I have a pair of Monocoques 15 x 10 and I believe they are approx 2 1/2 rear spacing, 4 3/4 BC. I am out of the country for work until the 23rd but can confirm the back spacing and send you photos when I get home. If that is of interest to you let me know. Jim Caughlin 503-580-6385 cell
jimc@woodburn.net