On Tue, 3 Dec 2019 at 23:47, Bill Dube via EV <[email protected]> wrote:
> Then why do they traditionally use chrome-moly for steel bicycle frames? They use it for up-market frames, or as a marketing tool on cheaper frames (ERW, non butted tube). Bicycles are another special case. They're designed to flex, both to provide suspension (that's why the fork blades are curved, not straight) and to provide the right rider feel without absorbing too much of the rider's energy input. They don't worry nearly so much on touring bikes with wider section tyres and shallower steering angles. I've repaired and repurposed dozens of bicycles over the years and the majority have been ERW, with the more exotic frames being the ones that needed cracks fixing. > A motorcycle frame built from chrome-moly steel or mild steel would be > _indistinguishable_ for the first few miles. They will handle > identically because the frames would flex identically. They would weigh > the same. Then after awhile cracks will appear in the mild steel frame, > and awhile later it will break. The Norton 'Featherbed' has near legendary status, but every single road frame was made out of mild steel. They don't appear to be having any issues with cracking despite being 60 odd years old. The race frames were made from Manganese Alloy Steel. They used thinner wall tubing and didn't handle quite as well as the road bikes, but the weight reduction was felt to be worth it. The were also 'lifed' every season because they were prone to cracking. -- Paul Compton www.morini-mania.co.uk www.paulcompton.co.uk (YouTube channel) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
