What is the diameter of the stock steering wheel rim on a Gen 3 USDM Prius -

Hi! New member here- Quick one: what is the diameter of the steering wheel Rim cross section on a 2011 or 3rd gen Prius USDM. I'm probably phrasing this awkwardly, but I'm not looking for the diameter of the steering wheel itself, but rather the diameter of the steering wheel cross section, it's width at the rim, or the thickness of the rim in diameter. To further clarify, I want to install a new "Spinner Knob," or what they used to call a suicide handle- it's a little spinning wheel that clips to the rim of your steering wheel and allows you to turn it quickly like you see maybe bus drivers in the city use..

If you've ever driven a third gen Prius you know that there's these awkward corners of the stock steering wheel that come down at the bottom and so if you use your finger at those corners it doesn't turn smoothly..

Anyhoo - I guess while I'm at it, I'm open to any suggestions for a high quality (read: probably using ball bearings and also durable) "suicide knob," or steering spinner thingee.. whatever is called... Thanks very much for the 411 in advance- and by the way I am pretty convinced that the Toyota engineers are probably some of the best in the known universe and the third damn Prius is an awesome little car! Hehe h Cheers! ~Z




(i hope this question isn't duplicative, I couldn't find it with a perfunctory initial search..)