This motor has an 11.45" diameter. It is a series wound DC motor with a double ended shaft. Our TransWarP 11 ™ Motor has been designed to ease the conversion process for people who want direct drive applications. It has many unique features that set it apart from any other EV motor currently manufactured. This motor has a "shorty" tail shaft housing from a Chevrolet Turbo 400 transmission fitted to the drive end-bell (may be ordered with or without housing!) This is because the drive end shaft is not the typical 1.125" single-keyed type, but rather a hefty 1.370", 32-tooth involute spline that is identical to the tail shaft spline of a Turbo 400 transmission. In other words, this motor was designed to replace a transmission and couple directly to a drive shaft! But we didn't stop there! We added double wide bearings on the drive end, added grease fittings (as you now have a slip-yoke assembly...). We chose the industry standard 1350 universal, so you can easily adapt it to any manufacturers drive shaft! We moved the terminals to the side of the motor to avoid road hazard damage, and to allow more clearance above and below. The motor also has brush wear indicators and a temperature snap switch. It has the same high efficiency fan and massive commutator and brushes as the WarP 11 motor. We even made the commutator end shaft the same diameter as the drive end of a typical WarP 11 - just in case you wanted to connect 2, 11" motors together! If that wasn't enough, we also provide a lifting ring and 8 threaded mounting holes in the commutator end bell. This way you will find it easier to mount, as well as having a method of easily attaching a speed sensor, alternator, air conditioner, etc.