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

6mm vs 1/4” Bottom Bracket Ball Bearings

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.

6mm vs 1/4” Bottom Bracket Ball Bearings

Old 03-17-22, 07:56 AM
  #1  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
6mm vs 1/4” Bottom Bracket Ball Bearings


Ball Bearings comparison




Noisy Bottom Bracket

Tools

New 6mm Ball Bearings


Replaced BB bearings with new, and the BB left side cup went threaded in deeper than before. Not leaving enough thread exposed to catch the threads on the lock ring.

Should I search for 1/4” bearings?
Or use a BB facing tool to shave the 0.70mm off the BB shell? I might have to borrow that tool.


hotbike is offline  
Old 03-17-22, 08:02 AM
  #2  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 9,060

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 2149 Post(s)
Liked 2,181 Times in 1,346 Posts
The cups are designed and ground for the radius of a 1/4" ball.
Grade 25 chrome steel 1/4" balls are readily available on line, at the LBS, or local industrial bearing suppliers.
dedhed is online now  
Old 03-17-22, 08:17 AM
  #3  
soyabean
Senior Member
 
soyabean's Avatar
 
Join Date: Feb 2022
Posts: 291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 164 Post(s)
Liked 110 Times in 79 Posts
Originally Posted by hotbike View Post
Should I search for 1/4” bearings?
They are 0.25" bearings, not 6mm. They are not the same.

If you are in a pinch and want to finish the job now, you don't need the retainer crown.

You can do it the old fashion way, simply grease in about 11 bearings to make up for the extra space in the cup's moat.

If you can, better to purchase the 9-bearing crown assembly. They are inexpensive and dollars each, a LBS should be able to sell one to you.

I posted a picture of one earlier in the thread below.

Pay no attention to the haters, just go with the facts.

Originally Posted by squirtdad View Post
very few new bikes come with the cup and cone bottom bracket anymore
soyabean is offline  
Old 03-17-22, 08:34 AM
  #4  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
“Ya’ know...”

I am looking online for bottom bracket bearings, and they’re all Sealed .

I did install 11 bearings each side, btw, and the grease held them in while I tightened the cup.

I really think the factories, the Chinese ball bearing plants, are producing a metric equivalent, and there’s no changing that fact.

I’m going to experiment to see if there’s a way to run this BB with the new bearings.

In the meantime,I’ve put blue Loctite on the threads, and marked with white paint so I can see if the cup is loosening.

Just a dab of white primer to check rotation
hotbike is offline  
Old 03-17-22, 08:43 AM
  #5  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,421

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3497 Post(s)
Liked 2,263 Times in 1,455 Posts
Don't use "bottom bracket" in your search.

ball bearings | McMaster-Carr But as mentioned these balls are widely available from different local retailers in most communities. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-17-22, 08:45 AM
  #6  
Iride01
MotuekaCascadeChinook
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 11,065

Bikes: Tarmac Disc Comp Di2 - 2020

Mentioned: 42 Post(s)
Tagged: 0 Thread(s)
Quoted: 4471 Post(s)
Liked 2,991 Times in 2,085 Posts
Just look for 1/4 inch ball bearings. Don't put BB in your search terms. You can get them from a local bearing supplier to industry in your local area in your area very cheap.

Don't fill it slam full with loose bearings either, then the bearings won't sit properly in the races. You need one or two bearings less than what you think is full. Even if the race was 66% full with bearings, then that'd be plenty.

Last edited by Iride01; 03-17-22 at 08:48 AM.
Iride01 is offline  
Old 03-17-22, 08:45 AM
  #7  
soyabean
Senior Member
 
soyabean's Avatar
 
Join Date: Feb 2022
Posts: 291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 164 Post(s)
Liked 110 Times in 79 Posts
Originally Posted by hotbike View Post
I am looking online for bottom bracket bearings, and they’re all Sealed .
Nope, I'm looking at a ton of 9-bearing 1/4" crown assemblies specific of bikes right now on amazon.

The LBS will have loads of them as they are very common for big box store bikes.

