Just refreshed by old 531 tourer with new cables and Conti 4 season tyres, but on removal of mudguards I have realised there is the potential (extremely slight I know)for the grub screws to loosen or the brake cable to break resulting in the yoke shooting on top of the tyre. Bike sure is nippier having lost nearly 8 pounds of racks/bags/mudguards and huge tyres. Due to the odd way I have to set up the brakes a shimano Y thingy will not work – I have to use the straddle wire and the 4 grub screws to set things up.
What’s the fix?

A bolt sticking out of the mudguard-mount-hole in the crown.

New cables that are single sided.

I watched a friend nose dive down a pit when his canti cable broke and the remainder grabbed the front tyre. Personally wouldn’t ride a bike with that set up.

The newer single sided design means this couldn’t happen.

TBF if you look after your bike it won’t happen – I spent 10+ years on cantis.

Always had a bolt or reflector bracket or something in there just in case.

Two zip ties. One looped around below fork crown and another looped loosely enough around straddle cable so as not to interfere but tightly enough to catch it it the cable snaps.

Also – never happened to me, like Cynic-Al I spent a long time on cantilevers (’87 – ’97) and I think that is because I looked after my cables and bolts. I am also building up one of my frames in a as complete as possible retro build and that will be using straddles again. Looking forward to using those Ritchey Logic brakes again!

mini-Vs? they’re compatible with sti/road levers.

http://www.chainreactioncycles.com/tektro-926al-mini-v-brake/rp-prod34580?ModelID=34580

I have to admit this is an issue I’ve never considered or had a problem with – and I’ve done a lot of miles on the tandem which has cantis.

Rode with cantis for years. Looked after my cables, but used the 2 zip tie method described above. Never had an issue.

Due to the odd way I have to set up the brakes a shimano Y thingy will not work

They come in different sizes, don’t they?

did the mudguards you just removed carry out this function?

edit forget that you said it in olden days mtbs used to ship with reflectors bolted to the mudguard holes to stop that happening – though I’ve run plenty without and still do on our retro tandem