Can’t seem to find a tire shop that balances tires and uses strip weights, most use clamp on zinc coated and they’re only balancing the outside, i know that they’re not going to put a clamp on weight on the outside when you have 20” aluminum factory rims, I don’t want to end up at the dealership and take my wallet for a balance spin and empty my wallet, I thought I was getting it done by discount tire but they ended up with clamp weights when they said they have the strip weights, truck has a weird intermittent shimmy at 48-50 mph, took back to wally world where I bought the tires from they just rebalanced them send me on my way good for a bit and shimmy returns and again let them know and the same dancing song plays over and over I’m out $600 and 7 months owning these tires.I read here there and most say road force balance and both wally world and discount tire said they do with all their tires. And the kicker the old strip weights from when the truck was new still on there wt… they both don’t believe me. In anyone’s opinion think I’m right the tires need the proper strip weights used to get the correct balance of these tires and rims that are on my truck
Hello, I am a former Tire Industry Association Certified Instructor and owned small family, quality tire business. We didn't bang out jobs, quality was a focus, not quantity as with the chain businesses. When a customer would come in asking me to match Wally World or DT, Mavis, etc. I'd suggest they go to them, knowing that we could not offer quality tires and service for their price. That's not the customer segment in which we were successful
Based on reading through your comments and that of others.....here's my offering;
1)Road Force Balacing is an excellent tool when operated properly. Properly meaning, when forces are excessive for the particular size tire being balanced, tire and wheel matching is a MUST. In order to achieve a satisfactory balance your RFB should be 10-14 or below. 20 can be felt. I typically shot for 10 or less. To achieve this tire and wheel matching is a must as well as careful and meticulous weight placement and sizing (meaning weights may have to be cut vs using the 1/4 oz. increments to which they are manufactured). I've dynamically balanced tires on a simple slow speed split plane balancer, used its matching, then put them on an RFB and achieved single digit RFB numbers. The key is...attention to detail (matching, weight placement and sizing, removing old weights prior to balancing, cleaning stick on surfaces with acetone then IPA before placement of weights, which I first put on with masking tape so I can reposition as needed after test balancing, relocation a 1/8 or 1/16" inch can move the dial) and not trying to do a set in 20 minutes.
2) Another consideration is tires being "out of round". RFB compensates for this to some extent by applying pressure. However, when placed on the vehicle, the roller force applied can exceed the weight placed on the tire when installed on the vehicle. A simple test for roundness is to jack up your vehicle, slowly rotate the tire while placing a piece of chalk on the ground just touching the tire tread as it passes the high spot. The key is to hold the chalk perfectly still in all axis. I like using an upside down disposable cup with a hole punch in the bottom into which I inset the chalk then move it along the ground until it touches the tire. Ideally, you should have a complete chalk ring around the tire tread. If not, note the gapping between the chalk and tire tread. More than .050 inch indicates a concern. Tire/Wheel matching will like NOT likely addresss this, unless you have out of round wheels. Which I've only seen when someone bent them.
3) A 3rd consideration is tire ballooning. Balancers don't spin tires as fast as when we drive them. I've personally see where tires with weak side walls will enlarge in diameter when above 50mph. Since the diameter/circumference of the tire is changing, it throws the balance off as compared to the diameter/circumference when balanced. So, while balanced perfectly on the machine, when you drive it is not. I've placed vehicles on lifts, put them in drive, brought the speed up to 70mph and did the chalk touch test. Then brought it down to 45-50, the chalk no longer touches. I've had to reject entire lots due to ballooning. I dumped the brand.
4) A 4th consideration....bringing this up because at one point you said they balanced and then changed....is tire to wheel alignment change. Soap is used to install tires on wheels. It is possible for the tires to be spinning on the wheel. Ford had a major problem with this on new vehicles several years ago. The balance kept changing. Using a grease pencil, as soon as the rebalanced tire are installed on the vehicle, mark the tire and the wheel. Note if these marks ever misalign. If they do, then you have a slippage problem. Too much paste soap used during installation can cause this, mostly with aluminum wheels.
5) 45-50 is the resonant mechanical frequency of the front suspension due to its mass. The slightest imbalance will add enough energy to excite the suspension into movement. If there is a worn component the effects are amplified. Check to ensure ball joints, tie rods, rack and pinion, steering linkages are not even slightly worn.
6) Wheel and Vehicle Mounting surfaces. All too often people neglect that the surface of the wheel hub and wheel mounting face can build up with rust, corrosion, or debris. Once the wheel is removed and reinstalled, this debris can get trapped between the two mounting surfaces causing a wobble like condition. Sometimes, when a wheel is removed, the rotor will loosen, and debris gets between the rotor and the hun. Effectively causing a wheel wobble similar to that if debris was on the wheel/rotor mounting surface. Although only slight, it has a major impact when extended out 14" to the outside diameter of a wheel. A simple expertiment of putting a paper match stick between the balancer mounting flange and the wheel changes the balance by 2oz. 2oz is 8x greater than when trying to balance to within 1/8 oz to achieve the low RFB numbers I speak of. The same is true for the balancer mounting surface. If its not clean, then you are misbalancing due to the effective wobble. In our shop, we wire wheeled every possible rotating mounting surfaces before installing replacement tire/wheels. Volume oriented shops don't even know what this practice is.
IMO places like Walmart, DT, Mavis, or any large tire chain typically hire inexperienced folks, hand them off to someone who has been there a while but never had any formal training and a taught "this is how ya do it", not "this is the proper way." Also, tire manufactures grade their products, within the same tire brand and model. Lower grade = go to the lower paying retailers. On top of this, I've found that Coopers are problematic for the exact reason you are having, especially if you are a vibration sensitive driver. Furthermore, the Industry groups customers in to 3 types; Price point focused, Brand focused, and Quality focused (will pay extra for the time needed for the service). When there is a disconnect in the customer type and the customer outcome expectations, situations such as yours exists. Your tires and your service provided exist solely because of price point focused customers, but it sounds like you are looking at factory balance expectation of a quality focused customer.
Above I've offered some things you can check on your own. However, IMO, do yourself a favor and find a High End tire shop which deals in expensive cars and tires where the owners are willing to pay the buckaroos to have a job done right and leave with a smile. Take your vehicle there, explaining what you've been experiencing. Let them diagnose it for you. Be warned and be prepared to buy a new set of tires and pay for the right balancing and installation job.
