Thread: Rear shock angle

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I’ve looked at a lot of street rod build pictures and have noticed the rear shocks at various angles and was wondering what angle would give the best ride quality?

I'm not sure it's a question of a certain ride quality at a given angle. My interpretation of it is that you want to install the shock so that its linear de-accelleration qualities are more and more progressive as it approaches full compression....without going over-center. At least that's how I install 'em.

Henry Rifle gave a valid explanation on here quite a while ago, saying that if you trapped a piece of string under the left rear tire and swung the other end of the string up to the frame or crossmember from its end at the right rear tire, you would describe the arc that tire would make on bump and that would be the ideal line on which to install the shock.

You never want the angle between the centerline of the shock and the centerline of the axle to exceed 90 degrees at full bump. Ideally, it should be right at 90 degrees at full bump to take full advantage of the shock in my opinion.

Aldan does a good job of describing it; http://www.aldaneagle.com/install.html

Most shock people says their shocks are most effective when operating nearly vertical. A static angle of 10 degrees from vertical is ideal, with the top of the shock towards the center of the car and the bottom of the shock mounted as low and as close to the tire as you can get it. Front shocks no more than 18 to 20 degrees.

OK, what about the front shock angle?

all that info is good but the shock angle will be a bit deferent for coil over springs leaf spring coil over shocks and strait axel like It1s10 said that is the way i like them. on the front if you look at some trucks or cars they are not tip in much the more you pull the in the angle the way i see it the more body roll you will have .but if the frame is narrow they will be at more angle to the shock so you want to make brackes to stand them off the frame and you do want the bottom of the shock as far to the end of the axel as you can get. this is a big deal on tub out cars and trucks if pull to much in at the top they are like a teeter-totter

with the coilover moving the shock 1" either way will change the spring rate. you need to know what the manf. says about that ,but i believe most start at around 28 degrees.
http://www.proshocks.com/srshocks/tech4a.htm

Angling the top of the rear shocks inward reduces body roll on cornering. Trucks that are more interested in load carrying don't lean them in as much.

Originally posted by R Pope
Angling the top of the rear shocks inward reduces body roll on cornering. Trucks that are more interested in load carrying don't lean them in as much.

yes i can see that to a point but not so on tub out cars or trucks

If you read the shock theory stuff it's accurate that the shock has it's greatest effect in a true vertical installation. There are charts that show the reduction in effect in relation to increasing angle of mounting.

That's all well and good. Then the reality of necessary compromise sets in. On a tubbed car, whose original intent was drag racing, you don't get much if any body roll (hopefully), and the pavement is relatively flat (again, hopefully), or at least not enough to be a significant problem. On the road you have to deal with turning (resultant roll) and uneven surfaces (potholes, shoulders, swales, crown, etc.). Axles (either solid rear, independent, or front beam axles or control arms) swing in an arc, and in the case of a "solid" rear axle, on say uneven pavement, think of one side as "fixed" (the none bump side), and the other being the outer end of the arc. That's why, if you look at a professionally engineered passenger car for instance, the shocks are angled. Sure, it's less efficient for straight up and down, but it's a reasonable compromise for the wide variety of driving conditions encountered. The shorter the "axle" the more vertical the shock because there's less arc effect.

Hay thanks guys. There is a little more to it that I thought.