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Wild Racing Bumpstop Guide

Wild Racing Bumpstop Guide

Dynamic Wheel Load

Over the last few years, the lower classes of dirt racing, such as B-mods and Modifieds have seen the ability to run bumpstops. I believe this trend is a good thing for all budget racers. Bump stops are a minimal cost compared to the price of racing, and can be a very good tuning device when setup correctly. This is our goal at Wild Racing, to give you the know how and confidence too run bumpstops.

First we need to understand the problem being solved by using a bumpstop. With racing trending to soft preloaded springs, we tend to have cars that are complacent in dynamic attitude. They travel to their dynamic state and do not produce the needed rear weight transfer when back on throttle.

This is where bumpstops come in. For this example we are gonna us load numbers that are not real. Lets say you're on a 500-pound RF spring, and at your 4" smash number the spring is producing 1,500 pounds of wheel load. Now Alternatively, a setup using a bump stop, will utilize a 350-pound spring and with a bump engaged at 2 3/4" of travel producing that same 1,500 pounds of wheel load at 4" of travel. With both setups we are reaching the same wheel load at the same 4" travel, but there are very important differences.

The bumpstop setup reaches its optimal load sooner, and maintains it though the corner longer. This has several advantages such as:
1. Camber/Caster will be at its optimum settings on corner entry middle and exit.
2. Softer RF spring at a preloaded state will build more energy and is prone to more rear transfer.
3. The center of gravity will be lower, and will transfer weight back to the rear faster
4. Creates more of feel for the driver, and the car will respond more to a small bump adjustment compared to a simple spring load change.
5. Will keep the RF out of the track to an extent, and wont waist any load with the frame rail digging in.

There are lots of advantages, and Wild Racings goal is to determine what bump rates and graphs that work the best with different track conditions, spring rates, and front end settings for the best driver feel and grip. This will decrease your learning curve and increase your understanding of your RF setup. Contact us today to learn more about bumpstops and all around setups!

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