The device accuracy is variable by increasing the target distance.
It is a compact unit, 1/2 the size of a attaché case.
Does not require large bulky frame work.
Does not require large specialized plates to be mounted to the hubs.
Universal to all race cars
Since you are viewing a laser beam spot on a target you have a VISUAL change in bump steer
vs. having to watch confusing dial indicator movement.
Shows camber change due to bump which can not be done by any other bump steer gauge.
The laser can be used for many other uses.
The precision of the unit never changes and is never affected by weather or temperature.
By utilizing graph paper for a target, engineers can plot bump steer and camber change simultaneously.
Here is a link to Xtreme Classics ( our customer ) where Mark uses our Laser Bump Steer on his GT40. At the bottom of his page shows
how he has graphed the laser beam. The left to right movement of the laser beam is bump steer ( toe angle change )and the vertical
movement of the laser beam is bump camber ( camber change ) during bump. Mark starts at minus 3 inches ( full droop ) below ride height
and moves the suspension through ride height and into full bump at 2.5 inches.
You can see in the bottom photo to your left where Mark shows that all that is required for our bump gauge is to attach the mirror to the hub and clamp the rotor from turning.
This leaves you plenty of room to work on the suspension during the process.
With dial indicator type bump gauges you have a big plate bolted to the hub and a huge frame with the
dial indicators on it that has to be removed in order for you to make your adjustments. How inconvenient is that?
By the way check out Marks products and services at Xtreme Classics. We highly recommend.
Advanced Racing Technologies, Inc., would like to thank Trackside magazine for allowing reproduction of the following article.
A.R.T. would like to add that this laser gauge also shows camber change simultaneous with bumpsteer . There is no known bumpsteer gauges other than this laser bumpsteer that has this capability.
"This is a quality bump steer gauge that anyone who is serious about their set-up should have."
Laser Bump Steer by Adam Patutka, A.P.E. Motorsports
"Advanced Racing Technologies' president Robert Phillips had the idea of using the precision of a laser to measure race car statistics, such as bump-steer, camber gain and others soon to come.
"The principle behind the gauge is very simple. Any light, (in this case a laser) that is reflected from a surface, will reflect at an angle twice the angle at which it struck the surface. Therefore, if the surface you are reflecting off has changed orientation, the direction of the reflected light will also change.
"This unit is designed to get the most use out of a laser and the space you have available. The kit includes a pen laser, two magnetic bases, a mirror, a laser shutter and holder and some graph paper. The set-up is very simple, but must be done carefully to obtain the best results. First, the car is made race ready with all fluids, tire pressures and driver weight of equivalent. The corner of the car that is to be measured is blocked at ride height.
The tire, shock and spring for that corner are removed and a jack is placed under the lower suspension member. The radius of the tire is measured and the center of the hub is set at that height to begin measurements. The mirror is attached to one of the magnetic bases, which is then attached to the brake rotor, with the tall side of the mirror going up and down. The laser, the other magnetic base and the laser holder are assembled.
"At this point, the shutter should cover the laser beam. Even a low power laser like this is dangerous. Exposing your eyes to a laser can cause damage. The base is set up about three to four feet from the mirror and at a height about three inches less then the radius of the tire. The laser should hit the mirror in the middle to allow measurement to be taken for the full travel of the suspension.
"Next, the target (a piece of graph paper) must be set up. This needs to be mounted between 60 and 96 inches away from the mirror. Calculations have been done for distances of 60,72,84 and 96 inches. Positioning the car so this target could be mounted on a wall at one of these intervals is helpful. When mounting the target, the further away from the mirror, the more accurate the measurement. Taken out far enough, the bump-steer can be measured to millionths of an inch. If you happen to need precision like this, the A.R.T. product is the only one on the market that can provide it. The target should be positioned so that the point of the laser hits the center of the graph paper. From here, it's just a simple case of marking the graph paper, first at the starting point and then at each interval of travel. The intervals you use will depend on the amount of suspension movement your car experiences. Most teams take at least two inches of travel and measure four inches both up and down. The beam on the laser is a little deceiving, an "X" should be made over every point and the center of the "X" should be at the center of the point. Once all of the points have been taken, the distance between the point are measured. A chart is provided that relates the radius of the tire, the distance between the points and distance from the mirror to the target. Using the chart with those three pieces of data, the angle traveled and the bump-steer measurements are obtained.
"This unit as many differences from the other units on the market. First, the accuracy of the results is controlled by the user. A simple spot check to verify results may need only the accuracy of 60 inches, while a trial and error session for a new suspension design might make it necessary to go to the 96 inch target distance. Additionally, the measurement is for bump steer for the tire that is on the car and not a average tire. The precision of the unit depends on the law of optics, which never change and are almost never affected by weather.
"I was able to go to the shop of A.P.E. Motorsports in Kensington, Conn. to test the unit. Adam Patutka and I spent some time with the car. The car was corrected to ride height with pressures, fluids and blocked at the corner we were checking. The set-up was simple and straight-forward. Once we had the set-up, taking the points and double checking them took less then ten minutes. The graph paper was then removed from the target and the distance between the points was measured. Once the differences were found, they were referenced to the chart and the bump steer were read.
"The bump-steer had been done on this car at the beginning of the season. After I finished writing down the measurements we obtained, Patutka pulled up the sheet from the initial test. The measurements were almost exactly the same.
"After working with this unit, Patutka said, "This unit has the potential to be more accurate then any other unit on the market. It takes a little more time to get the results, but the accuracy is worth it".
Retail $259.95
© 1996, Advanced Racing Technologies, Inc.
