Good morning, 650B!
It was because of this board that this conversion was made possible, so I wanted to share the results of my conversion.
The bike:
1985 Schwinn Tempo - 25"
Velocity Atlas Rear w/Velocity hub
Velocity Synergy Front w/Tiagra hub
Pacenti Pari-Moto 38C - actual measurements on rims 37.2mm
Tektro R559 brakes
12-28 8 speed cassette
Suntour 6-speed shifters in friction
Suntour derailleur of unknown model, label fell off years ago and I have never researched it further.
First neighborhood ride impressions:
Still feels as quick and lively as with 700x25 Veloflex Master clinchers. Nice and smooth ride. Tons of grip! I'm shocked at how planted this bike feels. The drop in height is more noticeable than I thought it would be, but it shouldn't take long to get used to.
~2mm tire clearance on each side of the chainstay. Plenty of room for fenders at the fork, although i'm limited to 45mm wide fenders without dimpling the front fender. As is typical, I won't be able to extend the fender down through the chainstays, I will have to have full coverage end at the top of the chainstay, but that should be okay with me. I don't ride in a super wet area, so the bottom bracket won't get soaked all the time.