Originally Posted by hotbike View Post
I really think the factories, the Chinese ball bearing plants, are producing a metric equivalent, and there’s no changing that fact.
Nope, the exact size is required for the right application, there is no substitute. SAE bearings, nuts, bolts, are still manufactured and regularly used in motorcycles and automotive.
soyabean is offline  
Old 03-17-22, 08:56 AM
  #8  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,421

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3497 Post(s)
Liked 2,263 Times in 1,455 Posts
As a bit of background, the world wide bike industry uses a (sometimes) confusing mix of SAE, Fractional and Metric specs. A classic example is a campy NT rear hub axle that is a 9.5mm diameter (not 3/8") but has 26 TPI. Due care when getting replacement parts is needed to have a properly working bike. Using almost but not quite parts is a good way to have problems and cause damage to the parts or fittings. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-17-22, 09:04 AM
  #9  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
This guy knows :
hotbike is offline  
Old 03-17-22, 09:19 AM
  #10  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
Only have to shave off paint and uneven surfaces, then the lock ring should catch
https://www.lavelocita.cc/guides-pag...nobody-does-it
hotbike is offline  
Old 03-17-22, 09:59 AM
  #11  
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 8,517

Bikes: 85 team Miyata (modern 5800 105) , '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque

Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 1745 Post(s)
Liked 1,376 Times in 834 Posts
Originally Posted by hotbike View Post

Ball Bearings comparison




Noisy Bottom Bracket

Tools

New 6mm Ball Bearings


Replaced BB bearings with new, and the BB left side cup went threaded in deeper than before. Not leaving enough thread exposed to catch the threads on the lock ring.

Should I search for 1/4” bearings?
Or use a BB facing tool to shave the 0.70mm off the BB shell? I might have to borrow that tool.


nope, get the proper size bearings the diffference adds up and there are other considerations like the races being machined for .25 or 1/4 inch, facing would not fix this

I am surprised that you are not spot on on the details, considering the level of precision and technical excellence of your fairing designs. any thing new on that front?
__________________
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light 56,57 or so)

squirtdad is offline  
Likes For squirtdad:
Old 03-17-22, 10:11 AM
  #12  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
Originally Posted by squirtdad View Post
nope, get the proper size bearings the diffference adds up and there are other considerations like the races being machined for .25 or 1/4 inch, facing would not fix this

I am surprised that you are not spot on on the details, considering the level of precision and technical excellence of your fairing designs. any thing new on that front?
Yes, we’ll sort of.
Not everyone wants a fairing, even if it’s just a handlebar basket with aerodynamic styling .
So I’m promoting a whole “Fairing/Pannier System” , and a stand-alone “Pannier Tailbox”.

This fits any rear rack, whereas the fairing only fits one make and model of bike, and with different handlebars, and I make my own mounting hardware, it’s a nightmare to install.

The Pannier/Tailbox combines a box on each side (of your rear rack) with a box on top of the same rack.

Pannier/Tailbox clamped on my work bench. 15” cube, fits racks up to 6” wide, pannier wells are 7” deep.


I might simply buy a sealed bottom bracket.
it seems like no one repacks bearings anymore.
hotbike is offline  
Old 03-17-22, 10:26 AM
  #13  
SurferRosa
Señor Member
 
SurferRosa's Avatar
 
Join Date: Dec 2018
Location: Pac NW
Posts: 5,837

Bikes: Old school lightweights

Mentioned: 73 Post(s)
Tagged: 0 Thread(s)
Quoted: 2434 Post(s)
Liked 3,257 Times in 1,756 Posts
Originally Posted by hotbike View Post
I am looking online for bottom bracket bearings, and they’re all sealed.
I buy from seller bctrade on eBay:

https://www.ebay.co.uk/itm/291407948168

Shipped from Cumming, GA.
SurferRosa is online now  
Old 03-17-22, 10:34 AM
  #14  
soyabean
Senior Member
 
