Slipping cranks?

I just took what could have easily been a very bad fall. I was on my Torker Unistar TX (5’ giraffe for any who might not be familiar), and as I started to pedal backwards, it felt like the cranks slipped. The wheel didn’t move, but the pedals moved about an eighth of a rotation or more. This caused me to fall and land on my back.
I’ve had this happen in the past, but the problem went away for some time, and I never fell backwards because of it. Any ideas as to what I can do to prevent this in the future?

i guess it is the hub/sprocket assembly
nothing else could really move.

No helpful advice but I have sympathy. OUCH. :frowning:

that would be a good movie shot, some guy racing something on his uni and one crank slips and then he goes into kangaroo mode, and then maybe that crank falls off and he starts going one footed then the other would fall off and he would coast/glide.

Expensive in terms of unis though. :astonished:

this happened on my 1st uni. I took it to the store i got it from(lbs) and they said it was hub slippage and was a defect on the hub, so they sent it back. it happened again after i got it back. That porbally means they’re some defective SUn hubs out there. So i would say, talk to the seller of the uni

That is a potentially dangerous situation. What happened is that the sprocket down at the wheel slipped. The sprocket down at the wheel is screwed on the hub and has a lockring to keep it tight. It’s all kept tight by screw on threads. When the lockring slips the sprocket will slip and then you’ll fall off the giraffe in a potentially uncontrolled manner.

It’s a poor design for giraffes. A better design would be to bolt the sprocket to the hub so it cannot possibly spin backwards and come loose. The Nimbus giraffe is built that way. Much safer.

There are two ways to fix your giraffe.

The best way is to get the sprocket spot welded to the hub. That will keep it from ever getting loose. But it also means you’ll never be able to remove the sprocket if you ever need to replace spokes on the drive side of the wheel. Not a big deal since you’re not likely to ever break spokes on a giraffe.

If you do get it spot welded on you have to make sure the welder doesn’t get it too hot and cause the sprocket to warp.

The second way is to take the unicycle to a bike shop and have them put the sprocket and lockring on using high strength RED Loctite. Have them clean and prep the threads first so you get the absolute strongest bond you can get with the Loctite. That is critically important. The RED Loctite will be barely strong enough as it is to keep the sprocket from slipping. You need to impress this fact on the bike mechanic since he may not fully understand the situation. Properly tightened with the RED high strength Loctite it should stay tight for you.

Those are great suggestions. I’m going to try the loctite.

i dont think this will be the problem but, is your chain tight? as i said, doesnt sound like its the problem but just checking the basics, the loctite is what i would go with so yer do that…

good luck with it

My friend had, and still has this problem, it is a good giraffe, but the chain just slips forward really fast every once in a while, just gives up the resistance for a second, which is enough to make someone fall.

The chain is quite tight. I’ve been adjusting the tension a lot. I’ve found that unless the chain is tighter than I would think it should be, the tension adjusters slip.