Cranks 'stuck' on the hub...

Hey everyone, a small technical issue here.

As posted in the Pictures thread a few days ago, I recently stripped my uni down to give it a thorough cleaning. Apart from one part… My cranks seem to be SOLID on the hub. The crank arms themselves that is, not the bolt holding them on (That loosened fine).

Right now I’m not overly bothered, as I’m quite happy with my crank length, but I’m considering trying some shorter ones at some point for some faster road riding. And obviously, anything jammed-on like that is just asking for trouble even if I don’t really need it removed.

I did try using a crank puller, but the (And here’s some real technical jargon for you) Thing that sticks inside and pushes on the hub is too small to reliably screw into the bolt-hole inside, so I didn’t chance it, in case I wrecked something in the hub (Wrecked cranks are cheap, wrecked hub… No thanks!)

It’s an ISIS hub/cranks, and the cranks are Qu-Ax ‘Lightweight’ 145mm’s.

I’ve asked my dad about this (He does bike repairs) And he’s a bit confused as to why an ISIS crank is so solid on the hub too (I didn’t even think ISIS tapered, so why would they be?) And although he recommended putting something larger on the crank-pulling tool to push on the hub, I didn’t try it, as I thought I’d ask here and make sure I’m not doing anything stupid.

Is there anything I can do to avoid breaking both things, and loosen this up a bit to provide an option to replace the cranks in the future?

Thanks all!

First of all, ISIS is tapered, and requires an appropriate puller to get the cranks off.

Second, the only difference between standard extractors for square taper cranks, and ISIS extractors is the size of the end. Square taper extractors will go into the spindle, and maybe do damage to the spindle threads. If all you have is a standard extractor like a Park CCP-1 or 2 you can make do by stacking 3 or 4 dimes at the end of the spindle before installing the extractor, and push against the dimes. Don’t try it with only 1 or 2 dimes, as the piston can press them into the spindle (more of a problem if you have an M15 crank bolt). Since KH hubs, and most uni hubs are M12 the dime trick works pretty well.

IIRC, I think your crank puller is for square taper instead of ISIS. The foot should be about as big around as a penny.

Anyways, I may be way off here.

FWIW, when I take my cranks off, until I use a crank puller, they are on pretty solid. You’d have to beat them off with a hammer (no thanks), hence whey people use crank pullers.

OK, I’ll answer you both with the same statement - I have no idea how big American coins are :smiley:

And yes, my puller is for square tapers, but I guessed it was worth a try.

I will try the trick with sticking something on the end (I have no idea what a dime is, but I’ll look around for something more suitable). My puller screws into the spindle as you said (And obviously won’t fit in the ISIS one!)

How will I know if I have an M15/M12 bolt? Or is it safe to assume most/all of them have the M12? :smiley:

Thanks both. I’ll have a proper look at it tomorrow.

As far as I know the only uni hub with M15 is the Koxx Light hub. So, it’s a fair bet that you have M12, and as long as you find some washers, or coins that fit inside your crank arm, but nest against the spindle without going in, you should be alright. Again, stack 3 or more because of the force generated by the extractor piston.

If you still can’t get them off, take it to a bike shop. Pulling cranks on a unicycle is no different from a bike.

dime: 17.91mm Ø x 1.35mm

Just get the Park Tool for ISSIS:

It has the BLACK handle. If you’re going to own a uni you need a set of Hex keys, a crank puller, and a pedal wrench. UDC should sell them as a pack.

Park has another tool that is BLUE for square tapered cranks. I own one of them too because my learner uni has a square taper crank.

One time, just one time, I used the wrong crank puller to remove my ISIS crank. I did have to use a hammer to get the tool out of the hub.

That’s how I learn everything.

Like I said, my dad does bike repairs, so all those tools are available in abundance. Apparently apart from an ISIS crank tool :smiley:

Maybe I’ll buy one and say it’s for his shop and just keep it in my uni bag!

Thanks for the replies all. Gonna go give it a try! is the official adapter, which is what I use with crank pullers (I own no ISIS/Octalink ones and several square taper ones).

Or one could get a universal puller.

If you already have a crank puller an adapter is probably the most sensible. The universal extractors just come with an adapter, or in the case of the Park universal it has alternate ends that slip on. I was suggesting washers/coins as an immediate solution for someone who has an extractor, and needs to get cranks off right now.

I got a cheap universal crank puller off fleabay. It has worked well for me so far and came with an adapter for ISIS cranks just like the one aracer posted. The outer diameter of my adapter is 15mm and the metal part the crank puller is pushing against is >5mm thick. I hope that will help you fashion yourself an adapter. If you already have one for square taper cranks, I wouldn’t invest into another for ISIS cranks unless you plan on using it a lot.

I once needed to pull the cranks on a uni at a 24 hour bike charity event. They had a full service bike repair tent onsite. When I asked them to pull my cranks they didn’t have the right tool to do it. The mechanic managed to pull the crank but not as simply as if I had my Park tool in hand. Apparently our ISIS hubs are not what they would expect to find on a bike. Shocker.

Bottom line… Our unis are more special than we realize.

ISIS is becoming rare on bikes, and even when it was more common it was never as ubiquitous as square taper. As a bike standard it failed due to weak under sized bearings; problem solved with external bb’s, but too late for ISIS to shake the bad rep.

Most (all). Good mechanics should know what ISIS is. Any full bike tool kit would be lacking if it didn’t have a tool for ISIS/Octalink cranks. It is certainly not a special uni tool.

For ISIS cranks, I just use a crank puller meant for square taper, but with a dime on its head so it doesn’t get stuck in the hole. It’s always worked perfectly so far.