whether he would do it and how much, if he is not far from you). Given how long you have had this problem and put up with poor shifting, maybe this is one of those cases where paying a professional to get the gears working properly would be money well spent.

[fatboy]

I have used newish dura ace downtube shifters and the front was different than plain friction; it's held on a spring rather than friction. Looking at the instructions step 1 is to install the boss cover so that the key bit points forward in line with the downtube. Second step is to add the lever (the image shows it pointing down as 90 degrees to the downtube). Then you turn it anti clockwise adjusting the bolt until the spring doesn't turn the lever. Then turn the shifter fully anticlockwise which is around 30 degrees. I have found this to work with a variety of front mechs without issue.

[peetee]

With regard to ChrisF’s original post, I have given his bike the twice-over and noticed the following;
The set-up he has (10spd Dura-ace down tube levers, 9 spd XT rear mech and 10 spd XT cassette) can be made to work cleanly and precisely. I achieved this by removing the aftermarket mid-outer cable adjuster and replacing it with a conventional part in the rear mech. However, the adjustment required is perhaps a bit too precise and certainly requires a lot more precision than any other ten speed system I have set up; groupset or amalgamation. The slightest deviation from exact cable position results in gear clatter and I suspect that alterations in the bikes geometry in real-world conditions may cause issues. I suspect the inherent flexibility of a traditional steel frame may be too much for the shift ratio and I wonder, as I sit here now, if there is any disparity between loaded and (in the workshop) unloaded frame dimensions that could account for my success in setting this up. I have not road-tested it yet but I could see how a small amount of give, or sag, in the frame when sat upon could pull at the cable routing enough to put the ‘workshop’ settings out of kilter.
So why would this set-up cause more issues than, my bike? It too runs 10 speed with a steel touring frame. As yet I cannot say for sure if the problem lay with accurate set-up or the cable routing as-was. I’m still exploring all the avenues, but one thing does jump ahead in my mind. Perhaps ten-speed down tube shifting IS too precise for that type of frame. STI indexing has an advantage in that it overshifts a fractional amount then drops back into its ‘slot’. This might be just enough to allow a flexible steel frame with STI’s to behave just as well on the road as it does in the workshop where an identical down-tube shifter bike wouldn’t.

[slowster]

So why would this set-up cause more issues than, my bike? It too runs 10 speed with a steel touring frame. As yet I cannot say for sure if the problem lay with accurate set-up or the cable routing as-was. I’m still exploring all the avenues, but one thing does jump ahead in my mind. Perhaps ten-speed down tube shifting IS too precise for that type of frame.

If this is an issue, 10 speed indexing with road shifters (i.e. very short cable pull per click) and a lugged Dawes Galaxy is the combination on which I would expect it to manifest itself. Years ago someone posted a photograph of the interior of a Galaxy bottom bracket shell showing that the chainstays had not been properly mitred and/or that the spelter had not penetrated sufficiently, and 531colin has posted a number of times about how floppy some Galaxies were due to poor QC of the frame manufacture.

[ChrisF]

Postscript from the OP: Sorry for the late reply but I have been away (using a different bike).

Thanks so much to PeeTee for the work he has done, and to Slowster for suggesting PeeTee.
After receiving my bike back, there was still a little jumping acrosss cogs in the highest 3 gears. But after a single turn of the new adjuster that PeeTee fitted, everything is working fine even under load.
PeeTee also sorted my front derailleur and improved my back brake!