# What size loose ball bearings and what tool to remove freewheel from hub?



## crclawn (Sep 26, 2010)

Hi, just got into maintaining my own bikes. two questions:

#1. What size loose ball bearings to rebuild hubs and what size to rebuild bottom bracket?

#2. What tool do I need to pull the freewheel from my hub that uses a cassett?


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## jeffj (Jan 13, 2004)

Depends what hub you have as to what size ball bearings are needed and how the freehub is removed. Some freehubs just 'pop' out from the hub and others need a 10mm or 11mm allen wrench.

You usually don't have to replace the loose ball bearings when you service a hub. Just clean everything out, put new grease in and adjust (if you have cone type bearings). For many Shimano hubs, you'll need a 15mm and 17mm cone wrench to adjust bearing cones and a 10mm allen wrench to remove the freehub. Not really much reason to remove freehub on those as the freehub is not meant to be 'serviced'. Just make sure the fixing bolt (that attaches the freehub to the hub shell) is tight.

Of course you should have a cassette removal tool and a chain whip to remove/attach the cassette before getting to the stuff underneath.


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## JonathanGennick (Sep 15, 2006)

crclawn said:


> Hi, just got into maintaining my own bikes. two questions:


Here's a site w/some helpful videos: www.bicycletutor.com.

There is also a book on mountain-bike repair by Leonard Zinn that's fairly helpful.

And there is repair advice on parktool.com.

The above are just some good sources you'll want to know about.



> #1. What size loose ball bearings to rebuild hubs and what size to rebuild bottom bracket?


Typically, if memory serves, you have 3/16" up front and 3/4" in the back. Typically you'll have 10 bearings per side in the front and nine bearings per side in the back. Those are *common* sizes and counts, but you really won't know for sure until you tear into the hub. I worked on a rear hub a while back having two different bearing sizes, with smaller bearings on the drive-side, and a different number of bearings on each side.

When you first open your hub, pay attention to what comes out. Count the number of bearings. Note whether they are different on the right and left sides.



> #2. What tool do I need to pull the freewheel from my hub that uses a cassett?


Your terminology's a bit mixed up here. The term "freewheel' doesn't go along with 'cassette'. Do you have a modern, nine-speed hub? Then most likely you need a chain-whip and a cassette lock-ring tool. However, if you really do have a freewheel, you'll need the tool that matches your specific freewheel, and there are several possibilities.

You might find this page to be helpful:

http://www.parktool.com/blog/repair-help/cassette-and-freewheel-removal


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## zebrahum (Jun 29, 2005)

Most bottom brackets these days use sealed cartridge bearings and are difficult for the home user to service if it is possible to do so. They start at inexpensive prices which means that it is usually more sensible to replace than to repair. Also, if you do have a caged ball bearing bottom bracket then it would be a good time to replace it with a sealed cartridge model if one is available to fit your crank and bicycle.


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## gmcttr (Oct 7, 2006)

JonathanGennick said:


> ...if memory serves, you have 3/16" up front and 3/4" in the back...


3/4"?...that would make for a mighty heavy hub.


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## JonathanGennick (Sep 15, 2006)

gmcttr said:


> 3/4"?...that would make for a mighty heavy hub.


LOL! Sorry. Guess I posted before finishing my morning coffee. I meant 1/4". My bad.


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## rlouder (Jun 26, 2007)

Freewheel or Cassette - Sheldon Brown

http://www.sheldonbrown.com/free-k7.html


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## mtnbiker72 (Jan 22, 2007)

Looking at your profile, looks like you have a Cannondale 29er 4. That should have Shimano M475 hubs. You will need 20 (10 per side) 3/16" bearings for the front hub and 18 (9 per side) 1/4" bearings for the rear. The freehub body comes off with a 10mm hex wrench like in this tutorial from Park Tools. The bottom bracket is not serviceable.


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## crclawn (Sep 26, 2010)

Thanks guys that clears it up. Just wanted to have some spare bearings before I get into some hub mant just incase I loose a couple of bearings.


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## jeffj (Jan 13, 2004)

I use one of those 'metal pencils' that have a magnet where you would typically have an eraser on a normal pencil to pull out the loose ball bearings and then drop them into a paper cup or one of those magnetized metal bowls you can get at the auto parts stores.

Also, if you are not very familiar with the order of the washers and spacers and which way they face, you can stack them in the order they came off and/or take a picture of them with a digital camera so you can get them back in the right order.

Once you know how to do it, it is not particularly difficult, but there are many opportunities to screw up if you are not meticulous enough and paying attention to details.

For garden variety Shimano rear hubs, here is what I do:

The cone wrenches you need are 15mm and 17mm. Also handy to have a pen style magnet and maybe a small flat bladed screwdriver and of course, some bicycle bearing grease, such as Phil Wood or Park Lube.

The rubber cover comes off easily by either pinching it or you can use a tiny screwdriver to carefully pry it up. Now is a good time to measure how far the hollow axle protrudes (on the drive side) from the rest of the assembly so you can put it back to the same when reassembling it. Loosen the two nuts on the non-drive side from each other, and then remove the first nut and the washers. Stack the washers in the order they came off in a place they won't get disturbed. Hold the axle in place from the drive side while you remove the bearing cone from the other side.

Use the pen magnet to remove the nine 1/4" ball bearings from the inner race on the non-drive side, and then pull the axle out from the drive side. Now, if the nine ball bearings have not fallen out from the drive side go ahead and removes them using the magnet.

Clean out the grease from where the bearings rest in the inner races using q-tips and/or paper towels. . . . whatever.

It's a good idea to take a 10mm allen wrench and make sure the freehub fixing bolt is tight (that connects the freehub to the axle shell).

Take your cone wrenches and tighten the two drive side nuts against each other tightly (on the axle) making sure the axle protrudes the same distance it did before (you did measure it, right?). Put some grease all the way around the inner race down in the freehub and use the small flat bladed screwdriver to _finagle_ them into place bedded down into the grease. You can lay a bead of grease onto the bearing surface of the cone (that's on the axle) too. The slide the axle through from the drive side making sure that no ball bearings come out of place (the fresh grease usually holds them into place).

Now put some grease into the inner race of the non-drive side and slip the ball bearing into place around the axle and then another bead of grease on the bearing surface of the cone and thread it onto the axle. Thread it down so when you turn the axle you can feel that the bearings are slightly "notchy".

Install the washers that were set aside earlier in the order they came off and thread on the outer nut. Tighten the two nuts down against each other and the axle should still feel slightly 'notchy' as it turns. Now, loosen the nuts from each other a little more than 1/8th of a turn and then tighten them back against each other. Each time you do this, the axle should turn just a little easier. Do this until the axle turns smoothly, but there is no more than just the smallest amount of discernable play in the bearings. Make sure you tighten the nuts pretty tightly against each other. Pop the rubber cover back into place and you are done.


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## alaskadude (Nov 9, 2013)

jeffj said:


> I use one of those 'metal pencils' that have a magnet where you would typically have an eraser on a normal pencil to pull out the loose ball bearings and then drop them into a paper cup or one of those magnetized metal bowls you can get at the auto parts stores.
> 
> Also, if you are not very familiar with the order of the washers and spacers and which way they face, you can stack them in the order they came off and/or take a picture of them with a digital camera so you can get them back in the right order.
> 
> ...


Great description.


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