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double to triple in line cable thingies

Posted: 17 Jul 2016, 1:57pm
by mattsccm
Now what were they called? They allowed you to shift across a triple chainset with double STi's. Like an inline cable adjuster with a lever.
Did they work.? Anyone got one? Could be fun to triple my SRAM hydro braked bike.

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 4:58pm
by Valbrona
Never seen anything like that.

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 7:13pm
by Brucey
I think there used to be a thing called an 'Erikson Gizmo'. Essentially it is a two-position inline shifter; the idea is that with it in one position, the (double) STI shifts between the middle and outer rings, and in the other it allows shifting between the inner and middle. I've never actually seen one, but I've heard tell.

I thought of making such a thing myself a while back, little knowing that such a thing had come and gone already.

One suggestion I have seen as an alternative to this (which might work with a short-pull mech...) is to modify a 'wing-type' ergo boss to give the missing shift. As is, I suspect that the cable pull is nowhere near long enough with one of these, so an appreciable modification is most likely required.

A snag with all these contraptions is that the cable pull required for a shimano triple mech (middle to outer) isn't always quite the same as that on a double, or indeed the inner to middle shift. But it is probably better than buying a new set of STIs, especially if the inner ring is only used occasionally.

cheers

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 7:45pm
by mattsccm
That's the beast. Eriksons.
My problem comes with the SRAM Hydro brake/shifters that I use.
No triple option. Not that I really need it, I use a MTB double but the idea appeals really.
I have an old bottle dynamo that is pulled onto the wheel by moving a lever attached to what is really a very coarse cable adjuster. 180 degrees turn pulls the cable which moves the bottle to the tyre.

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 7:52pm
by Brucey
OK, I've had a mad thought; If you have a DT lever boss, I wonder if you could fit a lever there, attached to a short length of cable, at the end of which there is floating cable stop (eg a Surly cable hanger for a rear canti?) into which the gear cable housing goes.

I think you might need something to stop the gear cable housing from flapping about (esp when the cable is slack) but that might give the right kind of functionality without too much effort?

-just an idea, anyway...

cheers

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 8:18pm
by mattsccm
Hmm.
I was wondering about a cam shaped pulley that at its smallest "width" works as normal but when moved the high point of the came takes up slack. Its really for the once a decade tour on that bike when I want to ride big hills with my usual excess of gear.

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 8:20pm
by mattsccm
Maybe your cable could be enclosed in thin metal tubing which would easily fix to the frame.
I am now thinking of mounting it under the seat for neatness.
Keep the bright ideas coming people.

Re: double to triple in line cable thingies

Posted: 17 Jul 2016, 11:29pm
by Valbrona
mattsccm wrote:Keep the bright ideas coming people.


Get rid of the SRAM kit.

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 2:20pm
by andrew_s
(follow on from Brucey's idea)
If you've a down tube lever boss, or a frame suitable for a clamp-on band fitting, you could think about scavenging a Shimano brake release lever, and fitting that, so that the cable stop position changed by one ring's worth.
You would probably want to have the "brake in use" over cam position for one pair of rings, and arrange a stop to block the open brake position correctly for the other pair of rings (always assuming that a brake release lever moves the cable stop far enough). It may be necessary to take the whole end of the caliper arm, and clamp that at the down tube boss in order to get the cam at the right angle.

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 4:41pm
by rjb
If you have a D/T boss how about going retro and using a D/T lever like Lance. :oops:

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 5:38pm
by Brucey
maybe adapt a QR centre-pull brake hanger mechanism, and use that as a gear cable stop?

cheers

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 6:22pm
by mattsccm
Getting rid of the SRAM won't work. Now if Campag did something I'd swap today. No one makes hydro brake drop bar shifters for triples. Actually the Erickson way is the best by a long way in this situation.

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 6:24pm
by mattsccm
Andrew s has the idea.

Re: double to triple in line cable thingies

Posted: 18 Jul 2016, 8:58pm
by cycleruk

Re: double to triple in line cable thingies

Posted: 19 Jul 2016, 9:51am
by [XAP]Bob
Just use a DT lever for the chainrings - surely the simplest approach...