Originally Posted by OldPilot
The chains on the 11 & 10 speed bikes are much thinner than the old chains, do Pro riders like yourself break many chains. To be able to spin a 55x14 you must be really stressing the chain?
I only use maybe 2 gears on flat ground & 4 gears (shifting between crank rings) on hilly roads. I never really road in the mountains so no point of reference. I guess except the mountain bike, but I am using 3/4 gears but all 3 crank rings.
I'm strictly a time triallist, hill climber in England. I rode on a junior national team as a young teenager and that is the limit of my road racing experience. (4 seasons) At age 17 I decided to specialize at time trialling as it fit my personality better.
As a kid I never broke a chain while racing in packs or training. Modern chains are amazingly strong and we (team) were kept in good, clean equipment. Plus, we were not as strong as adult males.
As a somewhat adult time triallist (21) I've snapped chains on hill climbs several times. Never on a time trial or training run on a flat course. Simple riding on the flat would require a very worn chain or defect to break in my opinion. I change chains fairly often and don't worry about it. Stress on a chain is most apparent on getting up to speed; once you are cruising in your biggest gear there is not that much pressure on the chain and the pressure is constant. Sudden surges are what break chains. Like while climbing or sprinting out of the saddle.
I would not worry, ever, about breaking a chain if you are a recreational rider and pay some attention to mileage and wear.