Freewheel - Shimano MF-HG20

[fish4bass]

The rear sprocket catches very frequently when I stop pedaling and causes the chain to continue forward vice the rear wheel spinning free and the chain occasionally comes off. Can you repair it ...i.e. can you take it apart and grease it?

[trevgbb]

no, replace.
This can be dangerous when riding as the chain can wrap up and catch in the wheel, throwing you off the bike!!
If you must ride, remember to keep the pedals rotating at all times to prevent this.

[DaveM]

Quick fix to try is to lay the bike on it's side and drip some chain lube in at the gap between where the part of the freewheel that stays fixed and the part that rotates is. That may free it up.

There is a tool that can be used to force grease into a freewheel, but you have to take it off the wheel. Beyond that, it is possible to open up most freewheels and clean them up. but few people do it due to cost to replace versus time to overhaul.

But do something. +1 that it is a bit dangerous to ride with it like this.

[fish4bass]

(09-20-2010, 03:22 PM)DaveM Wrote:  Quick fix to try is to lay the bike on it's side and drip some chain lube in at the gap between where the part of the freewheel that stays fixed and the part that rotates is. That may free it up.

There is a tool that can be used to force grease into a freewheel, but you have to take it off the wheel. Beyond that, it is possible to open up most freewheels and clean them up. but few people do it due to cost to replace versus time to overhaul.

But do something. +1 that it is a bit dangerous to ride with it like this.

---

Tried the chain lube ... it freed it up a little but it's still catching too frequent. I've tried finding the part on line to no avail. How do you "open up" freewheel?

[DaveM]

Here's a good article on freewheels:
http://www.sheldonbrown.com/freewheels.html

You should be able to buy a replacement easily though. If you have friction shifting (no clicks on the shifter) you can use pretty much any freewheel with the same number of gears (and sometimes ones with more. If it is indexed, you just need the same brand and gear count or something compatible. But carry on...

[X-RAY]

after reading over and over NOT to open them up, i did it anyway with the idea that if it didnt work, i was only out my time. i wound up doing 2 at the same time to regear my daughters freestyle so she has more grunt for the hills. it IS possible, and if you have the time, try it. if you ruin it, well, you were gonna buy a new one before you tried anyway, right?