At the motorcycle racers was a Dunlop tire tent where the techs were balancing wheels just by mounting the axle on V blocks, letting the heavy spot rest at bottom and adding weight to the top until the wheel would not come to rest in the same spot. I asked why no electronic spin balancer and he said this worked well enough, and these were high speed motorcycles. Got me wondering if you couldn't balance a car wheel this way.
I always clamped the axle in the vice and let it spin on wheel bearings and found the light spot on top and tested after putting on a weight and had 100% luck doing it that way took a couple minuets, never tried on a car
Snap-On had a balancer back in the 60s to maybe early 70s like that. It was a low tray bottom (red I think), 2 uprights with roller bearings that the central shaft rested on. That shaft was set into the wheel with cones like a drum lathe. Then there was some attachment that showed where to stagger two weights, somewhat apart. I'm sure there must be a google pic
had the tires balanced at a tire shop on an a sedan I had but still had a slight shake in front. a buddy jacked the front, loosened the bearings a little so it would spin easily and rebalanced them the way bike guy did it. no more shake.
I'm going to try this ^. I just mounted some new tires and the results of my cheap bubble balancer have been spotty. Thanks for the replies.
Why not just take them in and have them spin balanced at a reputable tire shop? Gravity balance may be good enough to get you there, but any tire shop worth a damn has a good spin balancer to get you really dialed in. Just because you dont feel a vibration doesnt mean they are balanced properly. If you plan on putting any kind of miles on those tires you need to have it done the right way. Uneven tread wear/shortened life of the tire can result...plus most tire joints if you pay for balancing once they usually do it for free for the rest of those tires' lives. Posted using the Full Custom H.A.M.B. App!
That's likely the end result. I've been hoping that since I have a tire machine (and a crappy bubble balancer) I could do tire changes on all my vehicles myself. The tire machine works a treat and I've been toying with the idea of buying a spin balancer but I don't really have the room for one and could only afford a used one.
The boat prop shop I go to has an antique gravity balancer that has $2000.00 worth of bearings in it.
FWIW a M/C wheel/tire combo is usually much narrower that for a car or truck, everything is pretty much in one plane. An imbalance might be harder to successfully compensate for if it were well to the inside or outside on a car/truck combo using the heavy side settles to the bottom method. Ed
Try splitting the weight. Two smaller weights on the inside and two on the outside that are spread equally on each side of the light spot. An old long time tire changer showed me that one in Texas in the early 70's and we didn't get many comebacks doing it that way. It doesn't look too pretty but works pretty well. The gravity balance is just a different way of finding the light and heavy spots on a wheel/tire and evening them out with weight than the bubble balance.
I've got old ET spoke mags so I'll be using stick on weights on the back side only, close to the center. But I do like the idea of splitting the weights 90 degrees apart or so.
This is known as "static" balancing and it works very well...just make sure that you dont end up with two sets of weights about 180 degrees from each other...that is called "counter balancing" and basically you are adding more weights to compensate for the weight you already added. It generally results in a high speed vibration that usually starts around 55-60mph. This holds true for hammer on wheel weights as well. If you see that your tire shop has two or even three weights hammered onto one wheel all spaced out, the person doing the balancing didnt know what they were doing. A proper wheel balance has one weight(or weights) on each side of the wheel. I cut my teeth as a professional mechanic as a tire jockey at Sears many years ago, so I know my way around a spin balancer! Posted using the Full Custom H.A.M.B. App!
This best describes the situation. There can be a substantial difference between 'static' balance and 'dynamic' balance. It is entirely possible to have a tire/wheel that is in static balance, no 'heavy side' to rotate to the bottom, but COULD have a heavy place to the inside and a corresponding, and equally heavy spot to the outside, 180 degrees opposite. That condition would not be apparent with a static balancer. When rotating at speed, those 'spots' are trying to align with the centerline of the wheel/tire and generate forces that, ideally, should be cancelled through proper dynamic balancing. In actual practice, it is common to have such an imbalance pattern but seldom are they, in fact, equal and directly opposite. All the more reason for a professional quality spin balance.
We used to have the front hub and spindle without grease on the bearings for balancing wheels. My dad balanced our own wheels for years that way. Worked fine. For those that are questioning how well it worked. Have you had problems with getting a decent balance from the tire shop with the spin balancers? I am guessing it depends on the person running the equipment but I have so I don't think that the gravity method is all that bad. I am just too lazy to mount and balance the tires now. Neal
In college back in the '70s I worked at a tire shop. Customers had a choice of bubble or the more expensive spin balance. More expensive because it involved jacking the car up and running it up to 70mph with me, the flunky, working the dingus that attached to the wheel that moved the weight around while my boss sat in the car with the heater on. Anyway, when we bubble balanced we always split the weight front to back. Even on mags, unless the customer didn't want those tape on weights on the front. I'm in that camp on my mags, willing to sacrifice whatever inside to outside imbalance there may be. I'll be lucky to ever see 65mph in my heap anyway.
Can't matter very much in that application given the enormous tire distortion that the tires undergo on acceleration.
I've balanced a number of tires this way on my Dynature tire truing machine. Granted, truing the tire helps dramatically if the tire is out of round, but I've also balanced new radials this way (splitting the weight inside and outside) with excellent results. The Dynatrue actually has a balance position on the switch which runs the tire rotation motor separately to create a slight vibration while the wheel/tire on the mandrel is settling heavy spot down (this thing is very sensitive). The old fellow that sold me the machine said he'd balanced tires this way for years, and swore by it. Being a contrarian by nature, I had to try it. The biggest drawback is the time it takes rocking back and forth as the heavy spot settles.
