Bicycle Tutor

My '76 Chicago Schwinn Collegiate has these oddball 597 BSD wheels and I'd like to replace these with a more popular wheel size. For one thing it's impossible to to find lightly knobby tires(for the snow which will hit soon) in that size. For another I think I want to go fixie with a flipflop rear. Third the front wheel has a shallow dent which made me set the front brakes looser than i'd like.

So what wheel sizes can I put on this thing? My local guy told me that the 590 BSD(the other 26 x 1&3/8) would be fiddly to get on, something about the axle fit...he is mumbly and not too talkative...I stopped trying to bug him further.

Here are some measurements that may help you guys help me.
(front/rear)
distance between fork/stay at top(tire space radius) 2.25"/2"
distance from the inside of the drop out to end of wheel space 14.25"/14"
inside clearance between dropouts 3.75"/4.75"
hub length 3"/4"
total hub length (tips of bolts) 5.75"/6"

don't know how much of that is useful.

The "other" 26x1 3/8 is the only thing that will be super close. You still won't have much choice on tires, but there are tires available for both these sizes. It's just going to be mostly low end Chinese made stuff.

I'm not going to figure out all your measurements , but your other options are to go slightly larger or smaller. I've seen several bikes with this size wheel swapped out for mountain bike 26" wheels (559mm). The rim would move down about 3/4 an inch. The big question is will your brakes reach that far or would you have to get longer reach calipers. You'd have lots of tire choices depending on how much clearance your fork and brakes have. The axle might be longer (it would be 100mm between the dropouts). But an old steel fork can be spread pretty easy.

Other way to go is up to a 700 wheel (622mm). Here the rim moves up 1/2". Clearance issues are tighter here of course.

Final option is "650B" size (584mm). I've never worked with these, but I believe they have become a little more popular recently. So there may be good availability around. It's probably the closest to what's on there now. But not every shop would have tires, tubes, etc. You'd probably need to mailorder most stuff.

Not sure about getting a flip-flop hub in anything other than the 700c. But if you check around, you may find something. Maybe get just the front wheel first to test before you buy both.

This has all the various sizes: http://www.sheldonbrown.com/tire-sizing.html

There is also a "junior partner" to the 700c, the 650c, usually found on the extra-small road bikes. This would be a good option, especially since you're looking at the fixie idea. Can't guarantee how easy they'll be to find -- try Google.