I estimate that static balancing takes care of the problem 60% to 70% of the time. That’s why it works so well. It’s also why you will find people who have not been able to get rid of a vibration by simply statically balancing.
Cars tend to be insensitive to static imbalance under 1/4 oz (5 grams) - which is why the increments in balance weights are such.
I estimate that dynamic balancing takes take care of an additional 25% to 30%. Plus cars aren’t nearly as sensitive to the effects of a dynamic imbalance. Hunter Engineering even factors this in on their high end balancers.
What percent is left is mostly Uniformity, which is a combination of both runout and structural stiffness. Most people call this “Out Of Round”, and they are mostly correct, but there is another part and given the way this is measured, it is difficult to sort the 2 apart. It can cause both up and down and side to side forces that mimic static and dynamic balance forces. In fact, you could correct non-uniformity by using balance weights (which would be purposely un-balancing the assembly), but that would only be effective at a certain speed range.
And lastly, people come in a wide range of sensitivities. My wife, for example, is very insensitive and can tolerate a whole bunch vibration.
Plus, the phenomenon of the “Phantom Vibration”: Vibrations come in different frequencies (meaning the car reacts at different speeds), and once a driver becomes sensitive to that frequency, they can pick it out very quickly - even if you remove the source of the vibration - as the road is inputting all kinds of short term vibrations. Hence you will find people complaining about a vibration even after it has been fixed.
Who Who: Fifth reason to balance your own wheels, you eliminate the bad balance. I once bought new tires at a well known tire store. Had bad vibration at 60 MPH, went back, they rebalanced, same problem. they said I had a bad wheel.
Took it to Pep Boys, they balanced it, no problems.
Took it to Pep Boys, they balanced it, no problems.
Pep-Boys? Really? That is the LAST place I’d buy tires from or have them balance my tires. I’ve only had one problem over the years with tire balancing. I personally driven over a million miles, so that accounts for a lot of tires on many different vehicles. I learned my lesson years ago about buying from a national chain. Good local tire places are by far the best place to buy from.
Static balancing is fine for some tires/wheels. But most modern tires need dynamic balancing.
Like so many things in life beauty is in the eye of the beholder. While I never wanted to get involved with mounting tires, etc., it was a much better alternative than carrying work to a tire dealer and waiting so I used an old Coats changer and bubble balancer for years and never had a complaint. Of course the vast majority of the vehicles worked on were light trucks with conventional steel wheels.
And as for wheel bearings and oil seals interfering with free fall balancing anyone curious might jack up a coasting wheel and tape a 2 oz weight at the 9:00 position to witness whether the method works.
@“Rod Knox” While I never wanted to get involved with mounting tires, etc., it was a much better alternative than carrying work to a tire dealer and waiting
I don’t actively advertise or pursue tire sales, but every car that comes in the door has 4 of them, it’s crazy not to offer to service or replace them. I have regular customers who tend to their tire needs somewhere else, but for a lot of folks it’s easier and more efficient just to have us take care of them. A decent tire machine doesn’t cost anymore than a scan tool these days, and tire sales are about the most profitable service per technician minute we have.
I have a couple of observations here. When ever I get a chance to go back into the garage area, which is getting harder to do these days, I notice that the balance machines have a static/dynamic switch on them, and almost all the time, the switch is in the static position.
When I was in the Navy, we had a Hobby Shop for auto repair and they got one of those computer balance machines circa late 80’s. Most people were not allowed to use the equipment like that, but the supervisor knew me and allowed me to use equipment that most were not allowed to use. The instruction sheet specifically said to remove the tire before attaching the weights as the pounding on of the weights would knock the machine out of calibration. I don’t know if that applies to todays machines.
It also recommended that you static balance the tires with a bubble balancer first, then finish balancing on the computerized machine.
@asemaster, no doubt any repair shop doing significant business will often face a flat tire on the lot or find a problem tire while making unrelated repairs and it is much more profitable to make an incidental repair rather than farm the work out and waste time dealing with a tire dealer. And my largest fleet customer had over 140 vehicles and contracted a fleet price with a local distributor but found it worthwhile to stock 235x15 tires and leave several with me to install as needed whenever a truck was in for any reason. It never occurred to me to stock and retail tires because doing so would pull me out of the shop and away from all the fun there. And for many years the tire business was very competitive, somewhat cut throat in fact. I imagine that is the cause for national tire chains to be so predatory. But more and more I see that local shops are stocking the fast moving tire sizes and apparently enjoying a profit doing so. A good shop owner must be able to recognize opportunity and jump on it.
@keith “The instruction sheet specifically said to remove the tire before attaching the weights as the pounding on of the weights would knock the machine out of calibration. I don’t know if that applies to today’s machines.”
This is made for use on motorcycle tires, but I bet it would be adequate for the DIYer who doesn’t want to pay $5/wheel for proper high-speed balancing.
I have watched some of the clowns trying to balance the tires,I think sometimes they get them off center in the cones somehow.
But all jokes aside,people doing things creates employment,I wouldnt spend a thousand dollars to keep from paying someone $20 to balance my tires,Scrooge McDuck can only squeeze the nickle so far.
I personally hate anything to do with mounting, balancing, or rotating tires. With me it was always a necessary evil.
When I worked for Nissan they had us check wheel balance on every new car during a PDI as weird as that sounds. The good part was that we got paid 1 hour extra for all 4 wheels so in that case it was a little more tolerable.
Great comments everybody! I had a high school weekend job as a midnight-to-8 am service station attendant at a gas/repair station near a freeway off ramp so I had to fix flats once in a while and used a bubble balance machine to verify it was balanced after I remounted the tire. As I recall the way I did it, if a certain amount weight was needed in one spot, I’d use four weights, not on that spot but about +/- 15 degrees from that spot, two on each side of the tire. Nobody ever came back asking for a refund, so it must have done something in the way of balancing the tire.
I realize HF sells an inexpensive bubble unit, and that the most sensible way is of course to just take it to a shop and pay them to do it. There’s a inde shop near where I live and I frequently stop in there to chit-chat if the mechanic isn’t busy, so I expect he’d do it for free.
But I was more interested in how a person would come up with a way to do it themselves, and with the skilled folks who post here, I knew some great ideas would emerge. Rod Knox’s idea is very clever. I’ve notice on my bicycle that yes, the valve stem, presumably the heaviest part of the wheel, does in fact consistently rotate to the bottom of the tire if allowed to rotate freely. So that seems like it would work and be easy to implement, if you could come up with a method that allowed the wheel to rotate freely enough, as some of the posts seem to confirm indeed you can. Another idea I thought was very clever – Wha Who is who posted it – was the home-made pipe/cable balancer.
So nobody has ever tried the float-the-tire-in-water technique? I wonder if tires even float in water, what with the weight of the wheel. Even if the didn’t, the auto-scientists here would figure out a way to make a heavier than water wheel float I expect …
I can’t imagine how hard this would be . . . a tire in a tub of water would look relatively even I wold think, and measuring now low one side as to the other? Tough, I would think. Get the bubble balance set-up Tester mentioned. I’ve used them before and they are simple and pretty accurate, short of the new stuff. Good luck! Rocketman
About three decades ago, we had a company picnic at this place I worked where one of the activities was to design and build a raft to compete in a race. One “engineering” group actually brought 4 mounted tires from a bug or something and expected them to float their platform. They started by tossing the wheel/tire combos into the water and as everyone else expected, they went straight to the bottom without hesitation…they never did live that one down…
For a DIY solution, what does everyone think about fluid balancing? Pour some antifreeze in the tire, and it’s supposed to distribute itself so as to naturally balance the tire.