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Old 07-14-2006, 12:12 PM
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xntrik xntrik is offline
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There are several things to consider.
Ride height, stock suspension?, tire type, anti-roll bar stiffness.

Front end alignment is not just the readings to "the vertical world" but the relationship of the suspension components to the chassis. Chassis rake changes the caster readings. +1* caster with the rocker panels level, then rake the car 2*, and the caster will read negative 1* caster... So if you have a lot of rake and try for 1* caster, the relationship of the suspension to the chassis/frame has changed greatly and bump steer will be affected.

Just remember when you change the caster any great amount you begin to affect the bump steer and roll steer characteristics of the front suspension, because the steering arm changes relationship to the chassis components/ idler/pitman arm. 2* caster with rake might make it drive squirrelly.

(roll steer= Say in a left hand corner as the body rolls to the right, the right front suspension compresses and does toe out, and the left suspension raises and toes in. So as the car increasingly rolls to the right in a corner the steering automatically is turning the tires to the right trying to straighten out the steering. Chassis engineers designed it this way 40-50 years ago. Have you ever watched a car pick the front wheels at the drags? As the wheels come up they camber way in at the top and the tires toe IN, when the suspension compresses the camber comes out at the top and the tires toe back straight or OUT...... that is why so many are squirrelly when changing gears and getting a lot of front end lift and body roll. The toe is always changing..... ye haw. Remember the straight axle gassers from the 60s era? More lift, less weight, and NO TOE IN CHANGE)

Does the control arm manufacturer have any recommendations?

Off hand, I would shoot for 0*+.1* camber, +1* caster, and from 1/16 to 1/8 toe-in. You might try a toe change from zero to 1/8 now as the only change to see how it drives. Most radial tires don't need much toe in, but it depends on the suspension type.

60s Fords with the forward strut type front suspension with that big rubber bushing in it needed more set toe-in because the suspension moved around so much for good ride. The wheels moved rearward 1/4 inch when driving at speed due to rubber compression.

Another thing I discovered is that new poly bushings in the rear end will eliminate MOST of the wierd feelings when cornering. People blame it on the front when it is really the rear end shifting around.

I have had a couple people drive my early 60s Ford in the mountains and they asked me what kind of rack and pinion/suspension conversion I had put in. They are shocked to find the stock front and rear ends with poly bushings= just set up well.

Sorry, didn't intend to turn this into a book.

edited: One final note.... by actual experience. Some tires drive squirrelly and some tires are great (H-V rated performance tires) when tried on the same car. I needed a quick set so I slapped on the identical size S speed rated Radial T/As and it drives like %^&*.


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Last edited by xntrik; 07-14-2006 at 12:23 PM.
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