I got a 20" GP trials entry uni a while ago, and a few weeks after i bought it, i noticed that the left crank’s nut was getting a bit loose every now and then. I didn’t think much of it, but recently it has been gettting looser and looser more and more frequently. Its a relatively simple task to tighten it with a socket wrench, but its gettin damn annoying havin to do that like every day…
Basically i tighten the thing until it feels nice and stable, wack the little cap back on and off i go, until a few hours later i hear a little knocking sound, and yep! sure enough the crank’s wobbling around like a plate of jelly in a Volvo. Oh, and somtimes the other one does it too… i guess its just coz its a crap unicycle, but if theres an easy solution to this problem id love to hear it… hell, even if its a hard solution, lets have it.
nonsense, tighten it untill it cant go any tighter, tighten the pinch bolt in the same fashion… and when the uni gets older it will stop playing funny games.
get your self a big allen key like 10 or 15 cm long so you can get some good torque on it and tighten it till your hand hurts
go for a torker DX or a nimbus hoppley for your next one. its a lil expensive (the DX) but itl last a realy long time. a pretty good discount is available on ebay. its the cheapest splined uni you can buy (stock)
The big thing in the above procedure is to use a torque wrench. The torque wrench will let you know that it is tight enough without being too tight (and risking a broken hub). You can do it without a torque wrench, but it requires some experience to know how tight to go by hand. I go to 30 to 35 foot-pounds when using a torque wrench on a standard square taper hub.
30 foot-pounds of torque is like hanging a 15 pound weight at the end of a wrench with a 2 foot long handle. Or a 30 pound weight at the end of a wrench with a 1 foot long handle. So if your wrench has a handle that is 1 foot long just pretend that you are picking up a 30 pound dumbbell while turning the wrench.
The other trick is to use a little bit of blue (medium strength) Loctite. That will keep the nut/bolt from loosening on its own due to vibration and other movement.
I know Sheldon is the best authority, but cranks loosen up a little with a few minutes of riding. I think the cranks get seated on the cranks with initial use. I’d suggest torque the bolts, ride for a few minutes to seat the cranks, then re-torque. If you use loctite (I don‘t), after the re-torque, then remove the crank bolts and apply the loctite, and torque again.