Sew-ups: 700c or 27"??
 

I got an early 80's Univega with non-std wheels which include Fiamme sew-ups. I am not a tubular fan, and put a 27" wheel on just to see if it fit. It fits better than a 700C (don't even have to change the brake pad position).

I thought I heard that all sew-ups are the same size (and closer to 630 mm clinchers). Is this true??

As far as I know, 700c clinchers are sewup size, 27" are about 1/4" larger.

There are some smaller size sew-ups for TT bikes, women's bikes, etc... but there have never been 27" sewups.

An early 80's Univega might very well have had 27" original tires and the owner may have put the sew-ups on later.

If they fit, they're fine.

The reading I did on my 1972 Paramount in the SLDB indicated that it originally had 27" sewups, so I started looking around for them. My brother has since found this.....

These would be 80's vinatge. Wobler is all that is recognizable on the tire. I cannot find any relivant infomration on the Fiamme rims (other than they are good and french).

All you need to know about tire sizes - http://www.sheldonbrown.com/tire-sizing.html

As for tubulars, they ONLY came in 700c, 650c, 24 in., 22 in., 20 in. and 18 in.. A 27 in. and a 28 in. tubular are the same tire and are 700c, the only difference is the marketing.

One other small correction, Fiamme rims are Italian. http://www.classicrendezvous.com/Italy/Fiamme.htm

Right, any tubular that says 27" is a 700c, and probably Continental
Any tubular that says 28" is also a 700c, and probably Vittoria or Veloflex

Sounds like your Fiamme rims and your 27 inch rims have the same radius to the brake pad, not very surprising. The wheels aren't the same in overall diameter, however. On some frames teh differences in diameter can render it tough to install anything but the original wheel size.

Sewups come in several base sizes, with 650 adn 700 being the most common. Within those, the overall diameter is a function of tire width. Widths (in 700) vary from 18 or 19 mm for very light velodrome and track racing tires to 25 mm for road training tires, all the way up to 28 or 32 mm for tubular cyclocross tires. Framebuilders need to plan for the range of tires a bike will be designed to accommodate, considering fender use.

Road (and tubular!) Fan

I think that because 27 inch is a common tire designation, it was used at times for sew-ups as well as 700. You'll see some tires labelled for teh UK market as 28 inch. Check carefully, because it theypre Vittoria Rallyes, they're probably same as 700.

Road Fan