I recently purchased a Bianchi Piaggio on craiglist with the intention of converting it to a FG for my girlfriend. Before I ordered a new wheel set online I decided to make sure my own 700c wheels fit on the bike. The back worked fine, but when I put a front wheel on, it seemed like it was about 1-2mm too long for me to be able to get it on. The Bianchi initially had 27x1 1/4 wheels.

I did a bit of an experiment, I took the 700c wheels and they fit on my own older road bike, which also took 27x1 1/4, and it fit. The wheels from the road bike also fit onto the Bianchi. The original Bianchi wheels fit onto the road frame as well. I'll note that my girlfriend is short, and the frame is a 48cm. Would I be better off ordering her a 650c wheel set (which I also have the fear of not fitting the mysterious front fork) or do I just have a problem with my wheel? Something with my fork?

I have a decent amount of bicycle knowledge but I'm far from an expert, so any help is appreciated. Thank you!

27 1/4 wheels are 8mm larger than 700c, so there must be some other factor at play. Is the fork spacing an issue? Do you have a tape measure and/or calipers? Do some measurements on the forks and the tires, old wheels are sometimes labelled wrong.

The size of the tyres might be an issue too...

No calipers unfortunately but here's what I have with measuring tape to the best of my ability:

Fork spacing: ~10cm
Bianchi 1 1/4 Wheel:~ 8.6cm
700c Wheel:~9.5cm
Road 1 1/4 Wheel:~10cm

Something to note, I suppose, the Bianchi is a bolt on and has obviously less distance between the nuts, but it still makes no sense why there'd be discrepancy between the road wheel and the 700c. The 700c wheel is also a touch out of true, but the back wheel I tested it with was extensively out of true and it firt with ease.

What are you even asking? Is the axle too long? WTF are you measuring?

Seriously, what the hell are you measuring? I'm guessing it's the axle spacing?

If i understand you correctly you're saying the fork is too narrow to fit the hub.While the standard for front hubs is 100mm,some old hubs/forks are 95mm.Some solutions to your problem are:
If there's a washer between the cone and locknut,remove it.
Coldset(bend )the forks a bit.
When installing the wheel,set one side in first the pull the other forkleg out a bit to clear the locknut.
I'm sure there's gonna be some folks predicting catastrophic failure and death when messing with the fork,but steel is flexible enough to handle a couple mm.I've bent, filed,clamped down and spread plenty of stays and forklegs and never had a problem whatsoever.

We need pics to help you. Is the hub not fitting the spacing or is the wheel to big vertically to fit in the fork? PICS!