Tiny Univega: Original Parts?
 

Hello. I just acquired a 48cm 1983 univega gran premio frame/fork. I am looking to build the bike into a single speed, but am curious about the original parts, especially the wheels. The bike was advertised on ebay as taking 700c with short brakes, but I want to know if it originally came with 650c's with long reach or regular brakes. The distance from the bar that holds the brake to the dropouts is 32.5 cm (much shorter than on my 49cm lemond with 700c's), so I think it could take it. As is, I don't have 650c/26" wheels to test, and I can't get my 700c rear wheel on because the cassette is too large. I think the 700c's won't give me enough stand over room.

Any ideas out there?

Thanks!

First Idea, If your single speeding then for the love of all in cycling that is holy please do not cut off any braze-ons. A 48cm in the wild is rare enough, so don't butcher it.

Second idea. For the sake of testing spacing use two front wheels if you can't get you rear in. Or you might have to go ahead and cold set the frame to use modern rear hubs.

If it really is a Gran Premio, then chances are it is NOT a 48cm, but a "50cm." The 50cm size was the smallest (AFAIK) of the professional racing sizes that Univega came out with. In this case, it would still take 700c tires.

Keep in mind that a more careful measurement might give you a much better indication. Typically, a "50cm" would mean that the center-to-center measurement of the top tube is around 49 to 49.5cm.
If you measure it again, and it falls in the 48cm range, then it might be that it takes 650's...

Hope this helps.

A 700x23C tire has a radius of about 33.4cm and a typcial fork length for a 700C roadie is 36-37cm. So if your 32.5cm measurement is correct, that frame cannot accept 700C wheels (at least not with a tire on ;). A 650x23C tire has a radius of about 30.9cm.

EDIT: I looked up a few forks for 650C and they seem to be 34-34.5cm long.

I used to sell Univega bikes and do not remember them ever using a 650B wheelset on any of their bikes. Could be wrong, though.

Photos?

Seriously, don't cut anything off. If it's really a 48cm, it's my size, and good upper end bikes are difficult to come by in that size.

East Hill

I don't see the reason to beg the OP not to "butcher" this frame as they made no indication that they plan to do so. Either way, cut it up if you want!!!! it's YOUR bike, don't let the vintage police tell you what to do! :)

I have a 48cm Bianchi that I'm converting to fixed gear for my girlfriend, it takes 700c wheels

hope that helps

ive seen these with 700c when searching for a tiny bike for my girlfriend. FWIW those things are pretty nice.