Bicycle Mechanics - Is any play too much? (Hub adjustment)

I have read when you adjust your hubs (cone and cup) that you don't want any play when the quick release is closed. The way I have been checking for any "play" is with my thumbs on the spokes next to the hubs, and my index fingers on the quick release (caps, I guess you could call them) and squeezing each side attempting to feel and hear if the hub rocks back and forth. Is this the way to do it, and should there be absolutely no sound or feeling of the hub rocking whatsoever?

I usually stick the wheel in the fork, clamp the QR, and shake the rim side to side at the brake caliper. It shouldn't have any play, and it should be loose enough so that when you leave the wheel alone, gravity will be able to pull the heavy side of the wheel down. (if the tire/tube is mounted, anyway...the valve will swing down)

I've also used my cheap old Park truing stand instead of the fork (to clamp the wheel in)...worked a bit better.

It shouldn't have any play, and it should be loose enough so that when you leave the wheel alone, gravity will be able to pull the heavy side of the wheel down. (if the tire/tube is mounted, anyway...the valve will swing down)

Theoretically. It also depends on what type of hub it is and what quality it is. This diagnostic test is not definitive, but it is a good indicator.

It can be hard to tell what is the perfect play. The ideal would be to have two dropouts laying around and clamp them with the QR. then perform the adjustment. When The bike is in the frame, or fork, the adjustment can be to tight and still feel good because you are judging thru the rim. If you could clamp dropouts(with no frame) in the QR you could then better feel the movement at the axle.
Most modern hubs do not compress as much when the QR is applied, while some of the older hubs need to be pretty loose when you do a free adjustment because the cones move in a bunch due to the loose tolerances.

I have read when you adjust your hubs (cone and cup) that you don't want any play when the quick release is closed. The way I have been checking for any "play" is with my thumbs on the spokes next to the hubs, and my index fingers on the quick release (caps, I guess you could call them) and squeezing each side attempting to feel and hear if the hub rocks back and forth. Is this the way to do it, and should there be absolutely no sound or feeling of the hub rocking whatsoever?
I'd say almost any amount of play is too much. The ideal condition of a cup-and-cone bearing is: zero play, and as little friction as possible. If you can't achieve that combination, it probably means you need a new bearing.

When adjusting a rear hub, I err on the side of just a little too much friction generally.

Parktool tells you what to look for and how to do it:

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

Bob

I'd say almost any amount of play is too much. The ideal condition of a cup-and-cone bearing is: zero play, and as little friction as possible. If you can't achieve that combination, it probably means you need a new bearing.
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Or he ran out of patience.

This is why MAVIC hubs are so cool; you adjust the bearings with the wheel mounted on the bike.

No guesswork.

Bollocks the heaviest part of a wheel is where it is welded not where the valve is.

Bollocks the heaviest part of a wheel is where it is welded not where the valve is.

Ah! now that is interesting; I'd no idea that part of the wheel was called the "bollocks"; I've always referred to it as the join, and being usually the heaviest part of the rim, will often help balance the valve when the tube and tyre is fitted.

- Wil

What the heck is a Bollock anyway?,,,,BD

I always go for as little play as possible, while still being able to spin the axle smoothly......If the rim/tire is moving side to side, then you're pretty loose IMHO.

Bollocks the heaviest part of a wheel is where it is welded not where the valve is.

This is an interesting theory since once you weld the materials together, and machine the sidewalls down to remove the excess, the weight of the material in the area of the weld as compared to the weight of the material in the areas surrounding the weld should be the same, non? Welding doesn't add material, it fuses (or...welds...) the separate pieces into one piece.

Now, if we are talking about a less expensive pinned rim there is a tongue in there that adds material. In that case it would definitely be the heaviest part of the rim.

And, there are also some rims that are welded, but use some kind of sleeve or tongue. Again, in this situation your general assertion would be correct.

And what about carbon rims?

Or he ran out of patience.

Notice that I said, "if you can't achieve zero play and little friction", not "if you don't have the patience to do so" ;)

This is an interesting theory since once you weld the materials together, and machine the sidewalls down to remove the excess, the weight of the material in the area of the weld as compared to the weight of the material in the areas surrounding the weld should be the same, non? Welding doesn't add material, it fuses (or...welds...) the separate pieces into one piece.

Now, if we are talking about a less expensive pinned rim there is a tongue in there that adds material. In that case it would definitely be the heaviest part of the rim.

And, there are also some rims that are welded, but use some kind of sleeve or tongue. Again, in this situation your general assertion would be correct.

And what about carbon rims?


In fact, nearly all forms of welding do add material. That's what welding rod is for, to fill in the gap between two to-be-joined materials. Even exotic, high-tech welding, such as TIG welding used in the most advanced aerospace components, typically use welding rod, which, in the welding process, is melted by the arc, and is fused to the liquid state metals on either side of the weld.

