Posted: 01 Jun 2013
Adjusting your bike’s drive chain should be the easiest job in the world, however it is remarkable the number of riders you see with a chain so slack it is virtually dragging on the ground. So how do you do it properly?
The first thing to do is read your owner’s manual. There is no fixed rule when it comes to a chain’s tension, each bike is different so look in your owner’s manual to find out what the free play should be. Ok, this sorted write it on your garage wall with a permanent marker so next time you won’t have to dig out the manual.
You only need minimal tools to adjust a chain, a few spanners and a ruler, however if your bike doesn’t have a centre stand you may need either a paddock stand or a mate to lend a hand.
With the bike’s rear wheel off the ground, loosen the axel nut and slacken off the adjustors by the same amount each side. When adjusting a chain always tighten the adjustors rather than loosening them as it makes the adjustment more accurate. Once the chain is nice and slack (or slacker than it was before you started!) do up the axel nut so it only has a very minimal amount of resistance then tighten the adjustors by the same amount each side, usually quarter of a turn.
Check the chain’s free play by holding the ruler against the chain at the bottom of its loop and then pushing it up and down to measure the movement. Don’t force it, just see how much easy movement there is in the chain. When you are happy you have the correct tension it’s time to check the wheel’s alignment.
Although most bikes have marks on their swingarm to help you these are notoriously inaccurate so instead measure from the centre of the axel to a fixed point on the swingarm. Check both sides are the same and hopefully this should mean your rear wheel is correctly aligned. You can measure it more accurately but this basic technique is good enough for a home DIYer.
Finally, before tightening everything up properly, give the wheel a good bash inwards to ensure the adjustors are properly located, double check the free play again and then tighten the axel nut. When tightening the nut always use a torque wrench set to the correct value (check your owner’s manual) and use your free hand to put some tension on the chain when you are tightening it.
By tensioning the chain as you tighten the axel nut you ensure the wheel doesn’t move and alter its position. OK, all done, nip up the adjustor nuts, lube the chain and give it a last check for tension and alignment. While you are on your hands and knees give the tyres a look over for tread depth and any damage and also check your brake pads for wear and your tyre’s pressures.