Anyone got any knowledge on these and able to help? PXW Junior (aged 14) has a Carrera mountain bike which he uses quite heavily - daily to and from school, goes cycling in the woods and trails at weekends etc. Bike was supplied by Halfords (as all these are - they are Halford's 'intermediate' brand, sitting below their Boardman range. It was the lad's choice, and seemed an OK spec for the £400 or so it cost) and for convenience has been serviced by them as well - he can get to a Halfords cycle service centre independently, and we are encouraging him to take repsonsibility for this himself. They did an 'annual check' a few weeks back, after which the chain was slipping. Went back, and chain was replaced, along with one of the gear sets which had become a little worn. That chain broke. Replaced again, and the replacement broke. Replaced with a 'better' chain - bike was fine for a couple of weeks and yesterday he came home with the chain twisted - never seen this before, but several individual links are buckled and twisted. I'm not sure exactly how he might have managed that, but wondered if any forum members had any thoughts/advice (apart from avoiding Halfords!); is there a stronger chain that anyone can recommend? I think he does put considerable force on it - cycles up some steep hills, and he tells me he leg presses 200kg at the school gym... Thanks in advance - any advice appreciated.