A "WM2" rim has an internal width of 1.85 inches and is not generally recommended for tyres wider than "90" (metric) or 3.50/4.10 section.

A "WM3" is 2.15 inches and therefore, is a more suitable rear rim width for a T140 so my personal opinion would be not to fit a WM2.

http://www.central-wheel.co.uk/rims/english_chrome_rim/english_chrome_rim.html

http://www.woodyswheelworks.com/rim_width_tire_size_chart.html


Also, unless the spoke nipple holes of this particular "WM2x18" rim have been punched/drilled at the correct angles to suit the hub flange diameter and width and also give the correct offset for a T140 rear disc wheel application then it may be completely unsuitable.