Bicycle Mechanics - Wheel Bearings

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Cleburne
05-04-05, 11:21 AM
I've inherited a bike from my oldest son and ride it almost daily for a couple miles before going into the office. Lately I've noticed the rear wheel has a lot (approx. 1/4 - 3/8") of horizontal play in it and I suspect the bearings need to be repacked or replaced. The only experience I have on bikes is changing the tires. Can someone offer expert advice on how I need to proceed? I'd like to learn to do it myself rather than depend on a local bike shop. Also, is there a good, fundemental maintance & repair book I can invest in to help with any other repair issues that may crop up?
Thanks,
Cleburne
powers2b
05-04-05, 11:28 AM
Search the forum for maintenance books.
This question is asked quite frequently.
Enjoy
I've inherited a bike from my oldest son and ride it almost daily for a couple miles before going into the office. Lately I've noticed the rear wheel has a lot (approx. 1/4 - 3/8") of horizontal play in it and I suspect the bearings need to be repacked or replaced. The only experience I have on bikes is changing the tires. Can someone offer expert advice on how I need to proceed? I'd like to learn to do it myself rather than depend on a local bike shop. Also, is there a good, fundemental maintance & repair book I can invest in to help with any other repair issues that may crop up?
Thanks,
Cleburnewww.parktool.com has a good repair and how to section. The aintenance book by Zinn is a good one.
jeff williams
05-04-05, 11:47 AM
http://www.parktool.com/repair_help/FAQindex.shtml
Being loose does not mean bearing replacement -though if you intend to use the wheel for a good amount of time -bearing and grease replacement is how you do it.
If you can find a junk wheel, play with it first.
The balls can be sized and purchased @ the lbs.
You need a waterproof bearing grease, I use Phil Woods specific for bicycles.
The play can be stopped by unscrewing the first nut, the tightening the second inside nut -which is a race (inside the nut has a concave face -this is one side of the bearing 'race'.)
The new ball, grease is to protect this race from wear.
The fun is tightening down the race and second nut to get no play -yet no binding of the bearings on the race.
You get into 1/8 turns to get it perfect.
If you simply tighten the race,(correctly) listen carefully to the balls turning -any gritty\less than smooth rolling and the balls are shot.
They false or true brinell? Anyway, if the hubs been loose, it probably false brinelled the balls.
http://www.precisionspindle.com/brinelling.htm
A visual inspection of the balls -If in anyway you can tell them apart from new -then they are shot.
Oh, and a towel under the hub to catch bearings as they fall out and carefully count how many per side.
Hope some of this helps -good luck...well, read the Parktool stuff and use less luck, more grease.
Cleburne
05-04-05, 11:58 AM
Thanks for the good (and quick) replies!
Cleburne
peripatetic
05-04-05, 12:33 PM
Clean and de-grease with Simple Green, rinse with water. I just got that from people on the forum, and it saved me a LOT of money over what the bike shop would have sold me. (Don't think the parktool site mentions what to use for this.) Good luck, I just did my first hubs about a week ago, and now I'm searching for bearings to take out and re-pack :D.
LV2TNDM
05-04-05, 02:52 PM
Don't mean to nit pick here, but the previous long post was a bit misleading.
The axle has the following components:
Outer locknut, washer(s) and/or spacer(s), and cone on each side. The "race" is the surface the ball bearings ride on that's press-fit into the hubshell. In most cases the race cannot be replaced. But it turns out that the races are very rarely damaged. It's the cones that get pitted first. If the cone surface is pitted, replace it. No need to go to all the trouble of overhaul if you're not going to replace worn parts. Pitted cones will continue to deteriorate.
Do not inspect the ball bearings. Count 'em so you know how many to buy, toss all but one and take it to LBS for correct sizing (even though rear hubs are almost always 1/4"). Purchase new grade 25 (or better) bearings. Never reuse old ball bearings. You cannot see imperfections in used bearings. Plus, buying grade 25 or better will improve the smoothness and durability of the hub.
Adjustment is the hard part. Rotating the cone on the axle provides the proper bearing pre-load. The locknut holds the cone and its adjustment in place. Notice, however, that tightening the locknut changes the bearing adjustment - it makes the bearing a bit tighter. The best way to adjust I've found is to lock one cone and locknut tightly in place on the axle (usually the drive side on freehubs). Clamp this locked-down locknut in a vise (or the axle in an axle vise if you're lucky to have one), and make all adjustments on the non-drive side. You want to result with an adjustment that is not loose - no side-to-side play in the bearing with the wheel on the bike. This is crucial. The rear hub adjustment can be checked with the wheel off the bike. Axle should rotate as smoothly as possible but with NO PLAY. Cup and cone bearings require there be no play, even if the bearing feels a bit "grainy" when adjusted to the point where the play disappears.
The front hub presents a different problem. When you properly close a front quick release, you compress the front axle, cones and locknuts. So a proper hub adjustment off the bike will be too tight on the bike. The ideal adjustment is a little play in the front hub, but as you close the QR, the play disappears. The result is a smooth-operating front hub that will last years. (Most bikes off the shelf have front hubs adjusted too tight, and they exhibit premature wear.)
The grease provides smooth operation and corrosion resistance. Bull Shot is my favorite. Grease all threads on the axle for ease of adjustment and future disassembly and additional rust prevention.
Good luck!
jeff williams
05-04-05, 04:04 PM
Don't mean to nit pick here, but the previous long post was a bit misleading.
The axle has the following components:
Outer locknut, washer(s) and/or spacer(s), and cone on each side. The "race" is the surface the ball bearings ride on that's press-fit into the hubshell. In most cases the race cannot be replaced. But it turns out that the races are very rarely damaged. It's the cones that get pitted first. If the cone surface is pitted, replace it. No need to go to all the trouble of overhaul if you're not going to replace worn parts. Pitted cones will continue to deteriorate.
Do not inspect the ball bearings. Count 'em so you know how many to buy, toss all but one and take it to LBS for correct sizing (even though rear hubs are almost always 1/4"). Purchase new grade 25 (or better) bearings. Never reuse old ball bearings. You cannot see imperfections in used bearings. Plus, buying grade 25 or better will improve the smoothness and durability of the hub.
Adjustment is the hard part. Rotating the cone on the axle provides the proper bearing pre-load. The locknut holds the cone and its adjustment in place. Notice, however, that tightening the locknut changes the bearing adjustment - it makes the bearing a bit tighter. The best way to adjust I've found is to lock one cone and locknut tightly in place on the axle (usually the drive side on freehubs). Clamp this locked-down locknut in a vise (or the axle in an axle vise if you're lucky to have one), and make all adjustments on the non-drive side. You want to result with an adjustment that is not loose - no side-to-side play in the bearing with the wheel on the bike. This is crucial. The rear hub adjustment can be checked with the wheel off the bike. Axle should rotate as smoothly as possible but with NO PLAY. Cup and cone bearings require there be no play, even if the bearing feels a bit "grainy" when adjusted to the point where the play disappears.
The front hub presents a different problem. When you properly close a front quick release, you compress the front axle, cones and locknuts. So a proper hub adjustment off the bike will be too tight on the bike. The ideal adjustment is a little play in the front hub, but as you close the QR, the play disappears. The result is a smooth-operating front hub that will last years. (Most bikes off the shelf have front hubs adjusted too tight, and they exhibit premature wear.)
The grease provides smooth operation and corrosion resistance. Bull Shot is my favorite. Grease all threads on the axle for ease of adjustment and future disassembly and additional rust prevention.
Good luck!
Nicely done, good post =way better than mine. Just a DIY newb as well.
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