Evaluation of the bump steer phenomena on 928
#47
Burning Brakes
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Old & New,
No - You did not 'hit my corn', but I felt 'I hit some others corn'
Yes, sometime the life is funny! <img border="0" title="" alt="[Wink]" src="wink.gif" />
But fortunately, Earl (and others) came and helped me - Thanks for that
<img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" /> <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />
No - You did not 'hit my corn', but I felt 'I hit some others corn'
Yes, sometime the life is funny! <img border="0" title="" alt="[Wink]" src="wink.gif" />
But fortunately, Earl (and others) came and helped me - Thanks for that
<img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" /> <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />
#48
Burning Brakes
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Ed;
I hope you understand my English now <img border="0" title="" alt="[Wink]" src="wink.gif" />
I think your toe-out is a result of ‘lifting at ball joint’
I tried this lifting technique, but still the car is not back to normal riding height when you put it back on the wheel – The moral is therefore, DON’T LIFT THR CAR IN CONNECTION WITH THE WHEEL ALIGNMENT PROCEDURE, and the reason for this is the ‘sticking’ rubber bushes and the toe change (Positive when lifting and negative when lowering)
My car is approximately 30 mm to high after a lift – even if I lift at ball joints – If I set the toe-in to +15’ at this height, then after the car is back to normal riding height, the toe has changed to approximately – 15’ (Toe-out)
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
I hope you understand my English now <img border="0" title="" alt="[Wink]" src="wink.gif" />
I think your toe-out is a result of ‘lifting at ball joint’
I tried this lifting technique, but still the car is not back to normal riding height when you put it back on the wheel – The moral is therefore, DON’T LIFT THR CAR IN CONNECTION WITH THE WHEEL ALIGNMENT PROCEDURE, and the reason for this is the ‘sticking’ rubber bushes and the toe change (Positive when lifting and negative when lowering)
My car is approximately 30 mm to high after a lift – even if I lift at ball joints – If I set the toe-in to +15’ at this height, then after the car is back to normal riding height, the toe has changed to approximately – 15’ (Toe-out)
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
#50
Burning Brakes
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No it's not. He actually set the toe to 1 degree out. When my car is lifted from the lower control arm (as far outboard as possible) the suspension barely (< 5mm) moves. Lifting the car the way he does changes nothing when it settles. We've measure before, during, and after and it's all the same. YMMV.
#51
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Ed,
I and a few others would like to know what this "lift by the ball joints" rig looks like. The next time that you are over there, could you take some pictures? Also, it makes me wonder what this guys credentials are. NO car is adjusted even close to 1 degree toe-out. Some front wheel drive cars are adjusted to toe-out. I have never heard of a rear wheel drive car that has any toe-out on the front wheels.
I and a few others would like to know what this "lift by the ball joints" rig looks like. The next time that you are over there, could you take some pictures? Also, it makes me wonder what this guys credentials are. NO car is adjusted even close to 1 degree toe-out. Some front wheel drive cars are adjusted to toe-out. I have never heard of a rear wheel drive car that has any toe-out on the front wheels.
#52
Burning Brakes
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He recently told me that he set it to 1 degree toe-out because he knew I autocrossed and tracked the car. Apparently, a bit more toe-out helps with cornering, at the expense of straight-line performance. I guess it helped, as I did win my autocross class two years straight. Also, considering that the tires have lasted over 10k miles (and look like they'll last another 5k miles) I really can't protest too much.
I don't have a digital camera (and in fact, still have a 1/2 roll of film from last year that hasn't been developed). If you can follow my description, perhaps you'll get an idea of the way he does it.
While on the alignment rack, he places the rubber pads directly under the lower control arm, but as far outboard without interferring with the excentric bolts or ball joint. He then carefully and slowly raises the car making sure the pads are supporting the full weight without affecting or damaging anything else. Lifting it this way, the suspension remains as fully loaded as can be expected, while still being able to spin all wheels. QED. ;^)
BTW, his credetials are impecable. He was the chief mechanic for several teams that competed (and did rather well) at the 24 hours of Daytona, and the 12 hours of Sebring. Often, he had to align the cars without the benefit of a machine. He would get them to race spec with just a level, string, and measuring tape. Now that he has three daughters, his jaunts to FL are usually to visit Disney World. YMMV.
I don't have a digital camera (and in fact, still have a 1/2 roll of film from last year that hasn't been developed). If you can follow my description, perhaps you'll get an idea of the way he does it.
While on the alignment rack, he places the rubber pads directly under the lower control arm, but as far outboard without interferring with the excentric bolts or ball joint. He then carefully and slowly raises the car making sure the pads are supporting the full weight without affecting or damaging anything else. Lifting it this way, the suspension remains as fully loaded as can be expected, while still being able to spin all wheels. QED. ;^)
BTW, his credetials are impecable. He was the chief mechanic for several teams that competed (and did rather well) at the 24 hours of Daytona, and the 12 hours of Sebring. Often, he had to align the cars without the benefit of a machine. He would get them to race spec with just a level, string, and measuring tape. Now that he has three daughters, his jaunts to FL are usually to visit Disney World. YMMV.