I bought my 4 year old a 12 inch bike with training wheels, are the pedals supposed to move when the wheels moving, he pushes his front foot down but even with the speed the back one never comes up enough that he can push that one down.

  • 4
    OT, I recommend removing the trainer wheels and pedals, and turn it into a balance bike.
    – mattnz
    Mar 21, 2021 at 21:59
  • 2
    Are the two pedals turning independent of each other? Mar 21, 2021 at 22:09
  • 2
    Are you saying that when one pedal is at the bottom, the other pedal is not at the top? Or that they can, and when the pedals are in that orientation your child cannot continue the pedaling motion?
    – Fing Lixon
    Mar 21, 2021 at 22:54
  • 1
    Wait. "Not completely"? Do you mean one pedal isn't completely at the top when the other pedal is at the bottom? Or that the child can't completely turn the pedals?
    – Fing Lixon
    Mar 21, 2021 at 23:07
  • 6
    A good picture of the bike would help us troubleshoot.
    – David D
    Mar 22, 2021 at 1:06

4 Answers 4


12 inch wheel bikes like this one:
enter image description here

are designed so that the pedals will not turn just by turning the wheels.
They are designed so that when the rider pedals the wheels turn.
Once some momentum is gained the rider can stop pedaling and the bike will coast forward. The rider engages the brakes by pedaling backwards - this is a coaster brake.

If your bike is a coaster brake bike you can visually identify a coaster brake bicycle by looking on the non-chain side of the bike for the brake strap.
enter image description here

There are many, many bikes in different colors and frame shapes with the same design.

  • Then how can my four year old learn to pedal, the back pedal does not come up enough for him to continue pushing
    – Brittany89
    Mar 21, 2021 at 22:02
  • Note that there are hand operated band brakes on kids bikes that look just the same at the back; that strap doesn't prove it's a coaster brake
    – Chris H
    Apr 3, 2021 at 9:54

Your bicycle was assembled incorrectly. Take it back to where you purchased it and ask that they fix or replace it, or take it to a bike shop to be assembled properly.

Let me also add a note in favor of @mattnz 's comment. Turning this into a balance bike may be the easiest solution. On the other hand, my child never took to a balance bike and needed outriggers.

  • It was bought on amazon. I think it came with the pedals already installed, ill have to double check
    – Brittany89
    Mar 21, 2021 at 23:14
  • 1
    @Brittany89 the pedals (actually the crank arms) should be able to be removed and replaced, possibly with special tools.
    – Fing Lixon
    Mar 21, 2021 at 23:17

I think my kids had similar difficulty in learning to pedal. My guess as to what you're describing is that even if the crank arms are totally vertical, he hasn't figured out how to push the top pedal forward to initiate the next pedal stroke. It might help to get him to point his toe down at the bottom of the stroke and point his toe up at the top of the stroke. This can help put force in the direction of rotation instead of pushing straight down towards the bottom bracket (where the cranks pass through the frame).


Hi I'm new here but in a similar spot

Our 12" bike has never had the pedals, crank or chain attached, I removed them on day two and created a better quality balance bike.

After that, you better check on the size of your 4YO as my girl at 4 1/2 is now too big for her 16", she took on that size just over 3 1/2. 12" balance bike was 2-3YO.

I am repurposing the 20" trek mtb for her but I need to replace the old twist shifter.

It's a fraction large but she does ride it ok, I think I'll change it back to the XC flat bar I used when my boy was riding it the same age.

  • Hi, welcome to bicycles. While interesting details, you should concentrate on answering the question, which was about an apparent difficulty continuing the pedalling motion. Note that this site is strictly question-and-answer, and not a discussion forum. You might want to take tour.
    – DavidW
    Apr 4, 2021 at 19:51

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