This may be a misnomer for a thread, but it applies to my Thorn tandem, so I'll put it here.
Our tandem is fitted with Shimano XTR "parallel-push" V-brakes. We've had the bike 12 years and it's done over 14000 miles. We haven't ridden it a lot lately but I've noticed how annoying the brakes are, in that they don't readily release the rims when they should. I've tried lubricating the pivot points, but that doesn't seem to have helped at all.
I consulted Jane otp, as one of the most experienced bike mechanics I know, and she told me that XTRs were discontinued, partly because of the very problem that I am experiencing. She directed me towards a reader's update on the late Sheldon Brown's marvellous website in which said reader suggested a way around the problem. It sounded a bit faffy, tbh, so today I spoke to SJS cycles to find out what they are putting on their tandems these days, and it is quite simply Shimano Deore, which is exactly the same as have given 38000 miles' worth of faultless service on my Thorn solo machine. So I hied me to Wiggle's website and I have shelled out £26 for replacements.