Hunter Road Force GSP 9700 experience....
hi brad and everyone...
i researched further on the internet about left pulling and came upon the term "radial pull". further research led me to read about the Hunter Road Force GSP9700. I found about a tyre shop in my city which has this equipment and made an appointment with him.
Over there the owner explained and showed me how the machine works and post all tyres psi to 32 psi took road force and lateral measurements of all the 4 tyres. and then he then stuck weights on the red line showed by laser.
next the machine made the wheels OK and then tagged all 4 wheels with Straight Trak Technology. It then showed various options on the screen as to installing which wheel where will result in how much total lateral pull in which direction. it had options of least pull and least vibrations and also alternate options to both.
i choose a option which resulted in 25 pull to the right. Now my tyres are directional and 205 55 15 Hankook V8 RS. So we had to undo 2 tyres from the rims and remount it inside out to keep it consistent with the rotation arrow. The 2 tyres were then re balanced after this.
I'm not sure if this affects the overall result as the 4 tag position chart was decided with the tyres being balanced in the other direction. so effectively 2 tyres were rebalanced after the deciding the 4 position chart because my tyres are directional. I'm not sure how much this has affected the actual result.
After this the car was aligned with a Hunter 511 machine. It seemed to be a pretty old design machine. did not have any 3d sensors but rather clamp ons with wires and a liquid based measuring device on top. Actually i was quite amused and surprised to see the best Balancing machine the Road Force GSP9700 partnered with a Hunter 511. :P
I told the owner to get a Hunter Elite Hawk Eye to complement the GSP9700 but he said he can get the same results with the 511 as the readings will be the same. Nevermind i told him i'd be happy if he can make my polo go straight.
After this we went on a test drive.... and my car went straight on level roads and on most roads. It drifts left as soon as there is left banking and camber on road. he told me this was normal and that my car is absolutely perfect. He told me to go home and drive my car over a variety of roads and come back in 2 weeks if i felt anything was wrong.
My Observations and Doubts....
1. While driving back over a distance of 20 kms i felt the car going Straight on most roads and for the first time in 4 months of owing the polo i really enjoyed driving it. It felt perfect. this is how my car should have been from day 1.
2. So in course of testing further yesterday i drove around with a friend on board. This time i felt the car tracks straight on most roads but is a bit more camber sensitive. i.e when i'm alone then on left cambered/banked roads the car goes straight but with a pax on board it drifts left in same conditions. What could be the reason for this ?
3. Overall I'm satisfied and at peace but a lingering query in my mind is that....
here in India most roads have in the range of a bit to excessive camber/banking on the left. Absolutely flat roads are rare. So if i'm driving on left camber roads 80 % of the time then should i not ask the alignment guy to direct the toe a bit to the right so that the car tracks straight on such roads ? But then i guess it will track right on perfect level roads.... right ? i'm a but confused.
cheers.
Update on left pulling & new observation.
Hi,
Thought i'll update about my left pull and subsequent solution post subframe alignment. The car tracks absolutely straight on most roads and feels perfect. I'm very happy and grateful for this thread and everyone's help particularly brad.
However i've been observing a new phenomenon which is bothering me...
The steering when turned to right feels slightly stiffer/harder than when turned to the left. As in if I'm getting 10/10 power assist while turning left I get only about 8/10 power assist while turning right. while turning right I feel more resistance. The steering wheels wants to come back faster/harder to center from right then from the left. The difference is not a lot but it's noticible.
I've tried tyre pressure 30 all around and 32 all around but same. i've also tried on 4 wheels from my friend's polo but same effect.
thanks.
What could be causing this ?