RE: [CR]'77 Paramount Tubeset Question

(Example: Framebuilders:Mario Confente)

Subject: RE: [CR]'77 Paramount Tubeset Question
Content-class: urn:content-classes:message
Date: Thu, 20 Apr 2006 15:17:36 -0700
Thread-Topic: [CR]'77 Paramount Tubeset Question
Thread-Index: AcZku5bh9YPlpProSyOMuGK97hLWmwADDoCg
From: "Mark Bulgier" <Mark@bulgier.net>
To: "John Clay" <jmedclay@yahoo.com>, "Classic Rendezvous" <classicrendezvous@bikelist.org>


John Clay asks:
> Do any of ya'll know what tubeset was used, and the wall
> thickness for all the pipes, on Paramounts in 1977?

The one tube you have anything like a way to measure non-destructively is the seat tube at the top - namely the seatpost size. There's still some uncertainty - a thicker tube can be reamed larger, and a thinner tube can appear to take a smaller post due to distortion.

But generally if the post is 27.2, you've got the lighter 531 seat tube, 21/24 gauge, about 0.8 mm at the butted end (bottom) and about 0.55 mm most of the rest of the tube including the top (single butted). This tube is often (usually?) called .8/.5, though it really isn't quite that thin in the unbutted section - like I say, more like .55 mm. But even the Reynolds catalogs often rounded this off to .8/.5, and I'll use that convention from here down.

If the seat tube is 27.0 or 26.8 you've probably got the 19/22 gauge seat tube, 1.0 mm / 0.7 mm single butted. (1.0/.7 SB for short)

The most common tubes to go with the lighter seat tube are: top tube .8/.5 DB, downtube .9/.6 DB, seat stays .9, chainstays .8 - but substituting the heavier downtube and/or top tube was also common.

The most common tubes to go with the heavier seat tube are: top tube and downtube both 1.0/.7 DB, seat stays 0.9, chainstays 0.8. You're unlikely to see lighter TT or DT used with the heavier seat tube.

Note the rear stays are the same thickness for the light or the heavy set. Though other stays were possible, in the 70s the vast preponderance of Reynolds frames had these thicknesses, for the whole size run of frames. Builders who wanted a lighter or heavier seatstay could spec 9/16" (14 mm) or 5/8" (16mm) outside diameter, or the relatively rare 1/2" (12.7 mm). But chainstays hardly varied in weight unless you special ordered superlight, or conversely, tandem stays. There were different shapes at the tire clearance point (round, round-oval-round, round rapid-taper, D-section, and indented), but that doesn't affect the ride or the weight at all. They were all the same diameter - French 22.0 mm being so close to Imperial 7/8" (22.2 mm) as to not matter - and pretty much the same thickness. I have never heard of any 70s production Paramount with 531 SL (superlight) but I could be wrong.

Reynolds did make other gauges especially for large-quantity buyers, so Schwinn could have used other tubes than what's listed here, but I sorta doubt it. Joe B-Z's suggestion to ask Waterford is an excellent one, they're the closest to the horse's mouth that we have.

Mark Bulgier
Seattle WA USA