Classic & Vintage - Suntour Alpine Gear (AG) Tech rear derailleur?

Dear folks,

I am thinking of running a 1x9 drivetrain on my 1983 Univega Gran Turismo (or possibly my Rivendell Atlantis -- sorry, Riv haters) with a wide-range 11-36 cassette in the rear and a 42t ring in front. I know that I could throw on a modern RD, such as a Shimano RD-M772, to handle the 36t cog, but I'd really prefer a more vintage look. I've tried my not-exactly-vintage-but-acceptable Shimano RD-M737 with the B-tension screw reversed, and it will shift onto the big cog, but it's noisy as hell because the guide pulley is too close to the cog.

So . . . I'm thinking of trying a Suntour AG Tech, which I know can handle up to a 38t cog. Here's what I'm wondering: Would the Suntour AG have enough horizontal travel to cover all the cogs in a 9-speed cassette? I've searched these forums and elsewhere, and I can't find an answer to this question, although there's plenty of other information. Has anyone tried it?

I guess if it didn't work, I could always use the old 8-of-9 trick to get the cassette narrowed down to 7-speed width, which would probably be manageable. But that would make the jumps between gears bigger than they already are. Anyway, if anyone has given this a shot, please let me know how it worked out.

BTW, I've read that the Huret Duopar RD can also handle a 36t cog, but they seem to be rather more $$$$ than the Suntour AG. So, I've rejected that path, at least for the time being. Thanks.

I know the Vinatge long cage Suntours the AG and GTs will handle a 8 speed and 32t fine I have seen this set up on a few bikes. I'm not sure if it would handle a 9 speed and a 36 cog.

A Duopar will handle 38 very nicely, provided that the derailleur hanger (or claw) isn't too short. I'd think it would handle 36 easily enough. AGs handle 38 easily also. I've never tried one on anything but a 5-speed freewheel, but I'd guess that they might manage 9 with the stops all the way out, or almost. You're going to be doing some serious cross-chaining in some gears if you don't get the spindle length just right, though.

I know the Vinatge long cage Suntours the AG and GTs will handle a 8 speed and 32t fine I have seen this set up on a few bikes. I'm not sure if it would handle a 9 speed and a 36 cog.

Thanks. Since 8-speed and 9-speed cassettes are the same width, an RD that can handle 8 should handle 9, no?


A Duopar will handle 38 very nicely, provided that the derailleur hanger (or claw) isn't too short. I'd think it would hand 36 easily enough. AGs hand 38 easily also. I've never tried one on anything by a 5-speed freewheel, but I'd guess that they might manage 9 with the stops all the way out, or almost. You're going to be doing some serious cross-chaining in some gears if you don't get the spindle length just right, though.

Thanks. At the moment, I have the 42t ring in the middle position of a triple crankset for which I have the chainline dialed in. So, I think I'm OK in terms of cross-chaining unless or until I switch to a different crankset.

Thanks. Since 8-speed and 9-speed cassettes are the same width, an RD that can handle 8 should handle 9, no? While you should be OK with RD travel my guess is you may have issues with skipping and holding gears on a 9 speed using a vintage RD.

At the moment, I have the 42t ring in the middle position of a triple crankset for which I have the chainline dialed in. So, I think I'm OK in terms of cross-chaining unless or until I switch to a different crankset.

As a foppish aesthete, it pains me to imagine a single chainring being run in the middle position. Please, no photos!

As a foppish aesthete, it pains me to imagine a single chainring being run in the middle position. Please, no photos!

:) Yeah, it's kinda ugly that way. If I like the set-up enough, I'll probably go to a single crankset. Much cleaner looking.

While you should be OK with RD travel my guess is you may have issues with skipping and holding gears on a 9 speed using a vintage RD.

Why on earth would you think that?

As a foppish aesthete, it pains me to imagine a single chainring being run in the middle position. Please, no photos!

oh come on now. we always need to see pictures. even if just to know how wrong it really does look.

Khatful has a Suntour Alpine gear that he set up with some crazy cog... maybe he knows something about the travel limits.

:) Yeah, it's kinda ugly that way. If I like the set-up enough, I'll probably go to a single crankset. Much cleaner looking.
Or you could go with a Guard ring. http://www.performancebike.com/bikes/Product_10052_10551_1031814_-1_400909_400002_400909
Thats just the first I came across Should be able to find a nice polished one.

VO has polished.
http://store.velo-orange.com/index.php/components/cranksets/vo-alloy-polished-chainring-guard.html

Thanks to all who've responded. Last night, thinking that I didn't really want to shell out $ for a new RD if I didn't have to, I decided to give my Shimano RD-M737 one more chance. So, I replaced the original B-tension screw with one that was 4-5mm longer and re-installed it. That RD now now handles the 36t cog just fine, and it shifts across the rest of the cassette without any trouble -- at least in the workstand. So, I may not need a new RD after all. I suppose the real test will come when I actually take a ride.

Grim: I've thought about a guard ring and might go in that direction. Thanks for the links.