Dave Stribling
November 10, 2016

Bumpity Bump

I have a 1965 Mustang hardtop with mid-eye leaf springs and 2 1/2-inch dual exhaust. I have 4 inches of travel before the axle hits the suspension bumpstops, but only 3 inches until it hits the exhaust. Where I may find longer bumpstops that would prevent the rear from hitting the exhaust?

Rob Nagy
Via the Internet

I am not aware of any longer bumpstops. But before I did that I would try a few other things. The 2 1/2-inch exhaust and the mid-eye leaf springs means you have lost at least an inch and a half of travel. You didn’t mention if your springs are 4, 4 1/2, or 5 leaf springs. Springs are terrible at absorbing energy; that is the job of the shock absorbers. The spring returns most of the energy back when it rebounds. Shocks keep things from overextending. Rule of thumb with any spring: The lower you drop the body, the stiffer the suspension needs to be. The first thing I would try would be a really good set of adjustable shocks to see if you can remove some of the travel. Three inches should be plenty if you have the right shocks.

Second, take a look at where your exhaust pipes clear the axle. Most systems bend in towards the center section of the rear axle. This isn’t just for clearance of the shocks. When you hit a bump with a live axle, the opposing side spring mount becomes the fulcrum point. By moving the pipe in to the middle, you take it farther away from the compression of the axle. I have seen some exhaust systems that run straight up and over, and they have had the same problem with hitting the exhaust. If both of those ideas fail, you may want to consider a stiffer spring or a helper leaf. The rubber bumper also acts as an additional damper in hard cornering.

This 1965 Mustang has a mail-order-style 2-inch dual exhaust, and although it has some restrictions in the bending, it is properly designed to give the maximum clearance. The pipes bend in towards the middle, but not enough to contact the center. This keeps the pipes away from the axle as it compresses one side or another.