Local shop is pretty small and didn’t have a bb smaller than 107mm, I just bought a Sugino RD2 crankset which is of course 103mm. It’s going on a single speed and the chainline shouldn’t be an issues BUT is it going to bottom out really fast or cause any kind of serious damage matching these up?
On the right is my tried and true un55 which is sadly 113mm I’ve used it across three bikes but I really want to give sugino a shot and I figured 103-113 would be way out out whack
by tristtaniskanye2
5 Comments
Also the non drive side not has thread sticking out is that okay?
https://preview.redd.it/6o0nhvyl6y1h1.jpeg?width=3024&format=pjpg&auto=webp&s=282fa9078c76dec8d263e3543dd947c9ea77da10
The old one is 113mm, the new one is 107mm, so you bought one that is 5mm shorter.
Your BB is 68mm, the other measurement is the axle length. If the Sugino recommended a 103, your 107 axle will push the chainline out 2mm – hardly worth worrying about.
And no, the BB should not stick out like that. Take it all out, clean the threads, put it back with some grease and tighten carefully.
>I figured 103-113 would be way out out whack
technically it might be. I was last year in a hurry to get my touring bike ready for tour and my UN300 was crunchy and clicking. I found a 10mm too wide UN71. Rode it 3000km and didn’t think about the width for one second. Next month leaving again for similar tour and I’m sticking to the same BB, don’t trust the UN300 anymore at all. My road bike has super narrow Q-factor which has started to bug me actually.
Critical thing is that the cranks and chainring don’t interfere with the frame. The best way is to check the assembly with the old BB and then see what effect a longer or shorter spindle would have.