Wheel Balance.. Finding the Right BALANCE

[Zderf]

Finding the balance between balance and appearance has surfaced as the real challenge here. I really got excited about the prospect of balancing my front Trigo/BFG's thru the magic of the Hunter 9700. See the story here:

Steering Wheel Shake, a Poll

Yesterday, after about three hours with the awesome Hunter 9700, rims verified good, tires checked for weight and roundness, new tires tried... this was sadly confirmed:

balancing pin drive Trigo wheels

Here's my compromise... Match mount the tires and wheels. Then static balance them for minimal weight gain in the center of the inside of the rim. Best possible compromise to get low weight balance without attaching weights to the outside of the rim (its an appearance thing).

Next best thing would be 17" rims that have enough width and offset so as to dynamically balance with minimal weight gain... with all weights on the inside of the wheel. This simply cannot be done with the period correct 15" wheels.

Regretfully,

Zderf

[Excaliber]

With a good spin balance machine it will also give you a "rating" on your overall tire "quailty". All tires are NOT created equal. BEFORE balancing I have the tire\wheel combo checked, often the tire has to be relocated on the rim. Sometimes a tire is so "far out" of specs (weight) it can only be balanced with a LOT of weight. The "numbers" are somewhat standard. Jaguar will not accept new tires from a manufacturer that fall out of their "specs", for instance. Ford, I suspect, will run "what ever". If you need a LOT of weight, whats wrong with this picture?

Ernie

[Mr.Fixit]

I think it's your tires. I have driven lots of 15" wheeled cobras at good speed, who's tires were balanced just fine with no visable weights on the outside of the rim.

[Zderf]

Maybe I didn't correctly make my point... my wheel and tire assemblies are balanced now. But I was not able to acheive the "state of art" loaded dynamic balance using the Hunter 9700 confuzer system. (Did I mention we tried with 4 different NEW BFG T/A 245/50R/15's without success?)

Rather, a more tradional method was used... STATIC balance after a "match mounting".

Clarification respectfully submitted for consideration...

Zderf

[auto10x]

A static balance is a guess at best. With any good computer balancer and stick-on weights will do a great job.
auto10x

[Zderf]

I'm about to give up here...

when one dynamic balances one MUST/SHOULD place the weights as directed by the Computerized balancing machine at both the outermost and innermost postion on the wheel. That puts weights on the outside of the rim.....

To avoid putting the weights on the outside of the rim (one goal of mine), you must then FOOL the balancer by placing LOTS MORE weight as far to the outside on the inner side rim so it has the same affect as if it were mounted completely outboard. There comes the rub.... that can often amount to WAY MORE weight added to your wheel/tire assembly than is considered acceptable.. like 7 / 8 / 9 ounces and up to account for a 1.5+ ounce weight hooked to the outside of the rim.

These 7.5X 15" Trigos simply do not allow one to get far enough to the outer face of the rim from the back side.... to cut the FOOL THE MACHINE WEIGHT down to an acceptable amount. The 18 / 20 / 22 / 23" rims available today are constructed such that you can hide ALL of the weights on the inner side of the wheel while achieving a complete dynamic balance.

We went through this for 3 hours on the Hunter DSP9700 Vibration Control System (this gave us the match mounting data), and a Hunter DSP9000 Dynamic Balancer where we checked each wheel for weight load differential and roundness (well within acceptable standards).

Once the assemblies were match mounted, the 9700 was calling for 8+ ounces (THE BEST VALUE ACHIEVED ON ONE OF THE NEW BFG's) to acheive the same result of 1.5 ounces applied to the outer lip of the rim, an UNACCEPTABLE AMOUNT BY ANY STANDARDS.

The final result for the static balance after match mounting was 2.5 ounces on one and 2 ounces on the other assembly, located on the very center inside surface of the rim. A subsequent spin-up on the DSP9000 showed both assemblies in an acceptable range.

For more info on the 9700 and all that is going on here... you can visit:

http://www.hunter.com/pub/product/product.htm

The acid test, of course, will come when the recipient vehicle is put on the road.

Whew...... thats it on this topic for me....

Cheers

Zderf

[auto10x]

When performing a computerized wheel balance usually there is no need to "fool" the balancer if it is properly "programed". Instead of entering the width of the wheel where wheel weights are traditionally installed, measure instead where you actually want to install them. Then with this data "programed" into the balancer you can proceed in a worthright manner with the balance.
However, since I'm not that familiar with Trigo wheels there might be other difficulities that I'm not aware of.
auto10x

[Zderf]

When performing a computerized wheel balance usually there is no need to "fool" the balancer if it is properly "programed".

Here I am again.... and I said I was done. Damn!

Poor choice of words on my part. Of course they programed the computer for that..... you can't FOOL the computer.

Was just trying to make a point. Sorry.

Regards,

Zderf.

[Excaliber]

And it's an interesting point. I see your delimna. I know MANY of the guys at the track use the old "bubble balance" as I have also. These guys (and myself) are running over a 100 mph. I've used both methods, the Computer Confuzer model and the bubble balance. The reason for the bubble balance is simple. We don't have a "Confuzer" at the track and, like myself, many of us are changing wheels\tires AT the track.

When I get those new shiny tires and I'm all excited I do the Computer Balance. Once the "newness" wears off and reality sets in, I use the Bubble. Works about the same as far as I can tell and is a LOT cheaper!

Ernie

[Bob In Ct]

Hey guys:
You're missing the most important feature of the 9700. It can not only balance the tire on 2 axis, but it measures force variations in the tire/wheel assembly. I had one Trigo/BFG that was perfectly balanced but had over 30 pounds of force variation when rolling.

Go to the Hunter web site.

Bob

[Excaliber]

Yeah,,,,the "Confuzer" (ha ha, I love that name) is a great machine. It's nick name STILL applies and I think one can still make a case for a good old fashioned back to basics bubble balance.

Ernie