Smokin Joe
Squire
- Location
- Bare headed cyclist, Smoker
I ordered a spare 20" tube for the trike today. The size on the tyre wall says 37-406 1.5". So I found a tube online, same size. One thing that puzzled me is what does the 37 mean? They seem to all come with different numbers from about 35 up to seventy something, if the other numbers are ok does that one matter and what the hell is it?