(This is also posted in the cyclocross forum, to which the brakes in question pertain.)
I want to try setting my straddle cable a bit longer on my Empella Frogleggs (old-school style wide cantilevers) but the one I have has been cut pretty short. Has anyone tried using a piece of brake cable instead of the dedicated straddle cable from Empella? Brake cable might be a bit thinner, and the metal nub on the end is a slightly different shape but if I am hoping it can work.

Unless it slips out of the barrel adjuster, or something else catastrophic happens, of course. Anyone have any experience with an improvised setup like that?

If the ball end is the right shape and size so that it fits nicely into the claw and assuming the clamp on the other arm doesn't have too big a groove it'll be fine. The ball end at the claw is the biggest issue. If the barrel shaped MTB end fits well then you can finangle the pinch clamp. But first try pinching the cable in place without cutting it and pull harder than you ever would on the lever. If it doesn't slip you're gold.

The ball end at the claw is the biggest issue. If the barrel shaped MTB end fits well then you can finangle the pinch clamp. But first try pinching the cable in place without cutting it and pull harder than you ever would on the lever. If it doesn't slip you're gold.
online cable store

I've done it on a lot of my own bikes and it works just fine. The only 'issue' is that you may have the head of the cable more deeply in the arm and you may not be able to release the brake as easily.

Thanks everyone. The Frogleggs seem quite forgiving of the type of cable--all you need is a stop at one end (it sticks out in an unsightly manner, but that is life) and cable thick enough that the grub screw on the other end will hold it. Brake cable seems to be working fine.

Sadly, a long straddle cable has not cured the crazy chatter of the steel forks on my Kelly. Back to the drawing board.