Hello Eric
My 1929 2 Speed Sports should originally have had an 8 inch (or was it 7 inch?) webb front wheel in the wider type forks.This brake was notorious for being too strong for the forks and indeed the 1930 bike had a reduced brake (down to 7 inch I think).
When I got the bike it came with two of the earlier 2 speed type 5 inch webb brakes laced back to back and since riding it I can say that these have proved to be quite adequate if not brilliant stoppers.
Sure enough, when I dismantled the forks I found that the mainstem had been broken and (thankfully) expertly repaired. I assume that this was done early in the bike’s life and the change of brake took place at the same time.
Anyhow, I would also suggest extreme caution in using a large brake especially in your lighter narrow-type forks (I think ?). I can recommend the use of two 5 inch brakes. You’re only problem might be finding another one to go with the one you already have. I saw one at an auto jumble once and baulked at paying £100. I have been kicking myself ever since as I have never seen another spare again.
