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How to replace bearings/freewheel tz21
#1
I don't know if I have what is called a freewheel/hub/cassette or what. I have a cheap bike with shimano mf tz21 freewheel. I tried to see if I could put a different shimano freewheel on but it didn't work, so now I am trying to put the original back on.

So I have a million bearings that looked like they were in two rows. I stacked them in there as seen in the photo, but when I put the locking ring back on, I can't get it tight without the cassette no longer spinning. Sure it spins if the locking ring is loose, but the moment I tighten it, no luck.

Did I maybe miss a bearing somewhere? Anyone know how to put this back on? I don't think there was a washer/space between the bearing originally, but was there? Seems odd to have two rows of bearings touching each other in the channel like that.

any ideas on how to get this working again?

Thanks!
  Reply
#2
Perhaps this will. Help. You need to stop the sprockets from rotating, usually a chain wrench is used.
Also for removal a special tool is needed. You just removed the bearing cover.

http://sheldonbrown.com/freewheels.html
Never Give Up!!!
  Reply
#3
Thanks George. I also removed the bearings as well....hence the problem. I'm trying to put the bearings back in and when I put the cover back on, it will spin when the cover is very loose, but once the cover is tighter (seems to self tighten when spinning) it gets harder to spin and then stops.

I saw Sheldon's post and trying to find out if the two rows of bearings in this one really just touch each other? I think they do, but having troubles with it spinning once we tighten the locking ring.

Anyone know where to find a reference doc on how many bearings it should have? Maybe I lost one somewhere.

Thanks!
  Reply
#4
Just get this freewheel removed, and replaced.

You will need something like a Park FR1. The hex nut in the picture may have to be removed.

This is the freewheel you have:
http://www.amazon.com/Shimano-Tourney-7Spd-14-28T-Freewheel/dp/B003B8JYPU/

It is not intended to be taken apart.
Nigel
  Reply
#5
Yep 10-4 to that Nigel. That's what Sheldon's info said too. Not for servicing. Just replace.
Never Give Up!!!
  Reply
#6
First, I totally agree that it should be replaced as freewheels are consumable items like tires and tubes. Not really intended to take apart and service like a cassette apparatus.
Next I will tell you that indeed there is a bearing missing. Now you have to order/find a replacement bearing which only come in a package, umm $2.50/bag + $4.98 Ship (estimated) = $7.48. Per say you get the bearings and then you replace them. Here is the bad part , the metal part the bearing are lying is probably worn (bevel marks) from many rotation the bearing have spun. On top of this we aren't sure how tight the "cap" goes on. So I am really gonna add to all this.. did you know there are bearing in the back side of the freewheel? YUP, how many are back there? Per say you take it apart to find out if all are still back you just completely ruined the freewheel although that was already done when the front cap was pulled off.
I'm just trying to show ya that somethings just can't be serviced.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#7
Hello Dear!

I also have a shimano mf tz21 freewheel. I take it out today for cleaning and all thoseo bearings appeared.

I'm trying to put it back but I have no idea of where the bearings belonge.

You picture is quite good to show the problem to set the bearings.

If you solved the problem please share the answer with me.
I would love to use my bike tomorrow!

Thanks!
Max
  Reply
#8
(08-24-2012, 04:09 PM)Max Wrote:  Hello Dear!

I also have a shimano mf tz21 freewheel. I take it out today for cleaning and all thoseo bearings appeared.

I'm trying to put it back but I have no idea of where the bearings belonge.

You picture is quite good to show the problem to set the bearings.

If you solved the problem please share the answer with me.
I would love to use my bike tomorrow!

Thanks!
Max

As I stated above these are not meant for servicing, but rather throw away and replace Sad . Sorry I know this is not what you wanted to hear, but it is the truth. The price of these are rather minimal or if you like find a similar one by counting the number of cogs and each cogs teeth take it off a used wheel, providing the freewheel is in decent shape and use that until you find a new one.
AGAIN TO ANYONE THAT TRIES TO SERVICE A FREEWHEEL IT CAN NOT BE DONE! Sorry about the caps but it gets attention.
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#9
As I stated above these are not meant for servicing, but rather throw away and replace Sad . Sorry I know this is not what you wanted to hear, but it is the truth. The price of these are rather minimal or if you like find a similar one by counting the number of cogs and each cogs teeth take it off a used wheel, providing the freewheel is in decent shape and use that until you find a new one.
AGAIN TO ANYONE THAT TRIES TO SERVICE A FREEWHEEL IT CAN NOT BE DONE! Sorry about the caps but it gets attention.
[/quote]

Thanks to ALL! but I just contact with an expert that do this in an easy way!
Here the link:
http://www.bikeforums.net/showthread.php/707342-Build-a-long-freewheel!!!!-Photo-heavy?highlight=freewheel+rebuild

Regards, Max
  Reply
#10
Well that was some definite schooling and reading. Thanks for the information! Now here is my reply. If just one ball bearing is lost or cracked or split then one has to order a bag of them not to mention if there is worn spots on the bearing races inside. For the person who REALLY does not have money to spend then I guess this would be a last resort option until they saved up or found a used one. Lets remember freehweels are cheaply made with the most inexpensive grade (100 or less) of bearings possible to work. I like shimano but when you buy low end shimano parts you are only buying the name!!! Anyone here will agree that the above process takes alot of patience, time, and effort.
However, it would be a cool project to attempt with all 64 or more bearings!
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#11
To add to Bill's not above, the link posted by Max is focused on salvaging out of production freewheels for strict bike restorers, not as a cost saving technique. To be able to do this, as Bill said, you need a large inventory of balls and/or freewheels - for just one bike, much less money to purchase a new freewheel.
Nigel
  Reply
#12
There's a big difference between "not worth the time, effort, and expense" and "it can not be done."

Rebuilding a freewheel is not that hard and the tough part is usually getting the lockring off which the OP already did (accidentaly). He took it apart by mistake trying to remove it and was just trying to put it back together. Fairly simple question with fairly simple answer.
  Reply
#13
Lots of information and links were given for how to rebuild, along with opinions that its just not worth it economically and otherwise. Poster has a choice.......
Never Give Up!!!
  Reply
#14
To fairly answer I guess I should have stated I stand corrected?
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
  Reply
#15
(08-28-2012, 01:05 PM)GeorgeET Wrote:  Lots of information and links were given for how to rebuild, along with opinions that its just not worth it economically and otherwise. Poster has a choice.......

Not trying to be a jerk and also not trying to single anyone out. I just don't want to see this place descend into "bike forums" world where anyone who doesn't know much is treated poorly and people routinely spout incorrect advice as if it were gospel.

All the regular commentors here have a wealth of good info. Hoping that they will all continue to do so. I'll continue to correct things I think are inaccurate. I hope others will do the same for me - I know I've been wrong before.
  Reply


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