ClarkinHawaii

When I am adjusting Shimano hub bearings, I tighten the cones until they are just tight enough that the looseness jiggle is apparent when they are not clamped in the QR skewers, but the jiggle is gone when they are clamped.

This works fine for my own wheels, because I always gorilla down with the same max lever tightness.

However, when adjusting hubs for other people, I don't know whether they will exert the same amount of tightness on the QR lever. Maybe they will, or maybe they will use less tightness, in which case their wheel will still jiggle after it is mounted.

So what I am really asking here is if the adjustment can't be perfect, is it better too loose or too tight? Seems like I've heard people on these forums take both sides of this issue (what else is new?).

Thanks for your help!

Jicafold

If your axle cones and locknuts are properly adjusted and tightend they can't move. Then however much force you use on your quick release should not make them any tighter.

Dan Burkhart 

Your method of tightening the locknuts with a slight bit of play which disappears when the qr is clamped is correct.If the play is completely taken out without the hollow axle being compressed by the qr, it's overtight.

Dan Burkhart 

The lock nuts and cones won't move in relation to the threads to which they are mounted, but the quick release compresses the axle which changes the bearing preload.

Jicafold

I'm trying to get my head around that. The quick release presses on the outsides of the fork, locking it against your already tightened and adjusted locknuts. How do you mean it "compresses the axle"?

Dan Burkhart 

Fixing nuts on a solid axle act in the way you describe, but a quick release squeezes the complete assembly enough to slightly deform the axle. Try it, you'll see.

hueyhoolihan

i think they are saying, that the QR pushes on the fork dropouts that in turn pushes on the locknut, that in turn pushes on the cone that in turn pushes on the axle threads. then in reverse order until the other end of the QR is reached. and so in total part of the axle is compressed.

i'm not so sure i buy it though. it's more likely, IMO, that the locknut/cone interface(s) has not been tightened enough and slack is being taken out there.

Dan Burkhart 

Fine, don't take my word for it.
Cone Adjustment

FBinNY 

The entire axle is slightly compressible, so when the ends are pressed together by the QR the long section in the middle of the axle shortens slightly bringing the two cones closer together.

Note that we're talking about small changes, Bigger changes occur when non-parallel dropouts cause the axle to flex into an arc. The can have a significant effect on the bearing ajustment.

In any case we're talking small changes.

Possibly the best way to confirm the adjustment is to use a stack of washers between the axle and QR and tighten the QR to riding adjustment, then chack the wheel.

For my part, I prefer to make the final adjustment on the bike, and check by what I call the Goldilocks method.

Mount the wheel and secure the QR as you would to ride. Now test for play at the rim between the brake shoes, where the multiplier effect gives you more sensitivity.

If you feel obvious play, that's too loose
If you're 100% sure that there's no play, that's probably too tight
But if you kinda sorta think there may be play but aren't sure, that's just right.

As to the answer whether too tight or too loose is better, slightly too tight is better, but there's more room for error to the loose side, because more than slightly tight damages the bearing races.

Jicafold

Wow. I did not know this. I do check my hubs by checking for play with the rim at the brake shoes because I have made the mistake before of only checking at the axle. I just never paid attention to what difference the quick release makes. Thank you.

ThermionicScott 

The recommendation I've heard is that when going from the "open" position toward "closed", the lever should start to meet resistance when it is pointing straight out. When the lever is then closed the rest of the way, then it will be tight enough to hold the wheel in place.

So I think if you adjust the bearings so that the above results in the play just disappearing when the lever is closed all the way, you can instruct the other people to adjust their QRs so that the levers begin to resist halfway out, and then their wheels will end up with the right bearing tightness every time.

(If the more experienced techs disagree with this, I'd be happy to learn more. )

FBinNY 

If you checked with the wheel in the bike, you didn't have to know more because you're testing under riding conditions.

79pmooney

But the cone and locknut on one side does move as a unit relative to the cone and locknut on the other side as the axle is compressed with the quick release skewer. So the hub that is set up with no play off the bike will have bearings that are too tight after the quick release is tightened. Nuts such as tracknuts do not have this effect as they are only tightening against that locknut, so hubs with nuts need to be adjusted to no play before placing on the bike.

