b'Measuring Bump Steer Lets taLk Bump steer Step 6. Bump Steer is used as a noun & a verb in racing. When you are measuring & adjusting your cars bump steerwe call it bump steering your car.When its done we care what the actual bump steer graph looks likehow much bump steer you have throughout your usable traveland which way it goes. We call gaining toe out in dive (suspension compression) as bump out and we call losing toe-out in dive bump in regardless if were actually toed in or out statically. Lets get some basics out of the way. This is not your Grandmas daily driver. This is your race car or at least the car you race with. In our world toe-in is the enemy & toe-out is our friend. We always want the car to have toe-out to some degreestatically, in bump & dynamically when turning. Always toe-out. One key reason we do not want to cross-over from toe-in to toe-out or vide versais the tires slip angle goes neutral when this happens. Said another way, when you have a small amount of toe-out driving down the road, the tires have a small degree of slip angle in the tread that creates grip. Tire basics 101:No slip angle = no grip. If the bump steer of your car causes the tires to go from toe-out to toe-infor a brief bit of time when the tires were right in-betweenthey didnt have grip. The feel in the steering is lightness. This is bad.The same happens if go the other direction from toe-in to toe-out. So, the moral of this story is we want to stay one side of the toe equation at all times. For Grandma Nellys Delta 88 Cruiser, make sure it toes-in ALWAYS. But for our hot rods were tracking, road racing or autocrossing, we need to make sure were always in a state of toe-out. There are crude ways & precise ways to do bump steer on your race car. How precise you do it probably depends on your commitment level to performance of your car. We use the Joes bump steer measurement system that makes the job quicker, easier, repeatable & more accurate. But it can be done less expensive ways. One is to clamp a laser level horizontally on the front rotors & project a laser point forward onto a light or white surface (wall, cardboard or whiteboard).The math is easy: If you place the whiteboard exactly 8 ahead of your FACL, divide the amount you see by 4. If you place the whiteboard exactly 10 ahead of your FACL, divide the amount you see by 5. If you place the whiteboard exactly 12 ahead of your FACL, divide the amount you see by 6. If you place the whiteboard exactly 16 ahead of your FACL, divide the amount you see by 8. The farther out you go, the more accurate you will be, but you gotta work with the space you have in your garage/shop. 8 & 16 make the fractions easier to do math with. Here are example instructions. With the shocks & springs out of the car, jack the spindle up to exactly ride height relative to your chassis. (Measure this before you take the car apart)Shoot the laser ahead onto a whiteboard 8 ahead of FACL & make a mark.Now compress the suspension exactly 1 from ride height & make another mark on the whiteboard. Do this again at 2, 3 etc.whatever you plan to travel your car in diveand make a mark on the whiteboard at each point. The amount of toe-out or toe-in will look exaggerated due to the 8 distance. For example, lets say your numbers look like this& do the math. At 1 dive from ride height you gain 1/4 toe outdivide by 4 & you actually have 1/16 toe out At 2 dive from RH you gain 5/8 of toe outdivide by 4 & you actually have 5/32 toe out At 3 dive from RH you gain 1 of toe outdivide by 4 & you actually have 1/4 toe out 391'