Originally Posted by
lonesomesteve
You may want to check your serial number to confirm the year and model because I don't think there was such thing as a 400t Elance in 1982, but I do know that the two 614s, two 710s and a 311 all from 1982 that I've owned all handled 650b x 38mm with 170mm cranks quite well. The touring and sport touring models in 1982 all had pretty similar geometry, though the racing models had slightly lower BBs.
That was a typo. The bike is a 1986 400t and has the same 7.2 cm bottom bracket drop. My math shows a loss of 6mm going from from 700x25 to 650bx38. Probably confirmation bias driven, but if that 6mm was added to the BB drop on a frame running 700x25 the drop would be 7.8 cm, still higher than the 8.0 cm Richard Sachs uses on his frames. The Soma Champs Elyse fork is a wild card, as I haven't been able to compare the exact leangth of the original fork and what difference the different headset will make. MKII eyeball sez I will gain 2-3mm of height forward.
PS. Chiming in on fork flex characteristics, I am a little disappointed in how heavy the Soma fork is. I looks like a mountain bike fork with out canti studs. I don't have the specs in front of me, but there is gobs of room between the blades, probably more than could be used by any crown mounted brake. Incongruous to the beefiness of the fork, there are no mid fork low rider mounts. Neither point is a big deal, but dose point to bean counter engineering.