Bicycle Mechanics - Cone adjustment

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View Full Version : Cone adjustment


bobbotron
04-21-06, 12:33 PM
Hey again. :)

So I was tightening up the cones on my front hub again after regreasing everything, and I couldn't for the life of me get it tight enough that there was no play in it, but at the same time not so tight it wouldn't bind. Actually, I would get it what I thought was perfect, and every time I tightened up the cone locknut I would introduce a bit of play to the hub. I think I should replace the cones, as they're a bit pitted, I think that might have had a bit to do with the difficulty I was having adjusting the cones. (Or maybe I'll pony up and replace the hub/wheel.) This is for my commuter, so it doesn't have to be perfect, but I want to make sure it's not going to be dangerous to ride, especially since I normally ride with front panniers. I ended up riding my other bike into work today (which turned out to be a good idea in it's own right,) but I am hoping to get this problem worked out soon.

Any suggestions? Is it alright to leave the hub with a little play, or a little too tight?


mikejavo
04-21-06, 12:47 PM
There is definitely an art to this, and many people will tell you different things. For me, it's a matter of feel. Basically, when tightening, I found I have to overtighten a bit, before I tighten the cones and nuts with wrenches. Then, you should have just a very tiny bit of play, which will get compensated by tightening the outer bolts or quick-release.

I've also seen tightening charts in the Barnett's manual, but I wouldn't even go there.

Wordbiker
04-21-06, 12:59 PM
I have found that accurate cone adjustments are most easily achieved while the opposite end of the axle is held in an axle vise. This allows both hands to be applied to the task, and the cone can be held while the locknut is tightened. Sure, you can make the adjustment without the vise, but it'll take more time and patience.

As for loose versus tight, I would recommend erring on the loose side. Too tight bearings tend to destroy themselves much faster and can pit your races, ruining the hub.


bobbotron
04-21-06, 01:12 PM
I have found that accurate cone adjustments are most easily achieved while the opposite end of the axle is held in an axle vise. This allows both hands to be applied to the task, and the cone can be held while the locknut is tightened. Sure, you can make the adjustment without the vise, but it'll take more time and patience.

As for loose versus tight, I would recommend erring on the loose side. Too tight bearings tend to destroy themselves much faster and can pit your races, ruining the hub.

Thanks!

I don't have a vice, but I will try this again after I have replaced the cones tonight. Godo to know about tight vs. loose, that's what I had thought, I have heard that if it's a little loose the wheel will wobble - is it bad wear on the hub too?

poopncow
04-21-06, 01:43 PM
Thanks!

I don't have a vice, but I will try this again after I have replaced the cones tonight. Godo to know about tight vs. loose, that's what I had thought, I have heard that if it's a little loose the wheel will wobble - is it bad wear on the hub too?

Some method to keep the axle from rotating when you "fix" the cone and lock nut makes a world of difference. (On the off chance that you have a nutted axle, you can achieve this by installing the wheel on the bike but just tighten one axle nut)

loose is better than tight, but you don't want it to be so loose that you can see the movement at the rim. You test for looseness by grabbing the rim and rocking it, rotate 1/8 or 1/4 turn and try again. Chances are that there will be differences, and you need to find the happy medium.

Have fun

HillRider
04-21-06, 02:53 PM
I don't have a vice.
Too bad, you're missing a lot of fun. :)

Wordbiker
04-21-06, 03:08 PM
Yeah Bobbo, I'm sure the wheel would wobble a bit if it were left loose. It's tough to explain, but experiment with it until you get the bearings "just right" in your own opinion, and it should be fine. As far as I know, there is not tool or device for measuring or setting cup and cone bearings, so let your best judgement be your guide, and be patient. No feeling of movement and no restriction when spinning the axle by hand is what you are shooting for.

It may be an old wrench's tale, but I was told to err on the loose side as the quick-release lever will compress the cones just a smidge more when closed. Maybe true, maybe not, but it seems to make sense to me as I've seen the effects of too-tight cones....not pretty, and requires a new hub and wheel rebuild.

One last tip: Bearings are cheap, and unless they look perfect when you clean them up, replace them with new good-quality bearings. Inspect your cones too, and a better LBS will carry replacements for those too. If you do replace cones, make sure that the dust covers/shields are not proprietary to the type of hub and/or pressed on. If so, they can often be pressed off and onto the new cones.

thekorn
04-21-06, 03:57 PM
What is probably happening is that as you are tightening the locknut, friction increases and you wind up rotating the axle a small amount with the locknut. To get around this, place a 9 or 10 mm wrench or similar object on the axle on the side of the freehub. This mimics the dropouts on your bike. Then install your quick release skewer and tighten. This will simulate the tension on the axle when the wheel is on your bike, and also the wrench will act like a handle to minimize the axle rotation that is throwing off your adjustment.

spunkyruss
04-21-06, 05:31 PM
.....I will try this again after I have replaced the cones tonight.....

Be sure to mark your axle with tape or something before you take the cone off of the axle. This will help you to keep the wheel properly positioned on the axle.

It can be a real pain in the butt to get eveything lined up again if you take both cones off of the axle without marking the original position.

operator
04-21-06, 05:41 PM
The other option is to count exposed threads.

bobbotron
04-24-06, 07:54 AM
Too bad, you're missing a lot of fun. :)

Ha ha, good one. :)

MichaelW
04-24-06, 08:01 AM
How good are your ball bearings? Low grade or worn bearing are out of round so it is much more difficult to get good adjustment. Replace them with a set of ISO grade 25 balls.
For fine cone adjustment, I hold the cone on one side and use a wrench on the locknut on the other side.

San Rensho
04-24-06, 08:52 AM
On one side of the axle, I set the cone and the lock-nut very tight. On the other side, I tighten the locknut against the cone so that it is tight, but so I can still move that side only when I apply a wrench to both sides. This lets you micro dial the cone adjustment. Dont worry about it backing off, the QR will hold everything in place.

Contrary to what everone else has said, when in doubt, make it TIGHT, not loose. After a rebuild, it will only loosen as it settles in. Loose adjustment will pit the race or cone or damage bearings. Tight adjustment will not. You would have to tighten the adjustment to the point where you can't turn the wheel before you could damage the cones, races or bearings.

Retro Grouch
04-24-06, 10:07 AM
I think I should replace the cones, as they're a bit pitted, I think that might have had a bit to do with the difficulty I was having adjusting the cones.

BINGO! Even a tiny amount of pitting will keep you from being able to achieve ideal bearing preload.