The Gearhead's Pitstop
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Hamartia Antidote
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Is this to improve 1/4 mile times or just everyday use? (ie Nitrous would be just 1/4 mile, supercharger would be for everyday use)
VCheng
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Anything and everything related to wheels would qualify.
(Or not. If this thread dies, it dies.)
VCheng
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Here is an older post from another website that I frequent, as an example:
PROPER WHEEL BALANCING TECHNIQUE
While the need for periodic wheel balancing is often emphasized, the proper technique to balance them is not often known. I wanted to present some of my thoughts in this regard.
Wheel Balancing is of two main types: static and dynamic.
Static wheel balance is done with the wheel put on a machine that finds its heavy spot and applies an equal weight opposite to it. This type of balancing removes the shimmy caused by the heavy spot. This type of balancing can work very well for narrow tires, such as motorcycle tires, but wider car and SUV tires require the second type of balancing to remove the wobble caused by heavy spots away from the center line of the wheel and tire assembly.
Dynamic wheel balance is done with a machine that spins the wheel and tire at a high speed and calculates out the weights to be applied towards the inside and outside of the wheel to cancel out both shimmy and wobble types of vibrations. More expensive machines also apply an extra roller to put a force on the tire to mimic the weight of the vehicle to take into account variable stiffness of the sidewalls. This type of road force balancing is usually recommended for high end cars operated at very high speeds, but most cars will not need it. (I am leaving out on-vehicle balancing for brevity since it is not used often.)
The should be noted that the balancing machine itself usually needs to be calibrated for accuracy at periodic intervals. Each manufacturer specifies the procedure and provides the calibrating slug as well. It is important to ask the shop if they have the necessary information and equipment to calibrate their machine.
There are two basic types of wheels: hub-centric and lug-centric. Hub-centric wheels are centered on the axle by their hubs, while lug-centric wheels are centered by their lug nuts, and not by the central hub. The correct method to mount wheels on the machine depends on which type of design they are.
The easiest way for shop to mounts the wheels is by front-coning, which saves them time but is the least accurate method. In this method, the wheel is mounted on the shaft and the centering cone is slid over from the outside and tightened. A better way to use is back-coning, where the cone is slid on the shaft first, and then the wheel is tightened over it by a special adapter on the outside. This method is preferred for hub-centric wheels and is not recommended for lug-centric wheels.
The most accurate method to properly mount the wheels for balancing is by using a back-cone and a proper flange adapter where the wheel is held in by slugs of the proper size in the lug nut holes from the outside.
A good shop will be able to differentiate between the two types of wheels and have the proper cones and flange adapters to accurately mount the wheels.
After a wheel has been properly mounted on the machine, the next step is to do a centering check. The wheel is spun and location noted. Then it is loosened and rotated 180 degrees on the shaft and tightened again before being spun. This will enable to machine to determine if it has been centered properly or not. Most shops skip this step to save time, and it is not the proper technique.
Then, it is figured out where to apply the weights, depending on the type. Some wheels use clip-on weights, some use stick-on weights, and some can use a combination. Stick-on weights are best because they do not damage the wheels in the long run, while clip-on weights can trap salt and debris and initiate corrosion, especially if they are hammered on or pulled off without proper care with the correct tools. Clip-on weights must be of the proper cross-section, for example, most Japanese steel wheels use the FN profile. A good shop will have the proper profile gauge and the necessary weights in several sizes to do a good job.
Some machines can even figure out how to apply all the weights from the inside so that no weights are visible from the outside, and also how to hide the weights behind spokes. Ask the shop if they can offer these options.
For stick-on weights, make sure that the surface is properly cleaned and dried before they are applied, otherwise they will not stick and may fall off, causing vibrations. Also make sure that all the old weights are taken off before the wheel is spun on the machine, otherwise you will end up with a ugly mass of weights on the wheel.
The last step is to spin the tire/wheel on the machine and apply the indicated weights. Then the tire is spun again and the machine should indicate a zeroed out condition for both inside and outside weights. Usually a second round of corrective weights are needed before the error is less than 10 grams or so. This accuracy is good enough for 100-140 kph. Higher speeds will require the errors to be below 5 grams or so, depending on the size and weight of the tire, and the design of the vehicle suspension.
