JVinci

Hey guys,

So I'm pretty novice to road bikes (well, all bikes I suppose) but recently purchased an old Miyata 912 on craigslist. Rides good, shifts well, and all was fine.

It was pretty dirty so I decided to give it a good cleaning. I started degreasing everything and was moving my way to derailleur, when I noticed what appeared to be a loose bolt. It was kind of cockeyed, not hitting the threads perfectly perpendicular, so I decided to loosen it and re-tighten it.

Well, the threads weren't very deep and with one turn, my derailleur came apart. It kind of jolted apart, exposing what I think is the tension spring and a washer.

When I tried to assemble it back together, my derailleur was just limp and wouldn't hold my chain tight anymore. Thus, rendering my bike useless.

Is this something a normal person with minimal tools can fix? I might be able to borrow some but I have no idea how to tighten this spring or even how much to tighten it by...

The pic isn't actually mine, but the bolt that I unscrewed.

Any advice?

eschlwc

your rd is a tough one to fully overhaul, because the stop pin does not unscrew. this makes full disassembly difficult but not impossible. with the stop pin removed, assembly is easy. with it fixed, you must load the pivot spring before tightening the bolt. it can seem impossible.

i've had two of these. the first, i fully overhauled, and it took an hour probably to resecure the pivot bolt with the spring loaded properly. recently, i bought a second one, but didn't attempt a full overhaul due to the fixed stop pin.

you can either attempt it yourself or give it to someone better qualified. if it were me without the experience, i would take it to a guy at my co-op i know.

the park tool site may have a tutorial. a vise may help a lot.

you could also post your location, and maybe someone here that lives nearby could help you out.

if you wanted to send it to me (seattle), i could help you, but shipping cost may make it infeasible. in perfect shape, these derailleurs are worth $50 or so.

The Golden Boy 

I would get a better derailleur. You now have a perfect excuse to get a better one.

I have one Arabesque derailleur- as pretty and cool as it looks, it shifts for garbage. I replaced the long cage Arabesque rear derailleur with a GT caged Suntour Cyclone.






For real, when you realize how nice the Cyclone shifts compared to the Arabesque, you're going to kick yourself for putting up with the "charm" of the Arabesque for so long.



It looks like they're going for around $50 on the ebay right now... Someone here might have one that they could cut a better deal on...

eschlwc

come on, gb. how many bikes did you have with shimano 600? what was the state of the freewheel?

both mine shifted great and very fast with 6-speed freewheels.

shifting groups look best when they match.

don't give up, op.



if i were to base my suntour cyclone experience only on my first experience with one, i'd give it a 'd.' fortunately, i've had several since then.

eschlwc

lord_athlon

You can tell on most of these, the cage pivot spring has lost tension compared to the mounting pivot.

edsall78

I was actually going to agree with GB on this one..I've had my share of those 600 arabesque RD..In fact i have I spare 600 Aabesque right now in my meager parts bin..

Its pretty much the only derailleur I've had issues with.

I like suntour and most shimano..but right now my favorite is the Nashbar/Microshift long cage RD..it shifts really nicely and super easy to install and mount.

dddd

I'm nearly certain that the OP simply didn't pre-load the cage pivot spring behind the fixed stop.

You'll need to re-loosen the screw, pull out the cage pivot shaft slightly, keeping the short spring end "peg" engaged with the hole or slot in the cage plate, then "wind" the spring by turning the cage in the direction that the chain normally pulls it, then push the cage pivot fully back into the spring bore as the fixed stop position is passed. The bolt can then be re-tightened, with the spring now pre-loaded against the fixed stop position.

It is important that the other end of the spring, deep inside the spring bore of the "A" knuckle, also is pegged into it's respective retaining hole, since normal chain and spring tension keeps this threaded junction from ever loosening.

I've seen these and Crane derailers with the pivot shaft threads somehow stripped out of the cage plate, so don't tighten more than the alloy threading justifies.

I've found much shifting improvement by changing out Arabesque derailers for later 600 S.I.S. models, which move less in response to any given amount of cable pull.

These would have been considered very good at shifting in their day when paired with Shimano's Uniglide cogs and chain.

philbob57

I liked my 600 EX - it was a big upgrade from my Simplex Prestige.

'02 nrs

posting as the arabesque bits are worth more these days to vintage bike restorers.if you removed the main attachment pivot its much more difficult to reassemble.this video is great but skips over how he reassembled the parts at 4:30. it is easily assembled in the same fashion as the cage pivot by using the bolt to bring the parts together.but its very easy to do if you attach a spare derailleur hanger which you can revolve the same way as you revolve the cage when doing the cage pivot.then draw up the main attachment bolt.

squirtdad

please leave the zombies sleeping

oneclick 

The outer end of the tension spring is secured by a bit of plastic at the top of the cylindrical shield.

This bit can break, and then the jockey cage does not tension the chain.

See:

https://www.bikeforums.net/classic-v...ing-cover.html

JVinci

Holy cow, who bumped this thread!?? Well, since my account login still works, I figured I’d come and close the loop on this old thread. Whoever said that I didn’t properly pre-load the spring when reattaching to the chain is the winner. Once I actually “wound” the derailleur before securing the chain, it began working correctly again. However, I have since sold this bike and moved on from vintage road bikes in general. It was fun for a time, but not something you want to try pulling a kid with lol. Good luck to all those who find this thread and plan on tackling this derailleur!

dddd

What the Arabesque rear derailer lacks in terms of adjustability of the A-B spring balance, it kind of makes up for by shifting so well on 26T or 28T largest-cog freewheels or cassettes.
It's ability to maintain a minimal chain gap between the upper pulley and the cogs is more critical today than it was back then, both because of the later availability of narrow-spaced Uniglide freewheels and especially because of the extreme flexibility of modern chains.

I had a harder time getting my Suntour Cyclone RD to follow a 13-28T freewheel closely, requiring me to back the B-tension screw off entirely and further to grind a bit of metal from the B-tension screw's lug on the B-knuckle. But wow does it shift great now, fully plastic-lined cable path up to the bar-ends (even the BB cable guide), UG 6s freewheel and Shimano HG70 chain.
I took this photo before the final grinding/filing of the B-screw's stop lug, getting the RD to swing forward a bit more really "tightened up" the shifting response!


This photo shows how the early Shimano rear derailers (including the 600 Arabesque) did a great job positioning the top pulley close to a 13-26T or 13-28T (shown) freewheel, right out of the box with no adjustments.
Again though, this close tracking of the freewheel's profile becomes doubly important when super-flexible modern chain is used.