I recently bought a vintage Raleigh Trilite, Scott Tinley signature model. I think it is circa 85-87. I am a road bike newbie, and love the bike, but the gearing is way to high on my inner chainring. I am tired of walking the bike up simple hills. I currently have a 53 tooth outer chainring and a 42 tooth inner chainring. I have gotten great support on this forum and guys have suggested changing the inner to a 38 or 39 chainring. I have a Suntour Cyclone Crank 7000 – also says on the back, Sugino Japan with a stamped 175 and 1GC. I have heard that my bcd is a 144mm. I don't know how to measure the bcd and if it is the same on the inner and outer chainring. The rear gears are as follows .
A. Biggest 23 teeth
B. 21 teeth
C. 19 teeth
D. 17 teeth
E. 15 teeth
F. Lowest 13 teeth

Is there an obvious swap out of a suntour product, or something else compatible? I would love to get in touch with my inner chainring.