Common Mounting and Balancing Mistakes
Success in a tire bay, as in any workplace, starts with mastering the basics. We’ve gathered tips from four tire equipment manufacturers to solve these everyday mistakes.
Tire Changing/wheel Balancing mistakes
Bead not properly placed on the mount head
The number one cause of complications and tire damage is not placing the bead properly on the mount head. But in most cases, the tire will be damaged if a very thick bead or other conditions prevent it from climbing up over the mount head. “At that point you can cut the tire either from the rim or from the mount head itself.”
Not adjusting for clad wheels
Although not as plentiful as five years ago, clad wheels are still found on many vehicles. The plastic face of the clad wheel can reach the edge of the tire.
“All of your machine interfaces where you might be doing work on that rim when you are in the tire changing process are at risk. You can adjust for it and the machines are fully capable of it. In fact, we’ve changed our mount head design to be very forgiving for clad wheels. But if you don’t identify the clad wheel, you can’t take the countermeasures.”
Innovating an error-proof process
What does that mean for a shop? “More sensors, more cameras, more machine vision, knowing what the wheel is, understanding what the wheel is, and automation wherever possible to make sure processes, where they can be formalized, are followed,” explains Liebetreu.
Internally clamping a black wheel
Table top tire changers quickly and easily grab wheels but leave marks on the inside of open spoke black wheels. “If you leave a bite mark and break the black paint or powder coating off the inside a black wheel with an open spoke design, the vehicle owner will be able to see it,” says Liebetreu.
Careless weight placement
Large wheels create problems when positioning clip-on weights. If the wheel is large, it is hard for the operator to tell if he is placing the weight straight above the spindle. But non-clip applications involving tape weights are an extra challenge.
“A lot of operators use the balancer’s automatic weight placement. If you are doing a tape weight on the inner plane, it will be pretty far against the spokes, but certain wheel profiles make it tricky,” says Liebetreu. The outer plane is closest to the operator and usually easier to do. “But sometimes folks put the weight in crooked or off a few degrees. The problem is the closer those weight planes get together on a wide wheel, the harder it is to get the answer right.”
Not centering the wheel on the balancer
Sometimes worn equipment or cones cause a tire to not center correctly on a balancer. But usually failure to center the tire is due to shortcuts and poor practices. Front coning is a big culprit. The back of almost all wheels is machined for centering while the front of the wheel is to be used for the center cap.
“If you have a lower-end machine you basically have to watch for that yourself or watch for a weight answer that just doesn’t seem logical. Many of our balancers have a more manual version of centering where you clamp, you rotate 180 degrees and reclamp. If you get the same answer for the balancer then you know it is the wheel that is out of round. If you get a different answer then you know the clamping is the problem.”
Not using a flange plate on a clad wheel
The risk of damaging a clad wheel is greater on a wheel balancer than on a tire changing machine. “If you don’t use a flange plate, if you just clamp on to that plastic wheel face, you are going to damage it. And you are not going to get a good clamp because that plastic is just going to give,” says Liebetreu.
Liebetreu shared ways to avoid the most common mounting and balancing mistakes during Modern Tire Dealer’s recent visit to Hunter’s headquarters in Bridgeton, Mo.
Failure to validate the wheel is centered
Back-cone mount and use a flange plate from the front whenever possible to best center the wheel. Some very wide wheels and larger light truck wheels may require spacers and larger cones to be front cone mounted. When in doubt, use a centering repeatability check to validate the wheel is centered.
“To validate the wheel is centered, the process is simple, mostly unknown and rarely done,” says Scribner. Clamp the wheel and take a balance measurement. Note the location and the amount of weight required to balance the wheel. Unclamp the wheel and reposition the adaptors and the wheel to a different clock position, reclamp the wheel. Take a second balance measurement. The weight amount and location should repeat closely to within the smallest round-off incremental size of wheel weight used.
Failing to center the wheel
Centering the wheel on the balancer is the critical first step to success in wheel balancing. Unfortunately, it is also the most common step to be overlooked.
Vanderheyden recommends collets instead of cones. “Wheels should be centered from the inside hub bore center only, not from the outside or against the hub nut. This ensures that the wheel is centered the same way it centers when it is on the vehicle.”
