Weights on outside of wheels

[Denise S.]

Just bought four brand new tires for my 65 corvette and had them balanced, they put the weights on the outside. Does it make any difference? Do I need to have it redone? I will not have be having the car judged at anytime in the future.

[Joe L.]

Re: Weights on outside of wheels

Just bought four brand new tires for my 65 corvette and had them balanced, they put the weights on the outside. Does it make any difference? Do I need to have it redone? I will not have be having the car judged at anytime in the future.

Denise-----

There are only two reasons to not place weights on the outside rim of the wheel:

1) For originality purposes (i.e. Flight Judging, etc.)

2) If they interfere with the installation of wheel covers.

If none of the above applies, it's perfectly fine to have weights on the outside rim. In fact, it can involve a superior balance. A good DYNAMIC balance requires the placement of weights on both the inside and outside rim (or, placement of adhesive weights at the centerline of the wheel). The factory only STATIC balanced the wheel/tire assemblies.

[Michael J.]

Re: Weights on outside of wheels

It usually is far superior a balance job, as Joe says, to put weights on both sides. I usually insist they do if possible, some of my wheels don't have a lip to allow it and thus the stick-on weights are on the inside. I don't even allow them to put weights inside only on my Top Flight car, I like to drive it long distances so need a good balance and don't care about the points deduct, better to be safe and a good driver than worry about silly points.

[Denise S.]

Re: Weights on outside of wheels

My thanks to both of you. Joe, I'm sure you would remember my husband Tom Stanton, he passed away 2 years ago and I decided to keep the Corvette and enjoy it. I knew he was always on this site getting advice especially when he had the 69. I remember him telling me how much help you were to him.

[Joe L.]

Re: Weights on outside of wheels

My thanks to both of you. Joe, I'm sure you would remember my husband Tom Stanton, he passed away 2 years ago and I decided to keep the Corvette and enjoy it. I knew he was always on this site getting advice especially when he had the 69. I remember him telling me how much help you were to him.

Denise-----


Yes, I remember Tom here on the TDB very well. I miss his posts.

[Roger P.]

Re: Weights on outside of wheels

I was curious if the wheels could be balanced on the car or if they had to be removed to be balanced. I am used to getting new tires and each wheel being balanced on a machine off the car. I want to re-balance my tires (now with about 4,000 miles) and would prefer not having to remove the knock-offs and go through the re-tightening procedure. If they have to be removed to be balanced, should the tires be rotated front to back... even with knock-offs?

Thank you,
Roger (50141)

[Michael W.]

Re: Weights on outside of wheels

Roger there are on car balancing machines available, but I don't think they'd work too well with the rear wheels as the posi rear end would have entire drive train whizzing around at a good rate of speed. The trailing arms would need to be maneuvered into normal ride height position on both sides.

I'd just leave well enough alone and forgo the balancing unless it's actually required and then just go for conventional off car methods.

[Duke W.]

Re: Weights on outside of wheels

Off-the-car "spin balancers" balance the tire both statically and dynamically. Static unbalance causes the tire to vibrate up and down, and this is typically felt at the suspension's natural frequency, which usually occurs in the 60-70 MPH speed range.

Dynamic unbalance means that the tire is unbalanced across its width, which can cause the tire to wobble. This is often felt as a slight "wiggle" in the steering wheel.

Vintage Corvette wheel/tire assemblies were just statically balanced with weights on the inside. If you want the tires dynamically balanced, but don't want weights on the outside, use stick on weights inside the spider. Modern off-the-car spin balancers can also be set to balance statically, only, with weights on the inside, and this may be satisfactory for vintage cars with relatively narrow wheels/tires.


The best modern balance machines have a tool that allows the tech to measure the distance each weight plane is from the circumferential centerline of the tire, so there's no Kentucky windage involved as was the case with older machines that assumed the weight planes were equidistant from the wheel circumferential centerlilne.

Most modern wheels and tires are "matchmarked". Line up the red mark on the tire with the white or grey dot on the wheel, which may be tough to see. If the wheel is not matchmarked, line up the yellow mark on the tire with the valve stem.

Some balancing systems such as the Hunter GSP 9700 can also measure out-of-round of both the tire and wheel, and IMO it's good to have this usually extra cost service done when new tires are installed, whether they are matchmarked of not, to insure that the assembly has the least out of round. The machine will indicate how the tire should be indexed on the wheel to achieve the roundest assembly.

An out-of-round condition of more than about .030" can cause a vibration at highway speed that is similar to static unbalance. If such occurs and the balance machine indicates "zero/zero" for necessary weight addition, then there is a good change that the problem is out-of-round and further attempts to rebalance the wheel/tire assembly will be fruitless.

The old on-the-car balancers only static balanced, but they compensated for significant drum or disk out-of-balance as long as the wheel remained indexed on the hub at the same position. They are considered obsolete due to tighter drum and disk balance by OEMs and are getting hard to find.

Duke

[Paul J.]

Re: Weights on outside of wheels

I was curious if the wheels could be balanced on the car or if they had to be removed to be balanced. I am used to getting new tires and each wheel being balanced on a machine off the car. I want to re-balance my tires (now with about 4,000 miles) and would prefer not having to remove the knock-offs and go through the re-tightening procedure. If they have to be removed to be balanced, should the tires be rotated front to back... even with knock-offs?
Thank you,
Roger (50141)

Boy, that brings back memories from 40 years ago. Putting that electric roller under the tire to spin it up and then setting the balance. Pretty scary stuff.

