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More questions about bearings(8 posts)

More questions about bearingsPeterRider
Oct 22, 2003 12:41 PM
First, thanks for the info in a post below on this page, lots of stuff I didn't know.

So, after doing some research on the web it seems that campy and shimano sell grade 25 bearings. If grade 10 bearings are available in bearing supply shops, I'll go to a supply shop and buy grade 10 (probably not going to feel the difference but it doesn't matter). So the questions are:

- what material should I ask for ? (DA front and rear hub - 2002 or 2003, 9spd - campy chorus front hub - 2002 or 2003, 10spd).
- what bearing size ? (would be nice to have the replacement ones before taking the hubs apart :-) ) Ah, I found it for DA: 3/16 22 pcs for front hub, 1/4 18 pcs for rear hub. What about chorus ??

Thanks !

Some answersKerry Irons
Oct 22, 2003 3:58 PM
You don't really have choices on bearing materials unless you want to go ceramic or plastic. Just ask for steel ball bearings. has PDF maintenance files with all the specifications.
mmm... this doesn't satisfy me....PeterRider
Oct 22, 2003 8:34 PM
- I've read the answers I got to my first post (bottom of this page), and bimini was talking about carbon or tool steel bearings. Are they used for hubs as well ?

- Of course I've been to the campy website, but their pdfs don't tell the bearings diameter. I've looked on the components page, also on the spare parts pdf, no information.

making this too difficult....C-40
Oct 23, 2003 5:31 AM
Ever thought of taking the hub apart and measuring the bearings yourself?

You don't mention what year of Campy hub, but the newer models with the oversize aluminum axle have bearings mounted in cages. Campy would like to sell you replacement bearings already mounted in new cages. I've had one apart, but didn't measure the bearings. They are obviously smaller than the common 1/4" and may be less than 3/16" (perhaps 5/32").

If you have older campy hubs, the drive side bearings are odd-ball 7/32". The non-drive side is 1/4". The fronts are 3/16".

The easy way to solve your problem is to buy a package of 100 balls in each of the common sizes 1/8", 5/32", 3/16", 7/32" and 1/4". then you will have every size needed for bike reapir. They are very cheap at places like or

The proper bearing material is a chrome alloy steel. Very standard stuff. Typical hardness is 65 or greater on the Rockwell C scale. Buying a grade better than 25 is waste of money. The mating components of the hub are not made accurately enough to reap a benefit from bearings with tighter tolerances.
seems funny.....divve
Oct 23, 2003 9:31 AM me that the bearings aren't metric sized?
bikes are funny...C-40
Oct 23, 2003 3:31 PM
Bikes seem to be an odd mixture of english and metric sizes. I've never seen a metric loose-ball bearing on a bike. Most hubs use 3/16 inch in front and 1/4 inch on the rear. Catridge bearings on the other hand, have metric O.D and I.D.. Pedal threads are 9/16" english. Steering tubes are 1-1/8 inch. You never know what to expect with bike "standards".
Does anyone ever wear out Dura-ace bearings?ekdave
Oct 23, 2003 5:50 AM
I mean, Ive seen Dura-ace hubs with zero maintenance go 10 years with daily use. Its not like they will rust. I dont know, seems like if you keep grease in it, the hub will last forever. If the balls HAVE gotten chewed up, then the races are going to be bad too. In that case, heck, just get some new hubs. Odds are you've put a billion miles on the those suckers. Most mass-merchants sell Dura-ace for around $150/set. Then you get a new freehub, new everything. Ride those until 2013 when everyone is running ceramic balls.

my wacky 2 cents.
difficult to measure....C-40
Oct 23, 2003 3:37 PM
With the original sphericity of 25millionths of an inch and a size tolerance of 1/10,000th of an inch, the average guy with a micrometer couldn't tell the difference between a ball that was new and one that should be replaced. They are so cheap that a good shop tosses the old ones and puts in new ones. The total cost for a set of new bearings (front and rear) is about $1.50.