yesterbik

Hello everyone,

On my Miyata Six ten, the rear derailleur did not hang on the spot on the frame (a Shimano SIS derailleur).






It s working ok, but if I can hang the derailleur the way it supposed to, it may work better.

What is your advice on the issue in order to repair/ change it?
Thank you for your help.

Mike

cxwrench

You've got the wrong derailleur on your bike. You need a 'normal' one w/ just the mounting bolt and not the built-in hanger.

Andrew R Stewart 

As CX Wrench said. The frame/dropout is designed for a "direct mount" der. The imaged one uses a plate mount (badly called a "claw mount"). If you got this bike from a business i suggest avoiding them in the future. This is basic bike stuff 101. Andy

Chuck M 

My wife's Bridgestone did not have the original Suntour derailleur on it. I bought one one eBay, removed the claw and hung it on the hanger with the same screw that held the claw on. If this works for you, you will need to adjust your limit screws.

79pmooney

It looks to me like you can both slide the plate derailleur hanger back in the dropout and rotate it clockwise to better align it with the dropout slot. Between these two, the derailleur mounting bolt will align a lot closer to directly over the iontegral hanger of the bike frame. Of course, the queston remains - why? when you have a perfectly good hanger already.

Your derailleur bolt should go into the integral hanger just fine. Both bike and derailleur are from the wonderful years and country of the very standardized bike frames and parts thanks to the Japanese.

There's actually nothing wrong about running the bike as you have it. (Do straighten out the hanger place and slide it back as I suggested above.) Folks here will sneer and you are carrying about an ounce of un-needed weight, have one more item to give you trouble and a longer reach and a little more wear on the derailleur but the issues from those probably won't show up for years. Now, if you hang out here and plane to post another photo, it might well be easier to just ditch the plate hanger than go through all the harassment again.

KCT1986

On some of the RD of that vintage, Shimano had some models that used a different type of upper pivot for the claw type. See the attached. Based on the attachment bolt on yours, it may be one of these models.

Andrew R Stewart 

Are the bike's shift levers also SIS (indexed)? If so then consider tossing that rear section of shift housing (between the stay and the der barrel adjuster) and using a "proper" SIS grade of housing. The current housing will compress more during each shift, then a SIS one, and this increases the amount of lever "overshift" needed during the shifting into easier gears. Andy

yesterbik

Thank you all for your input.

I follow 79pmooney advice and push the wheel deeper into the dropout. It looks better.
I will use the bike this way.

When I bought the bike, the seat post was stucked. It took me a few weeks trying to remove it. All good now.

Here is the photo of it after adjusting.
Happy biking everyone.

Mr. 66

The claw will prove problematic, it does not have the correct bolt for install and will flip around. Even with the correct bolt it will be inconsistent. Rear wheel may not stay in place under heavy load.

Hondo6

As noted above by KCT1986, Shimano derailleurs of that era typically used a different pivot mounting setup for claw-mount vs. hanger mount variants. The claw mount versions use a pivot axle integrated into the claw, while the hanger mount versions use a separate mounting bolt. The pivot spring is typically different between these types also, as is some other associated hardware necessary to hold the mounting bolt/pivot axle in place..

IF you can find a trashed derailleur of the same model and cage length that is (1) hanger mount, and (2) has a good mounting bolt, spring, and associated hardware, it IS possible to remove the hanger portion and related spring/mounting hardware and replace it with the direct-mount equivalents. The same cage length is needed because often the pivot spring is different based on cage length.

I've done that on a mid-1990s NOS Shimano derailleur to convert it from claw mount to hanger mount. Be advised that doing so is rather a pain in the butt. Also be advised that the return spring is fairly strong, and you really don't want to let things get loose during final assembly - parts can fly, and you can get your knuckles rapped hard if that happens.

But the swap/remount will give you a properly mounted derailleur that should function more reliably over the long term.

Once you find the model for your derailleur, you can find the exploded view for your derailleur at this site:

https://si.shimano.com/en/manual/search

The Park Tool article on derailleur overhauls is also a useful reference if you decide to attempt this.

yesterbik

Thank you Mr. 66 and hondo6 for your input.

I will look around and hope I can find a part derailleur for the conversion to ‘direct mounted’.

It seems a bigger job for me than I have thought.
I will update the progress if I find something.

Thank you all.

Mike

John Nolan 

If it were me, I'd just look for a replacement derailleur. If you're not near a co-op with a good parts bin, try something like a Shimano Altus or Acera.

Iride01 

But if there aren't any issues the OP is having with the current setup, then it would seem silly to replace it with something that is more appropriate yet doesn't do anything better.

John Nolan 

True enough.

guy1138

It is installed wrong and will be dangerous down the road. The "claw" has a hole at the back so it can be bolted into a corresponding hole on the dropout. But this dropout doesn't have that hole, it wasn't designed for a claw. The claw (and therefore derailleur) is only attached by the "squeeze" of the skewer, so OP only has the friction between smooth, flat pieces of metal holding the wheel in. Also, since the claw has a barrel adjuster (?!) threaded in the hole, it's sitting **WAY** too far forward in the dropouts.

That wheel is going to pop right out the first time they get out of the saddle to climb up a hill.

guy1138

It's really not. Find *any* Shimano mountain bike derailleur with the threaded bolt instead of the "claw", it it will work. Install it on the dropout, then grab the top part of the derailleur and **gently** pull towards you to straighten the derailleur hangar. Bend a little, relax, check it, and bend again until it is close. Be gentle, but don't be timid; these forged dropouts are tough stuff. It doesn't have to be exactly lined up in a vintage bike like this with friction shifting.

