New Tires + Hunter 9700

[Barry94]

I just installed a set of BFG Traction TA tires and had them balanced on the "Hunter GSP9700 Road Force Measurement System".

Yesterday, I drove about 600 km (375 mi).

I've owned the STS for about 7 years and it never has been this smooth on the road, at any speed.

If not for this site I would never have tried the 9700 balance.

It's worth the little extra for the great balance.

Some technical stuff......

If anyone is interested, here is the procedure the Hunter 9700 uses to balance a tire.

The operator mounts the wheel on the 9700.

(From here on, it's clear that the 9700 is in charge)

Then the 9700 asks that it's air hose be connected to the tire. (Monitor readout)

A large pressure guage appears on the monitor and the 9700 proceeds to adjust the tire pressure to it's own specifications. (The operator is not involved)

When the correct pressure is established by the 9700 it then requests the air hose to be removed.

Then the wheel is rotated slowly and next appearing on the screen (monitor) is a representation of the wheel.

I have the '97 STS chrome 7 spoke wheels and a 7 spoke wheel now appears on the screen.

Next, the 9700 slowly rotates the wheel forward and backward several times.

(Not a balance thing)

It's checking for bent wheels, runout in the wheel and tire.

If the specifications are outside the limits of the 9700, then the 9700 will ask the operator to break down the tire from the wheel and rotate the tire to a new position (as directed by the 9700) on the wheel.

Theory here is that two wrongs may make a "right".

Eg.. A high spot on the wheel matched with a low spot on the tire will average out.

If the tire/wheel is beyond specification (roundness) the 9700 rejects the process.

This all happens before the actual balancing.

Once the 9700 is happy with the wheel tire combination it then proceeds to the actual balance.

Since the 9700 knows the configuration of my wheels (7 spoke) it directs the operator to place the approiate weights BEHIND the specified spokes. (No weights are visable from the outside of the wheel)

I was fortunate, all my wheels and the new tires passed the "runout" phase with no problems.

The operator told me that he can spend up to a hour and a half balancing some wheels. Due to the mount/dismounting of wheel/tire combinations.

The unique part of the 9700 is that you simply cannot balance a wheel/tire if either are not round.

Note: The 9700 WILL balance out of round combinations if requested. however it then is not a "Road Force" balance.

You pay extra for "Road Force" balance.

Another note...

I asked for the "Road Force" balance, however since my wheel/tire combinations passed the 9700 test, the shop then did not charge me extra for the "Road Force" balance.

Just thought I would share some "techie" stuff.

Smooooooth sailing.

Barry

[sprucegoose]

Cool! Very nice report, I had never heard of this 9700 device before... Will definitely investigate it next time I'm in need.

I really liked those BFG traction TA's on my Eldo also. Very smooth running, quiet, and good gripping tires. A great bargain at the price I got them for.

[Chris]

I just bought a set of Traction T/A's and am very happy with the ride too. Maybe not as good as yours, Barry, but nice nonetheless

[Scotty]

Im going to look into that Hunter GSP9700 machine, thanks

[JohnnyG]

I'm a big fan of the GSP 9700, and have recommended it several times on this board over the last 2 years or so. A couple of things might be worth mentioning here. Such as, most of the settings can be overridden by the operator. I have had several balance jobs done with the GSP, but not ALL of them turn out perfect, not on the first try at least. I have never had the machine adjust my tire pressure, however, this may be a new software enhancement, or an option only available on a newer machine. The machine was set to reject tires as a bad tire/wheel combination if it hit 14 lbs road force; UNFORTUNATELY most Sevilles are sensitive to variations as low as 8 - 10 lbs., you must reject them yourself if you are not happy with the improvement provided by the machine. Next, you must ensure that when you have the tires mounted or checked, that they are FULLY warm and not flatspotted due to sitting in a cold garge or overnight in a dealers lot...this can throw everything off since the machine will not know the cause of the "low spot". New tires are pretty safe as they come off the rack, since there is not enough load to make them out of round yet...but remember, don't let a dealer park the car overnight in order to get it in the shop in the morning...the tires will be flat spotted enough to throw the balance off, well, maybe not the balance, but certainly the matching of the tire to the rim. I recommend a 20 mile run to warm up the tires, then get the car up in the air immediately in order to ensure a round tire and a great balance job.

Finally, and most perplexing of all, I had a set of tires road forced balanced, and accepted them as the best that they could get. Put several thousand miles on them after the balance, but was never REALLY happy with them. This was a 2 tire set of original Goodyears which were mounted on the car at the factory, now with over 65,000 miles on them! They are nearly worn out with a few wear bars showing. However, my LAST rotate and balance before my Florida trip was done on a Hunter machine that was NOT a GSP9700....and the balance was nearly perfect! They are so smooth now that I HATE to get rid of them! Too bad it took me 65,000 miles to get them right!

As a side note, I have recently read somewher that the green or yellow "dot" stickers you see on some tires are put there by the manufacturer to designate the low spot in the tire. The installer is supposed to place THAT dot at the valve stem to ensure the roundest mount possible when on the rim. The theory is that the valve stem should be the heaviest part of the rim, making a better match for overall performance.

Be a perfectionist when it comes to this, only YOU can give the final OK as to whether you accept the tires you buy. I have rejected tires that I would have LOVED to keep for other reasons, due solely to poor high speed balance characteristics. The end result is WELL worth the extra cost and effort.................... right Barry? BTW, You're Welcome!

[JasonA]

Barry and Johnny, thanks for the information on the Hunter machine! Where are these machines located? Caddy dealers? Specialty tire shops? Does the price of a Hunter balance include a lifetime balancing warranty, like is offered at conventional stores? Finally, how much is the balance job?

Thanks!

[JasonA]

I found a site where you can search for a GSP 9700 near you:

http://www.gsp9700.com/pub/search/findgsp9700.cfm

[JohnnyG]

The job can be time consuming, and therefore is not cheap. I have never heard of a warranty, and don't really see how anybody can offer a guaranteed balance unless it is REALLY cheap to do (can you say sales gimmick?). I can say that provided you don't throw a weight, and don't bend a rim, the only thing that should effect balance is uneven tire wear. A properly balance tire running "round" on the rim as the Hunter should be able to provide, should stay in-balance a long time.

These machines were practically invented for front drive cars, they seem to be more sensitive to out of round tires.