Originally Posted by
daniell
I have an old mountain bike which has a triple crank. Being that the chainrings need to be replaced, I am considering a 1 X setup. Measuring from the middle chainring, the chainline is 55mm. How would I calculate the needed chainline for a 1 X setup?
Thanks
Ideally, "by the book," for a 1x, you want the front chainline to be about 2 mm larger (further outwards) compared to your rear chainline.
If you run it with a "normal" cassette (i.e. not the ones with over 40T on the largest sprocket), you could go without the 2mm offset (how far inwards you can move the front chainring also also depends on your chainstay length).
How to measure the front and rear chainline
As far as I know, Shimano 1x cranks are designed to provide the wider chainline when used with Shimano Hollowtech II bottom brackets (and, if your frame has British, or "at least" Italian thread, you should be able to source a Shimano Hollowtech II BB).
P.S.
I see going from 3x to a 1x as a step back (
1x drivetrain pros and cons).
Relja