WarrenR

While installing new tires and tubes I thought I'd grease up the bearings. Should have paid a little more attention when dismantling. So after picking up all the bearings I could find on the floor I ended up with 22. I've spent some time scouring the web and can find lots of generic info but nothing specific to this hub as far as the bearings. I would guess that it's 11 per side but they seem awfully tight after reading how some like to see a little space between the balls. At this point I'd like to replace them and re grease. Any one know how many and what size for this specific hub. After I finish the front I'd like to tackle the rear which has the same part number on it. Are the number of bearings the same for both the front and rear hub?

Thanks

Andrew R Stewart 

The most common ball count for the front hub is 20 but some have had more and less. If you don't get an answer that makes sense to you go with 1 ball less then the max. The hub will spin and adjust just fine. For the rear there's greater consistency with 9 per side being the vast majority of ball counts. Also the ball sizes also vary ft to rr. the typical ft uses 3/16" and the rear usually is 1/4". Shimano has some component exploded diagrams on line, nit sure if a non shop person has access to them. Andy

wschruba

https://si.shimano.com/pdfs/ev/EV-HB-M525-2066B.pdf

Notes 10 3/16" ball bearings per side.

For future reference, www.si.shimano.com is their tech site--you don't need to be a dealer/have a log-in. There are a handful of legacy products that still haven't made it on after their big back-end upgrade, but they can be found by following this simple formula:

[type of document]-[product type]-[model designation]

In your case, you're looking for an exploded view [EV], for an M525 hub, so you would type in "shimano EV-HB-M525", which would likely take you straight to their landing page. Likewise, for items that require their own unique dealer manual (like the FC-M970), you can search for the installation instructions by substituting [DM] for [EV]. Generic user's manuals can be found with the [UM] tag, while service manuals can be found with [SI]. Not all items have all documents, just so you know. Shimano's 2 character product coding can be quite confusing until you get the hang of it, but they list it on the SI site, too ("word definitions").

HillRider

Many newer Shimano front hubs use 11x3/16" balls per side so if you found 22 balls, that's likely the number your hub used.