Anyone who has flown a tail wheel aircraft will attest to how inherently unstable it is to have the CG behind the main wheels. (There are those who have groundlooped and those that will ) Positive stability would be when the rear wheel wants to correct back to center. That's simply not the case with a reverse trike as the rear will want to continue it's deviation and the rider has to continually keep it in line (negative stability) If the track or alignment is off the issue is compounded. The factory alignment is simply not precise enough. Basically, the laser alignment keeps everything more centered alleviating the constant corrections we've gotten used to.
Cars can be off quite a bit on alignment and even the more extreme ones are still fairly stable and simply take a hit on tire wear.
The problem with BRP's alignment approach is that they very precisely set alignment using the frame as reference. This results in a wide variation in results and rarely gives correct alignment.
Now if the frame and wheels were perfectly aligned then the frame would be a suitable reference. The problem is, they are not. Nor should they be expected too.
You've got 2 front wheels sitting at the end of a complex suspension system with many components. Each component being 'Within Tolerance' which means 'Acceptable Variation'.
Each small variation in each component is multiplied as you go out to the terminus which is the front wheel. Multiply this times 2 (2 front wheels) and you can see where using the frame could be problematic. These values are small in normal terms and the end result must also be 'Within Tolerance'. But our Spyder requires a very accurate alignment. Anything less will cause issues.
Then you have the rear wheel mounted at the end of a very long swing arm, which again, has several components, each within tolerance. A bit off at the swing arm bolt and you're quite a ways off at the axle. This may be slight in terms of measurement but significant in terms of alignment.
But in reality, none of this is a big deal and exists in every vehicle.
Do you see car alignments done using the frame as reference? NO! And why not? Because the frame can't be trusted as an accurate 'Zeroing' factor. How is a car alignment done? By using the wheels as reference and in relationship to each other. The idea being to get all wheels going the same direction or 'Tracking' straight.
Laser alignment disregards the frame altogether. Instead, it uses the rear wheel as reference. First, you need to be sure the rear wheel is tracking straight. Once that is confirmed then you can align the front wheels to track straight relative to the rear wheel. Now you have harmony between the drive wheel and the front wheels, nullifying any anomalies in frame/suspension components. Harmony is GOOD!
So now you have straight, stable, efficient tracking of all 3 wheels. Mis-Alignment causes uneven front tire wear which is due, in part, to having to fight the rear drive wheel wasting power, fuel and rubber, not to mention your nerves, shoulders, arms and wrists as you fight to keep your Spyder headed straight down the road.
I don't mean to make this sound like some epic struggle. It is, many times, very subtle, even imperceptible. But the results can be sore hands/wrists/shoulders at the end of a long ride.
