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I have a custom road bike with (mostly) Shimano parts. I love to ride but I'm not so strong on the technical side.

I have quick-release wheels; I regularly (3-4 times a year) put the bike in a bag and travel by train to a cycling destination.

When I did so, upon re-assembling my bike, I noticed there was a lot of "play" in the rear wheel left-to-right. It rolls smoothly, but there is an intermittent....feeling.... as the wheel rotates when I am riding it.

The feeling is a feeling of some friction, but not enough to actually retard the forward motion of the bike or anything, just enough to allow my feet to feel it in the pedals. It appears to happen once a rotation, as if I am going fast enough, I can't feel it anymore, but when I am going slow, there's certainly a pace to it.

I've heard anecdotally from a friend I may need to adjust my cone & bearings, as they may have become too loose. Does anyone have any advice on how to do this, or things I should watch out for? I'm trying as much as is possible not to ride until I sort this, but since I commute by bike, it's urgent.

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3 Answers

up vote 3 down vote accepted

Pick the bike up so the problem wheel is off the ground. Grasp the tire and push it back and forth (left/right relative to the frame). If you can get any perceptible motion then the bearings are loose and need adjustment.

While the wheel is off the ground, spin it and watch the space between the rim and the brake block (assuming you don't have disk brakes). The space should be nearly constant, varying no more than about 1/2 mm as the wheel rotates. (Check this on both sides, since a dinged rim is also a possibility.) If it varies more than 1/2 mm or so the wheel is out of true and needs to be trued.

Both tasks -- adjusting bearings and truing the wheel -- are things that a competent basement mechanic can accomplish, but not particularly suited for a newbie, so in either case it needs to go to a bike shop.

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Thanks all for the good answers... I've got to go with Daniel's -- specifically for his final paragraph. I took it to the shop yesterday to have the bearings adjusted. Unfortunately it cost me $60USD, and they told me they didn't even replace any parts.... so I think I want to learn how to do this myself for next time. They said they "overhauled the hub". –  makdad Sep 16 '11 at 4:05
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Your description sounds more like a buckle in the rim. Loose cones can be felt by holding the rim and trying to waggle the wheel side to side. If it does, you have loose cones.

The once a rotation comment sounds more like a ding though. Once you've checked your cones aren't loose, try spinning the wheel and see if the rim appears to wobble in relation to the brakes. If it does it's most likely out of true (not running true). The simplest way to get good results in that case is to ask a bike shop to true it.

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If your bearing cones are loose, you should be able to feel it if you have the wheel off the bike, and wiggle the axle (not the quick release 'skewer' that slides through, but the hollow tube that the quick release skewer slides through). With the wheel on the bike, you would also be able to feel it by wiggling the rim side to side (perpendicular to the bike frame). If you try wiggling the rim side to side while it is on the bike, then you can watch the distance between the brake pad and the rim to see how much that distance changes to see how loose it is.

If you can feel the axle move in the hub, then yes, you probably need to adjust the cones. There should be a lot of "how-to" guides out there if you Google it.

If you are feeling a 'drag' once per wheel rotation, then you should make sure the rim isn't rubbing on the brake pads at some point in the rotation. Sometimes the axle doesn't seat itself all the way into the dropouts on the frame when you put the wheels on, and it will end up slightly crooked on the bike.

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Also if the wheel doesn't rub when not under load (ie: just spinning in place), but does when under load that would indicate the cones are loose –  Mac Sep 15 '11 at 3:30
    
I probably shouldn't have used the word "friction". It wasn't the brake pads or anything exterior - the wheel rotated freely on the bike while under no load, or while under load - it just was making some sort of internal vibration that could be felt on the pedals as that part of the hub "came around" on the wheel rotation. –  makdad Sep 16 '11 at 4:07
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