I've just found out where friction occurs in my BMX.

When I take chain off the Outer Part and spin the rear wheel the wheel will spin for several minutes but when the Outer Part can't rotate with the rest of the wheel (when chain is on) friction is caused by the Inner Part rubbing against the Outer Part enter image description here


How to find a replacement of the bad part(s) with the least friction? OR fix the friction IF that's a better choice?

What are these parts called?

  • I'm not sure if the two parts together are called a freewheel and I also don't know what other tags to add – BMXftw Jun 2 '14 at 16:04
  • Is it possible that this is a plain old coaster brake hub? Can't tell from the picture. If so, then it's serviceable by a neighborhood 8-year-old. – Daniel R Hicks Jun 2 '14 at 22:34
  • Most Freewheels are designed to be replaced often. Pro racers are known to replace them every day if not every race, not because the the teeth are bad, but because they torque going on inside is just so high (in races) that they would rather replace them than worry about failure or, in your case, "friction". Just get a new one. - (yes, almost 4 years old question, but it came up on the side so people are still looking at it for answers.) – BillyNair Jan 31 '18 at 20:26

Yes that is as single speed freewheel and those two pieces should not stick
There are some serviceable freewheels (White) but they are expensive
Pretty sure you need to replace the freewheel
Based on the rust it looks old
If you remove it from the bike and it sticks then for sure you need to replace it
You can try spraying a lubricant in the grove but most likely the bearings are shot

A freewheel is like $30 and it takes a special tool to remove
Take it to a bike shop
If you buy the freewheel from them the often install for free or a small fee

Or check youtube for videos on how to do it yourself
The removal tool for a single speed is like $25 so not worth it unless you are going to do it a few times

And if you are going to replace the freewheel then it is good practice to also replace the chain

As Brian stated this can also happen from a chain to tight.
Chain should have a little play.
And crank the pedal a few revolutions - some times the chain can be more tight in certain positions

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    you're more than likely right. but this issue can also be caused by over tightening the chain. although i doubt this is the issue, it is something worth mentioning. i've seen way too many bmx/single speeds come into the last bike shop i worked with severely tight chains causing this issue. – BrianC Jun 2 '14 at 16:47
  • @BrianC Agree, that is why I told him to test with it off the bike. I will add more. – paparazzo Jun 2 '14 at 16:52
  • @BrianC can you specify how "tight" is too tight? – BMXftw Jun 2 '14 at 16:52
  • Mid chain a little play - like 1/2 to 1 inch. – paparazzo Jun 2 '14 at 16:56
  • @Blam yes it sticks when removed (when I try to spin it the most it can spin is two revolutions).I know that I can't get a frictionless part but is there some sort of specification for amount of friction so I can compare them somehow? I really don't want to buy a part with more friction than I have to – BMXftw Jun 2 '14 at 16:56

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