Road Fan

Thanks, I read those blogspots and commented on them in BF C&V about a year ago. I would like to compare the geo numbers of your frame with the published numbers of my Special.

The Raleigh, Rudge and Humber versions were not "similar," they were the same in all functional respects. Differences included the chainring decoration, lamp bracket ornamentation, headbadges, fork crowns, and paint/decals. Same pedals, brakes, saddles, hubs, BBS, gearing, bars, stems, rims, et cetera.

Kilroy1988 

The Carlton is 72/72 or 73/73, I don't recall off the top of my head. It was a custom frame and really bears little significant resemblance to any stock, factory-built Raleigh bicycle of the time.

​​​​​​I hope in the future you'll consider the fact that some here put effort into documenting their builds and that the addition of half a dozen unrelated photos of other bicycles is in fact deemed intrusive by some. I made this thread to share my project, and now nearly half the photos are of your bicycle which has nothing to do with a Carlton Super Python whatsoever, besides the fact that it was made in England around the same time and meant to ride on the road.

-Gregory

Road Fan

I take your point about your effort. I did not intend to hijack it, but to enhance it. I don't recall reading a Have you asked the mod to remove my post? One of my posts has just been removed, I have not found that I can remove my own mistakes.

As I suggested before, I'm actually hoping for some collaboration, not to steal your thunder.

It's 72/72 or 73/73? Really? Your pic is clearly not of a square frame. And my opinion is that the geometries ARE very similar. The geo of mine measures (my measurements and instruments) very close to the info given in the adverts and Nimrod reviews that Peter Kohler put in his blogspot articles.

A better answer (and not insulting) would have been "sorry, I don't have the angle tools."

Kilroy1988 

Road Fan I recall measuring the angles rather haphazardly when I received the frame, and will re-measure them for you over the weekend. It certainly looks square to me in person, and I'm not sure how a couple of photographs can suggest to you that I must be wrong... In any case, I still do not see why it applies to your bicycle because this Carlton was made with custom geometry to client specifications, and by 1954 it was common to see different angles used for both front and back on bespoke English lightweight frames. The 1953 Carlton catalog specifically says of the Super Python that "frame angles, wheelbase, fork rake, and section to choice." It was totally custom. Elsewhere in that catalog and also the 1955 catalogue the preferred frame angles for other bespoke Carlton frames were "71/73, 72/72, and 73/72, or any combination of head and seat tube angles between 71 and 74 degrees." All of this was noted in the 1953 description of the Franco-Italia frame set, which was the most comparable one to the Super Python in general price and configuration.

In other words, this Super Python bears no historical relevance to the frame angles on a mass-produced Raleigh bicycle, despite being from the same period. By the early 1950s in England bespoke builders were experimenting much with what we would consider "modern" road geometry, and a variety of angles were used even by the same builders, as evidenced by the Carlton descriptions. This was true of most custom frames of the era and contemporary riders were savvy enough to be interested in such things as well.

I have no idea what happened to your post, as I certainly wouldn't bother to report anything of this nature to a moderator. There's no rule against you filling this thread with photos of your Rudge, but that doesn't mean I appreciate it. You're welcome to edit your own posts at any time, but can not remove them after a subsequent post has been made.

-Gregory

Road Fan

The Raleigh roadies about 1950 and later commonly showed about 70 to 71 rear and 73 degree front, with 2.25" fork offset. My own measurements corroborated the numbers reproduced by Peter Kohler, so of that I am quite confident. That gave their saddle location a lot os setback even with Brooks saddles, and actually rather low trail, rather like the manufactured French bikes of a little later time (Peug UO-8 and similar perhaps from 1965 until mid '70s, the Super Course, the International, and the first Competition 1969 model. My Rudge Aero Special also has chainstays about 45 cm - I don't recall the exact actuals, it's been a while since I measured them. But your frame looks like it has long chainstays, though my guess is not as long as a Trek 720 frame. I know about the Peugs because I have had a few, about the '50s bikes because of Peter Kohler's reproductions of original literature and technical reviews, and about the S-C, International and Competition because I have measured at least a sample of each. It seems that at least for these manufactured brands the riding geometry followed a similar style, or perhaps the mass-market bikes set a style that riders followed. With the rather low trail, about 46 mm if I have the wheel correct. That is not far from the geo of the 700c French randonneuses that have been discussed in Jan Heine's writing.

As far as the tubing, your bike has the sticker for fully double butted Reynolds 531 tubes, fork, and stays. Mine has the sticker for fully straight gauge Reynolds 531 tubes, fork, and stays. Not so different, though the Carlton is clearly higher specification.

As far as photos go, after some practice and in a few cases being able to measure the photographed frame or model, I think I can see squareness if the camera is not looking down at the bike and the lens does not have too much barrell distortion, though this assessment is subjective and very possible to be wrong. Looking down at the frame introduces parallax error. The photo can represent angles well and they can even be measured off of it if the lens distortion is low where the frame joint is. In your photo I measure 71 degrees at the seat tube/top tube. I'm a lot less confident of the measurement at the top tube/head tube, because that joint is off to the side of the lens field of view, where barrell distortion is stronger. This is based on my engineering experience evaluating and calibrating lenses for camera sensors for automotive safety detector systems based on camera image data. But I'm not here to give a lesson in physics, optics, or sensor engineering.

Please note, none of the information I am sharing has anything to do with the actual history of Carlton in relation to Raleigh. As far as your apparent previous objections to my inquiries, that question is settled in my mind. It's a red herring at this point.

Thank you for your willingness to provide actual measurements. I appreciate your discussion of Carlton frame offerings, though I have never seen any of that data.

sincos

That is awesome. Never even heard of BOA pedals before. So I guess the frame lays eggs and the pedals give live birth?

Kilroy1988 

I ended up not going out to the country property where the frame is currently stored this weekend, so could not measure it. I took three photos I have of the frame (two at least of which are posted here already) and ran the angles through an angle measuring app, getting nearly 72/72 square in one, 73/70 in another, and about 73/71 in the third... So indeed, it looks like real measurements will be the only way to tell! I'll do so as soon as I'm able, since now you have me curious as well.

Sorry for any flatness in my tone when expressing my opinion that these frames really are not comparable. I study a lot of post-war British lightweight bikes and have owned a handful recently, and do not find it prudent to compare bicycles made by almost any boutique frame builders to production bikes for a number of reasons... Not only was there usually a wide variety of tastes and a plethora of options for most of the former, but production bicycles were generally more conservative in design features. Comparing a Raleigh, BSA, Hercules, or Phillips lightweight provides worthwhile historical insight into the choices made by large-scale manufacturers of the time, just as comparing a Hetchins or Claud Butler to a Carlton might yield information about trends in the custom lightweight industry. However, the two industries were separated by at least a couple of years concerning most things, and in some cases several years or more.

Studying "trickle-down" technology and aesthetics is of course relevant to the overall appreciation of post-war British lightweights, but that's another story.

Concerning tubing... Throughout the 1950s about 90-95% of British lightweight bicycles used some combination of Reynolds 531 tubes. Its ubiquity makes it irrelevant to comparing the similarities of any frame in a significant way, as if one were to say two were similar because they had pump pegs or fender eyelets. It's just typical of the times!

-Gregory