Mountain Biking Maintenance and Repair : Install the Chain on a Mountain Bike

Mountain Biking Maintenance and Repair : Install the Chain on a Mountain Bike


A concept that you will hear more and more
about over the next few years is that of chain line. Chain line is basically the distance
from the center line of the bike, so the center line of the rear hub, or the center line of
the bottom bracket, out to where the optimal position is for our middle chain ring on a
crank. So to that position. So your common chain lines that you have these days are 47,
51, and there’s something like 57 to 58, outliers there. And knowing what the chain line is
and the attendant chain line of your crank set is really important for two things that
are becoming more popular: chain-guide application and single-speed application. So as you can
see, 47 millimeters, so that’s – 47 would be right there – so that would be from the
center of the bike – I guess I should show it better from here. From the center of the
bike out is 47 millimeters. So on this bike, that would be this cog right here. You can
see that because this is a really wide back end that?s not the real chain line. But if
you go here and measure it out and that looks pretty close to the middle of the cog set.
It’s like right there. So for a single-speed application, if we only had one cog back here,
we’d know where to put it, given what type of crank that we had and what length bottom
bracket spindle. So things that affect your chain line up front are: the width of the
bottom bracket; shell on your frame, which is a frame thing, you can’t really change
that; and then the length of the spindle on your bottom bracket. So there’s optimal length
that everything is designed for. In all sorts of manuals, it’s on websites. And if you just
pay attention to that stuff and be knowledgeable about it, it will help you in selecting the
right components to have a trouble-free setup for your bike.