throwing the chain in a sprint
this last weekend on our local race training ride (150-250 riders) i took out the tandem with a friend and fellow racer. it was the first time captaining in a group ride like that as opposed to a recreational group ride. i have stoked many times on tandems in training rides but not in about 15 years. anyways when we came to a sprint point we found ourselves in a pretty good position to sprint but had never sprinted on my tandem before. we moved into the right spot behind a good cat 1 racer who went a little too early and started to launch our sprint. just and we were really pushing the 53x11 the chain flew off the big ring. we stopped pedaling and shifted the chain back on but it happened two more times in the sprint.
i'm not sure if it's a simple as an adjustment to the front derailleur limit screw or something larger. i can't make this happen on the repair stand or even riding hard just in the sprint. i did swap the bb from the 118mm to something narrower like a 113mm or 110mm (i don't remember the width) and am wondering if the chain angle is now too much in the 53x11 with narrower bottom bracket.