replaced track (tie) rod ends on my vantage and took it down to dealer for 4 wheel alignment...
wasn't far out, but tech said he couldn't adjust the "caster" any more due to cars age (it's a 2009)...

I understand camber and toe, but what is caster and what should it be on our cars ana how bad is it if it's not proper. what needs to be done to restore it to proper specs?

thanks!

 

Caster is the angle between the steering axis and where the tire touches the ground.

Draw an imaginary line through the upper and lower ball joints. That line is not actually vertical, the wheel pivots around a line that is angled slightly toward the back of the car.

More caster angle improves high speed stability, less improves steering responsiveness. Too little caster and the car will be twitchy and require constant small corrections when trying to go strait.

I don’t think caster is adjustable on any of the VH cars, but so long as it is not way out, i.e. something is bent, then it’s not a big deal.

 

The only problem aside from what Charlie has said is that the car may tend to drift to the side with less caster. On cars that it is adjustable I tend to make the passenger side slightly higher to compensate for the crown in the road.

 

I could be wrong, but caster is adjustable on the Vantage. AFAIK, there is no way to adjust caster on the rear wheels, but caster can be adjusted on the front wheels.

 

Caster is adjustable on VH cars although some tend to not allow full range to set spec. Which is around 4.8* if your split is high enough you may have a drift to one side (least degree as mentioned above) in which you should dial down the high side. There isn't much adjustment range which is about 1.5* so you should have it set within .5* side to side. Example of caster readings LH 4.5* RH 5.0* usually left is lower to accommodate the crown of the road.

 

 

For my own education, how is the caster adjustment done?

On my Jaguar it’s accomplished with a shim stack on the upper control arm. Do you move the lower control arm on the AM?

 

Eccentric bolt @ the rear of the lower arms. Furthest out increases Caster.

 

thanks for quick response... here is the print out of the results


so it looks like caster is about +4.3 on each side...I don't track car, rarely get over 120 mph, and it drives very well, straight, no vibrations, no tire wear...

anything to be concerned about?

 

Nope, you answered your own question. Drives just fine. I would think max was 4.3 on one side and he matched the other side.

 

If you're not seeing excessive tire wear or cupping on the inside edge of the tire you're fine. What caster does is tilt (increase the effective negative camber of) the outside tire when you turn in to a corner, so you can run relatively little negative camber and have normal tire wear in normal driving and still have enough grip when you want to turn aggressively. More degrees of caster=more tilt of the tire during cornering.