I have a set of the brass 4:1 in a Taigen KV-1 and a set of steel 4:1 in a Taigen metal late model Tiger I. Just tested both on short grass and I would have to say the Tiger performed better than the KV-1. The Tiger floated over the ground and turned with no issues. The KV-1 ran good but did not float like the Tiger over the ground and was not as nimble in the turns. I would not be surprised if the two different suspension types had something to do with the difference in performance.

Erik from IMEX posted a picture of the brass gear sets with the dimensions in this thread... http://www.rcuniverse.com/forum/rc-t...endations.html