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Laser Wheel Alignment: Chassis Mounted Vs Wheel Mounted

Laser Wheel Alignment Systems

Laser Wheel Alignment Systems are a modern approach to wheel alignment. Wheel alignment certainly is one of the most significant setup parameters for racing cars. You would ask why… Because even things like moment center location and setup balance lose their importance, compared to wheel alignment. The alignment package has a massive amount of influence on the way that a race car behaves and performs.

One of the most common questions asked is which is best – wheel mounted or chassis mounted lasers? Answering such a query is not easy: a more precise question would be which laser wheel alignment method is better for accuracy. Then, we would have to say that the chassis mounted laser is the right answer. As to why it is so, please find below…

The Wheel Mounted Laser

The wheel mounted laser is very much likely to give mounting inaccuracies. Even if the hub or spindle adapter is flawless, it’s still extremely probable to have a burr on the hub or spindle face. Consider the following scenario: a simple piece of silicone 0.010″ thick left on the rear hub face will throw the laser off by 0.332″ by the time it reaches the leading edge of the front tire. Moreover, once we mount the laser to the wheel, that wheel now becomes the “master” reference point. In order to apply this method with accuracy, you will have to first check axle tube straightness, and then test rear end placement or wheel alignment. This rule is valid for all wheel mounted systems. On the other hand, what is also true for wheel mounted lasers is that the further you project the laser, the more accuracy you will gain. Still, in case that your mounting surface and adapters are not absolutely perfect, you will observe more inaccuracy again.

The Chassis Mounted Laser

Moving on to the chassis mounted laser. When it comes to chassis mounted laser and wheel fixtures, the fixture can be off, but the laser will not be. Considering the scenario we talked about earlier, if the wheel fixture is mounted with the same 0.010″ piece of silicone under it, that wheel will be off 0.078″. Undoubtedly, this still matters, but the inaccuracy is much less than 0.332″. Another fact that we have to mention is that only that one wheel will be off, because with the chassis mounted laser, the chassis is the master.

If we are to go into more depth about this laser wheel alignment option, it is worth remembering that when we mount the laser to the chassis, we’re able to measure axle tube straightness, as well as rear end placement and rear to front tire alignment simultaneously. This will save you a massive amount of time.

Mounting the lasers to the chassis also enables the user to make suspension adjustments and read the changes instantly. For example, if you decide to adjust a trailing arm or a panhard bar, you can watch the rear end location change as you turn the tubes. Your adjustment moves the chassis, which has the lasers attached to it. Once you square the lasers to the chassis, you can make any adjustment to the suspension and the lasers stay square.

Finally, it would be best to look for laser wheel alignment systems that have chassis mounted lasers that are adjustable. Having adjustable lasers allows the user to tune the laser to the master reference points, while also eliminating the possibility of a laser being “out of calibration”.






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