Not correcting residual imbalance
When balancing certain assemblies in dynamic mode, a certain amount of residual static forces can be created inadvertently; this can cause a vibration or customer comeback.
“A balancer that can quickly identify this residual imbalance and prompt the user to correct it before the tire is mounted back on the vehicle is a necessity for today’s vibration-prone vehicles. Counter balancing all static and dynamic forces down as low as possible is a requirement,” says Vanderheyden.
Not using pin plates
Pin plates or flange plates are a necessity to protect plastic cladded wheels and to center heavy truck wheels. A pin plate utilizes the wheel’s lug holes to be certain that even force is applied against the outside of the wheel when mounting in order to aid in centering. For heavy wheels, it allows the wheel to “climb” the collet uniformly to make centering on the tooling a snap.
Incorrect clamping which causes wheel damage
“All aluminum wheels should be externally clamped, but often what we see is that technicians will try to save time by internally clamping the wheel,” says Jones. This causes scratches on the inside of the wheels. Using a center clamping changer will prevent this type of damage.
Tire changer/Wheel balancer Mounting mistake
Inside clamping alloy wheels
On table top tire changers, avoid using clamping jaw teeth to inside clamp alloy wheels, which damages the rim. “Always outside clamp alloy wheels. Bead press systems are much easier to push the wheel downwards with the tire bead loosened when it is outside clamped,” says Scribner.
Reversed wheels clamped facing upwards
To prevent tire and rim damage, reversed drop center wheels can only be demounted and mounted when clamped upside down so the drop center balcony side is closest to the flange always facing upwards. “A wheel with negative offset is always suspect,” says Scribner. “Look inside the tire when bead loosening and find the drop center while lubricating the tire using a liquid lube and preparing the wheel for demounting.”
Too much or too little lubrication
Scribner recommends a lubrication product that is a vegetable oil-based paste with a short shelf life applied by a brush. Lubricate the rim barrel, rim drop center balcony edge and bead toe edge area. Avoid rim bead seats and tire beads.
“Do not use too much lubrication to prevent tire slippage. Index the inner tire sidewall to the rim edge when done balancing to be able to check for rim to tire slippage if vehicle returns. Too little lube and the tire doesn’t seat properly, and eccentricity problems can cause ride disturbance issues.”
Failure to minimize wheel RFV eccentricity
Scribner says to reduce RFV (radial force vectoring) eccentricity and provide a smoother ride, use a tire rapid inflation technique as recommended best practice by many tire manufacturers. The three steps are 1) with the valve core removed, perform a rapid seal, seating and inflation, 2) deflate the tire, 3) re-inflate the tire and install the valve core and bring air pressure to placard inflation pressure.
Mounting mistake: clamping from inside
Many technicians clamp wheels from the inside, which can cause the jaws to leave marks on the inside of alloy and steel wheels. Today’s wheels, whether alloy or steel, should only be clamped from the outside in. “This not only prevents the wheel from shifting or walking during demount, it can also stop the wheel from spinning on the clamps during mounting of the top bead.
Metal-to-metal contact
When changing a tire on a wheel with black paint or powder coating, having the mount demount head adjusted properly along with using a poly head instead of metal is a great way to eliminate metal-to-metal contact that can scratch or mar coated or painted wheels. This is a very common and costly mistake and is easily avoidable by using the correct technique and accessories.
Incorrect use of bead loosener
When using a side-mounted bead loosener, in the interest of speed, many technicians will place the side shovel too far from the bead of the tire, which can cause tire damage. Technicians may also place the shovel too close to a TPMS sensor causing breakage. Paying close attention to the position of the bead loosener relative to the wheel assembly is critical.
“A precise bead loosener that is hand controlled and has power in and out control gives the user a great amount of control when loosening beads, eliminating these types of issues,” says Vanderheyden.
Not using lube when demounting
“Almost every operator I see does not use lube when demounting a tire,” says Jones. “They say it takes too long to apply lube, but then they struggle to get the tire off the wheel, which costs them time and can damage the tire.”
It’s important to use the right amount of lube, too. “When you don’t use enough, you can damage the tire and wheel. If you use too much, you can create tire-to-wheel slippage and encounter vibration problems.”
