I just aquired this bike to replace the crushed 312 my wife ran over. It looks to be a step or two up the food chain from the 312, with adjustable rear dropouts, a chain peg, and nicer Shimano conponents (execpt for the Signature crankset). There are no markings on the top tube, the Miyata logo is only on the right side of the downtube, and the seattube has the 'triple butted cromo' decal on top and a 'Made in Japan' logo on the bottom. Can you ID this beast, or do you need more data/better pictures?
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Offhand, I thinking it's a 1987 model 512, which would be one step up from a model 312. There was also a 1986 model 710 with a similar color scheme, though it's spec'd with SunTour/Sugino/Dia-Compe components. The serial number will tell me if I'm in the ballpark on the age. A list of the component models would also help.

Serial # is OC28944, frame is 57cm.
Derailers, shifters, BB, brakes and brake levers (aero type) are all Shimano. I'm not well enough versed to say whether they're 105 or 600. Rear is indexed 6 speed.
Crankset and pedals are SR/Signature; the pedals look like MKS knock-offs. Wheels are Marvic MA 40. Rear brake cable is internally routed.
Bike is VERY light. I'm looking forward to a winter of rehabing it and riding my first century in the spring.
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Some close up pics of the derailleurs and brakes would help identify them, but based on the additional info it would appear to be the 1987 model 512. Those Mavic rims are probably replacements. Original would have been Araya or Wolber. Weight should be about 24-25 lbs.

OK, I got around to hiking out to the barn (through the snow, no less) to shoot some scans:
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Those are the Shimano Light Action series brakes and derailleurs, which were what was spec'd on the 1987 model 512. All things considered, the 1987 model 512 is the best match I can find. The components, tubing and colors match, though the color pattern varies from the catalog, which shows a steel blue to yellow fade, which may simply be a production change within a model year.

OK.
Thanks for all your help.
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Anyone give some specs/info on the 710? Someone's selling locally here and I thought I'd go check it out. Rough estimate on price?

That model was produced for at least 6 years. The specs varied quite a bit. However, it should be at least CrMo double butted tubing. Later versions were CrMo (non-spline) triple butted. I've seen it spec'd with Vx, BL and Cyclone derailleurs, depending on the year. Early models had 27" wheels, while later models came with 700C. Original prices would be about $300-$600 US, depending on the year. You get the idea, there was a lot of variation! If you can get a few specifics, the serial number or even the color scheme, I may be able to help out a bit more.

T-Mar,

Color is a light red with a grey-silver head tube. I can't answer much more, because I've only seen one obscure photo on CL. I'm going to call the guy and see if I can find out more. Would this represent a significant upgrade from my 310 with Shimano 105 comps?

BTW, why "105" and "600". What do those numbers have to do with anything on Shimano comps?

thanks,

mx

That would appear to be the 1984 model 710. CrMo double butted tubing with a MangaLight fork, SunTour Cyclone MKII derailleurs, SR Super Custom crankset, Dia-Compe 500N brakes, Sunshine Gyro-Master hubs laced to 700C Araya 20A rims.

You do not state the year of your model 310, but if it has Shimano 105 it should be from 1983-1986, so it is the same era. The model 710 is one step up from a model 310, but for me it is not significant. Curiously, the 1984 model 710 is listed at 1/2 lb more than the 1984 model 310, for the same frame size.

The Shimano component hierarchy, from the top, goes Dura-Ace, 600, 105, etc. The 600 group, in its various versions was a mid-range group, with 105 being a lower, mid-range group. Certain versions of these groups have collectibility, particularly the 2nd generation 600EX (aka Arabesque group) and the 1st generation 105 (aka Golden Arrow group). The Golden Arrow refers to the stylized bow and arrow logo. The logo was commonly printed in gold, hence the name, but it was also produced in blue and black. A model 310, with the Golden Arrow 105 components, would probably fetch a better price than the 710, as those components are showing more interest from collectors.

I've heard bad things about the Light Action RD.
Would I be wise to swap it out with the 105 off the 312?
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The Light Action derailleurs have a square opening cut into the rear parallelogram arm, to accommodate the pivoted, spring tension arm. This is a weak point. I have seen several rear parallelogram arms break at this point. Failure normally causes the chain to derail and jam between the dropout and small cog. It's inconvenient, but usually not hazardous. There are probably many out there, still functioning well, but they do appear to have a higher than normal failure rate. If I had a spare, compatible derailleur to replace it, I probably would.

The FD is a 'bow and arrow' 105. Looks pretty spiffy....
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