Loose Venture 150 IS crank? Any saving it?

I have a right side venture 150mm IS crank that has loosened 10 times over the last 2 years, Eventually I figured out that I had a cracked bearing and replaced the bearing. Once again it’s lose, and compared to a new crank I swapped from another uni, it’s definitely worn.

HAs anyone saved a worn crank, maybe with a shim made from an aluminum can? Or not worth the trouble ?

Have you reduced the thickness of the hub spacer between the crank and bearing as much as possible? the ISIS axle spline is tapered and reducing spacer may tighten the connection. Other then that, likely time for new cranks.

Let me back up one more step from JimT’s question. Are you using spacers? In my experience, as long as there is a spacer compressed between the crank and the bearing, and if the crank bolt is made very tight…then a crank with a worn ISIS interface should still work. This should be true, even when the crank bottoms out without spacers. The ideal setup is where the crank stops on the spindle somewhat shy of the spacer prior to tightening, then it is tightened more snugly onto the spindle AND compressing the spacer…but in the absence of those conditions, using spacers and tightening the crap out of the setup…should be okay. There is a lot of confusion about the ISIS standard.

I’m still using the original spacer. When I have it real tight, It still feels like I have a worn out pedal. ( cranks moves slightly ) I’ll try messing with the spacer and see what happens.

Roger at UDC:

In general, I’m a do-it-yourself kind of dude, but in this case I would just replace them.

As you see from the replies it’s complicated…

I had a Spirit crank that over time on my Nimbus 36 Oracle became loose (I think I rode with it a little loose a while by accident without noticing). Anyway, I first remedied the problem for a while by using smaller spacers. This pushed the crank deeper onto the axle and helper for a while. But as both the axle and crank had worn it eventually got loose again. I could see on the ISIS spline, particularly the axle but also the crank, and there were little notches where metal was missing. So I started using monster force. This sort of worked: I was able to ride another few hundred kilometers, but then my bearings went out and needed to be changed… and I could not longer get the crank off (I broke the crank bolt when using a cheater bar and had one bike shop try to bore it out and said it was unfixable and eventually had to get an auto shop to weld a metal lever on to get it off). After that I didn’t want to use monster force anymore (and with hints from this forum), then tried using locktite with only moderate tightening. This worked for a short while. Eventually, the crank and axle were so noodled that the crank was loose even with the crank bolt tight. I could feel it move back and forth when using my hand.

So I resorted to a real ghetto solution: I wrapped the inside of the crank with 2-3 layers of aluminum foil and then put the crank on and used loctite. Amazingly this tightened up the interface and worked great. Of course, then pulling/changing the crank became very difficult and tedious, as the aluminum foil could not be reused and sometimes it didn’t want to start (i.e. got bunched up instead of acting as a layer). But it worked and I was able to ride the crank and axle for a long while more (eventually tore 2 spokes out of the flange and replaced the hub – after over 10k km).

So yes, a “shim” out of aluminum foil is possible but it takes some precision and probably a few tries to make it work (I had “practice” rigging mtb rear suspension bushings over the years with layers of aluminum foil, the first time when I was on a multi-day trip without a chance for replacement parts – as a side note, many mtb rear suspension designs have a stupid setup where the aluminum bushing has to be pressed with a special machine and fit just right and mine were wearing out every 3-5 months! The manufacturer says the fast wear by design as it’s better to wear out the aluminum spacer/bushing than something else on the frame, but for around $60 parts that you cannot change without a special machine not so inexpensive – ok, rant over, but did it multiple times on 2 different rear suspension designs).

The only concern is that you can also damage the axle. On the other hand, as the crank was already on the axle, any damage is probably already done. If it’s tight, then should be ok. But every time it loosens and there’s some play it usually wears down some metal as it rocks back and forth for a while before you notice it when riding.

These are the obvious problems related to the ISIS crank interface that lead me to prefer Q-Axle interface. Sadly the selection of Q-Axle components lags behind ISIS but hopefully if enough people start to prefer it the selection gets larger over time.

Ah! I’ve been trying to decide between QuAx and ISIS. This helps.

When my Nimbus Venture 2 cranks became floppy, I saw it not as a problem with ISIS, but with the design of Venture 2s, which have a narrow point of contact with the hub. ISIS cranks that have a wider point of contact with the hub seem to be much stronger. Actually, my favorite ISIS cranks are the ones made by Qu-ax, so this new Qu-axle hub and crank design of theirs, though it may be a tiny bit stronger and lighter, to me seems unnecessary.