...for '48 Model 30. Chrono, etc, all correct but getting conflicting info on cable length.
If you cannot find what you want you can get some companies to make up a cable to your requirements .Not dear . I had a good orriginal outer and had a couple of inners made for a Dommie.
According to the Smiths Speedo cable book, for 1947 to 1948 this is as follows. From October 1947 to 1948 the Speedo cable length was 4ft 6 inch. To October 1947, the cable length was 4ft 8in. So as your is a 1948 model it is 4ft 6in long. This is for a model 30.
...Is that Smiths catalog to be found anywhere online?
I bought those Smith books at the Kempton Park auto-jumble and i bought them all as one lot. This is the first time i have had to use it to look some thing up. This must have been an ex dealers stock. As for it being on line i would not know.
Some of the cable suppliers have on line lists.
......that I have found are post 1954. Thanks again Anthony. Supplier in Canada has it for me.