When did Ford change the shape of the wheel spokes from oval to round?

During 1916, early in the 1917 model year. The wheels still had round felloes. Front hubs were still machined for a speedometer gear.

In addition to when the spoke cross section change it’d be interesting to know why Ford Motor Co felt it needed the change to a round cross section; was it for styling sake, increased strength, lower production cost, or a combination of all of the above. It’s fascinating to consider the strategy behind the evolutionary changes made to the Model T Ford over it’s production life. We’re very fortunate that the car had been documented so much over the years and to have such dedicated hobbyists who bring more and more information out to the enthusiasts .

Over the years I’ve turned quite a few spokes and have never tried to fashion an oval cross sectioned one nor attempted a trapezoidal hub spoke. Just the work involved in making the simplest kind of spoke has made me justify buying ready made spoke instead of taking on the labor of turning any more of my own. Unfortunately my early spoke turning was done with oak, before I learned about having to use shagbark Hickory. When done well natural finished wood spoke wheels though not original for most T’s really are an eye catcher.

I should have said the spokes were never oval shaped. They were teardrop Profile prior to the round Profile. The round Profile made sense because there was no way to install a spoke backwards. It was for saving time . Which equaled money.