Dropped 11-speed chain on Spa TD-2 compact double

[Cyclothesist]

Once you've tested it if the fang is too short you could extend it with a bit of diy engineering. E.g. a piece of shaped aluminium bolted (+/- epoxy) through the fang to extend its length. It's an option if you want to keep your long spindle BB.

[AndyB1]

On a Linear recumbent I had, with a similar long chain line, I put the top run of the chain through a plastic tube (to keep it off my trousers) which also stopped any chain whip.

[Brucey]

...... I put the top run of the chain through a plastic tube.....

how did you secure the tube?

[Brucey]

.... I can't get it close enough to the chain to be effective......

I think it should be easy enough to lengthen the dog fang by drilling a hole in it and then using a length of old spoke.

[Cyclothesist]

...... I put the top run of the chain through a plastic tube.....

how did you secure the tube?

There's a clamp on the tube mounted adjacent to the kickstand base plate on the pic.

[UpWrong]

Once you've tested it if the fang is too short you could extend it with a bit of diy engineering. E.g. a piece of shaped aluminium bolted (+/- epoxy) through the fang to extend its length. It's an option if you want to keep your long spindle BB.

I think a reflector bracket would be a good starting point for a diy longer dog fang.

[UpWrong]

On a Linear recumbent I had, with a similar long chain line, I put the top run of the chain through a plastic tube (to keep it off my trousers) which also stopped any chain whip.

Nice bike. I considered using some chain tube, but the chain traverses quite an arc on the 11-40 cassette so there would be some drag on the chain at times.

[UpWrong]

.... I can't get it close enough to the chain to be effective......

I think it should be easy enough to lengthen the dog fang by drilling a hole in it and then using a length of old spoke.

I think a reflector bracket would be a good starting point for a longer dog fang. I have changed the crankset but might return to that idea.

[Cyclothesist]

Once you've tested it if the fang is too short you could extend it with a bit of diy engineering. E.g. a piece of shaped aluminium bolted (+/- epoxy) through the fang to extend its length. It's an option if you want to keep your long spindle BB.

I think a reflector bracket would be a good starting point for a diy longer dog fang.

Good idea

[UpWrong]

I didn't have much confidence in the TD-2 double and the wide 119mm BB, and ideas for creating a longer dog fang had not materialised at the time, so I installed a Hollowtech 2 triple with 32-44 rings in the middle and outer positions. The middle ring was actually then a bit further out than the inner ring on the double with the long spindle. I ended up having to adjust the FD anyway. On the stand it happily shifted between the middle and outer SG-X rings. So I went for a ride and .... the chain broke. My fault for reusing an 11-speed SRAM powerlock connector. I thought I'd get away with it because the chain only had a few miles on it, and the link had come undone easily whilst squeezing the side plates.

I'm out of time today but will try to fashion a longer dong fang anyway from a reflector bracket.

[Brucey]

...There's a clamp on the tube mounted adjacent to the kickstand base plate on the pic.

I think any rigid mounting, in combination with derailleur gears, means that the chain must deflect/drag at times.

I have long thought that a more flexible mounting would allow such a tube to articulate as needs be. For example the tube could be tethered near it's midpoint, using a short length of cord. The cord would be long enough to allow the tube to assume any position warranted by the gear being used, but not so long that it could be dragged into the chainset. The tube would of course always drag, but only drag lightly, in accordance with it's weight.

[UpWrong]

So, have fitted a Hollowtech 2 triple crankset with only middle and outer rings (32/44) and fangled a chain keeper using a reflector bracket. Most brackets are 27.2mm or 31.8mm but I found one which was 28.6mm. I still need to road test it but it looks functional to me:

[Cyclothesist]

Nice. Only a test will tell you that there's sufficient rigidity in the catcher to prevent chain drop. You can probably get a good idea with the rear wheel raised by temporarily adjusting the FD low stop to allow an inwards overshift and seeing if the catcher keeps the chain on while you turn the cranks and try to overshift the small ring. Better to find out in the warm and dry.