In my experience, it is difficult to tell whether a bike was made for 27" or 700C tires.
The two Jack Taylor tandems I have measured, had the same clearance/stay/fork length, yet one was originally equipped with 700C, the other with 27". Obviously, they didn't bother. Both have ample clearance for fenders, one just a little more ample than the other.
With Alex Singers, you can tell - if a bike barely cannot take (relatively short-reach) Mafac Competition brakes (the pads have to be angled downward slightly) or Campy NR/SR "normal" reach brakes (a drop-bolt would be required) with 700C wheels, it was intended for 27".
To retrofit a bike with 700C wheels, simply use longer-reach brakes. For example, Mafac Racers work well on the above-mentioned Singers (one of which is featured, retrofitted as a randonneur bike, in Vintage Bicycle Quarterly No. 3).
Considering the difference in wheel diameter is slight, the handling should not be affected (unless it is a bike with very little trail and a very slack head angle). To be on the safe side, and to fill out that extra clearance, use some wide tires (28 or more actual mm). But the aforementioned Singer rides great with 700C x 23 mm tires...
Jan Heine, Seattle
>Date: Wed, 05 Mar 2003 13:32:02 -0500
>From: "Stratton O. Hammon II" <firstname.lastname@example.org>
>To: "email@example.com" <firstname.lastname@example.org>
>Subject: [CR]Change from 27" to 700C?
>Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854";
>When exactly did the American and English, especially Schwinn and
>Raleigh, quit using 27' rims and switch over to 700Cs?
>Is there any easy way of telling if a bicycle frame, from the '80s, was
>built for a 27" or 700C? I'm thinking here of bikes like '80s Mercians
>or Bob Jacksons?
>Louisivlle, Kentucky, USA