I have the Harbor Freight bubble balancer.
I put my last fully used-up set of four mounted wheels on it, just to see what happens.
There's a circle, as you know, and the tiny bubble is supposed to be in the circle. The bubble is much smaller than the circle. You could get maybe five bubbles inside the circle.
The wheels/tires were Hoosier mounted and balanced at our last National.
One wheel came up perfect, the bubble right in the center of the circle. Two wheels came up good, with the bubble inside the circle but not in the center.
One wheel came up not so good, with the bubble just outside the circle.
Is this as good as it gets from the tire guy? Should I check the bubble machine? Is it possible to calibrate it?
Spin balancing is preferred for high speeds, I think. But a bubble balancer ought to do a decent job. I am an autocrosser, and my harbor freight bubble balancer works great for me.
Calibration: Yes, you can. With no wheel on it, the bubble should be in the exact center. There are three screws on mine to adjust this.
Checking: You can check the balancer by looking at the bubble with a wheel on it. Mark the "heavy" side of the tire/wheel with a piece of chalk (if you have a weak memory, as I often do). Pull the wheel off, rotate it 90 degrees, and put it back on the balancer. The heavy spot should have moved with the wheel. A couple more times to go all the way around.
The bubble on my balancer fills up much of the circle. . .
I have all my tires balanced with Road force balancing …I also put my DB4 on a four wheel laser alignment…it is great at speed and the difference in balancing is truly unbelievable.
Good explanation of it RFB
Smooth-rolling tires and wheels can be the difference between having a vibration-free driving experience or a shaky one. If the tire and wheel tolerances are not examined, corrected, or are allowed to "stack up" rather than "cancel out" each other, the possibility of a balance or road force induced ride vibration exists.
Tires are made up of internal beads, body plies and belts that are encased in rubber, assembled and cured. Alloy wheels are cast, cooled and machined. And even though they both are built to tight tolerances, there is bound to be some unavoidable weight imbalances during the manufacturing process.
When you consider that a typical passenger car tire mounted on an alloy wheel weighs about 40 pounds, it's amazing that the total amount of imbalance is typically no more than three to four ounces, or about one-half of one percent. So, if the tire and wheel combination isn't balanced with add-on weights, being off even an ounce or two can cause vibration at highway speeds. Heavier tire and wheel combinations, especially those used on light trucks, require more weights to maintain the same low percentage of imbalance.
The GSP9700 Vibration Control System can also measure lateral and radial rim runout (out of roundness or side-to-side movement) to identify and separate wheel runout from tire runout. The system then calculates the contributions of the wheel and the tire to a potential vibration and presents the service specialist with easy-to-follow instructions on the appropriate corrective actions.
Last edited by DB4 Tim; June 13th, 2009 at 11:25 AM.
I've recently mounted a set of Hoosiers and used my HF Bubble Balancer. I could only get repeatablity 3 out of 5 times trying, so I decided to double check.
A local reputable shop had to put their computerized balancing machine on "Fine" (some shops do not have this feature) to find any discrepancy. Even then, only 1 wheel was only off just a 1/4 of an ounce.
Now I think at least my HF Bubble Balancer is OK.
I guess it's like looking at kids on a playground teeter-totters.
Balanced is balanced & you don't necessarily need a computer to tell you that.
__________________ Working hard to enhance my Carbon Fiber footprint....
2011 Stohr F1000 www.Area81Racing.com
Last edited by Revs2-12k; June 13th, 2009 at 9:35 AM.
A note to all this, I have used and been very successful with bubble balancing, I found the difference very noticeable like at Fontana when using RFB....ultra smooth track and long time at wide WOT....
I looked at the Harbor Freight ones last year, and was suspect when I saw the quality.
So- I made a simple one that mimics the motorcycle jobs. I just purchased a shaft and some split blocks from McMaster. I then mount the wheel to the shaft using 2 wheel cones and the split blocks. It rotates on bearings mounted to angle iron, and the heavy side always rotates to the bottom. I used this set-up since before Daytona last year, and did not note any out of balance condition. They only drawback is that this method is time consuming-not as fast as a bubble or spin balance.
I kick myself once an a while because I purchased a used Bada professional bubble balancer from a Goodyear store in Youngstown years ago. The balancing cone sat in a bath of ATF. It worked great. When I moved to FL, I never thought I would race again, so I sold the thing for $35 bucks at our moving sale. I tried finding a used one on Ebay, and they are going for 150-200 bucks plus shipping.
I feel better about my bubble balancer. I have been tempted to bring it to the races, and ask the Hoosier/Goodyear guy to just dismount and mount and let me do the balancing, in order to save a few bucks, but I haven't done that yet.
You know Bob, that's exactly how I balanced the go-kart wheels. It works perfectly and is 100% repeatable.
I was having a terrible problem with the front tires on my DB-1 shaking after 1 or more sessions. I got one of the Harbor Freight bubble balancer. Calibrated it by resetting a wheel 180 degrees then 90 and 270 degrees to get repeated readings. Thing works great. As I come off the track, if there is any front end shake, the tires get balanced. The last time 2.5 oz was added. Next time out, smooth as silk. Takes much less time than taking them back to the Goodyear Dealer and having him do it.
