My brother in law showed me an interesting garage sale find and I'm having trouble coming up with a manufacturer and model. The bike he displayed was original frame and fork, and a few parts, and I’m thinking it’s mid-late 80’s.

1. Features - lugged steel with aluminum main tubes and internally routed top cable. (we did the magnet test on the tubes).
2. The seat cluster does double duty – the thru-bolt is the seatpost binder and connects the seatstays to the frame.
3. Down at the BB shell there is a little hidden bolt that locks the chainstays in place, so the whole rear end unbolts for transport. It looks factory, not aftermarket.
4. Paintjob is a nice thick off-white pearlcoat.
5. There are the remnants of a downtube logo. One side says “MITE” and the other says “ALU”. No headbadge but there is a ghost of a sticker that looks like a capital "M" with a stylized circle and rays (see attached image. Please, it's a sketch from memory).
6. Downtube shifter mounts, pump peg, no derailleur braze-on, no rack eyelets. Three bottle cage mounts. Calipers, not cantis.

It reminded me of a 1988-1990 era Miyata but those frames were all steel and had a slightly different seat cluster bolt design. Close though.

I'll try to get photos of it. [edit] Photos coming.

I just did a search for the Miyata head badge logo and it looks exactly like my sketch (except for the 2 lines its a full circle). Duhh....that should be my clue. There is no question it's a Miyata, then. Now to determine which model had a collapsible rear triangle...

Strange that they'll mix aluminum tubes and steel lugs. that's just asking for corrosion between the two dissimal metals. Strange too that they would be providing bolts to de-mount the trear triangle. I would think that the (single) bolted joint would have been a major weak point in the frame. Maybe that's why the frame could be a rare one. The details don't make too much sense.....so far.
Pics please!!

Chombi
84 Peugeot PSV

I agree pics a must I would like to see this frame too.

The lug binder does sound like a Miyata, but they called their hybrid material frames Alumi-Tech. Raleigh also used a similar system but called their hybrid material bicycles Technium. Some of the Raleigh had model names ending in Lite (i.e Tri-Lite). Pics, particularly of the head and seat lugs, would help, as would the serial number.

The downtube logos are not complete and the "Alu" and "Mite" are partial words, all in caps. Therefore the name "Alumi-Tech" is very plausible because it clearly contains both.

I won't be over there for a few days but will try for pics soon, and will post ASAP.

Thanks for the input thus far.

I was wrong on a couple of accounts. It does have rack mount braze-ons. The bike is a 1987 Miyata Alumitech 6300.

12 whole speeds. Biopace. Dia-Compe. Gotta love it.

Thanks for the direction folks. I searched for Miyata and found an old thread that talked about the APA bonding and lugged frames, then an online jpeg listing of all older Miyata catalogs, and spent my lunch hour looking.