Down Tube Gear levers

[scottg]

[snip] At one time I had 3 very similar machines with downtube, bar end and Ergo levers. It was quite entertaining to catch myself reaching for a lever in the wrong place.

My doctor suggested multiple shifting systems for older cyclists to preserve ones mental agility.

In my case the Ellis Briggs has a d/t shifter for the front mech and a bar-con for the rear mech.

[Brucey]

..... SunRace because the shifter assembles (and dis-assembles) with a nut and bolt, so you can work with them. However, the shifters were the downfall of the system, because even new ones have so much backlash that you can't set up the indexing very well.

it's not just backlash it is sticky backlash. It is the stickiness that is their undoing. IME this is always fixable (which is just as well since it afflicts nearly every SA 5s shifter too), but it requires that you remove a tiny circlip, fiddle with the insides, and adjust the preload using shims 0.1mm in thickness.
Following this treatment, they can be as good as gold, apart from the annoying tendency for the rubber boot to fall off and be lost, a characteristic they share with some shimano shifters, eg. bar ends.

[Nearholmer]

Fascinating.

Dia compe wing shifters? I hadn't noticed those. (like the old SunTour command shifters?) Difficult to see from pictures how much room there is for your thumb?

Alongside the price, that’s what’s caused me to hesitate. I sort of imagined them leading to discomfort, or in an incident dislocation, of the thumb.

[rjb]

Here's a clever way of mounting trigger shifters using an extension bar.

[531colin]

Here's a clever way of mounting trigger shifters using an extension bar.
njo35d4m9z061.png

Also works with bar end and even thumbshifters

[531colin]

IMG_5976 by 531colin, on Flickr

I almost forgot I had these; prototypes for fitting D/T levers to drop bars.
Thats the right hand fitting, viewed from the back (rider's side)
You can (hopefully) see the square boss the lever sits on, equivalent to the downtube boss. (In the lower photo you can see there is a pinch bolt which allows adjustment of the lever angle.) The bit of ali. tube is notched to fit the bars, and gives the lever a bit of "stand off" so theres room for my thumb between brake hood and gear lever. Theres a stainless band which goes round the bar, tightened with a draw bolt.

IMG_5977 by 531colin, on Flickr

Lower picture is the same fitting from another angle, showing the turned ali. fitting which takes the inner cable through the ali. tube and stops the cable outer.

This all started with something I could make in my shed, but by the time I got to this prototype each fitting had CNC machined lever boss and cable ferrule, water jet cut end plate, and laser cut ali. tube, as well as sundry bolts and a stainless band.
Then when 10 speed (Shimano) hit, it needed a different setup. (Cable was a different distance from the downtube, as I recall).

More pictures here https://www.flickr.com/photos/52358536@ ... 526744484/....

and here https://www.flickr.com/photos/52358536@ ... 7242755206

slightly different prototypes.....drop me a PM if you want a set to play with

[Brucey]

my design of clamp also uses a drawbolt but a) even if the drawbolt is positioned centrally, it may still be possible to have a centrally positioned cross-drilling, because the female part of the drawbolt assy has a natural hole in it, and b) there is no special reason for the drawbolt to be positioned centrally anyway.

Between these two things, it is pretty certain that the standoff tube could be cross-drilled and used as a cable stop.

[531colin]

A vee brake noodle would be cheaper and better than my original part!

[Bmblbzzz]

I can understand some of the negative feeling for down tube shifters in this thread, in terms of the perception of safety, but I wonder if this unwillingness to take a hand away from the handlebars is partly a result of more modern frame geometry, with quicker handling? On some such bikes, it doesn't even feel comfortable to even look over ones shoulder without wandering into the middle of the road. With my old Evans steel lightweight I can take corners go over small potholes hands free.

That might be an exacerbating factor, if it's actually true that there is a trend toward quicker handling, but way back in the early '80s I remember it being difficult to change gear on bumpy surfaces.

[Bmblbzzz]

It seems clear that some people prefer mechanical simplicity and others prefer simplicity of use. Many, of course, would like both, and often these experiences do coincide or at least overlap, but in this case d/t levers represent the former and integrated shifters the latter, so we have to choose.

[Nearholmer]

^^^

That is very well put.

Things like Colin’s ingenious design, those DiaCompe wings, and that design with a shift lever on the front of the brake lever housing (Grenouille??) get into the middling ground where complexity of design/construction begins to increase, and integration creeps in, as they move up the scale of simplicity of use.

[Brucey]

....that design with a shift lever on the front of the brake lever housing (Grenouille??) .....

'gevenalle', I think

https://www.gevenalle.com/

[pwa]

And bar end levers are essentially just down tube levers attached to a bung to allow a different mounting position that some of us find preferable. Their cable run is almost as simple as that of down tube positioning, with low friction easily obtained.