KC8QVO

I had to take my bike apart to get it in a car after a 2 day trip. When I was putting it together again today I noticed the rear wheel was very wobbly. After inspecting it the axle was moving differently in relation to the hub itself. I have never felt that before.

So I took the axle assembly apart and pulled the cassette. I have not seen how the hub works before, I have never had a reason to take it apart before. What I figured is the parts that press against the ball bearings inside the hub (loose balls, not enclosed bearings) were not tight enough.

As to when the parts became loose - I am not real sure. However, I did not notice the slop when I took the bike apart earlier today. I can't say for 100% sure it wasn't already loose then, but for as quick as I noticed something being "off" when I put it back together I think if it was goofy when I took it apart I would have noticed.

When I worked on the hub I tightened up the bearings and found if they were too tight the axle wouldn't turn. So I backed off the tension until I had the axle freely spinning. At that point the bearing parts were just finger tight. That seems a bit concerning to me, but I got the slop out of the wheel and it is nice, tight, and true now.

Does anyone have any comments on the set up? I just got off a fully loaded trip - about 85 miles. I don't feel anything weird with the hub now, but if there are any pieces of advice to share about the assembly I am all ears. I'd like to avoid any damage.

ThermionicScott 

If you're not well-versed on how to maintain cup-and-cone hubs, that's where you should start. Riding them while too loose or too tight will wear them out in a hurry.

https://www.sheldonbrown.com/tooltips/hubs.html
https://www.sheldonbrown.com/cone-adjustment.html

tomtomtom123

There are a lot of videos on Youtube showing examples of how people adjust the tightness of cup and cone bearings in the hubs. You could watch a few for reference, as some people recommend different strategies or tightness. But one thing that really helps is if you have a vice to hold the bottom end of the axle while you adjust the top end of the axle. That way, you can have repeatable control as you fine tune it.

Some people say that if you have a quick release skewer, that there should be a tiny bit of play because when the skewer is clamped, the cones will compress a little bit. But I don't experience that on my hubs, so I adjust the bearings until there is no play. As you may know, the drive side locknut and cone are usually the first to be tightened. Then you insert the axle into the body and use the non-drive side locknut and cone to adjust bearing play. I clamp the bottom end (drive side) into the vice. Then I first aim for a little bit of play and tighten the non-drive side nut while keeping the wheel from spinning. I use the alignment between the spoke and the cone wrench for reference. Then I loosen the nut, tighten the cone wrench by 1/2 a spoke arc, hold the cone wrench in place and tighten the locknut. As you may now, an axle thread is typically 1mm per revolution. So if you have 32 spokes, each spoke arc is 0.03125mm of lateral movement of the cone. So half a spoke arc is around 0.015mm, or 15 microns, which to me is an optimal amount of tolerance. So by aligning the cone wrench to the spokes while keeping the wheel in the same position allows for fine tuning of the tightness. I keep repeating this just until there is no play.

Also, you don't want to overtighten the locknuts or else you might strip the threads. You can read your hub manual for how much torque to apply. I can't remember, but I think the low level shimano models state something around 12-15Nm.

If you had the cones too loose or too tight, you might damage the cones and cups. Typically the cones are more prone to damage than the cups. If you see any pitting of the cones, then you should change them with new ones. If the cups are pitted, then you'd probably have to change the hubs.

Also, new shimano hubs that are unlaced feel tight. But once they're laced, the spoke tension actually expands the cups a little bit and makes the bearings a little bit looser.

Unca_Sam

This is where a set of cone wrenches comes in handy. You'll likely need a 15 mm cone wrench and a 17 mm wrench for the lock nut. The adjustment is straightforward in that you want to eliminate 'play' in the axle while allowing the axle to spin freely with minimal friction. You CAN squish ball bearings, as the cup and cone are made to be harder than the balls.

1) Tighten cone against the bearings until you feel a little resistance; don't squish the balls!
2) Depending on the tolerances in your hub, you'll loosen the cone slightly until the axle turns easily. Not without resistance, but smoothly and easily.
3) Check for play in the axle. You can feel the axle shift better than you can hear or see it (sorry if you have carpal tunnel or something), tighten to eliminate the play, if there is any, and find that sweet spot where the balls are all engaged and not being deformed.
4) The hard part: Use the cone wrench to hold the cone in position while tightening the lock nut against it (or the spacer). Check for play.

Learned tip from cheaper hubs: I find it easier to tighten the cone a little too much at first, because tightening the lock nut against the cone frequently causes the cone to back up slightly. If it's a little tight before I tighten the lock nut, the preload is set just right when I'm done. now that I have a vise, I'll probably use that to immobilize the bottom lock nut before working on the top.

