This is, I think, the blue frame shown in the first post? 1870 g bare frame w/o fork is what a 753 frame in a larger size should weigh. A 531 frame, by contrast, would be over 2 kg. I'm not sure about the Professional or SL version of 531.

Interesting thing is the serial number is SB1843, meaning a fairly early bike, but the seat tube is 26.8 mm. We're also told that early bikes with that diameter seat tube are not 753, because at in the early years 753 was metric and hence 28.0 mm.

And the dropouts are drilled, which I think they only did to 753 frames - although maybe there were exceptions.

So based on the weight and drilled dropout I think 753; but I can't explain the diameter. Maybe it is 531 Professional - I dunno if SBDU used that tubing?

Here's the weight of my 753R frame. It's 60cm.

Frame: 1866 g
Fork: 694 g

Just for reference, '73 RRA, 22 1/2" (56cm) full 531

Frame: 1949g
Fork: 816g

I weighed a "55 cm" SBDU 753 frame less fork (actually more like 52 cm CTC, so a pretty small frame) at 1638 g.

https://www.bikeforums.net/classic-vi...h-respray.html

So, how do we explain the 28.6 mm seat tube OD, if it is 753 with that serial number?

This discussion prompted me to weigh my August 1976 Raleigh Pro Mk IV frame before I started the rebuild. The frame only had the 2 head set cups still in - everything else off. 59cm c-t. DL-180s were full 531. 27.2mm seat post. 4.5 lbs.

Simple arithmetic would call that 2040 grams but since I used a bathroom scale I cannot talk about grams - implies un-available precision. FYI I did pre-load the scale up to about 65 lbs so it was reading in a useful range. I think the 4.5 lbs is pretty close.

For Prowler:















If you need more HT lug photos let me know from what angle.

Thank you Ed. I hope others enjoyed the detailed snaps too. PM sent

His-n-hers? Cool.....

Yes. Too bad she has inherited the family's 'shrinking gene' and passed it along to our daughter, who's shorter yet, and rides a FELT with a shrunk front wheel. When I gave Gerald the numbers he looked at me and said, with a very straight face, "Well, Ed, we'll make it as small as we can and then we'll give it a hot wash."

We had matching 'Michaels Cyclery' waterbottles, too, until I lost mine.

Wonderful bikes and pictures!