IIRC, on the RV-12, there is no large axle washer between the axle nut and the Matco main wheel bearing. The washer used to be shown on Van's early drawings, but it's need/use was subsequently deleted. At that time, I confirmed with Van's and Matco that no large washer is required. As always, check with Van's and Matco to verify.
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B) - N124DH flying since March 2014 - 580+ hours (as of Dec 2017)!
through June 2018.