soyabean's Avatar
 
Join Date: Feb 2022
Posts: 291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 164 Post(s)
Liked 110 Times in 79 Posts
Originally Posted by squirtdad View Post
I am surprised that you are not spot on on the details, considering the level of precision and technical excellence of your fairing designs. any thing new on that front?
very few new bikes come with the cup and cone bottom bracket anymore
soyabean is offline  
Old 03-17-22, 10:46 AM
  #15  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
Originally Posted by soyabean View Post
very few new bikes come with the cup and cone bottom bracket anymore
I’ve been keeping a bunch of 25 to 30 year old 21-speeds going as a “fleet” to test my Fairing/Pannier System on .
Possibly looking at buying a new E-cargo bike if I do buy a new bike. Like an Urban Arrow.
hotbike is offline  
Old 03-17-22, 12:33 PM
  #16  
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 8,517

Bikes: 85 team Miyata (modern 5800 105) , '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque

Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 1745 Post(s)
Liked 1,376 Times in 834 Posts
Originally Posted by soyabean View Post
very few new bikes come with the cup and cone bottom bracket anymore
what is relavance? But it is true and that is my statement from a different thread, but it is clear Hotbike is working on an old bike. And a lot of C&V types including me will convert to sealed cartridge units (not that I have not done a ton of ball bearing bottom bracket clean, grease and adjust over the years)
__________________
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light 56,57 or so)

squirtdad is offline  
Old 03-17-22, 12:40 PM
  #17  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 9,060

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 2149 Post(s)
Liked 2,181 Times in 1,346 Posts
Originally Posted by hotbike View Post
“Ya’ know...”I am looking online for bottom bracket bearings, and they’re all Sealed
Google foo needs work. Search under 1/4" bearing balls.

https://www.google.com/search?q=1%2F...hrome&ie=UTF-8
dedhed is online now  
Old 03-17-22, 12:41 PM
  #18  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
Originally Posted by squirtdad View Post
what is relavance? But it is true and that is my statement from a different thread, but it is clear Hotbike is working on an old bike. And a lot of C&V types including me will convert to sealed cartridge units (not that I have not done a ton of ball bearing bottom bracket clean, grease and adjust over the years)
Yeah, well, my health has been improving lately and I’m doing a lot more mileage. So stuff is breaking more frequently as a result.

I might just scrape the paint off the bb shell with a file to see if the threads on the lock ring will catch the threads on the cup, then it will be serviceable.

Those Campagnolo “box sets” that include the facing tools are astronomically priced. The shop in Oyster Bay had two of them, but they were already sold when I got to the close out sale.
hotbike is offline  
Old 03-17-22, 12:49 PM
  #19  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 9,060

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 2149 Post(s)
Liked 2,181 Times in 1,346 Posts
Originally Posted by soyabean View Post
very few new bikes come with the cup and cone bottom bracket anymore
Plenty of new BSO's with cup & cone BB. Check out any Walmart or kids bikes.
dedhed is online now  
Likes For dedhed:
Old 03-17-22, 12:55 PM
  #20  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 9,060

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 2149 Post(s)
Liked 2,181 Times in 1,346 Posts
Originally Posted by hotbike View Post
Yeah, well, my health has been improving lately and I’m doing a lot more mileage. So stuff is breaking more frequently as a result.

I might just scrape the paint off the bb shell with a file to see if the threads on the lock ring will catch the threads on the cup, then it will be serviceable.

Those Campagnolo “box sets” that include the facing tools are astronomically priced. The shop in Oyster Bay had two of them, but they were already sold when I got to the close out sale.
Cheaper ones out there for home users. Last time I had one chased & faced I just took the bare frame to the LBS, let them do it, and paid my $20 rather than invest in a tool I'd rarely use.
https://www.bike-components.de/en/Cy...-Holder-p4171/
dedhed is online now  
Old 03-17-22, 12:56 PM
  #21  
soyabean
Senior Member
 
soyabean's Avatar
 
Join Date: Feb 2022
Posts: 291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 164 Post(s)
Liked 110 Times in 79 Posts
Originally Posted by dedhed View Post
Plenty of new BSO's with cup & cone BB. Check out any Walmart or kids bikes.
Agreed.

