I picked up this frameset a while ago and it has been sitting in the garage. There's no identification of the tubeset or manufacturer but the details indicated it would be a nice ride:

1) 27.2mm seatpost (Tange 1/2? 900?)
2) Diamond window cutouts on the long(ish) point lugs
3) Chromed, sloping fork crown
4) Clearance for good sized ( 700x30-ish) tires
5) Eyelets for fenders

Some obsessive searching on bikeforums lead me to T-Mar identifying this serial number M5D17154 as typical for a Miki built frame. They built frames for Centurion, Sekai and Sakai and this should be a 1985 frame by the serial #.

Anyone have any guesses? There was a picture of a 1984 Sakai Tri Ultra that had the same style of fork crown lugs, but it had BB cable guides and no eyelets on the dropouts.
https://www.bikeforums.net/showthread...=1#post6886614

Here's the frameset I have, fork and lugwork looks the same, but clearance and dropout eyelets indicates a more practical model:


Untitled by sychan168


Untitled by sychan168


Untitled by sychan168


Untitled by sychan168


Untitled by sychan168

Any ideas?

Steve

Bumping it to see if anyone has a id 80's Sekai 2600 thinks this might be a powdercoated 1985 Sekai 2600? I came across this today and the lugs and fork crown seem to be the same - can't verify if it has the diamond windows on the lugs.

https://ratrodbikes.com/forum/index.p...ad-bike.17045/

I dunno about the second one, but for the first, do you mean Miyata? The diamond cut-outs were on a few early 1980s Miyata built frames I have seen. The seatstay caps are also Miyata-esque. I'd suggest you look for your match to either a miyata or a univega.

I am not convinced that the fork is original. The chrome seems out of place for a miyata built frame.

I originally looked at the diamond lug cutouts and fork and thought the same thing "Maybe its a Univega with a fork graft", but then I looked up the serial number and it doesn't have a Miyata serial number scheme. The only scheme at matches is the Miki built Centurion/Sekai/Sakai type. And I looked on the bottom bracket of a centerpull Centurion Pro Tour that I have, and it has exactly the same serial number scheme, and those weren't Miyata made bikes either.

So I'm pretty sure its from the Miki factory, especially since the fork crown and dropouts seem to match up with the 1985 Sekai 2600 (but my mystery bike doesn't have the third bottle cage mounting under the downtube).
I'm mostly curious about the particular tubing used - I'll probably do the obvious thing and shine a flashlight down the seat tube to see if I can spot a seam on the inside.

Steve

Bumping with a quick observation - looking down the seat tube, there's no sign of a seam, and I can see where the butting for the 27.2mm seatpost ends, and the walls are obviously thinner past the butt. So odds are that this is a Tange 2 (or 1) tubeset. It should ride nicely - I'll build it up for my "beater" bike, but I've just been curious what model it originally was.

My best guess is that this is a Centurion Super Elite based on the photos. Highly likely if the original colour was black as the SE only came in that colour. If it is a Centurion then it was Tange tubing. Have fun!