Should the seat pivot?

Hey Guys, this was a major problem with my first uni (which was a hand-me-down) as I was riding if I turned my body to help make a sharp turn the seat would pivot and get stuck off center, and it would be really awkward to continue riding. So I had to get off and correct the seat. That unicycle got damaged, and recently got a new Sun Classic Unicycle.

This seat and post are a lot tighter, but the seat will still pivot on hard turns. Should this be happening or am I just turning to hard?

That shouldn’t happen! Try tightening the seatpost clamp some more :smiley:

That shouldn’t happen, your seat isn’t tight enough.

Beginners tend to make lurching, heaving turns. Sometimes you can smooth out your turns a bit, but you should be able to tighten your seatpost to the point where that isn’t necessary.

Two possible mechanical problems:

  1. You have a crappy seatpost clamp. Try to replace it. These things are not hard to find if you live in a place where there are a lot of abandoned bike carcasses. They are also not expensive to buy.
  2. Your seatpost is too short. If you have less than two inches of seatpost inside the frame, it will be almost impossible to tighten enough.

Some in the bike world swear by some hairspray on the seatpost (generally for the scourge of the slowly dropping seatpost on a MTB). It’s enough to give a bit of extra friction, but won’t gum up the works and can be easily removed if it doesn’t work.

Now, you just gotta find someone who uses hairspray. Paging the 80’s…:wink:

I’ve heard tell of using toothpaste as a low-budget friction compound. (It contains a very fine abrasive.) This is usually in the context of carbon fiber seatposts/tubes, but it might work for aluminum/steel. It would definitely be cheap to try. (Never tried it myself.)

We used to use hair-spray ( a tip-of-the-hat to the English major) to keep the hand-grips from twisting while riding our motorcycles. I don’t know it it will work on seat-posts.

On cheap unicycles with 22.2mm seatposts with no knurling I had problems all the time. Replacing the seatposts with knurled ones from helped fix it mostly, they still twist when riders crash without catching the unicycle but it shouldn’t happen during normal turning.
25.4mm or 27.2mm seatposts will reduce twisting problems due to greater surface contact- so keep that in mind if you ever decide to get another unicycle.

I agree with the other posts too- a new clamp or even a bolt instead of a cheap quick release could help.

Or even a Version with two bolts to prevent pivoting when falling on hard ground.

I’ll add a third that I saw recently:

  1. If the seat post clamp has slid below the notch in the frame then tightening the clamp at that location won’t help very much. Make sure the seat post clamp is directly over the notch in the frame when you tighten it.

A lot of Sun uni’s that I’ve seen have a steel clamp welded to the frame. If that’s the case with yours it is a serious under taking to remove it in order to use a different clamp. Instead, get a decent binder bolt. The quick releases that they come with are pretty weak by comparison. Also, the fit in the frame is sometimes not very snug on inexpensive uni’s, and can be improved with a thin shim made from a soda can.

Unless you want to break seat posts it is not a bad thing for it to move when it hits the ground in a hard fall. If you want to add something to produce more friction I would use carbon assembly paste. It’s for carbon fiber, but it will work on any cycle with a slipping seatpost. It’s commonly used on Ti frames.