1967 driving issues

[Jeremy H.]

Just finished a 67 BB conv, full frame off. I have had the car computer aligned. My problem is that when you accelerate the car pull slightly to th eleft then when you let off it comes back to the right. I have checked the suspension and everything seems to be ok. All alignment shimms are in still in place. When it was just a bare frame we measured the frame specs to make sure it was in align and it was. I have driven one other mid-year before that did the same thing, I was looking at buying it but didn't so I never found out what was wrong with it. Any thoughts?

Thanks

Jeremy Hedges

[Tom H.]

Re: 1967 driving issues

What kind of tires do you have? Had a 65 once with a bad set of radials that caused a similar condition.

Other things to look at would be shocks. Other suspension components would all be suspect until you start ruling them out one by one.

[Tim S.]

Re: 1967 driving issues

Jeremy,

It is my opinion that the problem lies in the design of the IRS. Under hard acceleration, the camber settings can change quite a bit. Thus, steering the car from the rear. In the past, I have not liked the rear camber settings that are given as ideal for the rear of the car. Im sure someone more knowledgeable than I will have a better answer to offer. Best of luck.

Tim

[Jeremy H.]

Re: 1967 driving issues

Coker bias plys. Already changed shocks once. I have other cars with the bias tires that don't drive like that.

Jeremy Hedges

[John H.]

Re: 1967 driving issues

Try swapping the tires front-to-rear and see if the issue persists; Cokers aren't exactly famous for being round or of consistent diameter.

[Ralph P.]

Re: 1967 driving issues

I had a similar issue years ago on a '66.... turned out to be one worn rear tire that was different diameter from other. Problem went away when that tire was replaced .

[Duke W.]

Re: 1967 driving issues

The car should have been aligned on a full four-wheel alignment machine that reads out the toe-in per wheel, not just the total, and there should be minimal difference between the values for the rear wheels. Also, the camber readings should be within 0.2 degrees.

Another issue could be tire dimensions. The type of tires you are using don't have a very good reputation for consistency or quality.

Jack up the rear and measure the tire circumferences. If the delta is more than about a half-inch, that could be a problem.

Swap them side to side and see if it pulls the other way. If not, then the tires are probably not the problem.

Duke

[Wayne W.]

Re: 1967 driving issues

I would suspect the thrust angle. Alignments are only as good as the operator.

[Jeremy H.]

Re: 1967 driving issues

Measured tires, they were off by 1.5 inches. Changed tires, problem fixed. Thanks for the help.

Jeremy Hedges
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