Triple chainset with no shifting aids on the chainrings

[ElCani]

So... things have moved on quite quickly!

On attempting to install the Suntour DT shifters, I discovered the 531 All Terrain downtube is oversized, so the band was too small. So... I mounted them on the top tube, using a short length of outer cable between the in-built cable stop on the DT shifters (using stepped ferrules) and the cable stops at the top of the downtube. A bit of tweaking to the front mech and it all seems to work perfectly, on the stand at least!

I've never seen DT shifters mounted on the top tube like this, but I can't see why it's a bad idea, apart from in a crash? Obviously the shifters work 'in reverse' but I'm sure I can get used to that as I only have one other (rarely ridden) bike with DT shifters.

Pics. Please ignore the mismatched cable lengths, all this is just for testing.

[hamster]

I don't think you will have any trouble with a bar-end shifter at all. I have run for years with un-ramped chainrings and bar-ends.
However to get indexed front shifting to work well I imagine that ramps are pretty much essential.

[Brucey]

…...I've never seen DT shifters mounted on the top tube like this, but I can't see why it's a bad idea, apart from in a crash? Obviously the shifters work 'in reverse' but I'm sure I can get used to that as I only have one other (rarely ridden) bike with DT shifters.

at one time gear levers were commonly mounted on the top tube. I think you could address both concerns if you mounted them the other way up?

The other thing you could do is to mount them on the stem, using a shim? Or a special bracket as per another thread?

cheers

[ElCani]

…...I've never seen DT shifters mounted on the top tube like this, but I can't see why it's a bad idea, apart from in a crash? Obviously the shifters work 'in reverse' but I'm sure I can get used to that as I only have one other (rarely ridden) bike with DT shifters.

at one time gear levers were commonly mounted on the top tube. I think you could address both concerns if you mounted them the other way up?

cheers

Good point! Although then the nice "Raleigh" inscription on the band wouldn't be visible...

A brief search for 'top tube mounted down tube shifters' didn't resulted in much in the way of pics. Plenty on the head tube and stem.

Edit: yup a stem shim solution is another option, but I think I'm going to give this a go for now, I like the uniqueness.

[Brucey]

the shifters mounting on my biframe are mounted on a special bracket which comprises a short length of 1-1/8" tube welded to a tab which engages with the stem nosebolt.

There is a picture here

https://forum.cyclinguk.org/viewtopic.php?f=5&t=136802

along with a few other ways of doing it

cheers

[Brucey]

...A brief search for 'top tube mounted down tube shifters' didn't result in much in the way of pics...

well they would have been called 'shifters' rather than 'down tube shifters' because at that time there was no 100% standard place to mount them. SA hubs used quadrant shifters mounted on the top tube from the start, and although they offered handlebar mounted shifters too, from quite early on, the quadrant shifter remained in production until the late 1930s at least, possibly a bit longer. In the late 1940s derailleurs were still in their infancy and gear levers (and the positions they were mounted in) were not yet fixed. A lot of manufacturers went with top tube mounts, especially on bikes that were not overly racing machines; indeed some derailleurs (eg cyclo) better suited a TT/seatstay cable run rather than a DT/chainstay run. On racing machines DT mounts quickly became the default.


this is a modern bike, but shows the most common TT mount


typical vintage TT mount

It is interesting to note that simplicity, robustness, reliability, low weight and lack of vulnerability to damage must have been factors in the use of DT levers as the default; it should have been possible from the start to have had a handlebar mounted derailleur shifter, yet this 'advantage' was largely confined to uses of SA hub gears (the 'trigger' was new just before WWII I think) rather than derailleurs. Could they have had STIs/ergos in the early days...? -of course not, but it rather begs the question of how so many races were won without them, if they really do offer the alleged advantages.

cheers

[peetee]

You may find that the bottom bracket axle you are using is too short. I have a 1990 MTB with a 113mm axle and it is too short. The front mech is on the inner bump stop when on the little ring and I have moved the bottom bracket out with a spacer to provide a clean shift. And what a shift, the crankset is a 7 speed triple Deore M730 and a M735 mech and friction thumb shifter. The rings are SR replacements, 24-36-46 with no ramps or reduced teeth but the shift is consistently better than any other system I have ever used.

[pete75]

Could they have had STIs/ergos in the early days...? -of course not, but it rather begs the question of how so many races were won without them, if they really do offer the alleged advantages.

cheers

Yes. Having dismantled a few Campag Ergos and Shimano Sti levers there's nothing in them which couldn't have been made by John Harrison in the 18th century albeit using different materials for some parts. If someone had invented them in 1935 they could easily have been manufactured.
Shifting aids only really needed on the front for indexed levers. I made a triple Stronglight 100LX shift perfectly well with Sora STI merely by using stainless pop rivets as shifting aids on the big ring. It was running 28 38 48 as I recall.

