My tandem wont stop!

[minor_LEGEND]

Does this tandem have drop bars or flat/straight bars? This will determine if you can use V-brakes or not.
As mentioned a 'drag' brake is common on a lot of touring tandems, it's a drum brake mounted to the non-drive side of the rear wheel & can be operated with a brake lever or for better dragging, wind it on with a thumbshifter so it drags continuously on a long descent.

 

[Ren Rawbor]

You can get V-levers for drops too, means using more modern parts again though (at least flat V-levers can look retro still)

 

[wiredfool]

The issue is probably either flex in the braking system, or poor friction.

To check the flex, pull the levers really hard, and observe what happens to the cable housing, at the cable stop, the brake arms, and the fork arms. If there's something flexing, that's limiting the force at the rim. If it's the housing, cable stop or brake arms, then start replacing there. If it's the fork, then you're pretty much stuck, unless you want to install a brake booster frame or change brake styles.

For the friction, it might be brake shoes, it might be the rims. Those certainly don't look like good pads, I'm a big fan of the koolstops, salmon are good for wet but they're quite abrasive on the rims. I've also used black (all weather) and grey (dry) in the past. I've had good experience with swissstop as well. If your rims are highly polished, steel, or old hard anodized that could also be the issue.

I've got similar profile (wide) cantis on my tandem, with koolstop salmons on it. The current rims (polished al) don't stop as well as the old (araya 26x1.75) plain aluminum rim, but that's more that the polished surface hasn't worn off yet. The braking is still good, just not _as_ good.

 

[bagpuss]

+ 1 for a brake booster.
I have one on the front of our tandem.

 

[bagpuss]

There is a good thread on the cycling uk forum regarding tandem brakes .

 

[minor_LEGEND]

I used to work at Thorn cycles building tandems, I wouldn't bother with cable travel adaptors or trying to make drop levers work with V's. We used to have great success with decent Suntour XC Pro canti's. Use good components is what I am trying to say here.

Without knowing how or where this tandem is ridden, it is hard to give the best advice. A daredevil pilot, confident in their abilities could probably be happy on regular brakes descending in the Alps, whereas someone less confident might feel the need for better brakes for use in the UK on our shorter, less mountainous hills.

 

[Old Ned]

On our race tandem in the late 80's we had DuraAce side pulls. OK'ish most of the time - but not in the wet. Riding a '25' in pouring rain we nearly ran down a copper who stuck his hand out when we were only about 20 yards away. We carried on with a shouted 'sorry'. Thankfully he wasn't waiting for us at the finish

 

[Jiveman60]

Absolute night and day, had it kicking around. Added new longer pads as well. I'll be getting one for the rear.