27.5 wheel in 26" MTB frame
The nutshell question is, do you think the cantilever brakes on an old 26" mountain bike have enough upward adjustment to accommodate 27.5/650B rims? My calculation for the difference in radius is almost exactly 1/2" (12.5mm). Is this within the normal adjustment range of typical canti brakes - or is there some way to make this work if it isn't?
This is an old fully rigid MTB. The frame is not pristine, but is in very good shape, no dents or cracks, just patina. I'm thinking of converting it to a more all-around, drop bar, gravel-ish bike to leave in our travel trailer which we keep in another state and use for a couple of months at a time. I have and have had very nice gravel bikes which I have been carrying back and forth. I'd like to come up with a cheap, but adequate bike to leave there and end the schlepping. Mostly fitness and leisurely rides paved and gravel roads and paths. No big mileage stuff, 5-25 miles here and there, no need for a super bike. I think I can do the conversion for $500 +/- since I have a set of 10 speed road shifters, a good enough crank and some stems and handlebars "in stock". Don't need new brakes, seat post, saddle, etc. The only expensive thing I'll need is wheels, and even with them, I'm thinking of a pretty modest price range or maybe even build my own. I'll probably go with a MTB cassette and rear derailleur. The RDs of basic quality that work with Shimano 10 speed road shifters (I.e. Deore 8 and 9 speed) are usually pretty reasonably priced on EBay - I've made that conversion a few times on my wife's road bikes as well as my original "cross/gravel" bike.
As for wheels, I pretty much need to get new wheels anyway since the old ones are in pretty rough shape including the rims and hubs. I think I'd like to go with 650B with ~35-40mm tires.
I've comfortably set up several bikes for myself, and have done some rough measurements. I think I can get the fit OK on this old frameset. It's nothing like modern mountain bike geometry.
So I think the only technical issue will be the rim-brake interface.
Any words of advice?