I'm going to guess that one of your lock nuts got loose somehow and the rotation allowed the cone to work it's way out. Since we don't know how long you rode with a loose hub, it is wise to replace the bearings and refurbish the hub so you can look for damage. It's not a right now kind of thing, but new grease and balls will prevent you from damaging the race surfaces further if you managed to scuff up a ball.

Bigbus

I did that once. When I spun the quick release skewer to make it easier to disengage the wheel and everything else from the frame and chain I accidentally spun the bearing adjustment nut along with it and loosened the bearing too. A simple adjustment and a re-tightening of the lock nut and all is good.

KC8QVO

Thanks for the info.

It sounds like it will be wise to tear apart, clean, and check for damage then reassemble with new bearing balls and grease.

I am set on the grease. I replaced my bottom bracket a few years back with a wider Phil Wood model. At the same time I got a tub of their grease also. I figured it would come in handy... Although, I do have some heavy duty waterproof automotive grease also (I want to say it is chevron, thick red stuff that is in a grease gun for ball joints and hubs). I am leaning towards the Phil Wood, but if anyone has thoughts there I'd be curious to hear at least.

Unca_Sam

Any grease is fine. More viscous grease apparently introduces more drag, but it's unlikely to be significant. As long as it sells out water and contaminants, it'll work.

andrewclaus

Here's another video showing at least one good pro tip on preloading bearings:

tomtomtom123

What the guy did in the video would work, but there might be a risk of over torquing if the nuts and cones already have high torque, since he's tightening both sides at the same time instead of loosening and then tightening one side.

Bigbus

I made the mistake of using that thick red sticky chevron stuff on my chain and sprockets one time. It really does repell water and attract dirt, but it also messed with my shifting because it's so sticky. I use it on my motorized stuff, but I keep it away from my bikes now and simply use wax on the chains and sprockets. Go with the tub of grease you got when you did your BB, you won't regret it.

KC8QVO

I got the hub taken apart today and mostly degreased. I will scrub the ball bearings and races again. So far no obvious damage. I don't see anything that looks like excessive wear. The bike has around 4,000 miles on it if that says anything. The races are smooth and I haven't seen any pitting or denting yet. I am trying to track down a cone wrench for putting things back together.

Unca_Sam

Best practice is to replace the balls when you refurbish a hub. 4000 miles is within the lifespan of the balls in the bearing, but it'll be difficult to see if the balls have been stressed out of sphericity with your naked eye. It's your call, but 22 1/4" G25 stainless balls will only cost you around $10-15, and you'll be set for another 2 years or longer.

davidad

If the bearings have their original finish there is no reason to replace them unless it makes you feel better.

Unca_Sam

I agree, but does OP know what finish unused bearings have?

davidad

Bright shinny and mirror like.

tomtomtom123

Shimano ball bearings 1/4" cost $2 for a pack of 18 balls. Part number Y00091310
You can find them almost in any big online retailer. They are steel, not stainless.

I got my balls from LBS because I needed them fast. I think they charged me 10 cents for each ball. They were unknown/unbranded.

Also, the LBS had a pair of double ended cone wrenches for around $9 (big brand LBS).

KC8QVO

I can't find the spec's on the balls, I suppose I can mic them. There are 9 of them each side, though. I checked the manuals I have found thus far online for the hub and can't seem to identify a spec for them?

tomtomtom123

you can measure the diameter of the ball bearings with calipers. All you need is for the diameters to match.

tomtomtom123

Oh, if you don't have calipers to measure the size of the ball, an easy solution is to take a photo of the ball next to an imperial inch ruler. You want to take the photo with the lens perpendicular to the ruler, as far away as possible but still close enough to be able to pixel peek on a monitor. You want the top surface of the ruler to be at the level of the midpoint of the ball. Since it's most likely 1/4" ball, and most metal rulers are 1mm thick, place something around 2mm thick underneath the ruler to raise the top surface of the ruler to around 3mm.

Open the photo on your monitor, zoom in as much as possible, and then measure the size on the monitor, comparing the size of the digital ball against the digital ruler in the photo. You can place a ruler against your monitor, or use a measuring tool from your photo editing software.

ThermionicScott 

Shimano hub, right? Almost always 9 1/4" bearing balls on each side unless you have one of the oddball Dura-Ace hubs with a greater number of smaller balls. You'd know.

davidad

The balls can't be stressed out of round. When they are worn they lose their finish.