London Fixed-gear and Single-speed SJS Cycles

In case anyone runs a search for such an ailment, thought i'd post this. Might help out another fellow newb. I learned some new shit, wanted to pass it on. If you have any clue at all about building bikes you'll prob be laughing by the time you reach line.2 .. this is purely for the simpletons like myself.

So my crank was making a weird knocking, clicking sound. Seemed to be particularly bad when just setting off. This had been going on for a good week or so, steadily getting worse. It felt nasty, made the bike feel real loose and rank. No good at all.

While riding and contemplating this weird disease my poor drivetrain had picked up I eventually decided it had to be the Bottom Bracket. Such is the beauty of single speed right ? There is so little that can go wrong. My chainline was straight, my cogs were all true, chain well lubed.. all that shit. So i tried getting the crank arms off.. no joy, those badboys were on hard-as-nails. Turns out i needed a 'crank puller'. Eventually bought one today on the way home from work. I'd already picked up a 'BB Tool' when installed the crank in the first place.

As soon as I'd got the crank arms off and took the BB tool to the lock-cup thing of the BB, it was emediately apparent it was well slack. I took it all out, gave it a clean, greased it up good n proper and then re-installed it.. turned it in super tight. Next just re-installed the crank arms and took it for a spin. wow.. a whole *world* of difference.

Thinking about it now I feel like a right tit. Such a simple thing. Anyway.. in case anyone else suffers a weird clicky, knocking crank. Try this. Might be your prob.

If it happens again, use some plumbers tape on the BB shells.

youve probably already realised it by now, but just to confirm that crank bolts do not hold on cranks in a square taper setup.

They are used to force the the cranks onto a tapered widening spindle, which stretches the area surrounding the crankhole.

This is well within its elastic limit, so the crank clamps hard onto the spindle gripping and stopping it sliding off.

After installing your crank arms, its actually pretty safe to remove the crank bolts and ride without them.

don't do that, just don't.

the cranks WILL come loose and you'll round out the square hole in the crank. This is actually a last ditch technique to getting stuck and knackered cranks off, ride for a bit with the bolts out.

Just grease EVERYTHING

not quite sure about riding without crank bolts, but if you did your cranks wouldn't come loose, they'd either come straight off or nothing at all would happen.

Anyway, here's the thing about annoying noises from your drivechain. Ride the bike and the clunk will either repeat with ONE pedal revolution or it wont. If it does, it's either loose BB, loose cranks, or pedal bearings (or possibly damaged chainring). If it does not (ie less frequent), its something based on the chain or wheel revolution.

Has loose BB problems with the conversion and now with the new track bike and the one-revolution thing doesn't hold - with cranks it's fairly regular but with the BB it's a function of how much strain it's under at any given moment, so can be more sporadic.

Crank bolt arguments are a bit C+. Grease, don't grease, whatever - just tighten them to fuck when you put them on and leave them well alone after.

Just thought I'd add a morsel to this post. I was investigating a clunk that would happen on every crank of the pedal - my chainring had become loose, rapidly, and the clunk was the ring pushing against the hex screws.

So I tightened them all up and the clunk has gone.