BMR Suspension TAS004 - Manual (Page 10)

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SETTING UP YOUR NEW TORQUE ARM SUSPENSION
1. Ride Height. The very first thing that should be done is to establish the desired ride
height. Previously the height was determined when the Watts link was setup during the
installation process. Most of the time, this setting will be fine however driving the car
will settle the suspension slightly and best determine if the height will need to be altered.
Drive the car 10-20 miles to insure a consistent ride height and verify suspension travel.
NOTE: the suspension should not bottom out except in extreme road irregularities or
very heavy dips. It is important to make sure the shocks do not bottom out to insure long
shaft seal life. If you are out of spring adjustment and the suspension is still bottoming
out, try changing the lower shock mounting locations and re-adjusting the springs. This
will give more shock travel and increase the spring tension. In some circumstances with
heavier vehicles, it may be necessary to increase the spring rate. In this case, please
contact BMR for technical help in selecting proper rates.
2. Trailing Arm Angles. With the final vehicle height determined, check the trailing arm
angles. For proper anti-squat, the trailing arms, when viewed from the side of the car,
should angle upward slightly from rear to front (front mount higher than rear mount). If
they are level or angled oppositely, lower the rear mounting point. This angle helps
determine weight transfer upon acceleration. Each vehicle, depending on front-to-rear
weight distribution will vary slightly and favor a “sweet” spot but a slightly upward angle
of 1-2 degrees generally is optimal.
3. Driveline angle. Driveline angle should not have changed however, for long u-joint life
and a quieter driveline it is important to make sure. If the angle is more than 2-3 degrees,
refer to the BMR torque arm instructions for the proper adjustment procedure.
4. Shock settings. An entire book could be written on this subject but we will just touch on
the basics. Your QA1 shocks have adjustments for both compression and rebound. It is
important to understand that a shocks job is to control the motions of the spring. For
optimal control, you never want the spring to collapse or extend too fast. Determining
those settings will be different for everybody since vehicle corner weights, desired ride
quality, driving behavior, etc. play a role in finding what is optimal for that individual. It
is generally best to start with softer settings and work your way up. The idea is to keep
the tire firmly planted to the asphalt. Too much of either adjustment will not only create
a harsh ride but will force the tires to bounce and lose traction during aggressive driving.
The following recommendations are very basic and intended for street driving. Begin
with the compression settings at full soft and the rebound settings two clicks from zero.
Drive the car over varying road conditions and work your way up to a setting that feels
firm yet still comfortable without excessive bounce over road irregularities. Once the
rebound is set, begin adjusting the compression until ride quality begins to suffer then
back a click. These settings should provide good all-around handling and ride quality,
further adjustment may be necessary for very aggressive driving habits such as road
course and autocross racing.