Wheel diameter

[pskipper]

When wheel diameter is quoted for a loco is it the full diameter including the flange or the diameter of the bit that touches the rail?

Thanks,

Philip

[GTB]

When wheel diameter is quoted for a loco is it the full diameter including the flange or the diameter of the bit that touches the rail?

The quoted dia. of a protype wheel is as measured over the tread, not over the flange. Put simply, yes, it's the dia. of the bit that touches the rail.

Because most (but not all) prototype wheels have coned treads, the convention is that the measurement point is at the root radius, where the flange meets the tread and model wheels follow the same convention.

The wheel profile diagram on the 16mm Association standards shows how it works for model railway wheels if the above is as clear as mud........

http://www.16mm.org.uk/newsite/files/de ... tml#wheels

Graeme

[pskipper]

Nope, that was perfectly clear, thank you. Some ebay bidding may be going on in the next day or two

[pskipper]

Thank you again, the loco in my signature now has wheels Nothing else yet but wheels are a good start