Nice find!!!!
Originally Posted by
SesameCrunch
The rear dropout is 120mm, the front is 100mm.
Sounds like both ends have been spread out to take modern hubs. Our very original (at least when I got it) 1970 MkIII is 110mm and 90mm. Have the rear tip slots been filed wider to take a derailleur hub axle? Check the alignment to make sure it was spread evenly. From what I've seen, this is done poorly more often than well.
Originally Posted by
SesameCrunch
Plus, this bike has so many of the original parts, I should stay true to the original.
I would not recommend staying so true that you find another S3B hub. One of Sturmeys blunders, the brake was worthless. I replaced ours with an S5 in a 36h 1953 AW alloy shell. Since you will need to do, or have done, some brazing on the rack, I recommend adding canti brake pivots and V-Brakes.
Since your rear has already been spread to 120mm, an interesting alternative would be an
X-RD5
Probably because of them being as much a Raleigh as a Moulton, originality doesn't seem to mean much with MkIIIs. At least compared to Series 1 or 2. Seems to me most get hot rodded rather than restored.