I don't have personal experience with how they weld rims, but from what I've personally examined, they also look to be conventional welds. The few really high-end rims I've examined, the weld has always been too cleaned up (ground and polished) for me to tell much of anything.

In fact, nearly all forms of welding do add material. That's what welding rod is for, to fill in the gap between two to-be-joined materials. Even exotic, high-tech welding, such as TIG welding used in the most advanced aerospace components, typically use welding rod, which, in the welding process, is melted by the arc, and is fused to the liquid state metals on either side of the weld.


My understanding of the process may be in error (I haven't welding anything for more than 20 years and it's probably a good thing, too, based on my initial efforts!) but don't you choose a rod based on the material you are welding? Doesn't this rod then become part of the liquid metal but is such that it is consistent with the material being welded? In the case of a rim, wouldn't this additional material then be machined away leaving behind it metal that is indistinguishable from what you started with? Let me know if I'm wrong here.

I know that Mavic runs a current through the rims and they are fused together without the use of a rod or (I believe) any inert gas. They even cut the hoops a little over-sized and calculate how much of the material will be used up during the process, resulting in a rim that has the correct BSD. I also believe that this process was designed specifically to not add any material to the join. It is hard to be 100% here as this is proprietary knowledge that they don't go into in great detail. With machining the excess material should be removed and the composition of the aluminum should be consistent throughout the rim, non?

This should be the big advantage over pinning a rim even though it is a more expensive process. I can't imaging going through all the trouble to make special alloys if your going to introduce a weak spot (or at least a section of rim with different properties than the rest) through the production process. It just don make no dad blern sense is all.

I would be interested to hear from some welders about this. (We know braze adds material so let's just skip that for now).

My understanding of the process may be in error (I haven't welding anything for more than 20 years and it's probably a good thing, too, based on my initial efforts!) but don't you choose a rod based on the material you are welding? Doesn't this rod then become part of the liquid metal but is such that it is consistent with the material being welded? In the case of a rim, wouldn't this additional material then be machined away leaving behind it metal that is indistinguishable from what you started with? Let me know if I'm wrong here.

I know that Mavic runs a current through the rims and they are fused together without the use of a rod or (I believe) any inert gas. They even cut the hoops a little over-sized and calculate how much of the material will be used up during the process, resulting in a rim that has the correct BSD. I also believe that this process was designed specifically to not add any material to the join. It is hard to be 100% here as this is proprietary knowledge that they don't go into in great detail. With machining the excess material should be removed and the composition of the aluminum should be consistent throughout the rim, non?

This should be the big advantage over pinning a rim even though it is a more expensive process. I can't imaging going through all the trouble to make special alloys if your going to introduce a weak spot (or at least a section of rim with different properties than the rest) through the production process. It just don make no dad blern sense is all.

I would be interested to hear from some welders about this. (We know braze adds material so let's just skip that for now).

Yes, welding rod is chosen specific to the type of material being welded, as well as considerations as to specs, strength, etc. When the item is welded, the welding rod and molten metal become one. Very often (I'm hedging here, as there are always exceptions), a well executed weld is stronger than the non-welded wrought metal. Differences in weight b/w the rod and the metal would be negligible, so yes, assuming a perfect grind, the resulting seam could be the same, or even lighter (assuming the weld was ground down to below the original surface level), than the rest of the rim. I was only taking issue with your characterization of welding not adding any additional material. On most frame welds, for example, there is definitely material added at all the welds, even for ground welds, such as on Cannondale frames.

Taking a quick look at my Mavic Open Pros, the weld is not ground down perfectly, but pretty well. Since it is a boxed rim, I am wondering if there is weld material internally. Clearly the internals couldn't be ground down, and would lend credence to the other poster's assertion that the welded seam has higher weight than other parts of the rim.

I have cut apart enough rims to say with something resembling confidence that there will be some material inside. Have you ever had a rim with a bit a left over material rattling around inside. Sometimes it is a shaving from when the spoke holes are cut but sometimes it is a bit of flash. The question then becomes if that amount of material added by the weld on the inside of the rim, and subsequently not machined off, weights more than the valve and extra little bit of rubber on the tube or not.For a pinned rim I think we all agree that this would be the case.

What I find interesting is that there are companies using slightly heavier spokes to balance the weight of the valve. If the join is truly the heaviest part of the rim, then this would add more weight to the heaviest part of the rim making it even more pronounced. Having ridden several of these wheels, I couldn't feel any seams or obvious imbalances. So I think you can see why I would assume that the valve is heavier than the material not ground down from the weld.

Any takers?