How do I calibrate a Coats 700 tire balancer?

The most common issue is tires and you said that it was speed balanced? How long ago? By whom? When tires are balanced there are weights that are clamped to the rim. If the weights are loose and fall off, the balance does no good. The speed is another issue, tires are balanced for a certain speed and until you reach that speed, it is usually not in balance. Lastly it could be brake rotors or a CV joint or bearing that is bad.

You need to explain this problem better. At this point I assume it is with your tires. Do you have steel or alum. rims are they stock or are they 22 inches more or less. Is the tire store having the problem with your car? FYI tire balancing needs to be done with dynamic and static balancing. If someone is trying to balance tires using stick-on weights so the weights won't show on the outside of the rim.? If so this is wrong. Weights should be installed on the outside and the inside at the edge of the rim where it meets with the tire. Hammered on weights not stick-on's. This needs to be done to insure dynamic and static balance is preserved. If you don't like the looks of a weight on the outside of the rim then you will have to live with the vibration. At the outrageous pricing of tires I prefer to see the weight.

Did you ever figure out what it was Brian?I have the same issue with my Coats machine.

Sound like out of balance tire or a separated tire or bearing but, the two most common causes are the ones. I suggest visit some tire shop and would like to have the tires inspected and balanced.

Some customers may comment on shaking/vibration in the steering wheel, floor or seat while driving at highway speeds (typically between 60-72 mph (96-115 km/h)) on smooth roads.

These specific vehicles may be sensitive to various rotating mass assemblies, especially if they are considered to be out-of-balance.

In order to correct this:
1. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary.
- Missing balance weights
- Bent rim flange
- Irregular tire wear
- Incomplete bead seating
- Tire irregularities
- Mud/ice build-up in wheel
- Stones in the tire tread

2. Set the tire pressure to 30 psi (205 kpa) COLD.

3. If the road test indicates a shake/vibration still exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic balancer. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as possible.

Important: Some GM dealers may have a Hunter GSP9700 Road Force Balancer. This will simplify Step 5 by not requiring dial indicators. If a Hunter GSP9700 machine is available, it may also be used to measure the radial force of the tire/wheel assembly. A guideline here is 18 lbs or less.

4. While on the balancer, measure wheel runout. If radial or lateral runout exceeds .020 in (0.50 mm) for aluminum wheels (.030 in (0.76 mm) for steel wheels), replace the wheel.

5. After confirming wheel balance and wheel runout, if any changes were made, road test the vehicle again.

6. If the smooth road shake/vibration still exists:
Important: The completed worksheet must be attached to the hard copy of the repair order.

Record Radial Force Variation readings if you have access to Hunter GSP9700 Wheel Balance equipment. Use the worksheet shown in this bulletin to record the readings.

If one or more of the tires have RFV readings in excess of 18 lbs, match mount the tires to get below 18 lbs. Readings of 12 lbs. or less are preferable for critical customer concerns.

If the RFV can not be reduced to an acceptable level, replace the affected tire with one obtained locally.

The screened tire program is no longer in effect for Bridgestone/Firestone, Goodyear and Michelin. Low speed screened tires are available from Continental General only, and only for the Buick LeSabre.

Road test the vehicle to ensure the shake/vibration has been resolved.

7. Replace both lower control arms on vehicles built prior to the VIN breakpoints shown. The new lower control arms may provide an incremental improvement to the vehicle ride. Customers who have become "tuned in" to the shake condition may still feel some shake in the vehicle after the new lower control arms are installed.
Refer to Lower Control Arm Replacement, (refer to the Parts Information table below for SI document ID numbers).

Important: THE CONTROL ARMS SHOULD ONLY BE INSTALLED ON VEHICLES IF, AFTER THE TIRE AND WHEEL DIAGNOSIS AND REPAIRS HAVE BEEN PERFORMED, THE VIBRATION CONDITION STILL EXISTS.

Hope this helps; also keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using Fixya, and have a nice weekend.

If they have been spin balanced properly, then the wheels and/or tires are out of round or you have a bent rim. The right way to check this is to use a dial indicator and measure the runout of the tire and the rim. A good tire shop should have the equipment to measure this. There is always some radial runout (difference in distance between the center of rotation and the outer surface, both on the tire and on the wheel). When the tires are mounted on the rims, If the high spots of the tires happen to be aligned with the high spots of the rims, this makes the total runout worse. If the high spots of the tires are aligned with the low spots of the rims, the total runout is better. There is a limit on how much runout is acceptable to give a smooth ride. The tire shop should also measure lateral runout, which is the side-to-side variation in the wheel as it spins, or "wobble". If excessive, this would be a sign of a bent rim. Also, with the vehicle jacked up so the weight is off the wheels, you should check for any looseness in the suspension and bearings, which can also cause vibration.

your wheels more than likely needs to be balanced one or more are out of round if you had the tires rotated before the alignment this would make the vibrating more noticible.but balancing should solve your problem.

the first thing i would do is have the wheel balancing checked and also have the tires checked for hops in them while spin balancing.

They ALL Must be Checked for Debris Behind the RIM < or Between Rim & HUM this is a Common Misshap upon Switching Wheels Also Be SURE they ALL are SET BACK against there Hubs.

Have you had the tires balanced

some things to do are to check that all the tire sizes match. if they do not you need to correct that. next is to measure the outside of each tire.... the diameter has to be pretty close on each axle. next is to roll each tire down the drive way.... if it wobbles instead of rolling straight one of the belts in the tire has shifted... replace it. next make sure you have the proper air pressure in each tire per axle

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