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New fatbikes have a ProWheel MPX 11 crankset 1x (hollowtech ii compatible set) and I get moderate clicking from mine, oddly, to my mind, not just when under power, but with less vigorous spindle spinnning.

I'm pretty familiar with hollowtech cranks by Shimano and getting preload set for the exterior cup bearings using that plastic cap on the left side. I've never heard a peep from these, and we have 2-4 in the stable. I have no good way to measure the actual torque on those shimanos given it takes an odd little can-opener type key. But again, never a peep.

Fatbike spindle/bb seems to give these clicks, but no feeling of play. Pulled the crank and checked tightness on the exterior-bearing bb, those seemed nice and tight. Put the cranks back on, tightened that plastic cap to about what I felt on the shimano (like 2 NM?), and locked the crank arm down well with the 2 M6 screws that hold it on the spline. Still, I get the clicking. Only when riding, though. Can't duplicate with complete zero pressure on bike stand.

Also checked pedals, they're tight.

Too little preload on the sides of those cartridge bearings? Too much? Another suspect to check?

EDIT: Still working through this, decided to try standing up to pedal for a good while, and no noise while standing, still or pedaling. I immediately checked seat post clamp and seat rail bolt, and both were pretty tight, but took another 1/10th turn or so each. Noise was still there.

But, this morning, which looking bike over for other potential issues, and wondering if maybe the seat itself were bad (cracked?) I noticed that the barrel-shaped nut that tightens the seat down in angle and to the rails was crooked, off by like 30 degrees. So, instead of a nice tight splined clamping force across a couple cm^2, I had a couple of cockeyed point loads. I remedied that, and I suspect that will be the real fix. Testing today.

EDIT: Testing shows it wasn't the poorly-clamped seat causing the noise, as the slight clicks are still there, though again, not on standing, and persists with very light pedaling, making me think it's likely not crank / pedal / spindle.

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  • Is the click audible only or can you feel something as well? Feb 1 at 18:56
  • Just audible. Can't feel anything. I am about 95% certain it's the BB/crank area. Not the headset as far as I can tell. I figured for sure it was going to be the BB cups b/c that's the sort of sound it most closely resembled to me, which has always been a simple fix by tightening up the BB cups. Feb 1 at 19:00
  • Does the clicking follow the crank rotation? Eg. it always clicks at the 12 o'clock position or something.
    – MaplePanda
    Feb 1 at 20:01
  • It could also be something like the pedal bearings. Feb 1 at 21:24
  • The click appears to be random in the rotation, and the pedal bearings feel good. swapping those out is a simple test there, but haven't tried it yet. The bike and all parts are brand new, and I've only put about 80 miles on it, all fairly tame, so I suspect something's not tight enough, or too tight. Feb 1 at 21:54

3 Answers 3

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It really could be a lot of things.

The first question is whether everything is greased that should be. This includes the spindle contact surfaces, the crank splines/lobes, the crank bolt, the bottom bracket cup threads or pressed surfaces as applicable, the pedal threads, and the chainring/spider bolts/lockring as applicable. Also check the torque on all the threaded parts in that list.

Switching the pedals with a known good pair and testing is one of the easier boxes to check and is a good one to do early in the process. Also make sure any housing/hoses in the area are secure.

One sneaky one that's easy to check and also easy to overlook is the spindle connection to the crank it's supposed to be permanently attached to. That sounds obscure but I've been gotten by it enough times now that I check it early once the obvious stuff is out of the way or whenever the cranks are out during troubleshooting. To test it, pull the crank, and push the tip of the spindle hard against a wood surface, such that the joint with the crank is getting a bunch of leverage on it. Keep it within reason, i.e. you're trying to simulate hard riding loads, not break it. Do it once in one direction then again in the 180 degree opposing direction, then back and forth. You're trying to pick up on any sound or movement.

If none of the above does it then the next thing to do would be do some deeper investigation about whether it's really the bottom bracket area.

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  • That stuff is all greased and tightened. Housings secure (and racer tape applied to protect paint!) Pedal check I haven't tried yet. I wondered about crank being a bit loose as well - or the chainring. It uses 3 torx heads to hold it into a splined interface. That was tight, but I didn't try cranking on the spindle. As I mentioned above, the odd thing here is that I get the click if I'm barely putting any force on the pedals too, suggesting it's not something that demands much to appear. I'm OCD about finding and getting ride of clicks, squeaks, etc. This one's got me so far. Feb 1 at 21:59
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The last time I had clicking I swapped out the BB and the clicking persisted and it turned out it was comming from the rear wheel quick release, I took wheel out and reseated it in dropouts and tightened it a bit more and the clicking went away.

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  • I've already done that since when I got it up in the stand I found I needed to re-adjust the bearings in that bike to eliminate some slight play. Alas, clicking persists. Feb 9 at 14:10
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Further testing confirms: It was the seat post

I pulled the seat post today, cleaned it. I applied fiber grip to the spot where it is squeezed in the seat tube. (It's all aluminum, post and tube, but fibergrip helps with that, too, IME.) I also put some grease at the very bottom of the tube, where it appeared there was a little abrasion / wear on the anodization, possibly from flex down there and slight movement. It really did sound like the clicks were coming from down lower, but clicks travel a long way in big hollow tubes.

Finally, I also pulled the compression ring, cleaned that, and greased it where it contacts the frame seat tube. Tightened everything up, took it for a mile ride, and I can't detect the clicking anymore.

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