BEn

hueyhoolihan

i'm not so sure i buy it though. it's more likely, IMO, that the locknut/cone interface(s) has not been tightened enough and slack is being taken out there.

feel free to believe what you want.

ClarkinHawaii

Now we're getting to the heart of the matter. Does slightly too loose damage anything? I'm talking about maybe perceptible jiggle but nowhere near enough that the rim touches the brake pad.

Dan Burkhart 

The problem with too loose is that the load is not shared by all the bearings. Either too loose or too tight can cause damage, but I agree with FB, SLIGHTLY too tight is better.If there is any perceptible play, I don't leave it alone until it's gone.

ClarkinHawaii

This sounds like an excellent way to make sure that we're all tightening to the same degree. I just tried it and the tightness seems fine. So this is what I'm going to standardize on, and tell my customers to do. Does anybody disagree?

ClarkinHawaii

I hear you on this, but in my situation the people take the wheels away and I'm not around to check when they mount them on the bike.

hueyhoolihan

seems good to me. but, honestly... i don't have levers on my QRs anymore, i have hex heads on them (see pic). so if i get a flat, don't wait up, i'll eventually get there.

davidad

Except for larger axles the normal steel axles compress a little making the bearings a little tighter.

FBinNY 

Go find a trash bike and saw off the fork ends and dropouts, and mount them on the axle with a normally tight QR to adjust the bearings.

I use the following trick to adjust cones while under load. I have a 5mm or so long stub that I sawed from an axle eons ago. I mount the QR skewer without the springs, and with the stub under the nut end. This allows me to mount a wheel and tighten the QR so it's secure on one side, but not at the nut end. I can then adjust the cones from that side while feeling for play on the compressed axle. (rear wheels require having the skewer head to the right, so the left side cone can be adjusted.

Obviously, if you use my rick, you'll have to use your bike as the frame of reference. Otherwise, adjust the cones for the barest perceptible play, and you should be within the working range for a proper adjustment in your client's bike.

FBinNY 

The nature of the problem is very different between too tight and too loose. (the below refers to the classic angular contact cup/cone bearings).

Overly tight overloads the bearing and the rolling balls stress the surface of the races in a way similar to driving a tank might damage the ice on a frozen lake that's thick enough for a car. It also overpowers the lubricant's film strength causing dry metal to metal. In short order, the contact area develops surface cracks and a flaking process sets in. Overly tight, is the fastest way to kill a bearing.

Loose is completely different. Bcause the contact is on an angle, the smaller part of the cone is not in contact with all balls all the time. The axle then tries to drop into the gap between the lower balls driving them apart. That causes two problems. The first is that each ball must lift the axle slightly as it passes the bottom, setting up a vibration, and a small impact load at that point on the non-moving cone. Also, the wedging action pushes the balls apart so they now are forced to the top, where they are all rubbing against each other rather than spacing themselves freely. The ball to ball rub is why too loose can increase bearing drag.

A slight looseness won't create major issues, and if I had to be more than a slight bit off perfect, I'd prefer loose since it's more forgiving.

Lastly a loose wheel creates issues having nothing to do with the bearing. The play needs to be accommodated in the brake adjustment, plus there can be handling problems such as high speed shimmy, or brake shudder if there's any play in the system.

So, focus on being close, but there is a margin of error, so there's no need to obsess.

ClarkinHawaii

Thanks, FB--I'll do it. I can't believe it's 0130 in the morning on the East Coast and you guys are still up and at'em. Hell, it's only 2030 here and I'm hitting the sack now. You young guys are something else!

ClarkinHawaii

My education continues--but I need to be fresh to glean the full benefit, so I'll hit it in the morning. Thanks again!

rydabent

Come on guys, you can argue all day that when the quick release is set it doesnt tighten the bearings, but it does. If you dont believe it, how do you explain the fact that if you set up the bearing with say one thousandth of play it goes away when you set the quick release?