Newer tracks, or very smooth tracks, such as Kansas or Southern National, allow for lower crossweight to be used since the track has enough grip to provide traction without help from the car. Bumpy, low grip, tracks such as Five Flags Speedway or Atlanta Motor Speedway don’t offer large amounts of grip, so crossweight is set higher at these tracks to make the car a little more stable over bumps and while the car is sliding on the worn out surfaces. Since crossweight adds weight to the left-rear tire, this provides more traction while on throttle (which is why Dirt folks call it “bite”). Specifically, bumpiness and grip level offered by the surface itself. Similarly, cars with higher left-side weights can get away with a higher crossweight.Ĭrossweight is often a key factor in forward traction, however, and is usually tailored to a track’s characteristics. Typically, a higher nose weight will need a lower crossweight to keep the car going around the track, while a lower nose weight will need a higher crossweight. Crossweight, instead, is used in conjunction with spring rates, nose weight, left-side weight, and track characteristics. Crossweight, by itself, is not an indication of whether or not a car will be tight or loose and should not be treated as such. While the normal “more crossweight = tighter” is a guideline, it is by no means a law. These are both ways to represent the same thing, and a crossweight percentage can still be derived from the individual corner weights if desired. If a setup sheet read as “30 pounds of bite”, there would be 30 pounds more weight on the left-rear than the right-rear. Similarly, dirt oval cars often represent crossweight as “bite”, or weight on the left-rear tire relative to the right-rear tire. For instance, if that value read as “-100 lbs to the left front”, then the left-front tire has 100 pounds less on it than the right-front. iRacing’s garage for the DW12 represents crossweight as “ xx lbs to the left front”. For Indy Cars, this value is the amount of weight on the left-front relative to the right-front. Both of these cars typically represent crossweight as a value of weight for a specific tire on the car. Indy Cars and Dirt Oval cars are the most dramatic departure from the common crossweight percentage value.
The way crossweight is represented for a given series or type of car can be wildly different. Values above 50% can be thought of as “positive” crossweight, values below 50% can be thought of as “negative” crossweight. While this is commonly kept at or around 50% for road racing cars, oval racing cars can vary wildly from car to car within the same class of racing. The percentage is calculated by adding the weight on these two tires and dividing that value by the total weight of the car (See diagram). An error in how the crossweight was set can make or break your race, even if everything else on the car is perfect.Ĭrossweight is the percentage of weight in the car situated on the right-front and left-tires. One of the most important details is the weight distribution because it plays so heavily into handling. Racing is about details, and making sure all the details are correct before you ever hit the track. Crossweight is a very simple concept but, along with many other things, past racing sims have over-simplified it to the point where you can run into problems in the iRacing garage.
Why would we move straight from springs to crossweight? When we dive deeper into bump stops (specifically shims, gap, and contact timing), preloads, and shocks, crossweight is going to come into play a lot. Last week we looked at bump stops, but this week we’re going to cover weight distribution, specifically crossweight. World of Outlaws ButtKicker Late Model Series.World of Outlaws CARQUEST Auto Parts Sprint Car Series.Force Dynamics Dallara iRacing Grand Prix Championship.Keyboard Shortcuts: Replay / Camera Controls.