My pedal came off my exercise bike/cross trainer. I have tried putting it back on, but the big screw will only go in so far. It is turning twice then getting stuck. Can anyone tell me what I need to fix this. I don't know the names of the certain parts etc to search myself.

  • Does the exercise bike use the same type of attachment system as a regular bicycle?
    – Batman
    Commented Feb 12, 2016 at 18:34
  • 1
    Important: Did only the pedal come off, or did the crank arm come off as well? If the crank arm came off then you probably need to take it to a bike shop. If just the pedal came off then likely the threads are slightly fouled. Still better to take it to a bike shop, but first you can try taking an old toothbrush and using it to clean out any crud in the threaded hole in the crank arm. Then look in there and see if there are still any tiny globs of metal that would foul things up. Commented Feb 12, 2016 at 22:53

3 Answers 3


Which side pedal came off? This answer might help, pedals don't both screw in the same way.

If not, can you attach a photo? If you don't know the names we can help figure it out for you.


Two things may have happened:

  1. It may have just unscrewed itself. As @likeprogramming notes, the pedals screw in differently. The left pedal must be screwed in counter-clockwise ("left") while the right pedal screws in the normal clockwise ("right") way. It is easy to cross-thread the pedal by having them at a slight angle when screwing them in. I find it is helpful to rotate the pedal bolt in the "wrong" direction for one total revolution before then reversing it and screwing it in, this helps prevent a cross-thread.

However, your description of the pedals only screwing in a few threads bothers me. If it's not because you're trying to screw the left pedal in the wrong direction and if it's not because you're cross-threading then ...

  1. there's a chance that the crankarm threads were worn or damaged -- and that is why the pedal came out. In that case, you will need to drill-and-tap a helicoil into the crankarm. This isn't something a normal DIY person can do, but it is relatively easy for a bike-shop and should only cost around US$20-40.

Here's a labelled diagram for the crank part names:

enter image description here


If you are talking about the threads on the pedal there are three (or more possibilities)

  1. It is cross threaded
    But if only one pedal come off then that is not the case
  2. Not cross threaded and everything is fine
    But you are just not lining it up correctly
    It can be hard to get even good threads to align some times
  3. Threads are damaged
    If it worked its way out then when it was barely in there was a lot of stress

Clean both pedal and crank threads with solvent and brush
If you don't have a parts cleaner type solvent then just a de-greaser or even dish washing soap
Put a dab of grease on the pedal threads
If you don't have grease then just stop and get some

Come in from the back side. If just the first few thread are messed up then coming in the back side should work. If you get several easy turns in before it sticks then most likely just some messed up threads on the front side. You typically don't want to force but if you have several turns in then you can force with a wrench to clean out the threads. If the works then try coming in the font side. If this does not work then take it to a shop.

  • 3
    Putting the left pedal on the right hand crank really isn't cross-threading as the term is commonly used.
    – RoboKaren
    Commented Feb 12, 2016 at 20:47
  • @RoboKaren That is how the term is commonly used in bicycle pedals.
    – paparazzo
    Commented Feb 12, 2016 at 20:51
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    In this context it's confusing because the common usage is this: ericpetersautos.com/wp-content/uploads/2014/11/cross-thread.jpg
    – RoboKaren
    Commented Feb 12, 2016 at 21:03
  • @RoboKaren OK then that is how I use the term in regards to pedals and how I used it in my (limited) answer. I think you introduce this helicoil thing a little premature so wanted to give the OP more guidance.
    – paparazzo
    Commented Feb 12, 2016 at 21:12
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    @RoboKaren so what is the term for putting a left hand threaded bolt into a right hand threaded nut, or vice versa? I have always used "cross threading" to mean "anything other than correctly threading", and wasn't even aware that there was a variety of terms for the various ways it could be done wrongly. Now I'm curious and hopefully can learn some new words.
    – Móż
    Commented Feb 13, 2016 at 9:39

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