Denny Anspach <danspach@...>
For those interested, here is some reproducible data on which I rely on selecting Reboxx replacement wheelsets for selected Accurail and Tahoe trucks. My goal is an amalgam of maximum rollability, and minimum axle end play.
The Accurail tests have been repeated several times over the years, and they are remarkably consistent.
Maximum rollability is a pretty obvious concept, but the effect of excessive end play is perhaps more subtle: excessive end play can cause significant problems with coupler centering, particularly with scale-sized couplers; and because of the relationships of the conical axle ends and the conical bearing holes into which they fit, excessive end play can also cause a significant drop or dip in coupler height, in addition to the unfortunate visual effects of just wallowing along like a drunken sailor.
Accurail's Bettendorf trucks are reportedly produced from four different molds (#s 1-4 stamped on underside of bolster ), which creates some natural variability. However, although the 1.010" axle sets do provide superior rollability (an average of 21 or 22 rolls on the Rolltester, scale 1-26), there is far too much irritating end play for my taste. However, by just substituting the Reboxx 1.025" axles instead, the end play is reduced to only a few thousandths, without a whit less rollability. A fine combination of truck and wheel set.
Tahoe trucks: I have only tested the Dalman two level, and Brian is right on: the Reboxx 1.010" axles provide an ideal mix of maximum rollability (21 rolls) and minimum sideplay. You can use a 1.015" axle, but there is a significant drop off in rollability (17), and ditto for 1.005 or 7" axles, with side play now added in.
Denny S. Anspach MD