I fixed cantilevers Forever. Trek 830

[Frankenorange]

Fit another pair on the back of the fork. We will then all chip in to pay for @Imlach to fly over and do a video of setting them up.

 

[novocaine]

Fit another pair on the back of the fork. We will then all chip in to pay for @Imlach to fly over and do a video of setting them up.

I'm not paying for your nurse to fly in.

 

[bikeworkshop]

Ive been looking at tandems recently and saw one with a set of cantis, a road type caliper and a drum brake on the rear!

Can't have to many brakes on a tandem. we've got disc, drum and 2 sets of cantis
4 brakes for 2 people - that's average

 

[Frankenorange]

Time for disc wheels to actually be disc wheels. Bloomin great 26" metal disc and a deep reach four pot caliper mounted off the seat tube.

 

[novocaine]

Time for disc wheels to actually be disc wheels. Bloomin great 26" metal disc and a deep reach four pot caliper mounted off the seat tube.

Buell.

 

[Frankenorange]

Wowzers! I was joking and there it is.

 

[Imlach]

 

[bikeworkshop]

Then we need an adapter to change that assumed 2x 20mm canti- cable pull
into 1x 40mm vbrake pull.
Sounds like a job for @novocaine

Here's a quick doodle of what I might lash together with things to hand by the counter:

 

[novocaine]

Then we need an adapter to change that assumed 2x 20mm canti- cable pull
View attachment 966452into 1x 40mm vbrake pull.
Sounds like a job for @novocaine

Here's a quick doodle of what I might lash together with things to hand by the counter:View attachment 966451

Errr, take your pick?

 

[bikeworkshop]

Errr, take your pick?
View attachment 966453

View attachment 966454

We need to increase the pull from 2x20 (assumed - the double lever is advertised as being for cantilever, and the OP is applying it that way) to a single 40mm v- brake pull to satisfy @Imlach 's "fixing cantilevers for ever"
Op already has double cable pull lever, and the bmx splitter used as a coupler would pull the same length in and out.
I think we might need a 3d printed leverage device?