Performance alignment
04-01-23, 09:15 PM
#1
Driver School Candidate
Thread Starter
Performance alignment
Has anyone performed a loaded with weights alignment ?? similar to a BMW alignment? with performance suspension parts? lowered springs ? adjustable camber ? adjustable caster adjustable toe? and performance struts and shocks?
Seen this and also have read technicians explaining that it can be performed on other performance vehicles.
The REAL Reason For Using Weights During Alignment? (No, It's Not What You Think.)
According to Dinan the purpose of the weights is to simulate the angles in the suspension when the car is driving at high speeds.
When you drive faster, you'd notice that your car "sits down" lower and closer to the road. As the car "sits down lower" the wheels spread wider.
This is caused by the aerodynamics of the car. Slanted windshield, slanted hood, underbelly, etc. BMW designed the car to go lower when you drive faster, not to go higher (float).
The alignment specs are therefor there, because they want specific numbers when you, the driver, need it the most - when you drive the car like it was meant to be driven. Not while you are at your shopping center parking lot driving speed. Makes sense?
The instruction by BMW is to do this:
1. Place the weights in the car.
2. Measure the height of the car: "fender to center of the wheel" to make sure the car is at the right height. The tolerance is 1cm (or a quarter of an inch IIRC - but it is very close to that anyway).
Anecdotal:
1)
I did my alignment a few time at a Dinan installer. He does it the way it is described above. His explanation to the use of weights was the down force at speed due to aerodynamics.
Results: With only me, the driver, in the car, and no passengers, the car handling and overall feel was "Amazing and Fantastic".
2)
I did my alignment twice at an indy shop that specialize in preparing and building M3 cars for race tracks. The owner does the alignment himself. In the past, BMW used him to travel around the country to teach dealership technicians how to do alignment. So this is a guy who teaches BMW how do alignment (it's worth repeating this twice).
The way that HE approaches the alignment is a little different than the above. He puts weights on the strut towers and in the trunk and keeps measuring the HEIGHT of the car (fender to center wheel) until the HEIGHT of the car is exactly in the middle of the spec provided by BMW. So basically, he doesn't care what the weight is. He just wants to make sure that the HEIGHT is perfect.
I asked him what's his purpose in doing it that way. HIS explanation is, that the purpose of the weights is to bring to suspension to be perfectly parallel to the ground. THEN you align the wheels to the correct numbers in the BMW spec.
After the alignment, he takes the car for a ride in some twisty back roads, that ends in a large empty parking lot where he will drive in a figure 8 at high speed making sure everything is just superb. Fun times. [img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]
It makes perfect sense to me.
Results: With me, the driver, as the only person in the car. No passengers. The car handling and overall feel was... you've guessed it. Beyond your expectation Fantastic and Amazing. You WILL feel the difference even if you are not Mario Andretti.
NOBODY EVEN MENTIONED THE WEIGHT OF PASSENGERS, ETC.
I DON'T KNOW OF ANY BMW DOCUMENTATIONS WHO MENTION WEIGHT OF PASSENGERS.
As a reference point: Up to that time, I used to take my car to a place who did my alignment without weights "because his machine compensated for the lack of weights in the BMW". He was very precise and I always watched while he's doing it. He always brings it to the middle of the spec. Guess what? The car felt "okay", but not even resembling the feel of the car after the two above shops did it using the weights. There was no resemblance whatsoever.
I can unequivocally say, based on my experience after the alignment, comparing the last one to the first two, that the first two guys alignment is perfectly correct, and the last one is absolutely wrong for the car. And that is AT ANY SPEED.
Do yourself a big favor and take your car to a shop that does the alignment like BMW says to do it.
Lastly, just a tip to the new guys looking for an alignment shop:
1. Ask if they use weights, if they don't, walk away.
2. Ask for a printout of the before and after. If they tell you that the printer is broken or they run out of ink or whatever other BS they tell you, walk away.
3. Try very very hard to go to a place that specializes in BMW or high end cars. Even if it means that you need to drive farther, or need to pay more.
4. Stay there to watch the alignment if at all possible (dealers will not allow you to watch, but they are ok of course).
Seen this and also have read technicians explaining that it can be performed on other performance vehicles.
The REAL Reason For Using Weights During Alignment (No, It's Not What You Think.)
67144 Views132 Replies44 ParticipantsLast post by Cometstar, Mar 3, 2022MatWiz
Discussion Starter·Mar 15, 2011 (Edited)The REAL Reason For Using Weights During Alignment? (No, It's Not What You Think.)
