wheels-inmotion
Active Member
Hi Guys
Reading the board over the last few weeks it seems some members are feeling alarmed about why the geometry is wrong on their car?
Without blinding anyone with science here are my thoughts and in order of accountability....
1: Most MB's have adjustable front and rear Toe. Front Camber and front Castor: The reason for this is by design MB knew these angles would change naturally so they allowed the option to regain the angles.
2: Road trauma: AKA the pothole, an unavoidable thank you for the road fund licence from the highways agency.... Fact is we hit them so over time it's probable the concussion will migrate into the chassis. Your only clue something has gone wrong after hitting one is a pull to one side or an off-line steering position when driving straight.
2b: Speed bumps and off road parking does not miss-align the chassis since this is done at reasonable speed and the tyre is more than able to deflect the bump/ kerb. Obviously speed is a factor here so if the angles are moved it's more of a crash than a deflection.
3: Wear and tear: Our cars live most their lives in the realm of worn, not worn out just worn. Since this period encompasses a long period of time it's probable the chassis angles will reflect this in tyre wear. The movement of the angles should still remain within the manufacturers geometric tolerance.... So how do you asses worn and worn out? My best advice is "sound"... If a bushing is worn to excess it will thump and bang... Some will say there will be play in the worn component and i agree but that comes after sound has been ignored so more advanced wear.
4: Incorrect ID: The MB is very hard to identify in regard to model and suspension type. I find very often the geometry report has overlapped the wrong chassis. To help the first three numbers on the VIN plate is also located on the windscreen and drivers side door pillar identifying the series.
5: Incomplete measurements: Always expected a geometry printout containing the before and after positions but more critically the report should display....
Rear
Camber
Toe
Thrust angle
Front
Camber
Castor
Toe
Most places don't measure the castor angle because it takes longer and is hard to explain to the customer if wrong.... You have paid for this critical information so be sure they comply.
I hope this helps.....
Reading the board over the last few weeks it seems some members are feeling alarmed about why the geometry is wrong on their car?
Without blinding anyone with science here are my thoughts and in order of accountability....
1: Most MB's have adjustable front and rear Toe. Front Camber and front Castor: The reason for this is by design MB knew these angles would change naturally so they allowed the option to regain the angles.
2: Road trauma: AKA the pothole, an unavoidable thank you for the road fund licence from the highways agency.... Fact is we hit them so over time it's probable the concussion will migrate into the chassis. Your only clue something has gone wrong after hitting one is a pull to one side or an off-line steering position when driving straight.
2b: Speed bumps and off road parking does not miss-align the chassis since this is done at reasonable speed and the tyre is more than able to deflect the bump/ kerb. Obviously speed is a factor here so if the angles are moved it's more of a crash than a deflection.
3: Wear and tear: Our cars live most their lives in the realm of worn, not worn out just worn. Since this period encompasses a long period of time it's probable the chassis angles will reflect this in tyre wear. The movement of the angles should still remain within the manufacturers geometric tolerance.... So how do you asses worn and worn out? My best advice is "sound"... If a bushing is worn to excess it will thump and bang... Some will say there will be play in the worn component and i agree but that comes after sound has been ignored so more advanced wear.
4: Incorrect ID: The MB is very hard to identify in regard to model and suspension type. I find very often the geometry report has overlapped the wrong chassis. To help the first three numbers on the VIN plate is also located on the windscreen and drivers side door pillar identifying the series.
5: Incomplete measurements: Always expected a geometry printout containing the before and after positions but more critically the report should display....
Rear
Camber
Toe
Thrust angle
Front
Camber
Castor
Toe
Most places don't measure the castor angle because it takes longer and is hard to explain to the customer if wrong.... You have paid for this critical information so be sure they comply.
I hope this helps.....
