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Compatibility - Shimano+Suntour??(11 posts)

Compatibility - Shimano+Suntour??muncher
Jul 1, 2002 12:58 AM
Anyone know if Shim STIs (I think RSX, possibly 105) are compatible with Suntour rear derails (don't know the model -but prob mid 80's - very short cage)? If it makes a difference, the set-up is on an 8 speed narrow cluster HG block.


Jul 1, 2002 4:16 AM
Why fool around with ancient Suntour parts when you can get a new Shimano rear derailleur for $20?
I agree......Dave Hickey
Jul 1, 2002 4:57 AM
You can find RSX, 105, or 600 derailleurs on ebay all the time for $5-$20.
Depends on your standards.Spoke Wrench
Jul 1, 2002 5:03 AM
I think you will be able to make it shift, but I doubt it will ever be as crisp and precise as a modern all-Shimano drive train.
Thanks - reason for the question is...muncher
Jul 1, 2002 5:27 AM
A friend got a bargain at a local sale on Sat - nice 7005 frame and asym Ambrosio "Team" new-build tubs, Campy pin, new saddle, etc etc, for £170 (about $250) - great looking, light bike.

However, it has mixed components, and try as I might, I just couldn't get the shifting to be consistent and crisp - tried new cable and housing, lube etc, but it's just not crisp at all.

I have never worked with Suntour components, and I just wanted to know what the deal is, before I go tell him to splash $60 for a 105 rear mech. Sounds like that's the solution though. Oddly though, it shifts fine on the bottom 3-4 cogs, but not the top, no matter where you set the trim on the derail. Just not quite right ratios I guess.

I know the guy that assembled it was pretty hopeless, as it has an 11 top, with a 12 lockring, so the chain doesn't sit! Anyway...

The suntour looks slightly "collectable" though, so he'll probably get some £ back, and it's still a great deal and a really nice ride.

Thanks for your replies.
don't feel rider
Jul 1, 2002 9:06 AM
had problems with my ex-wife bike in 1994 when she had suntour on her MTB bike. The thumbshifters didn't adjust as well as shimano. Wasn't sure if any of there road parts were superior. At least I was told that they were king in the 70's.

I found it was easier to adjust and shift better when I worked on the shimano drive train. I guess if you have thwe patient than the suntour may have worked ok. I'm surprise suntour made an 8 speed.

Hope your friend likes his new bike and gets the bug (gets hooked on riding). Maybe in a few years he'll buy a new one.

Not sure they did....muncher
Jul 2, 2002 12:45 AM
See the post below - I think it was a 7 set-up made to an 8.

One of the problems is that there is no adjuster on the derail, unlike Shim and Campy - you have to use the barrel on the down tube/head tube interface, which just all seems less positive. I suspect that the downtube levers must have had a decent adjust at that end originally, but I'm not familiar with the Sun system.

He's got the bug though - got home on Sat at 3, by 5 we were out and on the way to 20 miler. Trued the rear, then 25 on Sunday (before his legs exploded - "you can't average 25mph all day up these hills slow down and pace yourself/no - I feel great...ow, my legs have broken/heh heh heh").

All the more of a victory, given that he went there to get a MTB coz he thought that they were as fast on the road with slicks - but me and MJ talked him round, much against his will, and now he's one of the breatherin!
Glad to hear rider
Jul 2, 2002 10:01 AM
he got the bug. Once he starts pacing himself, than he'll ask you for some tips. Like how do you get you legs to recover (I have yet to figure a good method to that one)?

I started on the road with a Cannondale MTB with 1.6 tires, but have to agree it's alot more fun flying on a road bike.

re: Compatibility - Shimano+Suntour??JaeP
Jul 1, 2002 5:23 PM
Hello Muncher,
What kind of Suntour rear derailleur is it? Superbe Pro? Sprint? I still use a Superbe Pro rear derailleur on my 7 speed '89 Paramount and it works perfectly.
Umm dunno....muncher
Jul 2, 2002 12:37 AM
I'll have to have a look again tomorrow night - I didn't see anything like a model name on it, but I wasn't really looking for one at the time. Is there an obvious way of identfying the groups if there is no name on?

Are you using STIs with the Paramount 7?

My suspicion, given the "wrong" 11, and the rest of the clusters he was selling, is that the block was a 7 and he's made it up to 8, if that makes a difference.

Thanks for the reply.

Suntour IDJaeP
Jul 2, 2002 6:32 PM
Hello Muncher,
Most of the Suntour components would have some sort of name on them especially on the rear derailleur. The most popular names are Superbe Pro, Sprint, Cyclone, GPX. That's all I know 'cause that's all I'm familiar with.

Alas, my '89 Paramount has down tube shifters. I like downtube shifters. I have them on my 8 speed '99 LeMond Zurich and 8 speed '99 Schwinn Peloton. I like them 'cause they work and I'm cheap. STI's are nice (I have them on my Schwinn Fastback) but I think my downtube shifters will out last the STI's.