Wiggling cranks

I got a miyata about three years ago and totally destroyed the cranks because I wasn’t aware that they needed to be tightened. I now have new cranks but recently they started to wiggle and tightening them only helps for a few days. Could anything else be wrong? Also, what other regular maintenance jobs should I be doing, and how often?
-Mike

Usually when you get new cranks you have to tighten them A LOT but after a few rides they stay tightened. It’s like breaking them in.

Re: Wiggling cranks

On Mon, 2 May 2005 10:19:15 -0500, “unicyclemichael” wrote:

>Could anything else be wrong?

First off, there is a recommended procedure for tightening cranks that
includes grease and a torque wrench, while excluding hammering. Do a
search and thou may find. See if that helps. Alternatively, it might
be that when you rode with loose cranks, you damaged not only the
cranks but also the taper on the hub. If so, too bad - the only good
solution is a new hub.

>Also, what other
>regular maintenance jobs should I be doing, and how often?

The crank - square taper interface is surely the most important one to
check frequently, as it tends to loosen, and the results can be
‘dramatic’. Others include:

  • check your pedals for tightness
  • check your seat bolts for tightness
  • check your tyre pressure every few weeks (but you will notice that
    anyways)
  • rotate the tyre with respect to the rim by 1/8 to 1/4 revolution
    when it develops bald spots, e.g. from idling.

Klaas Bil - Newsgroup Addict

“When it comes to the family jewels, you won’t be having fun until they’re having fun. - Jake D”

Assuming that your unicycle has the square taper hub rather than splined; then it is VERY important that you do not ride it with loose cranks- it will destroy the cranks and hub.

There’s been lots of threads about sorting out loose cranks- a search should turn up plenty.

To briefly summarise them, with the old method you need to grease the axle before installing the crank, and hammer them on (lightly!) using strategically placed wooden blocks, and/or a wooden mallet, to protect the wheel and hub etc.

This ensures the crank is properly seated.

You also need to take a socket wrench with you when you go riding for the first few times, in case they do come loose again (in fact I always carry a light wrench with me on rides, just in case).

There’s a more recent alternative using a torque wrench with a guage, which is considered by many to be superior.

Personally, I’ve always used the greased hub/light hammering approach and found it sorts out loose cranks very well.

Main thing is DO NOT ride with loose cranks.

When riding trails on any square-taper unicycle (like my 29er), I always give the cranks a tighten before heading off. So for the time being, just remember to tighten them once every day you ride, and you should be fine for quite a while.

But yes, if the tapers are damaged from lots of loose-crank riding, they will tend to keep coming loose more and more easily, until you replace the hub.