Roger, if you balance the tire on the car you balance out the eccentricities of the hub, and as Michael said, the drivetrain on the rear. It is a superior balance, but you cannot rotate the tires and they will be out of balance if you remove them and do not clock them on the hub the same way that they were balanced. In addition, with knock offs you will probably knock them a little bit out of balance every time you tighten the spinners.

[Duke W.]

Re: Weights on outside of wheels

I was curious if the wheels could be balanced on the car or if they had to be removed to be balanced. I am used to getting new tires and each wheel being balanced on a machine off the car. I want to re-balance my tires (now with about 4,000 miles) and would prefer not having to remove the knock-offs and go through the re-tightening procedure. If they have to be removed to be balanced, should the tires be rotated front to back... even with knock-offs?

Thank you,
Roger (50141)

The first question I would ask is: Why do the tires have to be rebalanced with only 4000 miles of service? Have they developed an objectionable vibration?

Tire rotation will extend tire life and even out the unique wear patterns that can develop on the four corners, particularly on cars with IRS.

Divide the expected tire life by four, and that should be your rotation schedule. If the tires are not directional, start with an X pattern for the first rotation, followed by front to rear for the second, and then X for the third.

For example, if expected tire life is 40K miles then the rotation schedule should be 10K miles, and at the end of the final rotation period, each tire will have spent 10K miles at each corner. Some improvement in tire life may be had if the rotation schedule is halved to 5K miles.

If the tires still have service life at 40K miles they can be rotated front to rear, and they will be back in their original postions when newly installed with either the 10K or 5 K mile rotation schedule.

Duke

[Roger P.]

Re: Weights on outside of wheels

Hi guys. I was away this week, so I'm sorry for not responding sooner. I appreciate your opinions on wheel balancing and tire rotation. I really have no reason to balance the tires during most driving conditions, but I do have a vibration under heavy acceleration in first and sometimes second gear. We discussed this in the past, and several ideas were suggested. All front end components have checked out to be in good condition -- only the front stabilizer bushings show some wear. One suggestion was to check the wheel balancing. So, could worn front stabilizer bushings cause this type of vibration? Could a wheel being out of balance cause this type of vibration? Paul, you suggested that I check the tie rod ends. Per your recommendation, I had them checked and were told they were in good condition. Again, I don't have any vibration at any speed other than when starting out with HEAVY acceleration. Any thoughts? With knock-offs, should I do an "X" rotation or just front-to-back rotation?

Roger (50141)

[Duke W.]

Re: Weights on outside of wheels

A vibration only under high acceleration in first gear when the drivetrain sees maximum torque would indicate a possible driveline problem such as a worn U-joint, broken/deteriorated engine, trans, or diff mount, or even and improperly torqued wheel.

Duke

[Paul J.]

Re: Weights on outside of wheels

Roger,

As I recall, you got some good information on that other thread. Whatever the problem is, the components have not yet failed, so it is now a process of elimination. Concentrate on what Duke recommended, but remember that its harder to find it if its not broken or close to it. For example, U-joints squeak when they're closer to failure, but can have varying amounts of play and can vibrate long before they squeak.

As much as I hate to see old threads come back I wish that you would have tied this into that other thread so we could have easy access to the information and work the problem.

Paul

[Stuart F.]

Re: Weights on outside of wheels

Denise;

Is that really you? And you say you decided to keep the 65. That's great!! So good to hear from you on the TDB. I've thought of you and Tom often, and was intending to check up on you again soon. Do you still have the red C-6?

Regards;

Stu Fox

[Roger P.]

Re: Weights on outside of wheels

Hi Duke and Paul,
Thank you for your replies. The U-joints, engine mounts, front end components, and knock-off spinners have all been visually & physically inspected and were found to be in good condition. As you said Paul, something may be on its last leg and just isn't giving us a clue yet. The only things that were suggested in the old thread that I haven't tried yet - because it required actually doing it and not just inspecting it - was tire balancing and reducing the rear wheel camber. When I saw this thread on wheel balancing, it reminded me about the vibration. I recently installed new front shocks (they were shot) and rear leaf spring cushions (they were only 2 years old, but looked dry-rotted) and, although the heavy acceleration vibration isn't completely gone, it isn't as severe as it was before. I also don't remember having that vibration a couple of years ago before I rebuilt the rear suspension (trailing arms, strut rods, mounts, shocks, etc.). It sounds like wheel balancing wouldn't be associated with a vibration that only occurs under heavy acceleration, so I am beginning to think that it could be from too much rear camber. In the older thread, someone posted a bulletin from GM/Chevrolet which suggested to reduce the rear camber to eliminate this type of vibration. If I remember correctly, it said to bring it down close to "0". My front & rear camber, before replacing the front shocks & rear leaf spring cushions, was within spec from what I have read: left rear = -0.32* and right rear = -0.43* / left front = +0.48* and right front = +0.48*. Could the alignment be the issue?

Thanks again,
Roger (50141)