Wheel balance

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02-20-19 | 01:11 PM

#26

Retro Grouch

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Joined: Feb 2004

Posts: 30,225

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From: St Peters, Missouri

Bikes: Catrike 559 I own some others but they don't get ridden very much.

Quote:

Originally Posted by Lemond1985

Your valve stem serves as one. You can always tell your hubs are in good shape when a spinning wheel settles gradually, with the valve stem winding up in the lowest possible spot on the wheel.

I don't think so.

When I worked as a shop mechanic I installed a lot of bike computer wheel magnets. I assumed the bast place on the wheel to install the magnet would be the lightest point so I'd let the front wheel find it's balance point. Most often the lightest point was near the valve stem. If you think about it, when they make a rim, they remove material to make a hole for the valve stem and they add material where the extrusion is joined together.

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02-20-19 | 04:38 PM

#27

woodcraft

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Joined: Apr 2012

Posts: 6,017

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From: Nor Cal

Quote:

Originally Posted by Marcus_Ti

Have you noticed that if you have a friend hold your rear wheel up, you spin the cranks and get the wheel going as fast as the highest gear will allow....the bike doesn't "jump" around in his hand?

Like I said. Pendulums. They are a thing. In a stand driving a wheel hard you excite one.

No. I tried it (with my own hand) & the movement is pretty much the same either way.

I don't really get the pendulum idea since it's rate depends on length. It would have to be very short to swing back & forth multiple times a second

02-20-19 | 06:41 PM

#28

grayEZrider

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Joined: Dec 2016

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From: tennessee

Bikes: '13 Specialized Elite, KHS 223, '94 Trek 2120, 92 Raleigh technium, '87 Centurion LeMans, '86 Centurion IronMan, 2019 Canyon Endurace Al

every now and then..
A few times over the years I ran into a "wheel balance" problem it was always the cheap tire/rim not seating correctly. Actually a big problem on motorcycle tires, rarely on bicycles, But it does happen.

02-20-19 | 08:33 PM

#29

greatscott

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Joined: Feb 2019

Posts: 594

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From: Indiana

Bikes: 1984 Fuji Club, Suntour ARX; 2013 Lynskey Peloton, mostly 105 with Ultegra rear derailleur, Enve 2.0 fork; 2020 Masi Giramondo 700c, full Deore with TRP dual piston mech disk brakes

Quote:

Originally Posted by HillRider

The rotational speeds of bicycle wheels are low enough that the imbalance would have to be rather large to be noticeable. I've heard of some riders carefully balancing their wheels using thin lead strips wrapped around the nipples next to the rims but it's pretty rare.

Out-of-round or unevenly molded tires are the most likely the source of any significant imbalance.

I agree, even with tires if you get one that's a bit off, and this is quite rare by the way, you can turn the tire a 1/4 turn at a time on the rim till the vibration goes away, problem is with doing that you can't index your tire's label to the stem, the best you can do if once you rotated the tire and found the sweet spot you then have to move the other tire to match the position of the other so it looks better for whatever that's worth.

Todays AL rims are machined too which one of the things that does is balance the rim, it's the same principle they do with racing tires, they shave the rubber instead of adding weight. However I've never had an out of balance non machined pinned rim either, so not sure the importance of machining, I read it improves the braking surface but I can't tell any difference.