Camber and Toe In On Radials

[Patrick T.]

After reading so many good reviews from Members who swear by reproduction radial tires for the street, I bought a set of Coker Classic redline radials and powder coated rally wheels for the steet, and will keep the bolt on aluminum wheels and OEM's for show only. The car handles a LOT better, but I still experience a little wandering of the rear end, but nowhere as bad as with the OEM's. I was thinking that maybe an adjustment of the camber and toe in might be in order.

Right now I have the rear wheels aligned to factory specs, but the radials seem to have more tread width, and I'm not sure if the factory settings would be correct. For those of you that have switched to radials, did you find that the ride was greatly improved using the factory specs or was an adjustment required? Any thoughts? Thanks.

[Bill Clupper]

Re: Camber and Toe In On Radials

Not sure what year or tire size you are working with, but the later cars with 70 series tires used a diffeent bracket under the differential to mount the rear strut rods. It effectively changed the pivot point slightly to make it more compatible with the more modern aspect ratio tires.

[Patrick T.]

Re: Camber and Toe In On Radials

Hi Bill, I should have mentioned that the car is a '67 convertible and the tires are P205/75 SR15 and also the entire rear suspension has been completely rebuilt from spindle to spindle. Patrick

[Duke W.]

Re: Camber and Toe In On Radials

The new strut rod bracket on the '68s lowered the rear suspension roll center. This results in less camber and track change with wheel vertical movement, but it also reduces the inherent roll stiffness of the suspension with the same spring rate, so the car would understeer more than a C2 with the same spring and anti-roll bar set-up. For this reason you can't directly compare the C2 and C3 suspension. For a given spring rate and front anti-roll bar, the C3 would need a rear anti-roll bar to have the same roll stiffness distribution. The rear suspension design change in '68 was motivated by the "wide" bias play tires, which don't like a lot of camber change.

Correct me if I'm wrong, guys, but I don't think any small block C2 even with the various HD suspensions ever had a rear anti-roll bar. All C2s with rear bars are big blocks. The rear bar offset the increased inherent understeer in a big block configuration because of the increase in front weight distribution.

Duke

[Terry M.]

Re: Camber and Toe In On Radials

Duke,

You are correct, NO 1968-1972 small block came from the factory with rear sway bar - regardless the suspension option.

Terry

[Duke W.]

Re: Camber and Toe In On Radials

Radials don't like a lot of toe because they have longer contact patches and more inherent self-aligning torque than a comparable bias ply tire. My suggestion would be about zero camber, one to two degrees caster and 1/16 inch total toe on the front. A higher caster setting will improve steering feel, but make the steering a bit heavier.

If the rear is wandering around you may have unequal camber or toe on the rear which can bias the rear to one side or the other depending on road camber. I recall a couple of lengthy threads on measuring and setting rear camber and toe about four to six weeks ago (check archives). I'd suggest minus a half to minus one degree rear camber, and 1/16" TOTAL toe. The trick is to get the toe equally distributed on each side. It looks like from most of the guy's experience it's tough to find a shop that can/will properly measure and align your rear suspension, so you can add this to the DIY list. You begin by purchasing a roll of thin, strong string and a some yellow marking crayons. Aren't hobbies neat!

Duke

[Dave #24235]

Re: Camber and Toe In On Radials

I've got a 66 that I've run with radials for 12 years. To stop the bump steer and wandering, have the front end aligned with 1976 specs. 76 cars came with radials and the frame is almost identical. The radials are amazing, when the front end is set up for them. - Dave