Caster adjustment- how much?

ubercrap · Post by **ubercrap** » Tue Jan 10, 2006 6:59 pm

I decided to grind the existing metal on the subframe to create slotted holes on the front subframe mounts to adjust the caster instead of trying to drill it out and put slotted inserts in there. It has taken awhile to do it with a dremel (as you can imagine), but I have about 5mm of adjustment now on one side. That is, the subframe could sit about 5mm farther forward. How much adjustment translates into how much additional caster angle?

ubercrap · Post by **ubercrap** » Tue Jan 10, 2006 8:14 pm

OK, I think I answered my own question. It looks like I have about 7mm of forward travel available on the rear captured nut mounting point for the subframe (judging by the clean circle where it was mounted). I've got about 6mm now on the slotted front mounting point I've been working on so far. Very tedious...On the up side, I completed a prototype polyurethane radius arm bushing. It looks crude as heck, as I cut it with a hacksaw, then drilled the center with a wood boring bit, and put a radius on the edge by hand with a dremel, but it fits just fine and looks like it will work well. When installed, one can't see the imperfections, just looks like an awesome red poly bushing!

ubercrap · Post by **ubercrap** » Tue Jan 10, 2006 9:49 pm

So far...

raygreenwood · Post by **raygreenwood** » Wed Jan 11, 2006 7:49 am

At one time I had the calculations for the change in strut inclination versus how much castor. I think it was around 2mm forward increase to get you to about 2.7 degrees.
This will also depend for about .5 to 1.0 degress on wether your front end is level with the rear or not. That gets you a little bit of static castor. Ther best wqay to adjust this is on teh alignment rack. make sure what your normal kit is going to be in teh trunk...like tools that you always carry, spare tire and at least a 1/2 tank of gas in in there. Then have it aligned and adjust it on the rack. Turning castor is most important. Ray

ubercrap · Post by **ubercrap** » Wed Jan 11, 2006 10:39 am

I see, well, I didn't really answer my own question now that I read it again. So, 6mm of adjustment should be more than enough? Is the goal 2.7 ADDITIONAL degrees of caster?

raygreenwood · Post by **raygreenwood** » Wed Jan 11, 2006 11:31 am

I can't remember the stock specs...but they are about 1 degree. Generally I find that when you get teh car on teh alignment rack...you get about 1 dgree of camber. You can split it back and forth from side to side to balance it...via the captive slotted bolts that go side to side in teh front end....but there is no way to increase as it is stock. I find that when you can get right at 2.5-3.0 degrees max....it REALLy improves handling.
Additional castor adds steering difficulty as well. you may find that it requiers slightly more muscle to turn...but its not sigificant in feel. iwould not go much over 3 degrees. When castor gets too high it increases leverage on bushings and other parts. Ray