Got to do it inside thou, any wind will upset the process.
Unit is light and packs well.
Cheap fix to the problem.
Wishing you a good season.
I had a problem with my bubble balancer and front panasport c-4's. The wheel/tire combo is not heavy enough to compress the springs and the lack of a complete round lip on the inside where the drive pin holes are made it hard to center the wheel on the balancer head cone.
I made this attachment. It's an old cast iron pully with the spokes cut out mounted to the balancer head with screws. It adds weight and a narrower circle for the panasports to sit on. Now it's cake to get the wheel centered on the balancer cone.
It does take a little time. Takes me just as long to balance as it does to mount/dismount a tire with his Manual Tire Changer.
I'm not sure how accurate we have to get thus a bubble balancer may be fine and probably quicker. Mounting used tires, balancing is always suspect due to build-up. If I ever get a new set of tires, I'd take the time to balance them to the capibilities of the machine.
__________________ AMBROSE BULDO - Abuldo at AOL.com Possibly looking for FF FIT Conversion Candidate CURRENT: Intrepid Siverstone KPV3 Kart GONE: CITATION 87/93 FC, VD RF-85FF , 1981 FIAT Spider Turbo
Last edited by racer27; June 18th, 2009 at 4:30 PM.
I cut an even amount off each spring as well. I wanted to keep somewhat even spring pressure so there would be no wheel tilt. I still had the problem of the wheels not sitting well on the head so I added the pulley.
I almost always mark my valve stem on the tire. This will tell you if you have slippage between the tire and wheel. On my F500, I ALWAYS have slippage on the rear tires at Grattan due to some of the bumps. I just keep flipping the rear tires left and right each session to keep them close to where they started.
Let me start by saying that I no longer represent a tire company in any way. As to bubble balancing, for the typical race track in club racing it is good. I cannot claim one manufacturer over another but we used Coats as mentioned earlier in the thread. You had to ensure the oil level was filled correctly with the right oil. Also, anytime the bubble touched the line we would re-center it. I know that many people will say this or that about spin balancing. At trackside we had many of the competitor's customers come to us for rebalance after they went on track with spin balanced tires. There are many factors to include human error with the spin balancer. Let me explain some of what I was taught.
Assuming you have set up the balancer on a stable and fairly even surface and centered the ring we would check to make sure all old weights were off and that the tire bead was set on both sides. Sounds silly but it happens often enough that a tire bead does not set right. We had different fittings for the balancer for different kinds of wheels to make it sit level on the cone. Mark the sidewall of the tire at the valve to ensure there is no shifting, although the tire will move a little sometimes even if the tire mark does not shift. Our Coats had a little arrow where you were to put the valve on the cone. Place the tire and wheel gently on the balancer. I was never taught the triangualtion method of weighting. Always seemed silly to me, but it is out there if you find an old timer to teach it to you. We had weights cut by 1/2 oz to 3 oz in 1/4 oz increments. We would put the weight on the heavy spot and move it gently until we centered the bubble. We then marked the center of the weight with a tire crayon on the sidewall of the tire. Clean the wheel rim with brake cleaner and a rag. It is very important for the weight to stick. Then place the weight when the wheel is dry. Recheck the balance then take the wheel off and tape with at a minimum, good 100 MPH tape. DO NOT USE DUCT TAPE! It melts off of the wheel. Aluminum tape is very good but it is a pain in the butt to get off of the wheel, to include cuts on your fingertips. After you run the set of wheels on the car, do not be afraid to rebalce your tires. Even if the mark did not move at the valve, often the tire will set on you wheel and have a little bit of weight redistribution. It doesn't hurt to check.
At typical race tracks you can be off as much as 1/2 oz and 90% of drivers will not feel it. That is not to say that you don't strive for perfection though. On tracks with long straights and very smooth surfaces your margin narrows. If your trackside vendor uses a spin balancer ask them when they last time they calibrated it was. If it was not when they took it off of the truck they are wrong. Also if it is mounted in the truck they are wrong. The truck sits on a suspension that moves and can throw the readings off. We calibrated every day and if we got a couple of reports of bad balances. Anything over 3 oz of weight we would spin the tire on the rim 90% and rebalance. If that doesn't work then I suggest you take it back and get another. If you have heavy steel rims, think AS or NASCAR then more weight will be necessary. All of this seems like a lot but it gets done in 3-4 minutes at trackside after a couple of hundred practices I promise. Balance is important, don't stand for incomplete or shoddy work from vendors for the sake of time. Good luck, Dennis, former tire guy.
Hi, I have a Harbor F bubble balancer. With the bubble centered I put the wheel on the balancer. I get a reading, when I rotate the wheel the bubble dosen't follow the first spot but stays in the same direction on the spindle and some may show an increase out balance. Richard
Are you sure that the sharp spike is in the TINY hole in the center of the top "swingy" part? I often have difficulty getting the spike in the hole, so it balances properly. Try twisting the top part, and seeing what the bubble does. If I just set the top part on the spike without trials, weird things happen.
Chris, Yes, I think so. I took care about that. I returned the balancer but this one has the same problem. I,ve used bubble balancers before, American made, that had an arrow where you should put the core. If the guys are able to get a good balance it must be some thing I'm doing or not doing. Richard