Arabesque B-tension?
 

So I just finished (more or less) my latest build, a Nishiki mixte for street and light trail riding. I set it up with a 1x7 drivetrain, using a 40t chainring and a SunTour 13-32 freewheel. I bought this neato Shimano Arabesque long-cage rear mech a while back, and I thought I'd give it a go on this bike.

Now, I'm a SunTour guy, so this Shimano stuff is kinda unfamiliar to me. Instead of a B-tension screw (a la SunTour), it has a spring-loaded upper pivot. Servo-Panta whatsit. Supposed to automatically adjust itself, apparently. Lots of people like this gear, so it must work well, right?

Well, I'm not sure yet. Take a look at the photo, if you would, and tell me if that looks right to you. To my untrained eyes, it looks like the body of the mech needs to come forward some. I can move it forward with my hand, but after some shifting, it gravitates back to this position.

Is there any way to adjust this?

http://bikeforums.net/attachment.php...hmentid=325391

That's it. They're nice for their looks but performance isn't so good.

If you can take apart the lower A-pivot and perhaps drill another hole for one end of the spring to insert into, you could this way get the derailer to pull itself foreward, in closer proximity to the cogs.

But this older non-slanted parallelogram style just doesn't follow the contour of larger freewheels, so expect lazy shifting response as compared to a Suntour mech.

Thanks! I forgot about the spring holes in the cage, and got excited when you mentioned it! But I took a look on my way out the door this morning, and the spring is already in the lower hole, so that means drilling a new hole is likely my only option right now.

What about the opposite approach - are there multiple mounting holes for the upper pivot spring? I'm not averse to disassembling it myself to find out (and I do have a really nice SunTour Cyclone GT as a safety net), but does anybody know offhand?

I think you should not try to adjust the angle.

I say that after looking at four of my bikes with top sprung pivots. Two SX610s a Campy Rally and a Super LJ. They all hang about like that. They don't work the same way as your Suntours (or as well).

Well, if you decide you don't like it an want to get rid of it...let me know. I would love to have a long cage Arabesque.

I agree with GB; don't try to take the upper pivot assembly apart and try to mod it. You'll just be opening up a Pandora's box and kack a rare derailleur.

It shifts slower and less responsively, but it shifts the range like it's designed to. If you want something more responsive you'll have to move into a slant parallelogram like a Deore XT M730.


EDIT: I'd take that Arabesque off your hands too! :p

The one on my Bianchi is at about that angle.
http://i929.photobucket.com/albums/a.../photo-103.jpg

As with mine:

http://imageshack.us/a/img846/8256/hpim4660.jpg

Thanks for chiming in with the photos, guys - that helps a lot. Do all of you find that the cage spring is weaker than the upper pivot spring, as is the case with mine?

Which pivot spring that you decide to tighten should depend on what freewheel you want the derailer to conform to.

I always go tighter, not weaker, but switch to ball bearing pullies first so as not to create unwanted extra friction.

Drilling the B-pivot stop plate may require a good and sharp drill bit, I'd start with 5/64 or 3/32, which might be big enough for the end of the spring.

I might use an Arabesque long cage derailer with a triple, but not with a big freewheel (I don't like the sluggish shifting between the smaller cogs that results from the huge chain gap).

The Arabesque is one of the prettiest derailleurs ever and perhaps one of my least favourites because of it's primitive design, inferior shifting compared to it's contemporaries, and a return spring that is light that gives a nice shifting action but is also made of cheese and wears out prematurely.

Back in the day, people who knew better opted for this and think it cost less too...

http://www.disraeligears.co.uk/Site/...9-filtered.jpg
http://www.disraeligears.co.uk/Site/..._style%29.html

^ that's me exactly (except mine's a Cyclone Mk II). I'm just trying to give this Shimano a fair shake. :)

... in fact, I'm a bit of a collector. I have SunTours in small, medium, and large:

http://bikeforums.net/attachment.php...hmentid=325543

The short cage I purchased new in 1987, which is why it shows a bit more patina than the others. The (NOS) GT I purchased from a fellow BF member just a couple of months ago. And the Le Tech, while technically not a Cyclone, bears an obvious family resemblance.

I have successfully used the short cage with a 30t large cog, so it tempts me. The GT is the obvious candidate. But the Le Tech is oh so quirky, which seems to suit this build (who uses a mixte for offroad?). Hmmmm...

I'm rambling now, but at any rate, I'm going to give the Arabesque a few more weeks to grow on me. :)

That's cool!

If in a couple of weeks you decide it's not for you...;)

Essthreetee, you have a PM. :)

Should have known that trying to bolt a Shimano dérailleur to a SunTour dropout shifting a SunTour freewheel wouldn't be a recipe for happiness. This is so much better:

http://bikeforums.net/attachment.php...hmentid=328738

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