Very interested in this thread too.
Broke several over the last 12-18 months, although most were after a reasonable whack. My son is currently running the b44 and we have broke 2 in two weeks. Saw both incidents and they were really quite gentle knocks, they just snapped at the usual spot at the end of the thread. Its almost as if they are getting even worse.
At around £7 for one, plus postage, I am getting very annoyed.