According to Dinan the purpose of the weights is to simulate the angles in the suspension when the car is driving at high speeds.
When you drive faster, you'd notice that your car "sits down" lower and closer to the road. As the car "sits down lower" the wheels spread wider.
This is caused by the aerodynamics of the car. Slanted windshield, slanted hood, underbelly, etc. BMW designed the car to go lower when you drive faster, not to go higher (float).
The alignment specs are therefor there, because they want specific numbers when you, the driver, need it the most - when you drive the car like it was meant to be driven. Not while you are at your shopping center parking lot driving speed. Makes sense?
The instruction by BMW is to do this:
1. Place the weights in the car.
2. Measure the height of the car: "fender to center of the wheel" to make sure the car is at the right height. The tolerance is 1cm (or a quarter of an inch IIRC - but it is very close to that anyway).
Anecdotal:
1)
I did my alignment a few time at a Dinan installer. He does it the way it is described above. His explanation to the use of weights was the down force at speed due to aerodynamics.
Results: With only me, the driver, in the car, and no passengers, the car handling and overall feel was "Amazing and Fantastic".
2)
I did my alignment twice at an indy shop that specialize in preparing and building M3 cars for race tracks. The owner does the alignment himself. In the past, BMW used him to travel around the country to teach dealership technicians how to do alignment. So this is a guy who teaches BMW how do alignment (it's worth repeating this twice).
The way that HE approaches the alignment is a little different than the above. He puts weights on the strut towers and in the trunk and keeps measuring the HEIGHT of the car (fender to center wheel) until the HEIGHT of the car is exactly in the middle of the spec provided by BMW. So basically, he doesn't care what the weight is. He just wants to make sure that the HEIGHT is perfect.
I asked him what's his purpose in doing it that way. HIS explanation is, that the purpose of the weights is to bring to suspension to be perfectly parallel to the ground. THEN you align the wheels to the correct numbers in the BMW spec.
After the alignment, he takes the car for a ride in some twisty back roads, that ends in a large empty parking lot where he will drive in a figure 8 at high speed making sure everything is just superb. Fun times. [img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]
It makes perfect sense to me.
Results: With me, the driver, as the only person in the car. No passengers. The car handling and overall feel was... you've guessed it. Beyond your expectation Fantastic and Amazing. You WILL feel the difference even if you are not Mario Andretti.
NOBODY EVEN MENTIONED THE WEIGHT OF PASSENGERS, ETC.
I DON'T KNOW OF ANY BMW DOCUMENTATIONS WHO MENTION WEIGHT OF PASSENGERS.
As a reference point: Up to that time, I used to take my car to a place who did my alignment without weights "because his machine compensated for the lack of weights in the BMW". He was very precise and I always watched while he's doing it. He always brings it to the middle of the spec. Guess what? The car felt "okay", but not even resembling the feel of the car after the two above shops did it using the weights. There was no resemblance whatsoever.
I can unequivocally say, based on my experience after the alignment, comparing the last one to the first two, that the first two guys alignment is perfectly correct, and the last one is absolutely wrong for the car. And that is AT ANY SPEED.
Do yourself a big favor and take your car to a shop that does the alignment like BMW says to do it.
Lastly, just a tip to the new guys looking for an alignment shop:
1. Ask if they use weights, if they don't, walk away.
2. Ask for a printout of the before and after. If they tell you that the printer is broken or they run out of ink or whatever other BS they tell you, walk away.
3. Try very very hard to go to a place that specializes in BMW or high end cars. Even if it means that you need to drive farther, or need to pay more.
4. Stay there to watch the alignment if at all possible (dealers will not allow you to watch, but they are ok of course).
04-01-23, 10:06 PM
#2
So here's the thing: Lexus/Toyota's specifications for alignment are for an unladen car.
Besides that, there's like, one user in the 2GS forum whose car would actually need to consider aerodynamic load at speed...
Humouring the author, what I would have liked to see is the actual comparison of the unladen alignment specifications after each of his BMW chiropractor alignments.
Besides that, there's like, one user in the 2GS forum whose car would actually need to consider aerodynamic load at speed...
Humouring the author, what I would have liked to see is the actual comparison of the unladen alignment specifications after each of his BMW chiropractor alignments.
Last edited by firelizard; 04-01-23 at 10:09 PM.
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