Best brake clearance from older single-pivot brakes?

[mhespenheide]

I'm trying to resurrect an older '87 Bianchi. I'm astounded to find that the frame will fit Challenge Strada Bianca tires at 700x30mm ... but then the tires are uncomfortably close to the brake arms at the top of the tire.

I found this earlier thread: forums.thepaceline.net/showthread.php?t=197406 about modern brakes, but can anyone give a recommendation for more period-correct single-pivot brakes? Bonus points if they have a traditional QR on the brake calipers to help clear those wide tires.

Thanks for any pointers.

[Shoeman]

I have an 84 Trek 660 with some Dura-Ace 7400 series calipers seems like you be able to put a 700x28/30 under them. I run a 700x27 Pave with plenty of room to spare. Calipers look good and they seem to be pretty stout. I do use a more modern pad with them, so stopping isn't all that bad.

[papalok]

Weinmann Carreras clear 32s fine on my '78 Raleigh Super Course.

[mhespenheide]

I have an 84 Trek 660 with some Dura-Ace 7400 series calipers ...

On the bare frame, I get about 2mm of clearance. With 7400 brake calipers, I'm down to about 1mm or clearance or even a hair less. I don't know if I can do any better than that, but I though I'd ask for from suggestions.

What kills me is that the brake pads aren't bottomed out at the end of the slots. If they were, I'd have another ~2.5mm of clearance. If only the builders had pushed the brake bridge that little tiny bit higher!

[rustychisel]

anything built for old 27 inch tyres. Dia Compe springs to mind, but there's plenty of deep drop options out there.

No, hang on, that doesn't make sense. The issue is tight tolerances for brake bridges, right?

[martl]

anything built for old 27 inch tyres.
Speaking of which - do these even exist, and if so, are they larger than 28" 622, if so, were they common in racers?

I saw "true" 27 inch (ETRTO 630) only once, and that was a clincher tyre i grabbed some by mistake from my LBSs "cleanout: each part 1€"-box. Think they were used on some obscure french lower-quality randonneurs, or maybe british ones.

Oldtimers called their tubulars "27 inch" but any tubular wheel can be swapped for any 28" (ETRTO 622) clincher wheel without even thinking about brake pad height - there isn't a noticeable difference in diameter. I do it all the time on my #1 bike, i either use the CFK tubulars or the Mavic CXP33 clinchers.
That is true for any tubular wheel i've ever held in hands, even those that were made in the 1930ies. A recently bought Veloflex "28 x 25" fitted the 27"-tubular rim of my 1930ies Automoto just nicely.

[rustychisel]

Speaking of which - do these even exist, and if so, are they larger than 28" 622, if so, were they common in racers?

... there isn't a noticeable difference in diameter.

Yes, there is. About 4mm radius. I can't speak to tubular tyre stretch but with beaded clinchers it makes a difference.

[oldpotatoe]

Speaking of which - do these even exist, and if so, are they larger than 28" 622, if so, were they common in racers?

I saw "true" 27 inch (ETRTO 630) only once, and that was a clincher tyre i grabbed some by mistake from my LBSs "cleanout: each part 1€"-box. Think they were used on some obscure french lower-quality randonneurs, or maybe british ones.

Oldtimers called their tubulars "27 inch" but any tubular wheel can be swapped for any 28" (ETRTO 622) clincher wheel without even thinking about brake pad height - there isn't a noticeable difference in diameter. I do it all the time on my #1 bike, i either use the CFK tubulars or the Mavic CXP33 clinchers.
That is true for any tubular wheel i've ever held in hands, even those that were made in the 1930ies. A recently bought Veloflex "28 x 25" fitted the 27"-tubular rim of my 1930ies Automoto just nicely.

Any decent shop sells 27 inch tires(630 ETRTO)..Conti and others still make them.

I always thought tubulars were called '28inch', even tho nothing about them(including in metric countries)was '28 inch'. Lots of tubulars still have the '28'-on the side wall even tho they are essentially 700c.

[martl]

Any decent shop sells 27 inch tires(630 ETRTO)..Conti and others still make them.


i know they exist, only i've never seen them on anything that could rightfully be called a thoroughbred racing bike. Their availability is regionally influenced, over here where i live - not much. Apparently, calling a 28 tubular "a 27" is also more common here than elsewhere...

[mhespenheide]

...The issue is tight tolerances for brake bridges, right?

Right. The arms are fine; the tire is too close to the bottom of the brakes up by the brake bridge/bolt.

[icepick_trotsky]

+1 for Dia-Compe. Most of these were made to accommodate fenders, so plenty of space.

https://lh6.googleusercontent.com/-23Kn-Qc2rW8/TW5707nI01I/AAAAAAAAAGc/8o6mbYstd7E/s1600/Dia+Compe+1985+NGC+Catalogue.jpg

[palincss]

I saw "true" 27 inch (ETRTO 630) only once, and that was a clincher tyre i grabbed some by mistake from my LBSs "cleanout: each part 1€"-box. Think they were used on some obscure french lower-quality randonneurs, or maybe british ones.


ETRTO 630 -- aka 27 x 1 1/4" -- used to be the standard size clincher tire found on road/touring bikes sold in the UK and the USA during the 1970s and early 1980s. At that time clincher 700Cs were virtually unknown here, and anyone planning on touring was advised to use the 630s because "you could buy one in every Western Auto in the United States." During the bike boom, high end racing bikes used tubulars, while "sport touring" bikes used 27 x 1/4" clinchers.

The big change-over to 700C happened sometime in the 1980s, I'm not sure exactly when. There were millions of bikes made during the bike boom that took this size, many of which are still on the road which explains why this obsolete size is still available.