anyone who has this setup? Does it work ok?

Yes, put some Deore LX V brakes on my '92 Stumpy Comp about 10 years ago. They worked fine, but took them off earlier this year to go back to original cantis.

so no problems with the cable from frame-tube thingy to brake? good to know. Thanks!

From memory (which isn't great these days!), I ran a new cable outer (came with V brake kit) from the rear-most brake cable boss on the top tube directly to the rear V brake "J" shaped tube; thus bypassing the rear canti-hanger.

Don't throw your existing outer in case you want to go back to cantis at some point. By sheer miracle, I'd managed to keep it all together!

well, that's with these frames, there is no rear brake cable boss on the top tube... only this tube thing. inner cable just goes through

Can you post a pic, pls?

hope you can see what I mean:

No cable stop for the last bit of the V-brake setup then.

You can either have a cable stop welded on ... or go for full-length outer cables with zip-ties. I'd suggest the second option.

Or buy a problem solver bracket that you slip over the top tube. This gives you the missing cable stop.

ACOR also do stop clamps that go round the top tube.

One of these:

What diameter's the top tube...this clamps 1 1/8", 28.6mm.
£2 posted.

All the best,

thanks for all the help/info guys!!

I'll probably go for the full length outer for now. Or maybee I'll try to use the metal tube as a cable stop.

That sorta works OK.

you've tried the tube as cable stop idea?

what makes it not work good?

You could cut back the 'noodle' to the side of the seatpost. Bit of touchup paint to mask the filing and chopping, then ....
might be a bit messy.

or

use the stop end of a v-brake noodle, they often just pull off and place that on the end of the frames noodle and create a place for the cable to sit in.
Use a 135degree noodle on the v-brake and it might just work if there is enough distance.