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Old 05-10-11, 10:37 AM   #1
vins0010
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How tight should I make cup-and-cone bearings (hubs and bottom bracket)?

So, I've either got or fix up a fair amount of old bikes. This means a lot of cup-and-cone bearings. One thing that hasn't always been clear to me is whether one needs "pre-load" - meaning a little tight (right?) or leaves things a bit loose (for hubs) and allows the QR to tighten it up a bit for hubs...and just barely zero play for BBs. I did things this way and ended up thinking I left things a bit too loose as both hubs and the BB ended up developing some play pretty quickly. Alright, I figured, I need things a little tighter than that. So, I make things a little tighter. So far, so good. However, I recently noticed grease oozing (oozing isn't a big deal, I really load grease in there) from my rear hub. The grease I use is Teflon based and white. The oozing was pretty gray looking and I originally just put it in there a couple of weeks ago, so, now I'm worried things are too tight and some metal is getting ground into the grease. So, any thoughts? How tight should these cup-and-cone bearings be?
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Old 05-10-11, 10:44 AM   #2
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Old 05-10-11, 11:21 AM   #3
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check out parktools.com .they have everything you need .
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Old 05-10-11, 01:08 PM   #4
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Hollow steel axles require a small amount of play that goes away when the quick release is closed and becomes a slight preload that is necessary for good bearing life. The old style BB with adjustable bearings should have a slight drag when turned in your fingers indicating preload.
http://draco.nac.uci.edu/rbfaq/FAQ/8f.8.html
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Old 05-10-11, 09:58 PM   #5
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Tighten the cone until it *just* starts to rumble, then tighten the locknut down hard against that. Works out to pretty darn good rather better than 9 times out of 10.
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Old 05-11-11, 07:49 AM   #6
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Never "preload" a bearing it will ruin it!!!!!
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Old 05-11-11, 09:34 AM   #7
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Originally Posted by rydabent View Post
Never "preload" a bearing it will ruin it!!!!!
Where did you get that info?
http://draco.nac.uci.edu/rbfaq/FAQ/8c.7.html
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Old 05-11-11, 12:59 PM   #8
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Thanks, I think I have my plan for the future. For cup-and-cone bottom brackets, I will tighten until I can feel no play, with a slight drag while still able to turn the spindle with my thumb and forefinger. For my hubs, I'll take my lead from a paragraph from a link provided (pasted below). I'll tighten with the cone and locknut until there is just a very small amount of play, put in QR, tighten and check for any rattle/movement. If so, undo and tighten. If not, spin the wheel to see how it stop. If it stops with an "indexed oscillation" - or suddenly, then I'll loosen a bit. If not, then I am good to go - and I'll repeatedly check over my next few rides to see how it is going.

To test for proper adjustment, install the wheel and wiggle the rim
side-to-side to determine that there is no clearance (rattle), then
let the wheel rotate freely to a stop. If the wheel halts with a
short (indexed) oscillation, bearing preload is too high.
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Old 06-26-11, 01:24 PM   #9
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Quote:
Originally Posted by Captain Blight View Post
Tighten the cone until it *just* starts to rumble, then tighten the locknut down hard against that. Works out to pretty darn good rather better than 9 times out of 10.
I feel this method would result in excessive tightness. The cone moves in more when you tighten the locknut against it. I adjust solid axles by tightening the cone against the bearing balls, then backing off maybe just 2 or 3 degrees, then tightening the locknut. It's still rumbly when you twirl the axle in your fingertips. You don't want TOO MUCH preload.
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Old 06-26-11, 03:52 PM   #10
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davidid

From around 55 years of working on machinery. If bearings are "preloaded" that means they are deforming either the ball or the race, and the bearing will be ruined in short order. Couple that with probably assembling these bearing in a basement or cool shop, and then taking them out into the heat of summer preload is a certain death of the bearing. A bearing so tight to rummble is being damaged!!!
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Old 06-26-11, 05:51 PM   #11
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When I adjusted mine it was just learn as you go. After you tighten it and re-loosen it 3-4 times you will understand where you need to be for a good fit. If you try to remove "all" the play, you probably went too far. If you hear any knocking while pedaling uphill, it's too loose. Just keep re-doing it until the fit seems right. It will last a long time once you get it right.
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Old 06-26-11, 07:16 PM   #12
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The pressure should be somewhere between tight enough that there is no play in the axle and loose enough that the axle spins freely.
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Old 06-26-11, 08:46 PM   #13
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The pressure should be somewhere between tight enough that there is no play in the axle and loose enough that the axle spins freely.
Best answer yet.
It is really hard to describe this for some people and is best shown hands on.
Maybe if you have an especially cool LBS they will show you or you could pay them to do it and the turn the axle with your fingers to get a feel for what is "just right."
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