Originally Posted by
bulgie
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.
Yeah, Tx Mark, I'm well aware.
So they were way better than the broken ones and I'm pretty sure they were bound up and too tight as well. They are too small IMO but the Ace ones were not generic, they were black oxide like the originals and that bike sees minimal use so is probably ok.
I've used plenty of hardware store stuff in a pinch and at the drag strip, also on the road and everywhere in between, never had a failure from them and am pretty good assessing they're viability absent actual ratings.
Most of the time the stuff at the better hardware stores can get you by if you know something about it.
And don't get me started on torque to yield cylinder head bolts.
