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Old 2013-04-15, 08:45 AM   #1
WheelieDaft
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Creaking noise - ISIS crank? How tight can it go?

I got a creaking noise descending 2.5 miles of the Pennine Bridleway on Saturday, so I walked the last half mile to level ground. I checked the spokes and pedals and they all seem tight but I didn't have an 8mm ISIS Hex Key with me to check the crank.

The gap between the left crank and the frame was larger than that of the right and I was getting a creak when putting backpressure on the left pedal at the base of the stroke to control my speed.

I tightened the left crank at home on Sunday, but was only able to get about half a turn onto it. The gap is still larger than on the right.

This morning I again got a creak at the same point in the stroke on a steep downhill (I was deliberately testing it). It wasn't as loud as on Saturday.

I am worried that I might 'over tighten' the left ISIS crank and strip the thread in the retaining bolt. How much effort should I put into tightening it, since I don't have access to a torque-hex-key.

Should the gap be the same on each side of the frame (24" QU-AX Crossfire MUni)?

Hope someone knows a lot more about this than I do - I'm really puzzled.
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Old 2013-04-15, 11:15 AM   #2
MrImpossible
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Quote:
Originally Posted by WheelieDaft View Post
I am worried that I might 'over tighten' the left ISIS crank and strip the thread in the retaining bolt. How much effort should I put into tightening it, since I don't have access to a torque-hex-key.

Should the gap be the same on each side of the frame (24" QU-AX Crossfire MUni)?
I can't give you a number, but the torque to strip a crank bolt is quite high - enough that it would be painful to your hand. On my bikes I used to slip a piece of pipe over the allen wrench to get more leverage, and never stripped a bolt. I did strip the bolts on my Torker DX at a super low torque, but I think that was a defective uni (in many ways!).

I don't routinely tighten my cranks; I use blue loc-tite and tighten them up, then put a paint stripe on the bolt/crank so that I can see if it spins loose.

I think the spacing doesn't matter much, and it seems to vary enough that unicycles that use spacers to fill the gap, make a "hard stop" for the crank, can need multiple sized spacers.

Eh, this probably doesn't help! Creaking isn't a good sign, though, so be sure to get it resolved. Riding with loose cranks can ruin the crank pretty quick.
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Old 2013-04-15, 11:32 AM   #3
Coler
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It may be the pedal instead of the crank. Every time I have a creaking noise, it seems to be from a pedal not being tight. You wont be able to tell with you hand, but if you go to tighten it with a wrench, you should feel it move.
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Old 2013-04-15, 12:56 PM   #4
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Have you checked the bearing cap bolts?
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Old 2013-04-15, 02:14 PM   #5
tholub
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The recommended torque is something like 25 foot-pounds, which is a lot. If you don't have a long-handled allen key, you probably can't get that much into it; even if you do, you probably can't get much more. So, crank it down hard.

Also, some grease on the tapers is a good idea.
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Old 2013-04-15, 03:57 PM   #6
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I think it might be the spokes. Even on a twenty inch wheel I get a creaking sound when I put sideways twist on the wheel while almost stationary. The hub on your wheel is in suspension. Uneven pressure on the hub can cause it to twist which in turn may cause the spokes to rub making a creaking noise. With regard to the spacers,I always make sure there is no space between spacer and hub.I always use a narrow piece of piping to extend the hex key handle as mentioned in an earlier post.

Hope this helps.
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Old 2013-04-15, 04:02 PM   #7
WheelieDaft
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Thank you all for the replies. I'll get all my relevant tools out and see if I can find anything loose which I might have missed last time.

Extending the Hex Key sounds like a useful idea too, but I still think I'll try to be gentle with it.

If everything comes up tight then, yes, maybe it is just spoke noise. I'll let you know.
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Old 2013-04-15, 04:38 PM   #8
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Okay -tightened everything and most of it wouldn't move. I actually bent the UDC pedal assembly spanner tightening the pedals *coughs* so I need a new one of those now.

I could barely get any movement on that left crank isis bolt, but that crank still seems a long way from the hub *shrugs* I can see the very last part of the spline on the hub on that side, but nothing on the RH side, but that may be a design feature to allow for fitting a brake on the higher end models or something?

