alexalecu wrote:CaptainP wrote:I have been trying to install a 50t Stronglight CT2 chainring on my compact 170mm BB30 Exogram cranks. I've filed the hidden arm and it fits in the curve, but i still need to press the chainring on the crankset to get it to fit. When i install the bolts and all, the chainring ends up beeing uneven where the hidden arm is (closer to the frame). So the chain will run a bit to the left and right in the cage. Anybody had the same problem?
I had the exact issue with mine and I was conviced it was something wrong with the crankarm. I took it to the bike shop and, to my embarrassment, they fixed it in 5 minutes; the interface between the crankarm and the chainring was not clean, and all they did was to remove the chainring, clean both parts and reinstall - problem solved.
It sounds as if you filed down the crankarm; I suggest you to file the chainring down instead (i.e. round the corners).
I've already tried cleaning both parts, and the original Sram chainring fits like a glove, but the Stronglight just need at little pressure to settle, but then when fastened with the bolts it's uneven.
And don't worry i filed the chainring and not the cranks