Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Are All Ball Bearings Magnetic?

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Are All Ball Bearings Magnetic?

Old 07-17-18, 11:41 PM
  #1  
michaelm101
Senior Member
Thread Starter
 
Join Date: Jul 2017
Location: SoCal
Posts: 291

Bikes: Cannondale Carbon Synapse Road, Cannondale T2000 Touring, Vintage Mongoose IBOC Pro MTB, Vintage Peugeot 12spd racer, Old rusty Schwinn Manta Ray I neglected as a child, Diamondback Haanjo EXP Carbon & Metro, Specialized Roubaix Pro, RaleighSC Tandem

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 141 Post(s)
Liked 12 Times in 9 Posts
Are All Ball Bearings Magnetic?

Found nothing on this subject.
I removed old ball bearings from one of my hubs and they are CRAZY magnetic. Just received some new ones lableled "Stainless Steel" from Amazon. I thought steel was magnetic... The very barely stick to my magnet. I actually had to place them in the cup by hand...
Anyone have any thoughts on this? Thanks in advance!
michaelm101 is offline  
Old 07-18-18, 01:42 AM
  #2  
JoeTBM 
Droid on a mission
 
JoeTBM's Avatar
 
Join Date: May 2018
Location: Palm Coast, FL
Posts: 446

Bikes: Diamondback Wildwood Classic

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Liked 45 Times in 38 Posts
Stainless steel is an alloy and depending on the formula may not have magnetic properties

Here is an article that covers the magnetic properties [or lack thereof] of stainless steel

https://www.wisegeek.com/is-stainles...#didyouknowout

And if you found that interesting, here is another that goes a little deeper

https://www.kimballphysics.com/magne...ainless-steels
__________________
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com




JoeTBM is offline  
Old 07-18-18, 06:47 AM
  #3  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 32,253

Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!

Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Likes: 0
Liked 260 Times in 209 Posts
You probably bought 300-series stainless steel bearing balls which are non to very weakly magnetic. They are extremely good for corrosion resistance but not that good for hardness and wear resistance and are usually specified when corrosion resistance is of primary importance. More common are 400-series stainless balls where corrosion resistance is not as important but hardness is and these are strongly magnetic. Regular chrome steel bearings are magnetic and harder and stronger yet but not as corrosion resistant. For bicycle use chrome steel is the best choice for cost and durability.
HillRider is offline  
Old 07-18-18, 05:37 PM
  #4  
nfmisso
Nigel
 
nfmisso's Avatar
 
Join Date: Mar 2011
Location: San Jose, CA
Posts: 2,991

Bikes: 1980s and 1990s steel: CyclePro, Nishiki, Schwinn, SR, Trek........

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 383 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
The best ball bearing steel is 52100; it is very magnetic, and requires corrosion protection.

440C is a stainless steel, nearly as good a bearing material as 52100, it is magnetic, easy to pick up with a strong magnet. Better at not rusting than 52100, but not very good compared to other stainless steels.

Non-magnetic stainless steels do not make very good bearing balls, avoid.
nfmisso is offline  
Old 07-18-18, 09:15 PM
  #5  
WizardOfBoz
Generally bewildered
 
WizardOfBoz's Avatar
 
Join Date: Aug 2015
Location: Eastern PA, USA
Posts: 2,790

Bikes: 2014 Trek Domane 6.9, 1999 LeMond Zurich, 1978 Schwinn Superior

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1039 Post(s)
Liked 241 Times in 178 Posts
Originally Posted by nfmisso View Post
The best ball bearing steel is 52100; it is very magnetic, and requires corrosion protection.

440C is a stainless steel, nearly as good a bearing material as 52100, it is magnetic, easy to pick up with a strong magnet. Better at not rusting than 52100, but not very good compared to other stainless steels.

Non-magnetic stainless steels do not make very good bearing balls, avoid.
Good info, clearly explained. Thanks nfmisso.
WizardOfBoz is offline  
Old 07-18-18, 10:31 PM
  #6  
davidad
Senior Member
 
Join Date: Feb 2009
Posts: 6,280
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 441 Post(s)
Likes: 0
Liked 65 Times in 59 Posts
Grade 25C balls are overkill for our use. had SS in my DA 9sp hub and did not care for them. Replaced them with 25C.
davidad is offline  
Old 07-19-18, 05:57 AM
  #7  
termv
Senior Member
 
Join Date: Jun 2018
Posts: 62
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked 3 Times in 3 Posts
Crazy idea, could they be made de magnetized,
​​​by using the appropriate tool?

