abdon 

I'm building up a 49cm mixte frame that originally sported 27" tires for a 5'2" person. It looks like going to a smaller wheel size would make things fit into place beautifully.

Are there brake calipers that would let me go as far as 650c? If that's too much, how about 650b? Ideally I would like something retro looking.

krome

I'd look at 590 also (650a). I have done just that, 27" (630) to 650A (590), with a brief stop in between at 700c (622). For me it was because it required less reach, and there were some rims I like available in that size (Sun CR18).

kuan

By my reckoning you would need 78mm reach brakes.

krome

Are you accounting for radius? 630 - 571 = 59/2 = 29.5mm difference in BSD (change in reach required usually). That is for 27" (630mm) to 650c (571). That would be worst case scenario for conversion to 650c (which I don't recommend, unless you want triathlete tires and rims, or worse, schwinn steel rims). Conversion to 590 from 630 requires 20mm change in reach (to 650a) and conversion to 584 (650b) requires 23mm change.

Brake change may also be required.

kuan

Yep, 29.5mm change. Normal brakes have 45-50mm reach? OK so I'm thinking maybe 75mm reach at minimum.

hueyhoolihan

abdon,

i think you are on the right track. 27 mixte, in small sizes, with smaller diameter rims look nice.

had a custom 650c bike that looked real nice in my size.

i recently put a set of 559 rims on a bike made for 630 rims, looked good! but had the worst shimmy i ever had on a bike that was otherwise one of the most stable bikes i had ever ridden. who woulda thunk it?

BTW i worked around the brake problem by lacing up a coaster brake hub in the back and dispensing with the front brake altogether. ( not for everybody, i know). clean, oh so clean!

huey

abdon 

Ok, because I'm in Japan and this size is common here, i'm looking at 26 1 3/8 rims. The question now is, what flavor of 26 x 1 3/8 is the one used in Japan? The two types I see mentioned by Sheldon are:

26 x 1 3/8 (S-6), 597 mm, Schwinn, lightweights
26 x 1 3/8 (E.A.3) 590 mm Most 3-speeds, department-store or juvenile 10 speeds

If it is the E.A.3, it would be perfect.

krome

Stick to calling them by the metric size, it is less confusing. S-6, 597 iso should not be a popular size in Japan. 590 iso is very popular, globally. Avoid using 597 iso unless you are into Schwinns with that size (or some other bike with that size) It is a lot less common size.

Retro Grouch 

Good luck with that. The longest I can find with a quick search ate Tektro R556 - 55-73mm.

abdon 

I'll go back to the store to see if I can find an ISO number on the rim. With a bit of luck (and it looks like this will be the case) it should be the 590mm one. This also happens to be what the French would call 650a.

fietsbob

650B [584] is a popular conversion these days from, 27" [630]
or 700c, [622].
and so will have spare tires thru Pro bike shops.
some, comfy supple casing ~ 1.5" wide.

build up the wheels around Drum brake hubs ,
and the reach problem disappears.