To explain more fully, weekends have always been the preserve of family life and trying to race regularly on a Sunday caused much moaning from wives and partners of members.
Tuesday evenings don't clash with family requirements and worked well for the majority who like to attend regularly.
Also, when we had the electric club many many years ago it ran on a Tuesday night. Reasons at the time I think where that a Monday was no good as those who raced on a Sunday wouldn't have time to get the car ready again.
As far as I know no other clubs anywhere near us ran on a Tuesday (and still don't) and it didn't clash with other stuff like the "friday big shop" and going to the pub etc. At one point we had a venue change and ran on a Wednesday night.....it was like a Ghost ship....40 drivers to 15....strange but true....we soon moved back to Tuesdays