Was just an idea. However, I doubt this would have any real life implications.
termv is offline  
Old 07-19-18, 09:51 AM
  #8  
FBOATSB 
Senior Member
 
FBOATSB's Avatar
 
Join Date: Jul 2014
Location: Central Indiana
Posts: 1,693

Bikes: Old Schwinns

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 634 Post(s)
Liked 78 Times in 58 Posts
Originally Posted by nfmisso View Post
The best ball bearing steel is 52100; it is very magnetic, and requires corrosion protection.

440C is a stainless steel, nearly as good a bearing material as 52100, it is magnetic, easy to pick up with a strong magnet. Better at not rusting than 52100, but not very good compared to other stainless steels.

Non-magnetic stainless steels do not make very good bearing balls, avoid.
OK, before I get more confused, when we say a certain ball bearing is "magnetic", don't we mean that said ball bearing is composed of "ferromagnetic" material, for example steel, but may not necessarily be "magnetized"? I used to use a magnet to position new balls into their corresponding cups until I noticed the new balls were becoming magnetized by my doing so and thus sticking to each other. Hopefully only temporarily, but still I know of a great deal of lubricated machinery having a magnet placed inside in a strategic location, usually a drain plug, to attract and hold any ferromagnetic grit or filings so as to keep it all out of the bearings as much as possible. If magnetizing new ball bearings might attract steel grit to them I thought it prudent not to. If just they lose their magnetic fields guickly, maybe no big deal. I still use the magnet to quickly pull out old balls for disposal though.
FBOATSB is offline  
Old 07-19-18, 10:13 AM
  #9  
nfmisso
Nigel
 
nfmisso's Avatar
 
Join Date: Mar 2011
Location: San Jose, CA
Posts: 2,991

Bikes: 1980s and 1990s steel: CyclePro, Nishiki, Schwinn, SR, Trek........

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 383 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by FBOATSB View Post
OK, before I get more confused, when we say a certain ball bearing is "magnetic", don't we mean that said ball bearing is composed of "ferromagnetic" material, for example steel, but may not necessarily be "magnetized"? I used to use a magnet to position new balls into their corresponding cups until I noticed the new balls were becoming magnetized by my doing so and thus sticking to each other. Hopefully only temporarily, but still I know of a great deal of lubricated machinery having a magnet placed inside in a strategic location, usually a drain plug, to attract and hold any ferromagnetic grit or filings so as to keep it all out of the bearings as much as possible. If magnetizing new ball bearings might attract steel grit to them I thought it prudent not to. If just they lose their magnetic fields guickly, maybe no big deal. I still use the magnet to quickly pull out old balls for disposal though.
The balls will loose their temporary magnetism quickly, faster in the neighborhood of other temporarily magnetized balls and when exposed to mechanical force (bearing preload and loads for example).
nfmisso is offline  
Old 07-19-18, 10:20 AM
  #10  
FBOATSB 
Senior Member
 
FBOATSB's Avatar
 
Join Date: Jul 2014
Location: Central Indiana
Posts: 1,693

Bikes: Old Schwinns

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 634 Post(s)
Liked 78 Times in 58 Posts
Originally Posted by nfmisso View Post
The balls will loose their temporary magnetism quickly, faster in the neighborhood of other temporarily magnetized balls and when exposed to mechanical force (bearing preload and loads for example).
Thanks. That sets my mind at ease.
I am not an engineer, I just ride on trains.
FBOATSB is offline  
Old 07-19-18, 10:21 AM
  #11  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,278 Times in 798 Posts
Ceramic bearing balls are certainly non magnetic, of course.
fietsbob is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
le mans
Bicycle Mechanics
13
09-06-19 09:12 AM
Brocephus
Bicycle Mechanics
8
08-25-18 10:56 AM
I_like_cereal
Bicycle Mechanics
126
07-07-18 12:57 PM
dvai
Road Cycling
48
06-24-17 12:35 PM
CrankyFranky
Bicycle Mechanics
20
03-21-17 06:28 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.