What exactly will happen if your hubs have a little play?
 

Hi

How bad is it exactly if your hubs have a litle play in them? I understand it's not good to tighten the cones together when you are re greasing it, but how bad is the opposite?

Just asking because I'm wondering if it's good enough to let alone or if I should try harder... Finding it a bit hard to get it just right so should I err on the slightly too tight or the slightly too loose side?

Thanks

Define a "little play". You will get hundreds of answers. To me no play with no drag is what I aim for. Roger

Too much play is not good. Too much movement and fibration between the cone and balls will cause premature wear. A little play is good and wil be taken up by the qr.

You should err slightly on the loose side. A tiny bit of play at the rim, when the wheel is mounted is fine.

Well if I put my hand on the wheel and move it left to right I can feel it shift slightly. Sorry that's the best definition I can give you. I did try to aim for no play and no drag but I missed...

Well try to adjust the cones again but this time a tad tighter and retest. Sometimes the difference between sort of good and best is just another go round or two. Andy

To clarify, If you have bolt-on hubs you should try for no play or as little as possible when the wheel is off the bike, as it will be the same when mounted. With a q/r you will need a small amount of play when not mounted, which should disappear when on the bike. As long as there is no play and the wheel rocks back and forth when you move the valve stem to 3 o'clock and release I consider it good enough. If the hub either has play or does not move freely the cup or cones could be pitted or unevenly worn. It's even possible to have too many balls installed or the wrong size.

...the practical result of what you describe usually shows up in less precise feel to your steering and handling. ON a more macroscopic scale, if you leave the front wheel bearings a little bit loose on a gar (a different sort of bearing, they use roller bearings for cars, but still useful as illustration), you get very poor steering because the wheels tend to flop around incrementally instead of staying in alignment.

Before anyone jumps in here and says bikes are not cars, I suggest you try it out for yourself on your own bicycle.

Thanks for the advice. Will try to adjust it a little bit more and try not to tighten it too much. I guess it will get easier the more times I try it.

Your theory might be correct in the extreme but the real life of a riding bike suggests that "minor" hub bearing slop is often not even noticed. There are likely many thousands of bikes right now with slightly sloppy hubs and these bikes get to where they are steered well enough to not read of bikes "going out of control".


I have a few sets of Phil hubs with the common radial contact cartridge bearing slop. Even on the tandem the only time I notice it is when servicing the bike.


So the real question might be "how much slop can happen before I notice it when riding?" Andy

On cup and cone bearings this is dead wrong. There should be a slight amount of preload and no play at the rim when the QR is closed.


On radial bearings there should be a slight amount of play at the rim.

You can remove the QR and tread it through a nut large enough to go over the axle and install it on the right side of the hub. When you close the QR it compress the axle as it would be on the bike. Adjust the cone until there is a slight amount of drag on the bearing and tighten the lock nut. When the QR is opened there will be a small amount of play at the axle.

... Endless speculation on this forum...







:innocent:

For (adjustable) bearings to work properly and last long(er), optimal preload is important. Too much preload, as well as no preload results in accelerated bearing wear (bearing race pitting and ball wear).

Here is how I service hubs and chapter 7) explains the preload "tweaking":

Bicycle hub overhaul - Ciklo Gremlin

I'd rather have a little play than too tight with no play, and I'll spend whatever time it takes to get somewhere between those two. A little play may not matter mechanically (likely it doesn't) but it feels better psychologically to not have any.

What I think I've seen before as a quantitative definition of a "little" play is a couple mm side-to-side motion possible for a 700C rim, with the QR out. Then when the wheel is mounted and clamped in by the QR that play is less/gone.

Preload increases wear for no reason. Preload is employed for many different reasons unimportant to cycling.

...a car with loose front wheel bearings does not "go out of control" either. It just handles poorly.

Maybe you don't notice it. I notice it. Not making this up, but it's hard to double blind it.:)

...BTW, how did "less precise feel to your steering and handling" become "going out of control", anyway ? I :love: this place.:D

...can you quote me a source for this ?

I think what Racing Dan is talking about is when there's excessive (and there's that qualifier once again. Our passion is full of judgments and opinions) bearing preload the rolling surfaces go through a work hardening process as they are indented and rebound under the pressure of the balls. I think of it like a too heavy truck for the road's surface. The layers of road will flex and then in time crack.


Not every situation has had scientific research and a published paper. But the decades of hands on findings do speak just the same. Andy

Wheel Bearing adjustment by Jobst Brandt

...ball bearings and how they work have been thoroughly researched. Cone and race surfaces are case hardened, at the very least, in a quality bearing assembly. I honestly do not see how what you have described can occur.

Certainly excessive bearing load (to the point where the wheel no longer spins freely under the weight of the valve stem) ought to be avoided. But like @davidad, Mr Brandt, and a lot of other people I have preloaded both headset and wheel bearings on bicycles for many years now, with no noticeable ill effects.

But I'm a test subject group of one, which is why I asked for a source.

+1. Better to have no play, but a little doesn't cause any harm IME.

A wheel that spins freely under the weight of the valve is not preloaded.