Messed with 125 shifter karts for years, and that's how we balanced them. We'd hit 115 mph on the backstretch at Willow Springs and the balance was never an issue. We even duct taped over the stick-on weights as a second securing method if the stick-ons ever became disbonded.
Other than being round, a small lightweight kart wheel, balanced or not, has little in common with the much larger diameter, width and greater mass of an automobile and/or light truck wheel/tire. The dynamics of the latter are substantially magnified over the former.
Been doing the gravity wheel balancing on my cars for a long time. It works perfectly for me on my lakester at over 170 MPH the tires balanced this way work great. I have found the electronic tire balancing machines are not that good maybe due to the operator. but by doing it myself I know it works it just takes a lot of time to get it perfect.
Good point. I was just making a case that static balancing is an effective method of balancing on a wide range of applications, from big to small.
I have a "Parnes" balancer (for moto rims), kinda pricey for what it is, basically some super slick bearings and 2 cone set up, use it on jackstands like you described, works beautiful and balances them where I feel zero vibes, so it must be working. If you had a holder for the car rim it would theoretically work as well. I would think
RidgeRunner9, hendo601 and Henstray all make valid points. Static balancing is a single plane balance effective for thin rotating masses with little width relative to their diameter, thus little or no unbalance couple trying to cause a wobble to occur. Objects with their mass spread over a distance of their rotating axis create un-balance couples, like a crankshaft even with it's relatively small diameter. Now think 15' diameter wheel with a tire mounted. The farther away from the center of rotation, the larger the unbalance force. Now supposing the wheel is 7" wide the modern tire balancing machine is set to apply weights to those two rim edges or planes and knows the distance from the mounting face of the wheel. Any modern balancing machine is so advanced, that any trained operator would be hard pressed to make an error providing he/she has not been careless in being certain the wheel is mounted and centered properly on the machine. I had this happen on a set of aluminum wheels where a cone was being used and appeared to center the wheel but did not. Repeated balancing showed the just balanced wheel out of balance! The solution was an adapter that bolted to the lug holes of the wheel and mounted on the arbor of the balancing machine.
I should have defined in the previous post that static balancing does not mean the item is not rotating. While the bearing method and the bubble balancer are static or at rest, the old Stewart Warner strobe light balancers and the Hunter that clamped on the rim both had a friction motor that spun the tire and wheel and drum assembly on the car. THis is still, in balancing terms, a static or single plane balance and commonly the neecessary weight was evenly split and applied to both sides of the rim. The modern machines are dynamic balancers the definition of which is the ability to define two planes along the axis of rotation where weight can be added (or removed as in a crankshaft) to eliminate both the rotational out of balance and the axial out of balance couple. A very good simple explanation can be found at http://www.balance.net.cn/phe.htm
Imo, a go cart that's running 115 mph needs to be balanced. After all, how much rpm is that small diameter wheel/tire turning at that speed? If you have an imbalance of 2 oz, you're going to feel that going 115. I also use a bubble balancer and have good results so long as the tire/wheel combo isn't too wide. a 275-60-15 on an 8" rim is hit or miss but a 225-75-15 on a 6 or 7" rim does good and narrower wheels and tires are a cakewalk. Like mentioned, the couple imbalance is what will get you on wider wheels and tires. And someone mentioned running new tires for awhile before balancing? No way. It's very possible to have just the tread that has a heavy area so you may run for 5000 miles with it out of balance and that will make it wear unevenly. Besides, tires should be at least checked for balance at every rotation just because you are wearing off some rubber and you might be wearing down a spot that was a bit heavy. It may take 15 or 20k miles to get it to where it's felt tho.
I agree the go-kart tire/wheel should be balanced. My point was intended to illustrate how much greater a problem it will be for a much larger (in terms of diameter and mass) a light truck or automobile wheel/tire if not balanced dynamically. Static may not be enough. I think you make a very good point about balancing from first mounting. When I mount tires I always inflate them to 35 to 40 psi to fully seat the beads, then let them bleed down to 0 psi and re-inflate to operating pressure, then balance on an electronic balancer. On occasion I will find an unusual amount of imbalance, usually with steel wheels, and I will then break down the tire and rotate it 90 and/or 180 degrees and repeat the process. It is sometimes amazing the improvement in can make in correcting out of round or heavy side problems.
The more expensive practice of the spin-balance is worth the cost because neither the bubble-balance nor the gravity balance will indicate an out-of round tire OR wheel.
Almost all new tires have a small paint dot on the sidewall which generally denotes where the tire should be positioned in relation to the valve stem hole. The dot is usually where the steel belts overlap and cause a bit of a heavy spot, and since the valve stem hole means the wheel is lighter in that area it is a good idea to match them up. I have experimented with this practice with a few different tires on a steel wheel and found the amount of weight needed to balance the tire was significantly less when aligning this dot with the valve stem hole. I too agree with balancing tires as soon as they are mounted. You may have a seriously out of balance rear tire/wheel and may not ever feel it because it is not attached to the steering...and in as few as 5k miles you can cause some serious wear issues. Our spin balancers had an option to either round off the amount of weight to the nearest 1/4 oz or you could hit a few buttons and get the exact amount of weight required down to the hundredth of an oz. When you leave it on the "round off" feature and it says it is balanced then switch to the exact feature you will be amazed what you see. I have seen the machine tell me the tire is balanced then switch to exact and it is .28 oz out of balance, yet the machine rounded it down and said it was good!! Any good tire guy should be able (with a little patience) to get your tires down to .05 oz or less. We used to have contests to see who could get to .00 the fastest.
I have used both bubble and gravity balancers with several race teams I worked for, these went on race cars that would do 200+ MPH, worked just fine. You have to pay attention and it takes a little longer. My buddy has an Snap-On gravity balancer, I use it for all my vehicles, no issues at all.
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