What is your “Wheelbase” and what does adjusting it do? Wheelbase is the horizontal line between the front and rear axle center points. Adjusting the wheelbase changes weight distribution which in turn changes how the car reacts. Do not confuse wheelbase adjustments to using a longer or shorter chassis. That maybe a future tip of the week.11
Adjusting the wheelbase on most cars is as simply as moving some shims around on the rear axle hub carrier outer hinge pin(in most cases). Some cars do locate these shims on the inboard hinge pin, and some even have both locations available for adjustment. Making your wheelbase longer increases stability which is better for rough tracks or open fast tracks with high speed sweepers and corners. Longer wheelbase setups don’t rotate as quickly in sharp turns such as 180 degree switch backs or quick multi-apex corners. Shorter wheelbase car setups places more weight on the rear wheels which helps the car rotate quickly around sharp corners increasing steering response.
The wheelbase adjustment also affects the forward traction of the car. The longer the wheelbase(hubs rearward) the more weight is placed forward giving up some forward bite. Conversely moving the wheelbase shorter(hubs further forward) increases forward bite.
As with any chassis adjustment, there is a give and take here. Chassis tuning is all about finding that balance which gives you the fastest more consistent lap times. Don’t tune your car for “Hero” laps, you need to tune the car to be as consistently fast as you can drive it.