I got a Miyata “six ten” from the Goodwill a couple of weeks ago ($10). It was really dirty, but appears to be strait. I used an oxcilic acid to clean the chrome front fork which is marked Miyata manganese-molybdenum. I wondered if the bike had been in a flood, because the low rider rack mounts on the front fork were packed tight with mud. The picture about matches the catalog scan of the 1984 –Six Ten (https://bp2.blogger.com/_whtVpXkKwlQ/...0-h/img061.jpg ), but the component group does not, nor does the fork. The bike has Sun Tour Cyclones on it with bar end shifters.
Here is the sad and strange part; the rear derailleur hanger has been hacked off! I noticed that the Cyclone was hanging on a claw when I got it home but didn’t register that I was out of place. I loaned it to a co-worker for a week. The days we rode together I noticed that he could not get the derailleur trimmed to stop the drive train noise.
I have a couple of questions if they Miyata & Sun Tour aficionados:
Why would someone go to the trouble of doing fine upgrades on this bike only to hack the rear dropout mount?
Which rear derailleur should I put back on it? FWIW in my parts bin I have four different Sun Tour derailleurs worth mentioning: Cyclone, Cyclone II, Le Pree, & GT-V.

Thank you in advance for any input or advice.

Oh also –is the Miyata serial# data base complete or does T-Mar want or need the # off this one?

You have no way of knowing if the person who upgraded components also hacked off the derailleur claw, right? At any rate, for RD how large is the max rear cog? I'd lean toward the SunTour G-VT but it might be overkill if you don't have more than a 28t cog. And is that drive-train noise a function of a bent claw or something else?

Nice bike, btw. I picked up a 1986 610 a little while ago and plan on building it up with arc bars, mtb levers, and thumb shifters and 700 x 35mm Pasela tires.

Neal

The claw looks like it was added to the Cyclone. I guess you are correct the original owner may not have been the one to hack it. I have made several assuptions: The fork up-grade was made in the first few years of the bikes life due to it being stamped "Miyata" on the fork crown. The bike was loved in that someone took the time to put two stickers under the bottom bracket to identify it as there own.
Regarding gearing, I was unable to remove the rear freewheel last night, it has a SunTour 5 speed cog. I am replacing the some of the front chain rings, currently it has 52/48/32. I plan on spreading the middle gear between the two.
I am mistaken on the year. Upon viewing the link in the expanded format I see that the blue color is not quite the same and the "six ten" is in a different font. My bike has "six-ten" in a curtsive w/ soft edges.

It's complete in that the format has been decrypted, but I always welcome new data.

The bicycle has obviously had a few modifications, both to fthe rame and components. The serial number will narrow down the year.

All are good derailleurs, but on touring rigs, I tend to opt for a little more reliability and rigidity over weight. My first choice would be the V-GT, then the LePree followed by the Cyclone II and Cyclone. Of course, given that you intend to maintain a wide range triple, that could all change depending on which derailleurs have the actual capacity. The only one known to have a long cage, based on your descriptions, is the V-GT.

I appreciate the information.

I am leaning toward the GT-V at the moment, because it is the one that I know came w/ a mounting claw therefore, it will not look cobbled together. I will up date the post w/ photos and serial # tomorrow( hopefully).

Here are some pictures & a serial # :

Ouch. Looks like some fixie-kid got their hands on it.

If it (as it appears) the frame had been "modified" into a single-speed or fixed gear, that owner may have messed with the rear spacing and alignment a bit too. So, regarding the shifing noises, I'd make sure from the start that the rear end is spaced properly (... to whatever width you now perfer), and also centered correctly to the frame.

The early (late 1970s) Cyclone and Cyclone GT derailleurs as well as the Suntour "V" derailleurs could originally be had with an adapter claw. Of course, if you're not wanting to be to finicky about using the correct derailleurs for the year of the bike, you can also get brand new modern Shimano "Tourney" derailleurs factory fitted with the claws for only around $20 from your local bike shop (or online). They are not extremely high-end but have been updated over the years abd are certainly very smoothly functional and are intended for 6-7 speed freewheels. With one of these, you'll have a completely new product to work with rather than having to fuss with matching an older derailleur with a correct claw. As I recall, the old Suntour claws had a rather odd curve (toward the direction of the freewheel) stamped or forged into them when new. So if yours now has a straight (vertically flat) claw, this may be part of the shifting issue.

The serial number indicates your frame was manufactured in 1983, however it is quite a high number and the possibilty of an early 1984 model must also be considered. In this case the indicators point a 1983 model. There was a change in the Miyata logo from 1983 to 1984 and yours has the 1983 version. Furthermore, the 1984 version incorporated a bridge on the upper seat stays to act as a cable stop for the rear brake. This feature does not appear or the 1983 model or your frame and barring the fact that a previous hacked it off, like the rear derailleur hanger, would corroborate a 1983 model.

The two stickers are OEM, applied by Miyata. I have yet to determine the actual nature of these labels, but suspect they may be inspection indicators.

The catlog specs indicate the original derailleurs were SunTour Superbe Tech. These rear derailleurs had poor seals, resulting in pivot wear and sloppy shifting. Rarely did they last more than a year or two. So, it is not suprising that the orignal rear derailleur is not present, even in spite of the fixie conversion.

As you surmised, the fork is clearly a replacement. Miyata did not offer full chrome forks on the 610 and the low-rider bosses did not appear on this model until 1985.

The rest of the OEM specs can be seen here: https://bp1.blogger.com/_whtVpXkKwlQ/...0-h/img044.jpg

Thank you, Guys!
I rode it this morning to work, a very nice ride but a little more responsive than I expected. I cleaned up the Cyclones they were a mess, the little bolt that holds the back plate/axle spacer was stripped causing the derailure alignment to drift. The shifter tunes fine after cleaning tightning and replacing chain. I have left the Cyclone on the rear for now but may switch when I change out the freewheel.
Next request: Opinions on handlebars. Should I keep the randonneur bars,or should I switch too- (your suggestion here) ?


When I get it done I will post some after pictures.

Bars are a personal preference thing; I happen to really like the randonneur bars that came on my 610; they're wider than the earlier versions, but not too wide. I transferred them to my early 70s Fuji, as a matter of fact.

Neal

Why not have a good bike shop that does repair weld on a derailer hanger?

And I think that Stronglight is correct: chances are that your drivetrain noise problems are from misalignment, rather than from use of a claw to mount the derailer. So I'd pay for a frame alignment.