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wheel balance

roscoe

Jedi Knight
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About 4000 miles ago I decided to take all of my wheels with new Vredstein tires that I had mounted by hand (yowza, that was big fun using the three little tire irons...). I figured I should have them spun balanced and after reading all I could about how to do that with the splined hubs I found a local shop that could handle it. The result was OK, or should I say not noticeably worse but I was always leery of the amount of weight they used. Today I just finished flipping the tires on the front, due to wear on the outboard edges (next on the list are eccentric bushings for camber adjustment). When I was reinstalling the wheels I noticed that just by observing static balance while mounted on the hub, I could find the heavy side. It was painfully obvious they were significantly out of balance if I included the brake drum, which this procedure did. I proceeded to balance both front wheels this way and removed more than half of the weight AND ended up with the remaining weight in different locations on both wheels. Drove the car and WOW, very noticeable difference. Also found two broken spokes that were not noticeable until I pulled the wheel off by the spokes. Didn't cost me a dime except for band aids and peroxide.
 
Hi Roscoe,
Last Friday I finally replaced my 20 year old great looking Dunlops with Vredstein 165s. I brought the wheels to EuroTire, out of NJ, who shod and spun each using the proper balancer mounts. Although the car did develop the traditional shake at 55-60 MPH in the last 10 or so years, I did not expect the new tire would change much as the Dunlops were also properly maintained.

Well, I was wrong. When returning home and reinstalling the wheels, a quick ride showed that the new tires had drastically improved the level of speed-stability and smoothness that I had not experienced in the Healey for a number of years. Although I feel that proper balancing did contribute a portion of the improvement, I have come to believe the beauty of those old Dunlops was only surface deep and hidden problems had developed with age (boy I can relate to that).

Roscoe, wire wheel truing and balancing has always been a black art to me and I would appreciate hearing more about the process you followed in balancing your wheels on the car.

All t he best,
Ray (64BJ8P1)
 
Basically what I did was to jack the front wheel using the spring bottom plate. I removed all the balance weights (first marking where they were). With the wheel off the ground, I observed that when allowed to move from a stop, it would always end up with the same point on the wheel rim being at 6:00, no matter where I started it from. It was quite clear what point on the wheel/tire/brakedrum/hub assembly was the heavy point. I then started adding weight opposite to the 6:00 position. It was very sensitive and I ended up with a weight that resulted in no movement of the wheel, no matter what position I put it in. Voila!
 
Hi Roscoe,

Thanks for your instruction. So, as I understand, you used the gravity method. Were you able to determine the plane for applying the weights (inside or outside)? How did you handle balancing the rear tires?

I like the idea that you are back to balancing all running components as a unit as I always liked the on-car spin balancing (a service that has long disappeared). Again, thanks for the information.

All the best,
Ray (64BJ8P1)
 
Ray:

I had the same experience with my Healey many years ago. I had some beautiful NOS Dunlap Gold Seals bias plys on mine at the time. I spent lots of time and money truing wheels and balancing, all to no avail. There always remained a strong shake in that 50-60 mph range, made the car awful to drive. I remember removing all the tire weights at one point and it had no effect at all.

I finally bought some new radials, problem solved. I recall calculating the forces on those balancing weights at 50 mph. It is really a very small force, I seriously doubt if imbalance could cause so much vibration at such low speeds.

I think takes out of round tires/wheels or invisible internal cord damage to produce this sort of bounce, not tires out of balance. If your car has this problem, I suggest you start by getting new tires, it could save a lot of time.

Bill.
 
Healey 100 said:
... I seriously doubt if imbalance could cause so much vibration at such low speeds. ...

I think it can. At least on my Jaguar X-type, 50grams at the front wheels made the difference at 100km/hr

Hans
 
I got the same scuttel shake at 50 - 60 mph. The guys on this forum strongly suggested getting the brake drums ballenced. So I found a local machine shop to do the job and found out one of them was 134grams out and the other was 136 grams out. I'm still working out some brake issuse so haven't had a chance to road test yet. Hopefuly I'll be on the road by next week. I'll let you know what happens. I'm confident that it will make a huge improvement. The combined weight of 270 grams out of ballence on those drums would certinly be enough to make anything shake.
 
The guys at Hendrix can true the brake drum, wheels and tires. They are fast. UPS was 5 days each way. They do a fine job. I've been up to 85 mph the only shaking was coming from the wife.
 
OK, I have to fess up. I'm a helicopter mechanic. I own some electronic balancing equipment and have balanced airplane propellers and done track and balance on helicopter rotors for 30 years. I can assure you, from balancing masses that are less than the mass of the Healey wheel and brake drum assembly and many that are more massive, that in the 1500 to 3000 rpm range it is quite possible to feel the difference 20 or 40 grams makes at an arm of 6 to 10 inches from the center of rotation. Granted the spring and shock mount would absorb much of what you might feel in a car, I'm sure some gets through into the solid structure beyond. Since I can't static balance the rear wheel assemblies the same way, I've been planning to use my equipment with the rear end on jack stands. If I could come up with a way to spin the front wheels up to speed I'd have done that but the static balance seems to have done some good. I'll let you know what I find when I get around to doing that. Perhaps the best evidence of the benefit of what I've done is I no longer have to put my hand on the dash mirror to stop the vibration and get a clear image of the car behind me.
 
Don't overlook the rear brake drums as the source of any shaking. Especially if you have new tires.
When the rear brake drums were manufactured, they were not
machined to center.
If your rear brake drums are actually in balance, it would be by random chance, not by factory design ! Hendrix will take care of them for you and that will make a difference. If they are out of balance a lot, that wears flat spots on the rear wheel/axle shaft bearings.

Ed
 
Ed_K said:
Don't overlook the rear brake drums as the source of any shaking. Especially if you have new tires.
When the rear brake drums were manufactured, they were not
machined to center.
If your rear brake drums are actually in balance, it would be by random chance, not by factory design ! Hendrix will take care of them for you and that will make a difference. If they are out of balance a lot, that wears flat spots on the rear wheel/axle shaft bearings.

Ed
From my personal experiences since buying my Healey in '72....changed wheels, tires, rebuilt front and rear suspensions, but most of the steering wheel shakes were due from the rear wheels & tires, not the front! Hendrix did the drums and problem shake went away. Best $$ I ever spent on the shake!
Patrick
 
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