Gear mesh is very critical on these cars. I didn't have problems with them in the 3 or more years that I raced the DM1s. But the mesh I left between the spurs and the CB was on the tight side since I was running the Carbon chassis that flexes a bunch. With the King Headz chassis I didn't have any issues since it was stiffer than stock. I used 4 tooth difference and had no problems. I used to do the paper between the spurs and CB but even that was hit or miss due to the torsion of the Carbon chassis so later I did it by feel.