A Camber Bolt Question

ja9 · Postby **ja9** » Fri Aug 21, 2015 7:15 pm

I've been playing around with my wheel alignment and I'm having the following issue. My car is a race car so keep this in mind. Whilst rotating the camber bolts I seem to get maximum caster with minimum camber or vice versa. Why can't I get max castor and max camber at the same time. I know it's a bit of a compromise with camber bolts but is there anything wrong with my bolts, stretched or hole is elongated or otherwise, is it a possibility that the bolts are in the wrong way.
The reason I'm after maximum castor is because I'm running power steering and would like more feel in the steering. Before anyone suggests removing the PS that is not an option. I've already been down that route.
Any suggestions?
Regards - John

Magpie · Postby **Magpie** » Fri Aug 21, 2015 8:32 pm

Bushes? Lower control arm issues?
My car struggled to get much caster however after lower control arms, bushes, camber bolts replaced no caster/camber/toe issues.

Postby **NitroDann** » Fri Aug 21, 2015 9:42 pm

The way the geometry is designed means you cant have max of both. Have a good look and think next time you are under it and you will understand.

StillIC · Postby **StillIC** » Fri Aug 21, 2015 9:58 pm

ja9 wrote:I've been playing around with my wheel alignment and I'm having the following issue. My car is a race car so keep this in mind. Whilst rotating the camber bolts I seem to get maximum caster with minimum camber or vice versa. Why can't I get max castor and max camber at the same time. I know it's a bit of a compromise with camber bolts but is there anything wrong with my bolts, stretched or hole is elongated or otherwise, is it a possibility that the bolts are in the wrong way.

The front bolts set the camber. The rear bolts set the caster. Having said that...

...the front bolts, if set at max negative camber, will pull a touch of caster out relative to zero camber. It is simple geometry as to why this happens. Think about where you are placing the outer tip of the triangle (ball joint of lower control arm) relative to the chassis when you move the bolts around. If you move the ball joint out (set front bolt to maximum negative camber) you are also moving the ball joint backward by a small amount, as the triangle swings around the only point not moving, which is the rear mounting point. Moving the ball joint out, and therefore backwards, increases negative camber and reduces positive caster.

I don't imagine there is anything wrong with your bolts, but you cannot change the laws of geometry. But, if you were able to adjust the camber out at the ball joint, instead of at the inside front mounting point, the issue would be eliminated.

StillIC · Postby **StillIC** » Fri Aug 21, 2015 10:19 pm

ja9 wrote:The reason I'm after maximum castor is because I'm running power steering and would like more feel in the steering. Regards - John

BTW, extra caster will reduce steering feel in my opinion. But it will increase negative camber on the outside wheel when in a turn, thus giving extra lateral grip.

Anecdote...stop reading unless you are very interested....

Years ago I replaced the trailing links on the front suspension of my Datsun with adjustable links so that I could play with (more) caster. When I mounted the adjustable links, I dialled in a shed load of caster, drove it once, then pulled a bit out. Every weekend I would pull a bit more caster out until one day I was happy with the steering feel (especially immediate turn in). Some time later I decided to measure the length of the link as I had it set, and compared it to the length of the standard Datsun part. To my surprise I had the adjustable link set to the same length as the standard part to the nearest millimeter! I promptly removed the adjustable links and replaced the standard links. Lesson learned.

Dan · Postby **Dan** » Fri Aug 21, 2015 10:21 pm

StillIC wrote:The front bolts set the camber. The rear bolts set the caster. Having said that...

...the front bolts, if set at max negative camber, will pull a touch of caster out relative to zero camber. It is simple geometry as to why this happens. Think about where you are placing the outer tip of the triangle (ball joint of lower control arm) relative to the chassis when you move the bolts around. If you move the ball joint out (set front bolt to maximum negative camber) you are also moving the ball joint backward by a small amount, as the triangle swings around the only point not moving, which is the rear mounting point. Moving the ball joint out, and therefore backwards, increases negative camber and reduces positive caster.

I don't imagine there is anything wrong with your bolts, but you cannot change the laws of geometry. But, if you were able to adjust the camber out at the ball joint, instead of at the inside front mounting point, the issue would be eliminated.

Great explanation of the relationship between camber and caster!

ja9 · Postby **ja9** » Sat Aug 22, 2015 7:03 pm

Thanks for the detailed explanation. Why can't I get the same numbers left to right. I'm not off by a lot but it would be good to get the same caster on both sides. I've managed the same camber at the experience expense of caster.

Magpie · Postby **Magpie** » Sat Aug 22, 2015 8:19 pm

The lower control arms are easy to damage. As stated it is pointless trying to get things right if what you are working with is not as designed. It was only after I replaced bushes, tie rod ends and lower control arms was my alignment issues sorted out.