Originally Posted by
oddjob2
No on mtb brakes, no canti studs and rear stays may be too close together.
Can't comment on 650b.
i'd get that Bianchi in clean rideable condition, and let your gf ride it. After a few days then figure out if you need to do something drastic.
The ultimate outside diameter with 650b will be unless you find a very small cross-section tire, essentially the same as the narrow 700c tired wheels. 650c is considerably smaller. 622 for the 700c and 571 for the 650c, so take he difference and divide by two to get the radius difference, 51mm / 2 = 26mm more brake reach required.
In the small chance that bike has 27" wheels you will pick up 4 mm of additional clearance with a similar cross section of tire if you were to change to 700c.
To get 650c to work you will need of course different wheels, very long reach brakes (Tekro might make one but the calipers are designed for a much larger cross section tire). The handling of the bike will be a bit different as the trail will change.
Tire Sizing Systems gives the overview and detail.
Even if you get the wheels exchanged, the top tube length will be most likely longer than you want as the bike was designed to work with bigger wheels. You then will still not be comfortable even though you can reach the ground straddling the top tube.
A 650c wheeled road bike (other than on a triathlon designed bike) will most likely get you there.
A 24" wheeled road bike will too and your position will be pretty good most likely.
A mtb. with a small frame and shorter top tube (look for a 14" frame) might be your sealth best choice as they show up, will be cheap and can be converted into a road bike with different cockpit, saddle, tires. (don't forget to look for shorter cranks) 155-160-165 mm would be best, so you may want to splurge for those too.