It's a long story but here it goes. We have fought rotor loss with the CDF from the beginning, particularly bad in wheat. Also had a lot of problems with overthrashing in dry soybeans resulting in severe shoe overload. The CDF worked great in green stem conditions but we always had a dirty sample. We put in a precision farm parts progressive rotor. So far sample has been very good but in dry conditions still getting some shoe overload. We are not sure if we ever had the CDF set properly with regard to the clearance under the front of the grate and getting it to zero at the back. We noticed a huge amount of wear on the second row of cylinder bars and we felt like the staggered rotor may help with this wear problem. In our area conventional combines have always dominated the market. R series (52, 62, etc.) never caught on as we were losing dealers at this time. The walker machines seem to do a very good job in our small, irregular fields. Currently running an l-3 side-by-side with the 62. Sample is equal or better, capacity a little less, but still very acceptable. I guess we are trying to get the rotary to work the same as the conventionals as far as getting a good sample in highly variable conditions.