I play a mechanical engineer in my office, and would venture that the gross weight spec drives the: brake capacity, wheel bearing life, suspension bushing capacity and life. And tire capacity, though this seems to have plenty of margin (maybe because they know some people will not maintain reasonable tire pressures).
Most Evs don't see copious annual mileage, so some of these effects would not appear for a long time. Brake capacity can be improved by better cooling, or using higher friction coefficient and/or temperature pads (or larger rotors/drums). Be careful with high-performance pads; if they are not meant for street or autocross use, they may not "bite" right away until they get very hot. Kevlar and semi-metallic pads may be rough on rotors, and most autocross pads require "bedding" which is not a trivial task on public roads. Harder suspension bushings are available for almost any car that people race. Maybe more importantly, the springs, sways, and shocks are tuned for a given weight, cg location, and inertia(s). If these are left alone, the car will ride lower and the suspension will move more for a given input (bump, roll, pitch). That means it will bottom out more... When the suspension bottoms on a bump, you'll feel a jolt. When the suspension bottoms in a corner, you are in for a wild ride because you no longer HAVE a suspension (it's like bolting the wheel to the frame through a piece of rubber). The overall car body is designed for stiffness, and the strength falls out of that (oversimplification warning). So greater overall mass means lower resonant frequencies; no big deal, it effects ride quality and suspension precision. This is probably effected much more by the body mods to mount the batteries. However, there will be that much more damage in a collision. Unless you are driving Lee Hart's HammerCar. The areas around the suspension attachment points may fatigue prematurely or crack if the suspension bottoms hard. - GT Interesting analogy... > Tom Shay wrote: > > If you > proposed hauling around 1000lbs of cement in a stock ICE > Escort you'd be considered crazy, but for some reason if you > change the cement to batteries it somehow becomes OK.
