Originally Posted by
HTupolev
It's true that I'm not familiar with the tire clearance of literally every single model of bicycle ever made. I wasn't claiming that nobody had ever made a super-tight-clearance bicycle in the 60s or 70s; I was saying that it was typical for there to be wider clearance.
Also, I just
looked up photos of a 1978 Benotto 3000, and it's not obvious what about its geometry would dictate a limit of 23mm. The tires it's wearing in those images are about 23mm wide judging by the frontal shot. The fork and rear brake bridge clearly have room for far more, and the chainstay bridge is also positioned very high out from the tire. The only thing that might be preventing a much larger tire from being installed is the chainstay profile, which is hard to make out in the shots... but even if it
is the limiting factor, you wouldn't really need to alter the bike's "geometry" to widen that up somewhat.
It's also bizarre that you're acting like I should have known that "world champion geometry" refers to the geometry of a single model of bicycle that Francesco Moser happened to ride to the rainbow stripes in the later years of the period being discussed. A whole lot of people rode bikes that could readily fit 28s or bigger to world championships in the 60s and 70s.
Also, I just
looked up photos of a 1978 Benotto 3000, and it's not obvious what about its geometry would dictate a limit of 23mm. The tires it's wearing in those images are about 23mm wide judging by the frontal shot. The fork and rear brake bridge clearly have room for far more, and the chainstay bridge is also positioned very high out from the tire. The only thing that might be preventing a much larger tire from being installed is the chainstay profile, which is hard to make out in the shots... but even if it
is the limiting factor, you wouldn't really need to alter the bike's "geometry" to widen that up somewhat.
It's also bizarre that you're acting like I should have known that "world champion geometry" refers to the geometry of a single model of bicycle that Francesco Moser happened to ride to the rainbow stripes in the later years of the period being discussed. A whole lot of people rode bikes that could readily fit 28s or bigger to world championships in the 60s and 70s.
I have a couple vintage Benotto 3000's, (82 and 83) and those can clearly fit a 25 mm. But the particular bike I am referring to is the "Aguila de Tachira" version, of which 100 frames were made in 2018 matching original specifications, at a hefty price tag. This frame cannot fit a 25 mm. Maybe the front fork can, but there is not enough clearance in the rear.
I'm sorry if you are offended if I seem bizarre, but I guess it is a bizarre to own as many bicycles as I do.
Here's a picture of the rear brake, where you can see the tight clearance. If you don't believe that it won't fit a 25 mm, well...
But back to rim brakes, I think these skeleton brakes are not too pretty (and a pain to keep clean), but they sure as ever have more than enough braking power on the steep mountain climbs which surround this city. Someday I might throw in some 250 euros to get the Record model, just for the pretty part.
