Should qr pressure be considered when adjusting/tightening cup & cone hubs?



Verve2

Member
Jan 26, 2018
15
8
3
43
Looking at various threads and videos, some talk about getting the hub to where you can feel just a half a hair of lateral play and anticipate the pressure from the QR compressing it enough to take up that play. Two issues:

What I'm finding is that even at the point where I can't detect lateral play, if I grab one end of the hub and pull up and down hard, I can feel play - it's small but it's there. If I tighten the cone more, this previously described bit of play disappears, so it tells me that there must still be some play in the hub even after I can no longer detect lateral play.

An LBS tech I talked to dismissed the idea that the QR will compress the hub - he said he's been doing it for however many years and has never even heard that, he tightens it to where he thinks it needs to be without considering the QR pressure.

What's your method for getting hubs to the perfect tightness?
 

dabac

Well-Known Member
Sep 16, 2003
2,298
288
83
52
Quick-releases do compress the axle. A mechanic denying that is not a good sign.
Now, exactly how bad it is can be harder to judge.
And we don’t know how tight that mech sets his bearings either.
Maybe he sets them loose enough to achieve the same thing unintentionally?
Rim brake fronts and vertical dropout rears don’t need much q/r force to stay put, and may well survive just fine at the tiny, tiny amount of excess pressure occuring during wheel installation.
Disc brake fronts and horizontal dropout rears need a considerable amount of q/r force to stay put, and I wouldn’t feel comfortable running those w/o compensating for compression during bearing adjustment.
How - that depends.
Some use spacers to let the q/r load the axle as when mounted on the bike and the adjust the bearings with the q/r closed.
I’ve tried that and wasn’t overly impressed.
If I have access to a vise, I have very good control of how much I tighten the bearing. I set it a little loose, install and try it out.
If it needs to go tighter, it goes in the vise again and add 1/8-1/4 turn.
 

Verve2

Member
Jan 26, 2018
15
8
3
43
If I have access to a vise, I have very good control of how much I tighten the bearing. I set it a little loose, install and try it out.

If it needs to go tighter, it goes in the vise again and add 1/8-1/4 turn.
The text in red is the key - how do you gauge if it's too tight/loose?
 

dabac

Well-Known Member
Sep 16, 2003
2,298
288
83
52
The text in red is the key - how do you gauge if it's too tight/loose?
I do an initial setup, pull at the axle to judge amount of play.
Install in bike, push rim sideways to judge remaining play.
If there still is any, I remove wheel, rest it on the vise and clamp the lower side locknut. Then I add a fraction of a turn, install in bike and try again.
By keeping close check on how much I turn the cone in, I’m confident I’m not adding too much preload.
 
  • Like
Reactions: steve