The newest small-frame Standers use Hydrogear 10A pumps (as all Standers did for a while), but the newest large-frame Standers now use a Parker pump. I was wondering if anyone knows why Wright switched to the Parkers and when the switch occurred. Is there a durability or groundspeed advantage to the Parkers? Also, I was wondering if anyone knew the history and serial number breakdown of the hydro pumps used on fixed-deck Wright Standers. I have a partial history; please correct it or fill in my gaps. Here's what I've pieced together (with some guessing): Early Standers used hydrogear 10L pumps which did not automatically return to neutral--they had a looped piece of metal over them and external springs (ref: http://twww.wrightmfg.com/user_images/1/Documents/11184958832.doc). SN 0-11935 Used Hydrogear 10L with Ross MF16 motors and went 6.1 mph (6.9 mph with speedup kit). SN 12000-20425 (large) or - 20303 (small) Used Hydrogear 10L with Ross MF14 motors and went 8 mph (large). SN 20303-present Small frame Standers use Hydogear 10A pumps which automatically return to neutral (no metal loop) and go 7.5 mph with the fatter tires (ref: http://twww.wrightmfg.com/user_images/1/Documents/11185196905.doc). SN 20425-? Large Standers also used the Hydrogear 10A pumps, some were rated at 8.4 mph. SN ?-Present Large Standers use Parker pumps. From surveying the stock at my dealer: the newest small-frame Standers still use the Hydrogear 10A pumps, but the newest large-frame Standers use a Parker pump.