It seems there is some concern the CTC20 I used was not used in the CTC16 and therefore not interchangeable for swaps. I checked the dc resistance of the ctc20 tire versus the ctc16 tire I have as spares. Well for all concerned, they were identical. Both flys had the same lug arrangement and the same added cores for aux signals. Only the mounting plate holes were different, but who cares! Really, if a failed ctc16 or ctc20 can be saved by drilling s few holes and rearranging some pickoff coils I certainly would go for it.