Do not ride it the way you have it, it is dangerous. There is nothing keeping the claw from slipping forward against the dropout of the bike, which will pull the rear wheel out of the dropout and almost certainly lead to a crash.

Hondo6

FWIW: a used hangar-mount Shimano FD-L553 is available on eBay right now for $23.49 + applicable sales tax. This includes shipping to a US address.

https://www.ebay.com/itm/384345277020

I believe KCT1986 is likely correct and that this is the model derailleur you have, except you have the claw mount version. (If your RD isn't that exact model, it's another very similar model from the same era from Shimano.)

I have no connection with the vendor, nor have I done business with them; I just posted this as an example. As others have said, any Shimano mountain or mid/long-cage road derailleur from that era would likely work. Just be sure it's hanger mount vice claw mount.

If you want to stay with your current type of period derailleur, replacing it with something like that would IMO the best course of action. As other have noted, it's not properly mounted as it is now and may in fact not be reliable or safe.

Approx $25 seems to me a small price to pay for peace of mind. YMMV and financial situation may vary.

John Nolan 

I agree...I wish I had realized that before I made my previous post.

guy1138

Everything you said is *not wrong*.

However, this SIS RD that OP has on there is nowhere near correct RD for the bike. OP should just get any long cage/mountain bike derailleur, slap it in, pull out the hanger a little bit and send it. It's friction shift, so it doesn't care about pull ratio.

guy1138

Nothing you said is wrong, but the RD on OP's bike isn't correct for the year, or even the period.

This is an '85 610, SIS appeared only on Dura Ace (which this definitely isn't).

It looks more like a 2000s-today Walmart bike RD. OP should just use any direct mount long cage road or mountain bike RD; they'll all work for friction shifting.

Hondo6

Actually, I'm reasonably sure the RD is a Shimano RD-L5XX series. It has the correct "Shimano SIS" embossed into the outer parallelogram plate. The typeface, relative size, and location match those for the L553.

Documentation (EV) for the L553 is dated Jul 1989. That documentation is likely a bit later than the derailleur's release. So the derailleur is at most around 5-6 years younger than the Miyata frame in question. It's also a SIS-capable derailleur.

Seems to me not out of the question that the bike's owner was doing a 5 year update few years after SIS was released and decided to install this derailleur with a view towards future indexed shifting. (They also might have installed it to replace an original derailleur that failed or was damaged.) Personally, I'd consider late 1980s components on a mid-1980s frame to be generally period correct, even if not the original equipment. But YMMV.

guy1138

I'd separate the indexed period from the friction period.

They were so enamored with indexed, that they threw on the incorrect claw style RD on a bike with forged dropouts? I mean, it's *possible*; I;ve seen so many crazy guys with "good ideas" come through the shop, I don't discount anything. But isn't it more likely that the bent rear derailleur hanger threw the original RD up into the spokes and the previous owner threw a POS parts bin RD on there and sold it on to the next guy?

Regardless, OP doesn't need to know the whole history of the patents on slant parallelogram rear derailleurs, he just wants the bike to work. Slap anything on there, tweak the hanger into the general right position, and ride away!

Iride01 

Without a better picture, I can't say I agree that the wheel is too far forward in the drop out. On those old style horizontal dropouts, it wasn't uncommon for us to have the wheel sitting forward in them.

And not all the DR's back then with that type mount screwed into a hole on the dropout. I had several growing up that had a sort of t-nut to fit in the slot and clamp it firmly. In the drawing providing in reply #6 that nut is shown with the screw and marked as #18.

Hondo6

You are correct that the mounting hardware originally supplied with the OP's derailleur had a nut designed to fit into a horizontal dropout slot. However, at this point we don't know if the OPs bike has the correct nut or not. If not, that would likely be a problem.

Frankly, I'd guess it might not. It appears to have a derailleur adjusting barrel holding whatever nut is on the back side in place. That substitution in turn argues that the correct nut and bolt were not available (I'd guess either both or neither would be present on a replacement derailleur) and that "alternative hardware immediately available" was used to mount it by whoever originally installed it.

And even with the correct nut, I don't see how a derailleur adjusting barrel could be torqued tight enough by hand to hold the derailleur reliably in place. Replace the derailleur adjusting barrel with an M5 bolt and lock washer and it might be reliable.

I'd still argue for replacing the current RD with a hanger mount derailleur, though. It would likely work more reliably, it's what the frame is designed for, and it would be aesthetically better.

Hondo6

To each his own; I wouldn't worry about it. Many owners do change components on a frame they like as technology changes and/or parts wear out or are damaged. Often they don't use the same parts as were originally installed.

You have a point here. The RD was indeed more likely a replacement for a trashed original RD than an intentional upgrade. However, we have no idea when that was done or by whom. Or why, for that matter.

In any case, I'd hardly call any derailleur from Shimano's Light Action series a POS, even if it came from a spare parts stash. These were (and still are, if in good repair) reputedly very nice shifting and reliable derailleurs.

Any discussion of slant parallelograms would be irrelevant to the topic at hand. And in any case, a 1985 Miyata frame postdates the expiration of SunTour's slant parallelogram patent (1984).

I also wouldn't assume the OP doesn't care about aesthetics. It's a nice vintage Miyata. My guess is that he likes the bike's current vintage look and wants to preserve that, but just wants it to work better and more reliably.

Replacing the current RD with a hanger mount model of a current Shimano Tourney/Acera/Altus/whatever would indeed take care of the latter two; it would also look as out of place as a turd in a punch bowl. Replacing the current RD with a hanger mount version of a good RD from the 1980s would do all three and can be done at a comparable cost.