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Been getting questions about widening kits. Not many people know the answers behind why they’re bad, so here we go. Forewarning: I’m intoxicated The biggest geometric reason is bump steer (which skyrockets with a widening kit). The very second one is roll center dynamics. To find roll center, draw a line through your ball joint on the top a-arm and the bolt at the chassis. Do the same for the bottom. Where they intersect is your instantaneous center (IC). Now draw a line from your IC to your contact patch on your tire. Now do this for both sides. Where those last lines (yellow below) intersect is your roll center (green below). *note, I drew a blue line below just because I didn’t have the patience to line up and draw 3 more lines on my phone. It should be mirrored.* The roll center is the point around which the entire quad wants to rotate. You want your roll center as close as humanly possible to your center of gravity, but this can’t happen very easily for quads. You may be able to see that as you compress the suspension, the IC lowers as the tire goes up. If you don’t fully grasp that sentence, you should fully process it before you move forward. Since the IC lowers with suspension bump, so too does the line between the IC and contact patch change. With that, so does the intersection between the left and right sides. Basically, as the quad travels across rough terrain, the movement of the suspension changes the point around which the quad wants to roll. Sometimes for the better, sometimes for the worse depending on the roll center’s relationship to the center of mass. Longer arms make the roll center movement more subtle and therefore more predictable. Tire selection matters too. As long as ride height is maintained, taller tires will result in a lower roll center and smaller tires a higher roll center. DO NOT CONFUSE ROLL CENTER HEIGHT WITH HEIGHT OF CG. You want your roll center aligned with your center of gravity if ever possible. If your roll center is below your CG, you will roll to your right in a left hand curve. If your roll center is ABOVE your CG, you will roll left in a left hand curve. Caster and KPI/SAI (same shit really) play into this as well. In a left hand curve, the inside tire will push into the ground more because of the jacking effect (explained in a few above comments). This also means that your relationship between the IC and contact patch have changed because while the tire pushed down, it did so from turning and had nothing to do with the arm positions. So in a left hand curve, your roll center will push down and right just a little bit, helping the quad want to pull to the left a little more than it wanted to. What does all this mean for you? Lowering your quad will move the roll center and CG farther apart, causing more roll. This is mitigated by more evenly distributed tire loading under cornering forces. Installing taller tires and re-adjusting ride height to suit will make it want to roll more, not only from the side buckling of the tires but also the widening of RC and CG. Wider arms are always better with roll center. Period. More offset offers better RC/CG distance, but with anything non-power steering, always (and by always, I mean 100% of the time) prioritize scrub radius over roll center. Remember, this thread is specifically meant to help everyone. If you have a question or need a better definition or further explanation, comment or sign up and ask. Otherwise, I’m just shooting in the dark on what people need to know. Sent from my iPhone using Tapatalk