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View Full Version : What if I slightly alter the stock backspacing?



WA 2 FST
05-11-2004, 06:53 PM
I am seriously considering a set of Boyd Coddington wheels for my L. I have a set on my '69 Stingray, and when I talked to the distributor I've used they told me that they suggest going with a 6"-6.125" backspacing on a 9.5" wide wheel.

Since the stock L wheel is 5.8", would going to 6" be a problem as far as inside clearance? We're talking less than a 1/4" here. I'm going to stick with the stock size tires.

At the same time, I don't see why it would be a big deal building them with 5.8" BS in the first place. :confused: This makes even less sense when you consider that I have 17x9.5s on my Stingray with a 4.75 (on-center) BS. Those work fine.

Thanks.

Tex Arcana
05-12-2004, 09:33 PM
Okay, this is gonna be a lesson on suspension dynamics, so pay attention, there will be a quiz tomorrow. :p


What you're actually talking about is "offset", the amount the centerline of the wheel hub is offset from the actual centerline of the tire. This by itself isn't such a big deal; but when you take into account that this offest in conjunction with the rest of the suspension geometry affects the handling, then making changes to the offset could be problematic. By moving the offset one way ot the other, you change the scrub radius, or the distance between the actual tire center line, and the intersection of a line drawn thru the upper and lower outer balljoints to where said line intersects the pavement. If this line hits anywhere else other than that tire centerline, the distance from that centerline to the ball joint line is called the scrub radius.

Now, one would think that eliminating the scrub radius would be a good idea, but they've found that some is necessary to promote good handling, especially under braking.
Considering that the Lightning's handling is absolutely excellent right out of the box, I would be very hesitant to mess with its suspension geometries, unless I got advice from a suspension expert. One small change could turn your wonderfully-handling L into a nasty-handling beast that can get away from you at the worst possible moment.

Just food for thought. ;)