[ElCani]

...A brief search for 'top tube mounted down tube shifters' didn't result in much in the way of pics...

well they would have been called 'shifters' rather than 'down tube shifters' because at that time there was no 100% standard place to mount them. SA hubs used quadrant shifters mounted on the top tube from the start, and although they offered handlebar mounted shifters too, from quite early on, the quadrant shifter remained in production until the late 1930s at least, possibly a bit longer.

Fair point, I suppose I was thinking of examples of 'bodges' like mine, rather than originally-specified set-ups. Nice pics!

You may find that the bottom bracket axle you are using is too short. I have a 1990 MTB with a 113mm axle and it is too short. The front mech is on the inner bump stop when on the little ring and I have moved the bottom bracket out with a spacer to provide a clean shift. And what a shift, the crankset is a 7 speed triple Deore M730 and a M735 mech and friction thumb shifter. The rings are SR replacements, 24-36-46 with no ramps or reduced teeth but the shift is consistently better than any other system I have ever used.

Thanks, but the range of the mech is fine (loads of margin in the innermost and outermost positions) and as I said above, it now seems to work well!

[pwa]

…...I've never seen DT shifters mounted on the top tube like this, but I can't see why it's a bad idea, apart from in a crash? Obviously the shifters work 'in reverse' but I'm sure I can get used to that as I only have one other (rarely ridden) bike with DT shifters.

at one time gear levers were commonly mounted on the top tube................

I would probably clip those with my knees, but I do pedal with my knees close to the frame. Not everyone does.

[bgnukem]

Back to the OP, I've had issues with poor front shifting from middle to small 'ring before caused by the front mech hitting the seat tube before travelling far enough to push the chain onto the small 'ring, as stated upthread. Also with poor outer-to-middle shift caused by a 10t difference between 'rings when the mech was designed for a 12T difference. I think the 700CX front was designed for a 10T difference.

Also have a big 'ring where the shift pins are not sticking out far enough, I think faulty manufacture, and the chain is reluctant to shift from middle to outer without lots of rubbing against the big ring.

I had some Campag ergopower levers back in the 8-speed days and the front shifter had a fine ratchet rather than fully indexed shifting. Worked great. Wish someone still made such a shifter as it was much less hassle than getting indexing to work using a mixture of transmission parts!

[julianm]

Wello done with using your old Raleigh - I've done the same with my old Blueridge. I'm using a Stronglight triple with an inexpensive chain, Shimano 8 speed cassette & friction bar ends & get good shifting throughout. I'm not often in the big ring, it's there more as a bash guard really, but it will shift OK anyway. I can't remember the name of the chainset, but I picked it up for the 180mm cranks.

I've got some old SPD pedals on now & find the bike works very well as a winter knockabout on filthy lanes & needs very little fettling other than a wash down & re-lube after a ride. Congratulations on building a £3k `gravel bike` for probably quite a bit less!

[hamster]

I had some Campag ergopower levers back in the 8-speed days and the front shifter had a fine ratchet rather than fully indexed shifting. Worked great. Wish someone still made such a shifter as it was much less hassle than getting indexing to work using a mixture of transmission parts!

Chorus and Record still have it. But sadly now the shifters only have a preposterous number of gears on the other side.

[531colin]

Didn't Shimano at one time have two pairs of abbreviated teeth as "shift gates" on middle and/or big ring ....and would this help Brucey's point about odd/even tooth counts?
With friction front shifting, you can fit a chain catcher https://forum.cyclinguk.org/viewtopic.php?f=5&t=59793&start=45 and then run with the lower limit stop further "out" than you can without the catcher. (and the shift cage further "in") Indexed shifting might not work like this.
Probably like most people who started riding before indexed gears were invented, I don't find a problem using triple chainsets without shift pins and stuff like that. I'm running 2 Stronglight big rings currently where I have removed the shift pins. Just occasionally, the bottom run of chain would snag on the "wrong" side of the pins and get carried round to form a horrible chain jam at the front mech. as I was shifting to a smaller ring. I guess some bit of the chain flicks right when the rest of it goes left, but I have never watched it happen!

[RickH]

I've never seen DT shifters mounted on the top tube like this, but I can't see why it's a bad idea, apart from in a crash? Obviously the shifters work 'in reverse' but I'm sure I can get used to that as I only have one other (rarely ridden) bike with DT shifters.

I don't know about you & your riding style, but I would most likely catch shifters there with my knees anytime I got out of the saddle. Doing an accidental, possibly multiple, gear shift with a knee on a steep bit of slope would not be my ideal scenario. Probably not very pleasant on the knees either!