I was just re-quoting what another grossly uninformed user wrote earlier.

Originally Posted by squirtdad View Post
very few new bikes come with the cup and cone bottom bracket anymore
soyabean is offline  
Old 03-17-22, 07:30 PM
  #22  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,255

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1415 Post(s)
Liked 1,005 Times in 680 Posts
Originally Posted by Andrew R Stewart View Post
As a bit of background, the world wide bike industry uses a (sometimes) confusing mix of SAE, Fractional and Metric specs. A classic example is a campy NT rear hub axle that is a 9.5mm diameter (not 3/8") but has 26 TPI. Due care when getting replacement parts is needed to have a properly working bike. Using almost but not quite parts is a good way to have problems and cause damage to the parts or fittings. Andy
The metric diameter/inch thread pitch combination arose because the non-English makers were using lathes made in England which are only geared to cut inch thread pitches but which can cut arbitrary diameters.
dsbrantjr is offline  
Old 03-17-22, 07:49 PM
  #23  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,421

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3497 Post(s)
Liked 2,263 Times in 1,455 Posts
Originally Posted by hotbike View Post
Yes, we’ll sort of.
Not everyone wants a fairing, even if it’s just a handlebar basket with aerodynamic styling .
So I’m promoting a whole “Fairing/Pannier System” , and a stand-alone “Pannier Tailbox”.

This fits any rear rack, whereas the fairing only fits one make and model of bike, and with different handlebars, and I make my own mounting hardware, it’s a nightmare to install.

The Pannier/Tailbox combines a box on each side (of your rear rack) with a box on top of the same rack.

Pannier/Tailbox clamped on my work bench. 15” cube, fits racks up to 6” wide, pannier wells are 7” deep.


I might simply buy a sealed bottom bracket.
it seems like no one repacks bearings anymore.
And shops have learned that quoting BB overhaul on a loose ball system might be a stickey situation when they have to call the customer, after the parts are all taken apart, and quote for a replacement BB altogether. The supply chain has done a good job at moving the replacement parts for loose ball units further down the quality and availability scale. As a lifer in the service dept at a LBS (of over a dozen LBS) we find quoting for the replacement is less costly and more effective in getting a happy customer. During that last couple of C-19 years our overwhelmed the LBS service departments and many have found to help more people faster they should refuse some service jobs that can become time sinks when hard to get parts are needed.

The good news is that loose ball BB units are fairly easy to service by those without special tools or repair stands. I have seem quite a few bearing units with wear damage (bearing track pits and such) but with fairly fresh grease and a story of a friend's help to keep the bike running. Most of these times the bike still is rideable but the rider can still feel the problems, just less so. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-17-22, 07:53 PM
  #24  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,421

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3497 Post(s)
Liked 2,263 Times in 1,455 Posts
Originally Posted by dsbrantjr View Post
The metric diameter/inch thread pitch combination arose because the non-English makers were using lathes made in England which are only geared to cut inch thread pitches but which can cut arbitrary diameters.
I have heard this many times before but recently read a post somewhere disputing this. If I come across it again I'll post it here. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Likes For Andrew R Stewart:
Old 03-18-22, 07:27 AM
  #25  
hotbike
Senior Member
Thread Starter
 
hotbike's Avatar
 
Join Date: Dec 2006
Location: Long Island, New York
Posts: 3,667

Bikes: a lowrider BMX, a mountain bike, a faired recumbent, and a loaded touring bike

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 245 Post(s)
Liked 71 Times in 59 Posts
Okay,
I drove my van to ace hardware as soon as they opened. Against the back wall are the parts bins. Ball Bearings- picked the box , it has everything from 7/16” to 1/2”
But the quarter inch are looking scarse.
took the whole box to the cashier.
Counted them on the counter....
25 @ 31¢ each
I needed 22 to put 11 in each side. Or should I go 12? What if I drop one?
I bought all 25
hotbike is offline  

Thread Tools
Search this Thread

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

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.