Tuning out front end bounce

[bret]

Originally Posted by MattO

So I have a 2005 GMC Canyon on QA1 coilover shocks in the front and I'm getting alot of front end bounce as if the shocks were at the end of their life span. I hope this isn't the case because I JUST had them rebuilt about 5k miles ago.

The shocks are single adjustable and if I make them more stiff then it helps, but only a little, so I'm wondering if I may want to switch to a stronger spring, or keep playing with the shocks.

The rear is leaf spring with non adjustable gas shocks if that matters.

If it is bouncy that typically means you need more rebound force in the shock. While the QA1 single adjustable shocks do have a rebound adjustment, it also significantly affects the compression side as well. While this may not be a factor in a "normal" weight car, it can become troublesome in a heavier vehicle like yours. Turning up the rebound enough to resolve the bouncing may increase the compression enough to give you a harsh ride. The trick is to find a shock that will allow you to increase the rebound with a minimal affect on the compression side.

The other problem you might be experiencing...the QA1 is a twin tube shock...the working diameter of the piston is 1". The same OD mono tube shock has a piston diameter of 1.78"...almost 3x the effective working area. The bigger the piston, the more efficient the oil control. Very important on a heavy car or one where you want precise and repeatable performance. A twin tube design is typically adequate for most civilian cars, but the mono tube design has been incorporated into the higher end units such as Penske, Ohlins, JRI, ...and RideTech (you knew it was coming, didn't you? )