Go Back  Bike Forums > Bike Forums > BMX
Reload this Page >

ball bearing size for GT bmx hub?

Notices
BMX Dirt, vert, flatland or street? Drop in the BMX forum to talk to other 20" riders around the world. What is the best BMX bicycle for you? Learn all about it here.

ball bearing size for GT bmx hub?

Old 12-05-21, 01:56 PM
  #1  
rickpaulos
Full Member
Thread Starter
 
Join Date: Aug 2007
Location: middle of the Great Corn Desert
Posts: 438
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 114 Post(s)
Liked 144 Times in 85 Posts
ball bearing size for GT bmx hub?

took this hub apart and found 3 different size balls in it. 1/4" - 7/32" - 3/16". 14mm axle.
anyone know what the correct ball bearing size is?


right side cage.

left side:

Last edited by rickpaulos; 12-13-21 at 11:40 PM.
rickpaulos is offline  
Old 12-05-21, 04:28 PM
  #2  
Js760
Newbie
 
Join Date: Nov 2021
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked 10 Times in 3 Posts
Can’t help out, but you might get a better answer on the GT owners FB page.
Js760 is offline  
Old 12-09-21, 03:18 PM
  #3  
cbrstar
BMX Connoisseur
 
cbrstar's Avatar
 
Join Date: Jun 2016
Location: Canada
Posts: 774

Bikes: 1988 Kuwahara Newport, 1983 Nishiki, 1984 Diamond Back Viper, 1991 Dyno Compe

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 399 Post(s)
Liked 108 Times in 69 Posts
It's tough to tell which one is which. But typically rear bearings are 1/4" in most rear hubs. You might want to check your front hubs to as I have a feeling the original owner got the bearings all mixed up for both hubs.
cbrstar is offline  
Old 12-10-21, 03:37 PM
  #4  
canopus 
Senior Member
 
canopus's Avatar
 
Join Date: Mar 2009
Location: Kingwood, TX
Posts: 1,592

Bikes: Road, Touring, BMX, Cruisers...

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
Liked 172 Times in 110 Posts
Make sure you don't have one size on the drive side and a different size on the non-drive side. It looks like a std hub with freewheel. Hazarding a guess, the large bearings go on the drive side and the smaller ones on the non-drive side.
When a hub destroys itself like that, bearings can travel through the hub to the other side.

You need to remove the axle & freewheel and look at the cups and cones.
__________________
1984 Cannondale ST
1985 Cannondale SR300
1980 Gary Littlejohn Cruiser
1984 Trek 760
1981 Trek 710
Pics
canopus is offline  
Old 12-13-21, 11:39 PM
  #5  
rickpaulos
Full Member
Thread Starter
 
Join Date: Aug 2007
Location: middle of the Great Corn Desert
Posts: 438
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 114 Post(s)
Liked 144 Times in 85 Posts
After a bunch of trial and error...

The hub shell is threaded on both sides. freewheel standard 1 & 3/8" on one side, odd ball 1 & 3/16" on the other side (the side with the 16 tooth ACS FAT freewheel). The cups are different sizes. Smaller on the side with smaller freewheel threading. The cones are the same outer diameter but the bearing surface is cut smaller on one cone. and one cone is shorter. So left and right specific cones. 5/32" balls on both sides seems to work best. larger sizes have the balls running on the edge of the cones, not in the center of the bearing surface. About 15 balls on each side. Seems sensitive to having what I'd say is enough. Turned much smoother if I took out one. (kinda like a headset). 14mm axle x 1.0mm pitch. What the hardware stores call extra fine pitch (but they don't carry that anyhow).

The ACS FAT freewheel is noticeably fatter than normal single freewheels. I found out that ACS also makes left side drive specific freewheels. This ACS FAT seems better quality than the endless stream of bso single freewheels.
rickpaulos is offline  

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 -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.