Originally Posted by
merziac
I had some break a couple years ago, lack of lube at install may have been part of it.
Ace hardware in Newport had replacements so it worked out ok.
I also had two Avocet bolts break, luckily not both at once, two incidents. Probably the front bolt broke both times (but too many years ago to remember), since that's the one loaded in tension by your weight. It's possible to put more load on the rear bolt if you sit all the way on the nose of the saddle, but most people don't.
I'd caution against using hardware store bolts unless they carry high-strength heat-treated bolts. Metric bolts go by strength "class", rather than "grade" as with SAE bolts. I'd try for class 10.9 or higher (there's also a class 12.9, super strong), since the ones on the Avocet have been shown to be marginal as-delivered, and they might have used high-strength bolts. So you don't want to substitue a lower-strength one to do the same job.
I think class 10.9 are roughly twice as strong as generic hardware store bolts, maybe more than twice.