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? about QR hub adjustment

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bjanga

bjanga

Turbo Monkey
Dec 25, 2004
1,356
0
San Diego
Hi everyone. I noticed two weeks ago that the axle ( I think its the axle . . . the threaded part and not the skewer ) of my QR hub had only one thread exposed on the left side and several threads exposed on the right side. Thinking that it was bad that one leg of my fork was resting on a very thin area of the axle, my friend and I managed to remove the axle from the hub and adjust the nuts ( that preload the hub bearings? ) so that the axle protrudes an equal amount on both sides of the hub.

Is it possible that the hub is now longer or shorter than 110mm wide? I have had problems with braking power ever since. I though this was due to worn pads, but now after replacing pads I am still having difficulty adjusting the brakes. Specifically, the rotor is VERY close to the outside edge of the caliper. The caliper itself is actually worn from the rotor rubbing it. I believe that the braking power problems stem from the fact that the rotor is being slightly bent inward by the outside pad and so does not make even contact with the inner pad.

Other things:

1.) the nuts that preload the bearings were loose today.

2.) the bearings feel like they are completely thrashed. I am guessing that this is because they were unevenly loaded during the time that the axle was not 'centered'. Can I replace the bearings? There are two types . . . sealed cartridges and loose ball bearings, right? I am unsure about which type are inside my hub, although it is a cheap hub so I would think that it doesnt have sealed carts.

Thanks for any help or insight. I know nothing about hubs, and I will not have acess to a digicam for another few days.
 
skurfer333

skurfer333

Monkey
Apr 21, 2005
249
0
Raleigh, NC
if i'm understanding you correctly, then what you did was fine. Moving the axle does not affect where the hub sits in the dropouts, and does not change the width of the hub since both are determined by the locknuts on the axle.
To fix the brake problem first try loosening the mounting bolts that secure the caliper to the frame. With them loose hold the brake lever in so that the pads bottom out on the rotor, then tighten the bolts while keeping pressure on the lever. If that doesn't work try using spacers to move the caliper to the right position. If the difference is too much then get your mounts faced so that the caliper will sit in the right spot.
If your bearings in your hub are "loose" then they will just be rolling around in between the cone/race or in a retainer. If you can actually see the ball bearings when you take the locknuts and cones off the axle then it is loose ball bearing. If your hub has cartridge bearings then the inside of your hub will have two donut-like rings that hold the bearings. The bearings are inside these cartridges and you will not be able to see them when you look inside the hub.
Since you said your hub is cheap it most likely has loose-ball bearings in a retainer.
Also, if the locknuts were loose then you can try to tighten them again and see how it holds up or put some type of thread-locker on it. Medium grade (blue) locktite is what I use. The way to tighten them is to hold the cone (which actually contacts the bearings) with one wrench and the locknut (which contacts the cone) with another and tightening the locknut down onto the cone.
 
Wumpus

Wumpus

makes avatars better
Dec 25, 2003
8,161
153
Six Shooter Junction
Edited due to lack of sleep.


1) You probably didin't tighten them enough unless they were loose before you recentered the axle.

2) I don't think that the axle not being centered had anything to do with the bearings getting thrashed. Too loose/too tight preload on the bearings. Not in time service. Poor quality bearings or races.
 
johnbryanpeters

johnbryanpeters

Hero
Sep 27, 2001
36,804
18,372
Making moss sad in New Haven, Vermont
Wumpus said:
By moving the axle you have also moved the rotor in relation to the caliper. The reduced brake performance is due to one piston having to extend much farther now to get the brake pad in contact with the rotor. You need to reposition(shim) your caliper.

1) You probably didin't tighten them enough unless they were loose before you recentered the axle.

2) I don't think that the axle not being centered had anything to do with the bearings getting thrashed. Too loose/too tight preload on the bearings. Not in time service. Poor quality bearings or races.
Click to expand...
Ummm... No. :nope: Moving the axle to the right or left should have no effect on disk position relative to caliper.

If bearings feel rough, you probably tightened the cones too much. Might be addressed by replacing bearings, or might need to replace hub if races have been damaged.

Get someone who understands how to do it show you how to properly adjust all the bits. It's easier than us trying to describe the procedures.

J
 
Dartman

Dartman

Old Bastard Mike
Feb 26, 2003
3,911
0
Richmond, VA
bjanga said:
Hi everyone. I noticed two weeks ago that the axle ( I think its the axle . . . the threaded part and not the skewer ) of my QR hub had only one thread exposed on the left side and several threads exposed on the right side. Thinking that it was bad that one leg of my fork was resting on a very thin area of the axle, my friend and I managed to remove the axle from the hub and adjust the nuts ( that preload the hub bearings? ) so that the axle protrudes an equal amount on both sides of the hub.

Is it possible that the hub is now longer or shorter than 110mm wide? I have had problems with braking power ever since. I though this was due to worn pads, but now after replacing pads I am still having difficulty adjusting the brakes. Specifically, the rotor is VERY close to the outside edge of the caliper. The caliper itself is actually worn from the rotor rubbing it. I believe that the braking power problems stem from the fact that the rotor is being slightly bent inward by the outside pad and so does not make even contact with the inner pad.

Other things:

1.) the nuts that preload the bearings were loose today.

2.) the bearings feel like they are completely thrashed. I am guessing that this is because they were unevenly loaded during the time that the axle was not 'centered'. Can I replace the bearings? There are two types . . . sealed cartridges and loose ball bearings, right? I am unsure about which type are inside my hub, although it is a cheap hub so I would think that it doesnt have sealed carts.

Thanks for any help or insight. I know nothing about hubs, and I will not have acess to a digicam for another few days.
Click to expand...
Look here for proper adjustment of cup and cone hubs...

http://www.parktool.com/repair/readhowto.asp?id=105

You have to take into account the compression from the QR skewer.

Mike
 
bjanga

bjanga

Turbo Monkey
Dec 25, 2004
1,356
0
San Diego
Thanks for the links, guys. I disassembled the hub today to try and mess with it some and my puppy demolished my neat little pile of parts. So now I need to find a replacement ball bearing and cone. :(

On that note, can cartridge bearings be replaced? If so, are they user serviceable or would they need to be shipped to the factory?
 
bjanga

bjanga

Turbo Monkey
Dec 25, 2004
1,356
0
San Diego
They give a real easy-to-understand writeup. Something tells me that I want hubs with cartridge bearings when I get the chance though ;)
 
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