I just purchased a cruiser bike online that I had to assemble.

When I rode it for the first time, I notice my pedals felt shaky, whether pedaling or coasting, and when I did pedal every few seconds they made a crack/pop. I don't feel anything abnormal when this happens.

Turned the bike over, and I noticed the chain shakes too. It is tight, but the wheel looks as if it is up as far as it can go- it looks like if I adjusted it further to loosen the chain, I'd be at risk of it falling off.

I opened up the wheel sprocket- no broken ball bearings

Does any one know why this is happening, and if its an easy fix or defective bike that I need to return?

  • Further diagnosis needed - try hanging the bike up so the rear wheel is off the ground. If you push the pedals by hand, does the shakeyness show up? Then pop the chain off the front chainring to separate front from back. Does the shakeyness stay in the pedal/crank area or is it gone? Try and isolate things down to one area. Last resort is to take it to a bike shop for a tune-up.
    – Criggie
    Sep 16, 2015 at 21:31
  • Just tried it, yes it does still shake. Not visibly, but you can feel it if you place your hand/foot on the pedal, or are riding it.
    – rogue
    Sep 16, 2015 at 21:34
  • OK pop the chain off the chainring and let it sit out of the way. Try and see if its coming from the bottom bracket area, or the back wheel.
    – Criggie
    Sep 16, 2015 at 21:39
  • I took the chain off, no shaking in the pedals, but if i turn the wheel and Hold the chain while its on the wheel's sprocket i can feel the shaking
    – rogue
    Sep 16, 2015 at 21:40
  • 1
    I tried riding it before it was fixed to see if i could feel anything. With in 20 feet it made a loud pop and the rear wheel stopped. When i got off i saw the rear where was crooked and would not turn. Upon further inspection, i sae the ball bearing was sticking out of th coaster brake and the brake was all bent. I chalked it up to bad bearings? And returned it. Im currently waiting for the same bike to come in the mail. Ill let you guys know if it does the same thing
    – rogue
    Sep 24, 2015 at 1:51

2 Answers 2


The popping sound could be coming from the chain not lineing up properly on the freewheel. This can happen if the chain is either bent and or twisted or if the chain is not the proper size for the sprocket. More than likely it is a bend or twist in the chain.

  • It could be a tight link in the chain, too. Tight links show up when pedaling backwards, usually visible either between the cogs (as a point in the otherwise-flat chain) or around the cogs (as a point in the otherwise-round chain)
    – mwalker
    Feb 17, 2016 at 0:15

They are flexing too much. You may need to make a pedal upgrade. Also, your chain is clearly too long if your wheel will fall off if you try to slide back your tire. You should probably take about 3 links out of the chain then the bike should run fine.

  • 1
    Mike, welcome to Bicycles.SE. For an intro to how this and other Stack Exchange Q & A sites work, please Take the Tour. This site doesn't work like a traditional forum; it's focus is detailed and well researched answers to specific questions. I have combined your three answers into one and deleted the other two, as well as standardizing the grammar and spelling a bit.
    – Gary.Ray
    Feb 26, 2016 at 14:17

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