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...