I put another half turn on the bearing retainers and made sure I could still get 10+ spins out of the wheel afterwards so I know it's not overtightened.

Can't see anything else I can do to it now, if it creaks and everything's tight it'll just have to creak
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Old 2013-04-15, 04:42 PM   #9
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Quote:
Originally Posted by WheelieDaft View Post
I could barely get any movement on that left crank isis bolt, but that crank still seems a long way from the hub *shrugs* I can see the very last part of the spline on the hub on that side, but nothing on the RH side, but that may be a design feature to allow for fitting a brake on the higher end models or something?
No, that's likely the cranks (or the hub) being out of tolerance, which is pretty common with unicycle cranks (unfortunately).
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Old 2013-04-15, 06:12 PM   #10
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as cranks get broke in and worn out they creak so no worries
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Old 2013-04-15, 06:16 PM   #11
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[QUOTE=WheelieDaft;1580899]Okay -tightened everything and most of it wouldn't move. I actually bent the UDC pedal assembly spanner tightening the pedals *coughs* so I need a new one of those now.

I could barely get any movement on that left crank isis bolt, but that crank still seems a long way from the hub *shrugs* I can see the very last part of the spline on the hub on that side, but nothing on the RH side, but that may be a design feature to allow for fitting a brake on the higher end models or something?

Tighten the right hand ISIS bolt . Tighten firmly but do not over tighten. Check if there is a spacer on the left hand side. I don't think there should be a gap.
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Old 2013-04-15, 07:19 PM   #12
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Some unicycles come with ISIS spacers that are too thick, so the cranks are not on far enough to prevent movement, which over time can lead to creaking.

There is no such thing as the crank being on "too far", but there is a point at which you will have all of the crank spline taken up with spindle and you won't be able to force the crank on any further with the ISIS bolt; the bolt head will bottom out on the spindle.

Be careful over cranking an ISIS bolt, they can strip, I had one do this when I first started riding, had to drill it out and use an EZ Out to remove the bolts.

Use grease when installing an ISIS crank, keep a variety of spacers on hand so you optimize crank position, 2, 3, 4mm spacers are what I end up using on all my set ups.

Cranks, unless excessively worn, can almost always be made tighter, the exception being the above case where the ISIS bolt bottoms out on the spindle. I have only had this problems on Venture II's.
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Old 2013-04-15, 07:28 PM   #13
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Quote:
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Some unicycles come with ISIS spacers that are too thick, so the cranks are not on far enough to prevent movement, which over time can lead to creaking.

There is no such thing as the crank being on "too far", but there is a point at which you will have all of the crank spline taken up with spindle and you won't be able to force the crank on any further with the ISIS bolt; the bolt head will bottom out on the spindle.

Be careful over cranking an ISIS bolt, they can strip, I had one do this when I first started riding, had to drill it out and use an EZ Out to remove the bolts.

Use grease when installing an ISIS crank, keep a variety of spacers on hand so you optimize crank position, 2, 3, 4mm spacers are what I end up using on all my set ups.

Cranks, unless excessively worn, can almost always be made tighter, the exception being the above case where the ISIS bolt bottoms out on the spindle. I have only had this problems on Venture II's.
Note that the design of ISIS is for the crank torque to be tight against the crank stop, not against the splines. So, being tight against the spacer is what's supposed to happen. But, some of our applications don't have spacers at all (Schlumpf, for example), and most others suffer from out-of-spec manufacturing. But that's just something you have to deal with as we don't have a lot of alternatives.
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Old 2013-04-18, 03:09 AM   #14
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I had that problem on my Torker DX (the older one w/ a 10 spline hub). I kept increasing the torque, first 45 ft lbs, then w/ blue locktight, then red (permanant) then upping it to 65 (the absolute max for that bolt). It would still loosen after a while, then on the ~ 6th time tightening to 65 ft lbs the bolt broke off inside the hub.

The Machine shop prof at my local junior college got the bolt remnant stuck in the hub out for me for free . It turns out the bearing was leaking grease and it got on the threads. I cleaned it thoroughly w/ acetone, tightened w/ a new bolt and blue locktight to 45 ft lbs and it never loosed again.
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Old 2013-04-18, 11:43 AM   #15
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Thats sounds horrible
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