2

I'm thinking about converting a 1994 Trek 820 to drop bars. I already have the bars, brifters, rear wheel equipped with 9-speed cassette, etc. lying around, and I can get some compatible brakes, so as far as I see, my only issue is the front derailleur, because of the different pull ratios of road vs MTB shifters.

My question is, do you know of a top or dual-pull road triple FD? If not, what are my options? There's the Problem Solvers clamp pulley, but I can't find it in stock in any shop that delivers to Austria

Edit: Seat tube diameter is 31.8 mm.

Improve this question
5
  • Maybe route the cable with clamp-on cable stops under the downtube? Or simply use a two speed crankset?
    – Michael
    Apr 20, 2021 at 16:40
  • @Michael I like the idea of routing the cable on the downtube, but the frame doesn't have a screw hole for the cable guide under the bottom bracket, so I'd have to drill and tap one (assuming I even find a clamp that fits the downtube). Using two chainrings is an option too, but do you think I can get shifting to work properly even so?
    – Victor Stanciu
    Apr 20, 2021 at 16:48
  • 3
    @VictorStanciu: There are no big retaining forces required to hold the guide under the BB. Double sided tape or (super) glue should be sufficient, a hole isn't necessary, the FD cable alone would do the job.
    – Carel
    Apr 20, 2021 at 18:58
  • @VictorStanciu: A cable stop on either end (or even just on the down tube in front of the seat tube) is probably sufficient. The CX70 front derailleur is available with top pull. But it’s two speed only.
    – Michael
    Apr 20, 2021 at 19:34
  • @Michael Two speeds is acceptable, but the CX70 is impossible to find.
    – Victor Stanciu
    Apr 20, 2021 at 20:16

2 Answers 2

Reset to default
2

There are no top-pull Shimano road front derailleurs. (Edit: This was wrong, they've made FD-CX70 in a top pull variant. It's contoured for cyclocross doubles and it's 10-speed. 10-speed FDs on 9-speed chains can be tricky or impossible to adjust to be free of rub, alhough manipulating the cage may solve that.)

A few different companies have made clamp-on pulleys like that. Origin8 is another one.

A lot of cross bikes have a pulley mounted to a braze-on. You can get the pulley part an from framebuilding suppliers, dead frames, etc. They usually use an M6 bolt. The question then arises would just doing it with an M6 rivnut be strong enough. I think it probably would be, but it would be an experiment.

If the downtube is a diameter you can find a clamp-on housing stop for, I think that's the good way. Put a housing stop there and a BB cable guide on. The hole for the cable guide is easy to drill and tap, and many shells have one there anyway.

The other clamp-on housing stop way is get a 31.8 one and clamp it on the seattube under the FD, then do continuous housing zip-tied to the downtube looped down and around the BB. This is easy to do, but the upwards-opening housing makes it the worst option because water contamination will foul it.

Remember to add an in-line barrel adjuster to any of these setups.

Improve this answer
5
  • 2
    There is at least one Shimano cyclocross 2 speed front derailleur with top pull on my Cyclocross. I think it’s a CX70. Unfortunately OP wants a triple.
    – Michael
    Apr 20, 2021 at 19:32
  • @Michael to be honest, I'm willing to give up the large chainring, a double would be just fine, but the CX70 seems impossible to find.
    – Victor Stanciu
    Apr 20, 2021 at 20:08
  • 1
    @Michael I was oblivious to that, thanks.
    – Nathan Knutson
    Apr 20, 2021 at 21:03
  • 1
    I was able to order one from Taiwan and it works pretty nice. My location is Germany, so shipping might vary.
    – hannes101
    Apr 20, 2021 at 21:23
  • 1
    I accepted this answer because it came closest to what I ended up doing. Due to a massive stroke of luck, I found a guy on a local marketplace that was selling an unused frame-mounted backstop made by Problem Solvers with an inside diameter of 38.1 mm (a size they don't manufacture anymore!), which is precisely the diameter of the downtube of the bike in question. So I'm going to mount a cable guide under the BB shell and route the cable under it, so that I can use any 3x9 road FD I want.
    – Victor Stanciu
    Apr 21, 2021 at 17:20
0

An option you could consider is 1x9 setup. To do that properly, you need:

  • A crankset for one chainring
  • A narrow-wide chainring (one of the necessary two components to prevent chain from dropping)
  • A rear derailleur with clutch (the second of the necessary two components to prevent chain from dropping; there are some models that have 9-speed pull ratio and clutch at the same time)

There are however several drawbacks if going this route:

  • 1x setups are notoriously inefficient -- to be able to go up hills, you need a ridiculous cassette like 11-51 teeth cassette (it may be difficult to find such a cassette for 9-speed along with a compatible rear derailleur and this means you can't reuse your existing cassette so expense is high), or a small enough chainring. The most realistic of these options is the small enough chainring. However, it may mean your flatland gear is the 11-teeth sprocket, and the smaller the sprocket and the more extreme the chain angle, the worse the drivetrain efficiency is.
  • The amount of parts needed for a proper 1x setup where the chain doesn't drop on every bump of the road is so large that it becomes quite expensive
Improve this answer
1
  • 1
    Thank you for your suggestion, but this is way too much work, and the 9-speed cassete doesn't give me nearly enough range for my usual riding without at least two chainrings.
    – Victor Stanciu
    Apr 20, 2021 at 19:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.