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PostPosted: Fri Apr 05, 2013 7:11 pm 
Old School Grand Master
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I'm taking a bike apart to clean it properly and put new cabling etc on. Not really a fan of the Suntour groupset that's on there, so I am thinking about putting some Shimano (ST-M095) shifters on while I'm at it.
However I have no spare 7-speed Shimano mechs, so I'm thinking about keeping the Suntour (XCM) mechs.

I know both are 7 speed, but do the pull ratios etc match? Tried a Google search, but found no definite answer. Anyone mixed those up before?


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PostPosted: Fri Apr 05, 2013 7:36 pm 
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Raging_Bulls wrote:
I'm taking a bike apart to clean it properly and put new cabling etc on. Not really a fan of the Suntour groupset that's on there, so I am thinking about putting some Shimano (ST-M095) shifters on while I'm at it.
However I have no spare 7-speed Shimano mechs, so I'm thinking about keeping the Suntour (XCM) mechs.

I know both are 7 speed, but do the pull ratios etc match? Tried a Google search, but found no definite answer. Anyone mixed those up before?

I have a mix of SunTour XC Expert 8-speed thumbs with a Shimano rear mech LX (RD-M550), and it works real fine.


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PostPosted: Fri Apr 12, 2013 10:35 pm 
retrobike rider
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I ran a Suntour XCE rear mech with some Alivio 7 speed shifters on my Diamond Back for a while and it worked fine.


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PostPosted: Fri Apr 12, 2013 10:39 pm 
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can't remember the exact spacing but i think it was close enough that it works ok i did, i had suntour shifters and shimano 7 speed xt mechs and shimano cassette and it worked fine


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PostPosted: Fri Apr 12, 2013 10:47 pm 
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Forgot to update, thanks for bringing this topic up again.

Been riding with XT 730 pods in combination with the XCM rear mech for a few days, and the rear shifting is sloppy from 3rd to 6th gear. Adjusting will improve matters in 5th and 6th, but then it'll be sloppy in 1st to 4th and when going for top gear. I know the pods work fine because I used them on another bike before. I know the mech works fine because I used that before as well. Inner and outer cables are all new and greased. So something is wrong.
I read elsewhere that there seems to be a slight difference in indexing, which can cause sloppy shifting in some of the gears. Not sure if that's true, but I'm starting to believe it.

Either way, I have to overhaul the controls again because the brake levers are the wrong kind, which has prompted me to order a set of 3x7 capable friction thumbies while I'm at it. That should solve any kind of indexing problems.


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PostPosted: Sat Apr 13, 2013 8:28 am 
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Your experience agrees with my memory. Early 90s 7 speed suntour cassettes had a different spacing between the smaller cogs of the cassette than the bigger ones. Also I don't think sunour mechs had floating jockey wheels. Therefore any difference in spacing between cogs (sprockets) compared with shimano won't be taken care of because the shimano shifter will have the index notches designed to be at different spacing points (than suntour). You may cope better with it by fitting a shimano mech, as the floating jockey wheel should theoretically allow some more leeway (and this would explain jonny's setup working fine). However this isn't really fixing the root cause which is incompatible shifter and cassette.
If you want indexed gears my opinion (and I now I will probably get some ire for this off people who say "it worked ok for them") is that you should either get a replacement suntour shifter to use with the existing cassette and suntour mechs .......or get a shimano mech to use with the shifter and a shimano hub and cassette (obviously this is the more expensive route).
Good compromise might be to use a shimano mech and possibly go for a friction shifter like you describe.

There - I've said it. Whether a mixed setup works for anyone else is all fine and dandy but the fact is 7-speed suntour parts were all designed to work together and were not designed to be mixed with shimano. I would have loved a suntour xc comp set up back in the day but in the end I didn't go for it because shimano cassettes were much more widely available and also supported by british hub makers like hope etc.
Suntour xc comp and pro groupsets as a whole were in my view superior to shimano dx and xt. Though shimano may have had a slight edge in terms of shifting performance and spares availability, I believe suntour pedals, brakes and headsets were superior to shimano. What the lower end groups were like I don't know for sure, but I think shimano would probably have slightly had the edge in shifting there too.

I won't bore you with info on where suntour went wrong and why they disappeared from the market, but it all seemed to go downhill from when when they introduced xpress shifters (as I recall).


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PostPosted: Sat Apr 13, 2013 11:01 am 
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Thanks for that post Raymond, at least now I know for sure that it's not a lack of setup skills. I'd prefer to have only Shimano parts on the bike, so putting the Suntour shifters back on is not an option.
I'll either have to look for a Shimano Freewheel that'll fit the Laïti's unusual axle arrangement or go for friction thumbies.

For now I'll go with the latter option. Next winter I'll figure out how to remove the cassette (the procedure is completely different from normal screw-on cassette removal) and go for a Shimano screw-on cassette.


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PostPosted: Sat Apr 13, 2013 11:08 am 
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As Raymond said above it will work but the best results will be with a Shimano mech on Suntour cassette with Suntour shifters (i daresay it would be better than a 100% Suntour indexed setup)


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PostPosted: Sat Apr 13, 2013 4:07 pm 
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SunTour spacing


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PostPosted: Sat Apr 13, 2013 5:38 pm 
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Sheldon Brown's spacing sheet shows the same thing really, now that I start to look in-depth.

The Suntour Ultra freewheel has equal spacing and is compatible with Shimano, but the Microdrive one isn't. I have a Microdrive.
There really is a difference in the spacing, which explains why it's so sloppy.
I guess that's my problem, and also the reason why mixing works for some but not for others.

Guess I'll need to look at how the cassette is attached to the Laïti's rear axle and see what's possible. If I need to replace the cassette and the mech anyway, I might as well go all the way and bring the bike into the 20th century with a 3x9 setup.


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