I’ve searched but haven’t been able to find what the effect of changing track width using shorter/longer hubs while keep them mounted with the same amount of axle in the hubs. I know that the general rule of thumb is longer hub equals more grip, but every reference to that is assuming that track width remains constant and so really all that is saying is that a stiffer axle equals more grip. I know the answer is get some different length hubs and test it out, but I’m trying to get an idea of the effect before dropping coin on something that may not be a valid tuning avenue.
So you want to know the effect of widing the track with larger hubs instead of spacers?
Rear track width mainly controls rear end stability and rate of inside rear wheel lift. So altering the track width while keeping the same amount of axle covered by the hub is going to adjust that mostly, but you won’t get the change in side-bite that you typically see with a hub change that changes the amount of axle exposed.
A wider rear track is going to lift the inside slower and make the kart more stable in general. A narrower rear track is going to make the kart more reactive, lifting the inside rear more aggressively.