I've given up the idea of finding a nice cottered crankset and instead gotten a chainring from
SunXCD which I thought would look nice with Stronglight 49D crank arms.
Ran into a problem with the bottom bracket. I tried installing a cheap sealed 111mm JIS Sunrace unit which looked to be proper length for a Stronglight single. The crank however seems to sit "too close" to the bottom bracket shell, so that some of the little chain ring bolts on the inside hit the bottom bracket shell. Those are original Stronglight bolts, maybe I could use some other ones which won't protrude as much. The chain line with this bottom bracket is around 42mm though, which is correct for 120mm spacing on the rear.
However, there is (almost) no space between the crank arm and the chain guard
So I definitely need a longer bottom bracket if I want to use the Stronglight cranks with the chain guard. But how long? A sealed JIS 115mm is already meant for a double. I am afraid that the chain line will be off by too much.
I should have measured the chain line with the original crank, the bottom bracket it came with is a mix of Tange and Shimano with a Shimano D-3NL spindle (122.5mm). That seems like way too long to me!
Aslo, the original crankset seems to have wider
"tread" in comparison with the Stronglight, which means more distance between the crank arm and the chain ring.
