Ken, I use the new Hunter GSP9700 down at the Chevy dealership I work
for. The reason for the road force info is the new trucks with rack and
pinion steering have a lot of feedback to the driver. The oversized
tires that guys run make the problem worse. Just like you hear the
NASCAR racers talk about changing the air pressure one pound to change
the handling. The soft sidewalls of radial tires work like a spring.
I have balanced my own tires for years on a bubble balancer. This year
I took them down and checked them on the Hunter. They were spot on with
only 6 and 8 pounds of load variation. Anything under 25# is good.
Goodyear and Firestone used bubble balancers for years at Daytona and
never had problems. It was SOP not to use more than 1 1/2 ounces of
weight on a wheel. If the weight came off, it would not be undrivable
with that small of a off balance. I remember the tire guys cussing a
bunch of times when they had to keep dismounting a tire to move the
inner liner to get the balance close enough to use only a small weight.
You have remember I started racing on Goodyear Blue Streak Stock Car
Special treaded tires, like 1964.
Doug Odom in big ditch feeling old
Ken Bond wrote:
>
> Folks,
>
> I recently got an e-mail from a friend that discussed a new tire balancing
> machine from Hunter. I DON'T KNOW THE INDIVIDUAL who sent the message to
> my friend and have NO DIRECT information about the product so please read
> with a bit of caution. IF legit, it might be worth trying to find
> one of these units in your area of the country
>
> KEN
>
> ******************
>
> Topic: Hunter GSP9700 Tire Balancer
> AutocroSSer
> Senior Member
> Member # 13
> posted 13 May 2001 01:48 PM
>
> When I went to the Hunter Engineering Seminar last month in SoCal, one of
> the machines that Dave Scribner showed to us was the Hunter GSP9700 Tire
> Balancing machine.
>
> www.gsp9700.com
>
> This is the "Big Kahuna" of tire balancing machines. Not only does it do
> static and dynamic balancing, but it ALSO does something they call "force"
> balancing. Basically, it takes a weighted roller and pushes against the
> tire while it is spinning on the tire balancing machine. Doing this, it can
> detect variations in sidewall stiffness (i.e. "spring force" of the tire
> sidewall) and compensate for them with the tire balance job.
>
> It is ALSO capable on nice spoked rims (i.e. my ROH ZR6s or stock SS rims,
> for example) of knowing WHERE the spokes are and hides the weights (stick
> on) that go on the "outer" part of the rim BEHIND the spokes. The "inner"
> weights are hidden back where you can't see then, in the conventional spots
> (lip of rim).
>
> Net result : NONE of the weights show AT ALL! I mean AT ALL.....can't even
> see them looking straight-on at the wheel, not even on the rim that is
> inside near the rotor! For you car show freaks who want the PERFECT looking
> wheel with NO weights visible on the inner rims, this is the trick for you!
>
> So, my street tires had developed a vibration starting about 70-75 MPH or
> so. I found a nearby shop that had a GSP9700 (Custom Alignment in Mountain
> View CA) and decided I'd give it a shot. Cost for 4 wheels was $57 out the
> door, with me dropping off the tires/wheels and picking them up
> the next day.
>
> On the force variation, my tires varied from 4 lbs to 28 lbs (4, 17, 21,
> and 28 lbs on the 4 tires). This means that (uncompensated) the worst tire
> was essentially pushing back with 28 lbs MORE force at one spot on the
> wheel rotation. While that sounds like a lot, most tires are within that
> range.
>
> After AutoX yesterday, I bolted the rebalanced tires back up (had been on
> my AutoX rubber for the last week or two). Took it for a test drive......
>
> This is, BY FAR, the BEST balance job I've EVER had on a set of tires. The
> car is SMOOTH AS GLASS at 90-100 MPH. So smooth it's almost eerie . You
> can release the steering wheel (quickly) at 90 MPH and it doesn't shimmy
> whatsoever! (not even a mm!)
>
> Needless to say, I'm VERY impressed! I was a bit skeptical about spending
> $60 on a balance job, but sure am not skeptical anymore!
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