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I've been maintaining my own bike for a while now, the one thing I haven't been able to fix is the pedals wobbling. This is a little hard to describe but hopefully it's understandable, and I've attached some pictures. The pedals wobble perpendicular to the crank arm, i.e. they move vertically. When I am riding, I hear a clicking noise especially when I'm pedalling hard, which I think is the pedal wobbling in the same way, but under more load. I've done a lot of googling and all I've found is either steps on removing the pedal (which I don't think is the issue as it seems tightly attached to the crank arm) or steps on fixing the crank arm itself, which I also don't think is the problem. Again having said all that, I'm very much new to this, so any corrections or advice would be massively appreciated. I did have a mechanic address this problem about a year ago, he mentioned it was difficult to adjust my pedals specifically but he was able to fix it, although I didn't ask him at the time exactly what he did. My concern is that if I don't fix this, it may cause damage elsewhere and lead to more expensive replacements.

down wobble up wobble

The bike is a Trek FX 7.4, I haven't replaced any of the pedal or crank components but I also am not sure specifically what model the pedals are, although I can probably try to dig this up if it's helpful!

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  • I just noticed in the picture that one of the screws holding the pedal onto the body is loose, that isn't the problem here, I just didn't tighten them back up enough when I removed the pedal from the body to try and figure out what was causing all this! Aug 22 '20 at 12:43
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    Pedals are like chains and tyres consumables. They do quite a lot of hard work and need to be replaced. Higher end ones may be cleaned and readjusted, but with most the implied workload and spares are more expensive than a new pair.
    – Carel
    Aug 22 '20 at 13:38
  • thanks @Carel, I take it you think I should just write them off and get some new ones, which makes sense! Do you recommend a particular brand or style, I know that some require a pedal wrench to install or remove (which I don't currently have), so if those aren't really better I may try to find some new ones similar to these! Aug 22 '20 at 14:49
  • @whiterainbow The RaceFace Chester or Crankbrothers Stamp 1 are both excellent flat pedals. Those have a 6mm hex hole for installation and removal.
    – MaplePanda
    Aug 22 '20 at 17:42
  • It is worth noting that slight scratches are visible on the crank arm just below the pedal. These could be caused by the U-shaped outer shell of the pedal hitting the crank arm, and this could account for the clicking. Aug 23 '20 at 3:02
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Examine the pedal and crank arm.

enter image description here

(Note that the above diagram is not exactly like your pedal, but the basic construction is the same.)

Note that there is a shaft that runs inside the pedal, from crank arm to the end of the pedal. The pedal bearings (inside the central housing of the pedal) ride on the pedal shaft. Likely the bearings have gotten loose and the pedal is rattling around on the shaft. If this is the case you should go ahead and replace the pedals.

But carefully examine the shaft as you move the pedal up and down. Where the shaft mates with the crank arm you will be able to see 10-15mm of the shaft, and you should not see ANY motion between this shaft and the crank arm. If you see any motion there (while you move the pedal up and down) it means that the pedal is unscrewing from the crank arm and the crank arm will be very quickly damaged (if it isn't already).

Further, grasp the crank arm and move it in and out, checking for any flex between the arm and the crank shaft inside the bottom-bracket. Any motion here must be corrected immediately (tighten the crank nut) or the crank arm and possibly crank shaft will be damaged.

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  • thank you for the diagram, this is great! It does seem like the pedal is moving on the shaft, there is no movement between the shaft and the crank arm or the bracket, so I think I'm good and I just need to replace the pedals. Again, big thanks, I've been trying to puzzle this out for ages! Aug 25 '20 at 2:39
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Is the pedal spindle moving in the crank arm? If so stop using the bike immediately. Loose steel pedal spindles wallow out the threads in softer aluminum cranks. Sometimes this can be fixed with a helicoil in the crank but often it's a ruined crank.

As you say the pedal clicks it's more likely that the pedal bearings are destroyed. If the pedal body is moving on the spindle this is the case. As Carel said in a comment unless you have high end pedals with serviceable or replaceable bearings just get new pedals.

Many pedals have a 6mm hex head in the end of the spindle for easier installation.

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