Today's topic is rear weight. I want you to picture in your mind a top fuel dragster. They are all rear weight. Look at where the driver is, engine, transmission and rear housing. If you look at the chassis and it's design all space frame.
Now when they are towed to the line the driver steers the car there. When they place the car in the burn out box they place it in a particular location. They then get it fired. They check the lane for any debris and once ready the driver does his burnout and the rear tires go from wide to narrow and crown. Then once he's done they very carefully guide him back to where he will then stage himself into the beam to get ready for launch. If you pay close attention they guide him back to a precise location and they make sure the car is pointed directly down the track. Also it's imperative their tires are matched and aired properly. If one tire is even an 1/8 short on air pressure we know for every pound is an 1/8 of an inch the car will pull or push in that direction.
We also know once they launch and they are on their way all the weight is on the rear tires so steering input is null. Case in point is when they crash everything happens in nano-seconds and the weight never gets back towards the front so steering is useless. They only steer once they have chute deployment and engine off.
Now imagine if in the center of the track they try to turn left at max speed?? We with our cars enter the turn, then hit the middle or apex, desire to flat foot it all while turning and physics is deeply involved and then exit. With rear weight and physics tells us that the rear wants to pass right through and continue heading out of the turns. As we go through the turn the weight goes from the rf then onto the rr and once we are now headed out of the turn the weight should return to all 4 corners with the aid of the shocks. If your car has rear steer, housing misalignment either left or right and a right rear snubber the car cannot deal with all of it and worse the tires suffer greatly.
I've seen many cars and their chiefs see this and they pump spring into the right rear and then the car goes back out and when the driver is actually driving the car the car gets loose, more tire scrubbing, more friction, times come down and we are slower.
With any vehicle whether it only turns left or left and rights you want the rear to follow the front. If you run rear steer and think it only affects the turn you are mistaken. When the car hits bumps on the track and if you run toe out the heaviest tire steers the car so we see guys literally steering left and right down the straights and as the weight shifts from the tire hitting the bump he has to correct the car and as we know the chassis goes up and down with each swipe of the wheel so your rear trailing arm mounts are moving up and down so the rear turns left and right as well as the front. This scrubs tires, you lose speed and of course it affects turn entry at the other end. If they are level in the rear they cancel each other out and the rear stays straight or within a few thousandths.
So rear steer is a built in band aid for cars with poorly designed front ends that cannot turn by just the steering wheel, add in rear weight, weight transfer at throttle down, physics and other inequities like wedge and it's not the track surface, it's not poor tires. You have a built in issue right off the very jig table. And you are not alone most of those you race against suffer to some degree the very same issues. There are cars though that we see who do not. Those cars either hire someone to address ALL the issues and correct it or they are fortunate to have a knowledgeable individual to alter that car and have it work.