mstateglfr 

There is a project frame on ebay that was auto-pushed to me and piqued my curiousity since I cant perfectly nail down what year it is. https://www.ebay.com/itm/Vintage-80-...643c%7Ciid%3A1

The frame sticker says Tange Champion double butted tubing, but looking thru catalogs and pics I havent found a 610 with Tange Champion tubing that is DB.
There are no bottle bosses.
The serial # is H540185 which indicates 1979.
Brake cable guides are brazed on the top tube.
Brakes are centerpull.


The 1979 catalog has a 600 model. The 2 seat tube bands on the catalog bike dont match and the rear brake cable routes under the top tube with split cable housing. The catalog bike's fork ends are chromed.
The 1980 catalog has a 610 model. The color matches i think(burgundy) and it has centerpull brakes. Top tube brazed cable guides are present. The catalog states the 610 uses Miyata tubing(higher level bikes this year use Tange Champion).
The 1981 catalog has a 610 model. The color matchest i think(burgundy) and it has centerpull brakes. Top tube brazed cable guides are present. Bottle cage bosses on the downtube are present. The catalog states the 610 uses Miyata tubing.


So since the color matches, there are no bottle cage bosses, it has centerpull brakes, and the top tube has cable guides- this is most likely a 1980 model year frame that was built in '79 and held over, right?
The factory either used Champion tubing for some reason or mislabeled the tubing for some reason then.

Mistakes happen(mislabel) and substitutions happen(different tubing) in manufacturing. I do wonder which is the answer here though?

mechanicmatt

Not knowing jack about Miyata, I know 610's were supposed to be a touring model. This lacks so many eyelets, rack mounts, canti-mounts, and bottle mounts, I feel like it may be a respray of a frame that isn't a 610.

I don't know anything though.

mechanicmatt

I take it all back...looks like this one. 1981 Miyata 610 (<-linky).

Spaghetti Legs 

Mine is a little later with canti brakes but tubing sticker like the one linked in post 3 above. Weird thing - mine has stickers on the BB just like yours except mine are "H" and "A".

noobinsf 

Is it possibly a Canadian model? I search "1979 Miyata 610," and I only find one other person who thinks he has a 1979 610 with Champion tubing: https://www.roadbikereview.com/threa...g-info.364793/

There is no indication that his is Canadian -- I'm just guessing at an explanation.

mstateglfr 

The Canada possibility is one I considered since I think all the online catalogs are technically from Canadiaville. So the small quirky difference may just be due to what was spec'd north and south of the 49th parallel.

Thats a good possibility that I forgot about, thanks for adding.

Hobbiano 

Where does it say it's double butted?

mstateglfr 

Good call, it doesnt. I went down the rabbit hole of looking at the stats for various years and got that confused.
Ive always just assumed Champion tubing was double butted, especially the red version since that is what turned into Tange 1 with the green version being Tange 2. <---that may be me misremembering.

Hobbiano 

I think it matches what's in the 1980 catalog. Notice they say it uses chrome molybdenum tubing in the description, and in the specifications they state it is Miyata Chrome moly, and the sticker says Tange Champion Chrome Molybdenum seamless tubing, and under that, on the same sticker, Miyata Industry Co., LTD. The only thing that doesn't seem to match, if you zoom in on the sticker in the catalog, is the green lettering for the word Champion.