Help: Installing Cranks

Hey, I tried searching but I didn’t really find anything. Probably because it’s a stupid question :o But here’s the deal: I just got a set of KH moments and I don’t exactly know how to put them on the hub (don’t worry it’s an ISIS hub). I haven’t really tried yet, but I certainly don’t want to do anything wrong. Thanks for the help :slight_smile:

Just wail on it with a rubber mallet. Then tighten the crankbolt and away you go.

Seriously? lol, I thought about that but that’s why I started the thread.

If the hub already has a set of cranks on it, then you’ll need to take those off. You should use a ISIS crank tool, but sometimes they come off easily without one.

If it doesn’t have cranks on, are the bolts already in the hub? They will have a regular spanner or hex key fitting. These too will need to be removed.

I like to put some copper based anti seize lubricant on my splines before attaching the cranks, it’s not always needed, but it’s a good idea.

Now, look at your tyre (if it’s an old tyre), you should see an area where the tread has worn down more than usual. This is where you normally idle, stop, etc (where your stronger foot is forward). Make sure that when you attach your cranks, this point has moved to somewhere else. You will get more life out of your tyre.

Finally: attaching the cranks. Put the left crank on the left hand side of your uni and the right one on the right. Make sure they are at 180o to each other. I.e. when one is pointing straight down, the other is straight up. Push them as tightly as possible, and then either use a rubber mallet or a block of wood to make them even tighter. (The wood is to soften the blows and not mark/damage your new cranks)

Now, put in the bolts and tighten them. Ride it and see if it loosens. If it does, tighten more, maybe use an extender, I use my seat post. You don’t want to over tighten them as they can shear off or destroy the head. Both of which aren’t good.

Well that was a bit long and simple, but I hope it helped. If I’m wrong on any aspect, I’m sure someone will call me out.

EDIT: Basically, what ^he^ said, but maybe use some anti seize.

I don’t think that the mallet/block of wood is necessary with ISIS cranks, you don’t need to force them on nearly as hard as square taper cranks.

Thanks so far, but what about the little rings that come with a hub? Sorry if anyone already mentioned it, but I don’t know all the technical terms of things:o

Also, does it matter which side of the ‘hub’ you put the cranks on, because I know it matters if put them on the wong side of the unicycle itself (or ride backwards too much haha).

Bloody Koxx ISIS must be different then… I was hitting it for half an hour and it didn’t move! Instead I moved on to a bigger hammer and forgot the wood. That really messed up the thread in it though :frowning:

This was no help at all was it.

The rings go on before you put on the cranks, they are spacers. Grease and beat on the cranks heartily with a hammer and wood block. Being put on to loose is what screws up cranks, you want them wedged on so tight they won’t move at all, even during a big jump. Even a tiny bit on play will wear the crank splines. Tight is right !:slight_smile:

ISIS cranks and hub interfaces are tapered slightly and once properly alligned should require no more than some light tapping to get them to the point where the bolt can be installed.

Tighten the bolt up firmly (there is actually a specific torque weight specified for this however I don’t know off hand what it is.) and you should have no problem with them coming loose.

The bolt will only tighten them up as far as the spacer so overtightning will not do any good and might cause stripping of the bolt threads

If you are having to beat them on then I might suggest that they are not properly alligned to start with.

Some lube on the hub splines will assist in installation, and a few drops of blue lock tite on the bolt will also help keep everything in place.

Why you should beat it on

Greasing a taper and beating it on is standard mechanical practice for any tapered interface. Motorcycle flywheels, diesel engines, uni splines all have the same trouble. A tiny grain of sand or speck of metal will not allow the bolt to tighten up the interface. If this happens on an engine the flywheel it may come off at speed. By beating it on, you crush tiny imperfections, as well as bend and deform the metal into near total contact. Sure, you want the splines greased, and of course properly aligned. But then use a hammer. The grease is to fill in gaps in the splines to exclude water, preventing it from corroding on solid over time. The bolt cannot pull the crank on properly, you would snap it off before it pulled the crank on as tight as a good whump with a mallet.

Using this technique, I have never had a flywheel wobble or come loose, nor had a crank loosen or be damaged.

Thanks for the advice. I ended up having to beat pretty profusely, so maybe I didn’t have them alligned right… But I don’t have a crank puller so I guess if they get messed up I’ll know why :stuck_out_tongue: I have just a little wiggle room with the spacers on either side, but that’s how it was on my other uni, which seemed to hold together fine. The grease definitely helped though, which was a nice tip, so thanks again :slight_smile:

Btw, I might have a koxx wheelset with a KH rim for sale soon… so keep your eyes open if you’re interested! (or PM me now, haha)

Seriously? I had to beat on my crank for a while to get it to touch the spacer. I had it aligned too. I agree with feel the light. Moments need way more than light tapping to fit all the way on.

On snowmobiles the drive clutch is a taper bore and you are to clean the crank shaft and clutch so it is smooth and then apply a very light amount of grease then install clutch thighten bolt to lets say 80 ftlbs then lossen the bolt and retighten to 60 ftlbs. I have had some that by just sliding the clutch on the crank and trying to take it back off that it will not come off unless you use the puller, Thats a nice fit. On uni cranks I think a light tap from a rubber hammer is ok but the most important thing is the grease to lessen the friction on the two surfaces.

I’ve never done anything special with cranks to install.
I just tighten them well and get going. With square taper cranks they sometimes start to come loose, I carry the hex wrench with me for a little while after a crank installation for this reason. After the second tightening they’re usually good to go. I do the same thing with pedals.

I also don’t do any big drops or anything until I know everything is on well.

The ride,-they get loose-then tighten again method

Very very popular, also not ideal. :roll_eyes: The bolt tightens up the first time,against 10% of the metal taper interface. The surfaces are held apart by the highest points.

Normal riding makes the cranks go loose, as this tiny bit of metal gives way. So then you tighten the bolt etc. This procedure will result in worse crank wear, rounding of corners, not to mention more work. Properly installed cranks have 70% metal contact (bs # lol). They will stay tight until you use a tool puller on them.

Put the uni on it’s side, over a stump or wood block. Protect the top crank with wood, and hammer away. Using a 3 lb mallet, hit the wood with enough force to convince yourself you have smashed the splines together.

I know that is not very helpful to the precise folks. I could say hit it hard enough to kill Rambo but not the Hulk or Iron Man. You really do want to distort metal, how much is your call. Two good thumps that would bust both your knees should be enough.

I took my cranks off when i first got my KH20 just to check everything out and see how it all went together.

Same thing here – I had to give it quite a few good smacks to get the cranks to seat nicely against the spacers. I was a little worried being as I hadn’t ever messed with splined cranks before. Glad to see others in my same situation.:smiley:

In answer to your question, Yes; seriously. As I mentioned I tap them on until I can get the bolt started then I tighten the bolt until it bottoms out the crank on the hub spacer.

If others are having to hammer them on then so be it. I have three KH Unicycles all using ISIS hubs and cranks. I have removed and reinstalled the arms at least twice on both my 20 & 24 inch models and have not needed to beat them on. I haven’t had the need yet to deal with my 36er cranks.