First of all you English is perfect. I wish the people I work with could write as well as you. It would certainly make my life easier. LOL.

Re. 1717 vs 1518. I pretty much had the same thoughts. I am hoping that the larger diameter rotor will help efficiency but there is going to be only one way to find out for sure so stay tuned for that one. Even if it isn't more efficient at least it will have easier time moving a big truck with huge Big Joe tires and Axial wheels.

Thanks for your help nuz69.