I wish everyone smooth motoring!
PROPER WHEEL BALANCING TECHNIQUE
While the need for periodic wheel balancing is often emphasized, the proper technique to balance them is not often known. I wanted to present some of my thoughts in this regard.
Wheel Balancing is of two main types: static and dynamic.
Static wheel balance is done with the wheel put on a machine that finds its heavy spot and applies an equal weight opposite to it. This type of balancing removes the shimmy caused by the heavy spot. This type of balancing can work very well for narrow tires, such as motorcycle tires, but wider car and SUV tires require the second type of balancing to remove the wobble caused by heavy spots away from the center line of the wheel and tire assembly.
Dynamic wheel balance is done with a machine that spins the wheel and tire at a high speed and calculates out the weights to be applied towards the inside and outside of the wheel to cancel out both shimmy and wobble types of vibrations. More expensive machines also apply an extra roller to put a force on the tire to mimic the weight of the vehicle to take into account variable stiffness of the sidewalls. This type of road force balancing is usually recommended for high end cars operated at very high speeds, but most cars will not need it. (I am leaving out on-vehicle balancing for brevity since it is not used often.)
The should be noted that the balancing machine itself usually needs to be calibrated for accuracy at periodic intervals. Each manufacturer specifies the procedure and provides the calibrating slug as well. It is important to ask the shop if they have the necessary information and equipment to calibrate their machine.
There are two basic types of wheels: hub-centric and lug-centric. Hub-centric wheels are centered on the axle by their hubs, while lug-centric wheels are centered by their lug nuts, and not by the central hub. The correct method to mount wheels on the machine depends on which type of design they are.
The easiest way for shop to mounts the wheels is by front-coning, which saves them time but is the least accurate method. In this method, the wheel is mounted on the shaft and the centering cone is slid over from the outside and tightened. A better way to use is back-coning, where the cone is slid on the shaft first, and then the wheel is tightened over it by a special adapter on the outside. This method is preferred for hub-centric wheels and is not recommended for lug-centric wheels.
The most accurate method to properly mount the wheels for balancing is by using a back-cone and a proper flange adapter where the wheel is held in by slugs of the proper size in the lug nut holes from the outside.
A good shop will be able to differentiate between the two types of wheels and have the proper cones and flange adapters to accurately mount the wheels.
After a wheel has been properly mounted on the machine, the next step is to do a centering check. The wheel is spun and location noted. Then it is loosened and rotated 180 degrees on the shaft and tightened again before being spun. This will enable to machine to determine if it has been centered properly or not. Most shops skip this step to save time, and it is not the proper technique.
Then, it is figured out where to apply the weights, depending on the type. Some wheels use clip-on weights, some use stick-on weights, and some can use a combination. Stick-on weights are best because they do not damage the wheels in the long run, while clip-on weights can trap salt and debris and initiate corrosion, especially if they are hammered on or pulled off without proper care with the correct tools. Clip-on weights must be of the proper cross-section, for example, most Japanese steel wheels use the FN profile. A good shop will have the proper profile gauge and the necessary weights in several sizes to do a good job.
Some machines can even figure out how to apply all the weights from the inside so that no weights are visible from the outside, and also how to hide the weights behind spokes. Ask the shop if they can offer these options.
For stick-on weights, make sure that the surface is properly cleaned and dried before they are applied, otherwise they will not stick and may fall off, causing vibrations. Also make sure that all the old weights are taken off before the wheel is spun on the machine, otherwise you will end up with a ugly mass of weights on the wheel.
The last step is to spin the tire/wheel on the machine and apply the indicated weights. Then the tire is spun again and the machine should indicate a zeroed out condition for both inside and outside weights. Usually a second round of corrective weights are needed before the error is less than 10 grams or so. This accuracy is good enough for 100-140 kph. Higher speeds will require the errors to be below 5 grams or so, depending on the size and weight of the tire, and the design of the vehicle suspension.
I wish everyone smooth motoring!
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