[EvenKeel]

Having my 335i aligned post installation of new tires. Asked the SA if they weigh the vehicle down prior to alignment to ensure that the suspension geometry is in the right position pre and post adjustments. His response:

"We don’t use weighted sandbags anymore. They are way too messy. Now we use ride height specifications, and the machine compensates for it."

He's a good guy and has been helpful in the past, so I don't have a reason to not take his word. That being said, any insight would be appreciated?

[noro]

The effect of weights in modern cars is essentially diminished. It is mostly driven by the fact that the suspensions are now stiffer (less deflection) and the overall weight of the car has increased meaning the effect of downforce as a percentage of car's weight has gone lower and lower. That's the whole point of weights is to simulate the downforce at highway speeds where the alignment matters most.

I've been aligning my cars without weights with 0 issues.

[kenwelch]

I used Hunter Alignment equipment as an Automotive Technology Instructor (40+ years).

This video shows the latest style alignment equipment by Hunter Engineering. They also make the KDS II system for BMW. Worth the short viewing so you can see how things have changed and how much faster measurements can be completed. Actual adjustments take longer, if no adjustments are needed then the technician is finished, customer pays the same amount.

This is a link to their accessories section. Scroll to page 6 to see the targets (picture below) that can be used to check ride height and more using the modern system. The targets are mounted to the fender wheel openings as a reference for ride height. The specifications for correct ride height are incorporated into the alignment data.

http://www.hunter.com/Portals/0/Media/5414-T.pdf

This is the link to the BMW KDS II system that includes “four live ride height targets”.
http://www.hunter.com/Portals/0/Media/5757-T.pdf

[noro]

That video is awesome! Thanks for posting. I have two problems with it.

1. The key to alignment is the initial setup not the adjustment itself. The careless way with which the dude in the video snaps the sensors onto the wheels is pretty much going to screw up everything.

2. The hunter equipment relies heavily on the lock to lock ranges of the factory steering rack to find the center. For some cars.. like my E30 M3 with a Z3 steering rack this process will always result in a steering wheel that is off center.

As always, there are mechanics that do things in a procedural manner and come up with bad results and there are the ones that "just get it".. Machines will never replace "though process". If you found a mechanic that "thinks" stick with him.

[bueller]

Originally Posted by noro

The effect of weights in modern cars is essentially diminished. It is mostly driven by the fact that the suspensions are now stiffer (less deflection) and the overall weight of the car has increased meaning the effect of downforce as a percentage of car's weight has gone lower and lower. That's the whole point of weights is to simulate the downforce at highway speeds where the alignment matters most.

I've been aligning my cars without weights with 0 issues.

^ What he said.

I used to have my 993 corner balanced. The place I would take it, I think it was Chapmans in Redondo beach, was a drive through place, you would stay in the car and they would even get you to hold your wheel straight and they would adjust the steering wheel so it was dead straight.

B.

[kenwelch]

Originally Posted by noro

That video is awesome! Thanks for posting. I have two problems with it.

1. The key to alignment is the initial setup not the adjustment itself. The careless way with which the dude in the video snaps the sensors onto the wheels is pretty much going to screw up everything.

2. The hunter equipment relies heavily on the lock to lock ranges of the factory steering rack to find the center. For some cars.. like my E30 M3 with a Z3 steering rack this process will always result in a steering wheel that is off center.

I believe that your concerns for the “set-up” quality are based on old equipment methods that used mechanical based sensors. The current technology digital camera based equipment does not require the same slow individual wheel run-out compensation used by old equipment. I have used both types of equipment as an instructor (several generations in 40+ years).
To address your two concerns:
1. The wheel sensors are attached to the tires not the rims, preventing rim scratches and dents. The vehicle is rolled forward which does an accurate four wheel sensor run-out compensation. This is more accurate than the old equipment and all four sensors are compensated in one movement of the vehicle.

2. Hunter equipment has never used the “lock to lock ranges of the factory steering rack to find the center”. In the video and on all generations of Hunter and other brands the caster swing is done to a specific number of degrees of turning both to the left and right for the equipment to do the calculation of front Caster degrees.
The turning does not take the steering box to full lock each direction to measure Caster. If you watch the video carefully the technician is rotating the steering wheel to achieve a specific left and right turn based on degrees. In the old days the technician would have to watch the protractor on the turn plates at the front wheels. This is now being accomplished with the digital cameras and targets (sensors) at the wheels.

I agree that the Technician still needs to know how the equipment works.

[xantdieselx]

Originally Posted by kenwelch

I believe that your concerns for the “set-up” quality are based on old equipment methods that used mechanical based sensors. The current technology digital camera based equipment does not require the same slow individual wheel run-out compensation used by old equipment. I have used both types of equipment as an instructor (several generations in 40+ years).
To address your two concerns:
1. The wheel sensors are attached to the tires not the rims, preventing rim scratches and dents. The vehicle is rolled forward which does an accurate four wheel sensor run-out compensation. This is more accurate than the old equipment and all four sensors are compensated in one movement of the vehicle.

2. Hunter equipment has never used the “lock to lock ranges of the factory steering rack to find the center”. In the video and on all generations of Hunter and other brands the caster swing is done to a specific number of degrees of turning both to the left and right for the equipment to do the calculation of front Caster degrees.
The turning does not take the steering box to full lock each direction to measure Caster. If you watch the video carefully the technician is rotating the steering wheel to achieve a specific left and right turn based on degrees. In the old days the technician would have to watch the protractor on the turn plates at the front wheels. This is now being accomplished with the digital cameras and targets (sensors) at the wheels.

I agree that the Technician still needs to know how the equipment works.

Great video. I worked as an ASE certified alignment tech for 7 years. I started on the D111H and finished up when the DSP models were just coming out.

I'm only in my early 40's and it's amazing to see how much the technology has changed. You know I still have most of my special alignment tools from back in the day - rear toe tool for Taurus and Tempos, Camaro/Firebird camber tool and a tie rod sleeve hook (just to name a few). I have no idea why I hang on to them.

[EvenKeel]

Good stuff. Thanks.