In 1924, Advance – Rumely introduced the “Light Weight” line of Oil Pull tractors which featured a pressed steel frame in place of the heavy channel built up channel iron frame. Rumely completely redesigned the engines, transmissions and drive train used in the Light Weight line as well. The drive gears were completely enclosed and ran in oil, a big advantage over the exposed gears of the Heavy Weights as dust wore exposed gearing badly. The Light Weights were generally more compact tractors than the preceding Heavy Weight designs particularly the Model E and Model F.

The Model R featured a two cylinder engine with 7 13/16 inch bore and 9 ½  in stroke running at 540 rpm. There was force feed lubrication to the engine combined with splash lubrication in the bottom of the crankcase. A Manzel lubricator fed oil to the force feed lubrication system. The engine was equipped with a DU4 Bosch magneto, Donaldson air cleaner and a Seccor-Higgins Carburetor. The transmission offered 3 speeds ahead and one in reverse. Type R was rated at 25-45.

The Museum’s Model R has the serial number 526 making the tractor built in 1926.

The Museum’s Model R is fitted with a disc type flywheel which was introduced on the Light Weights to replace spoked flywheels. The disc type flywheel was disliked as it seemed to magnify engine sounds. As well, it was claimed disc type flywheels could ring like a bell under certain circumstances. Rumely in response to complaints changed back to spoked flywheels on their tractors. Many tractors produced with disc type flywheels had the spoked flywheels installed at a later date.