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Discussion in 'Motorized Bicycle General Discussion' started by Kevron99, Dec 1, 2009.
how do I balance my wheels? and how do I know if it is balanced?
Balancing is easy as long as you're not using 'Slime' in your tubes. If you are, forget it. Raise the wheel so it spins freely. The front wheel is easy the back requires removal of the chain. Let the wheel rotate and when it stops the heavy side is at the bottom. You can use solder and wrap it around the spokes at the light side of the rim until the wheel will stop at any point and not show a heavy side. Your bearings need to be good, well adjusted and lubricated and you need to assure that there is no friction acting on the wheel to interfer with rotation. As I said at the start. 'Slime' or any similiar product in the tube will make balancing impossible due to it moving around inside the tube.
Fantastic...thank for the tip.
wheels that are straight and true do not show heavy sides . I am really suprised that nobody mentioned bent axles, besides being straight and true. A wheel that is straight and true is a balanced wheel. Dont forget that the cones must not be worn unevenly, and the axle must be straight. To straighten and true a wheel is alot more complicated than putting what???? on your what??? :-/
Sorry Blakenstein, but that may not be 100% accurate - while it's good advice to be sure, just being true doesn't equate to being balanced as well. "Defects" in the rim like the butted joint on a steel rim and density variations in alloy ones (cheaper ones in particular) and the much more common density variations in the tire itself all add up, not to mention just the valve stem itself - almost always what ends up on the bottom of a free spinning wheel, showing that even it's minuscule weight has an effect (if it doesn't - check yer bearings). The only problem is the "heavy side" may not show just from hand-spinning the wheel what with grease density and resistance (in particular with a just-trued rim as odds are it's got nice, new, thick grease in the bearings too), if you could hook it up to a balancing machine and spin it up to speed - it'd tell a whole different story
Granted - this I got from balancing performance motorcycle rims, but the theory is the same. If there's enough of an effect to bother balancing a nicely trued bicycle rim at the limited speeds we use them at... *shrug* I have no idea lol, I don't think so... but it just may reduce some vibration, always the "Holy Grail" of the MB enthusiast On a motorcycle it's simply a safety issue as an out of balance rim can contribute to the dreaded "tank slapper" high speed wobble - I don't see that happening with motorized bicycles tho... if it did - I'd be screwed lol, I've always got big old clumps of mud on my mountain bike rims heh
i spent some time worrying about balancing my wheels, but i blew it off. i used to work at a hi-end tire store years ago, and also raced SCCA autocross and solo racing. we had tire matching grinders, on-car balancers, all the goods.
one of the things i learned, is that the frequency, modulation, harmonics, whatever you want to call it, occur at about the same speeds, usually at 33mph (+ or - a few,) then again right near 60mph (and again at greater speeds, but we're not concerned with that here.)
at those two speeds is where you'll feel your car start to shimmy if your wheels are out of balance (this isn't taking into account bent wheels, warped rotors, loose parts, etc.) when you power out of these ranges, your vibration goes away.
given that these bikes top out when the vibrations would occur, i don't think balancing is justifiable, and just another thing to get all excited about for nothing. they don't balance the wheels on racing bicycles, either.
if you could somehow dynamically balance a bicycle wheel, one good skid, a pothole, anyhting that could slightly deform your wheel would throw it out of whack.
what 2door's talking about is "static" balancing, which is basically finding the heavy spot (usually the valve stem) and compensating for it on the other side. in theory, this would work on a bike wheel, but i don't think you'd feel any effects except psychological.
a properly trued wheel with correct spoke tension and smooth tires are all you really need.
if you went thru all the trouble to balance your wheels, and then you're rockin' some dirt grabber knobby tires, you just wasted your time.
even if i could get my bike to 90 mph, i wouldn't worry about balancing the tires, because since they have no speed ratings, they'd probably blow off the rims anyway...
I have to agree with Bairdco. Some time back I suspected a balance problem and did the fishing sinker thing to fix it (no slime back then). After perfect balance my vibration was still there. Turned out to be el cheapo Target bike tire.
Just for the heck of it (mad scientist syndrome) I purposely weighted the wheel WAY out of balance. Guess what... no vibration. I had about half pound of lead on that rim before it became noticeable. And still wasn't the same as a bum tire.
Thank you Bairdo and BarlyAwake you replies prompted me to go and spin a wheel from my high end bike, and I am very happy to report that the valve ended up in a different place each time I spun it and NOT on the bottom. It seems that the valve is not heavy enough to upset the balance - must have something to do with the valve hole in the rim that compensates for added valve weight. If your bearings are good, your axle is straight, your hub races and cones are not worn unevenly, your wheel is straight and true then you need not worry about balancing it, but if you want to put something on your spokes, go ahead and do it.
P.S. Congratulations BarleyAwake on your advancement to moderator and that is a beatifull job you did of rebuilding your bike after buddy mangled it.
I too concure with Bairdco regarding the benefits of balancing a bicycle wheel. It has been my experience that cheap-o tires, the ones with built in lumps will cause you greater road problems than balance. We're just not going fast enough for it to really matter. I gave the advice above because it was answering a man's question. Guess I should have elaborated on my feelings a little more when I had the chance. I've balanced my wheels and could discern no difference in ride. I typically cruise in the lower to mid 20s but occasionally romp on it for short periods and at those speeds the bikes feel the same with or without the efforts of balancing. There there's the 'Slime' thing. Why go through all the sweat of balancing when you have a glob of rather heavy viscous liquid rolling around inside the tube?
spin your wheel....look closely.....wait for it to stop spinning.....like others have stated.....your valve stem should be at the bottom.......yank those stupid reflectors out....they serve NO purpose....just pay attention when assembling the wheel/tire......hope this helps....
But that reflector looks so cool... going round and round... round... and... round... getting very sleepy... round... and... round.. eyelids very heavy... round.. and... rou...
You are getting sleepy......your eyelids becoming heavy.......you yearn to stay alert but.....you can't.....soon you will succumb .......and will do to my bidding......
another thing you can do is match the tire to the rim. when you spin your wheel and find the heavy spot, try deflating and moving the tire 180 degrees. if the heavy spot's still in the same place, it's your rim. if not, you can mess with the tire till you get your rim to stop at random.
it still probably won't show any improvement in your ride, though. we all know that the faster you go, the more vibes these engines put out.
if you can feel a shimmy or get speed wobbles, you have other problems. i've rebuilt a lot of old girl's cruisers before, and going fast downhill would shake them to pieces...
yeah !....exactly !....a lot of mitigating circumstances are involved.....but this isn't rocket science.....play around with them......high speeds will tell you a lot.......