I have a Univega Super Strada frame (unclear what year) which has non-original 700c wheels. I have 700x25c tires on the bike, and there is only a hair of clearance between the front tire and the brake caliper. I just replaced the rear wheel, and the rear tire is rubbing on the brake caliper. I don't know what wheels/tires this bike originally had, but my understanding is that 27" wheels have greater tire OD than 700s do. A lot of the components came over from another old 80's univega, which had 27" wheels but I couldn't get the 27s onto this frame at all - thus the 700c wheels.

Is it worth trying 23 wide tires vs the 25s that are on there now? The current tires are also 'flat resistant", could that be part of the problem? I use this bike as a commuter, and am not crazy about the idea of a smaller tire than 25.

Any ideas would be appreciated.

What kind of dropouts do you have, horizontal or vertical? If horizontal, adjust the position further to the rear.
If vertical, you can make a sorta crescent-shaped shim to put between rim and axle to lift it a little.
27" wheels have a larger bead seat diameter than 28"/700C - 630 mm vs 622. So they'll be bigger for the same tire width. Doesn't mean they're always bigger though.
There's a lot of dishonesty in tire sizing, just b/c one 25 fits doesn't mean they all fit, and the other way around.
One unorthodox tweak is to fit the rear brake to the front of the brake bridge instead.

The problem is worse in back than front, not quite touching in front but I have had to stop and pick leaves/grass clippings out of the gap in front.
The R dropouts are not true horizontal but incline up/back. Axles are already set as far forward/down as possible.
To clarify- I have 700s on now, never had 27s on this frame - they were on the old frame.
One thing I'm wondering is, what tires would this bike be designed for, wouldn't the "design" tire be no less than a 23? I picture a 23 providing only a tiny bit more clearance. Also is there a table of typical tire OD that anyone can direct me to?

It could be just the brand of tire you are using Not all 25s are the same size, make that most 25s are not the same size. Some tires are larger than others Michelins for example. Roger

If you can't get a 27" wheel in the bike but the brakes don't work with 700c, maybe the calipers are replacements?

While some bikes were made with VERY little tire clearance, and the front is often the tighter area, Univega also did make some smaller road bikes with the 650B tire size (584 rim diameter). Andy.

This is a big frame, would they ever have built a 58-60cm frame with that wheel size?

The brakes are replacements. I put Nashbar store brand road calipers on it, but the calipers are not the clearance problem. The rear bridge where the calipers are mounted is almost as close too the wheel as the calipers are. Ditto for the fork in front.

Seems familiar...

These are michelins, so maybe that's part of it.
I did my best to measure the tire height, it seems to be pretty close to 25 mm from the rim OD to the top of the tire profile. What is the 25 supposed to correspond to - is it this measure?
How much could I expect this to change if I put a diffrerent brand tire or a 23 (or both) on the bike? I know this is not the ideal commuting setup but it's a nice fast bike (I don't commute every day but when I do it's 27 mi each way) and not mostly city riding.

Yup, I'm that buyer..

As noted, there are 25's and there are 25's. I had an early 1990's Trek 1420 that came with 700-25 tires that fit and cleared with no problems. When these wore out I bought a pair of Performance's house brand tires in the "same" size and these rubbed everywhere and were unusable. You may have run into the same problem. That said, good 700-23 tires are quite durable and most models should fit you bike with no clearance problems.

584 to 622, that's a 19 mm difference in radius. While not impossible, it makes me wonder about the character of the bike.
If a 622/25 is a tight fit, then a 584/25 would be a suspiciously roomy fit for a dedicated road bike. OTOH it wouldn't be roomy enough for both wide tires AND fenders.
And there's the issue about brake reach. How much difference is there in caliper brake reach BTW?

You got a racy bike from a time that skinny tires were in vogue. I don't know either what it originally came with, but at the time, 700c's were usually tubulars in the USA while 27's were clinchers.

There are smaller tires, and you might have to live with them.

650B conversion sounds fun but usually it'd cost several times the price you paid for an old bike. You need longer brakes, wheels, tires. That's fine if you want to make the commitment. It gives you room for bigger tires plus fenders.

Yeah, I'm done putting money into this bike. If it works out with 23s, I'll keep it. If not then it's going for sale as parts..

Can anyone suggest a manufacturer who might run on the smaller side? I can't find any such info on line.

My Vittoria Rubino Pros and Zaffiro Pros run true to size or perhaps a little smaller, particularly the Zaffiro. Also they are both durable and modestly priced so both features should please you.

I'm not suggesting a 650 conversion (And I won't say how much I dislike the thought). I said that some small frames Univegas had 584 wheels, that's it. Now knowing the frame size I doubt that it came with 584 wheels, even if it was a touring bike. Having read more posts I think my first part of my first post is more likely. The design is probably a really tight 700x25 (and what's now labeled as 23s) fit. Andy.