Oooh, I have some of those charts too. I think the 531 magic was also in my 1970s era Bob Jackson, and less so in a 1974 Paramount and late 70s Vent Noir. The BJ did not have a model marquis transfer on the frame other than multiple BJ labels, but, no fender eyelets on the Campy dropouts, a 531 db tubes-stays-fork blade sticker, normal (57 mm) reach brakes, and no braze-ons for cable guides or shift levers. Compared to a Vent Noir of similar era, I sure liked the handling much better. And compared to the Paramount, better handling and lighter. That bike is/was a smooth riding rocket. Come to think of it, the mid-80s Mercian, which disappeared in the 'ought-8 divorce garage sale.
Mike SLO CA On Wednesday, June 21, 2023 at 5:18:40 PM UTC-7 Ted Durant wrote: > 6:07:06 PM UTC-5 campyo...@me.com wrote: > > One is made of the more unusual “531 Professional” tubeset, which featured > thinner walls for lighter weight than standard 531 tubing. > > 531 Professional is rumored to be less durable than 531 because of the > thinner walls, but I regularly ride the 531 Pro Singer (built in 1983) > without any problems … and I’m by no means a “light” rider. > > > The durability issue is dent resistance and strength in a crash. If you > don't smash your frame against a bedpost (how my mother wrecked my first > Holdsworth...) you won't have a problem. > > Attached for some nerdy fun are a couple of charts of tubing specs. > > [image: TubingChart.jpg][image: ReynoldsTubeGuide.jpg]On Wednesday, June > 21, 2023 at > [image: 531-tubes.jpg] > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/4bbe90ce-cb47-4c5c-9828-28f1ec06b610n%40googlegroups.com.
