Suntour Cyclone RD, can't adjust it from 7 spd to 6 spd?
02-18-11, 10:05 AM
#1
Steel80's
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Suntour Cyclone RD, can't adjust it from 7 spd to 6 spd?
I have a Suntour Cyclone MKII RD, which supposedly is able to handle up to 32T on my Vitus. It was working well with a no-name 7 speed freewheel with (I think) 28T as the biggest, and a KMC Z-chain, and Campy friction shifter.
As an experiment I tried a 6 speed Shimano "corn-cob", which only goes up to 20T. Strangely, I can't get it to shift onto the 20T, and I'm out of adjustment! This does not make sense to me since I know it can handle the range. What am I missing?
As an experiment I tried a 6 speed Shimano "corn-cob", which only goes up to 20T. Strangely, I can't get it to shift onto the 20T, and I'm out of adjustment! This does not make sense to me since I know it can handle the range. What am I missing?
02-18-11, 10:12 AM
#2
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Off the cuff, did you check your B screw as well as limiter(s)?
02-18-11, 10:17 AM
#3
Unique Vintage Steel
Is this on the same wheel or a different one with a different hub? I wonder if there is a difference in the placement of the freewheel in relation to the dropout that may be the issue.
02-18-11, 10:38 AM
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OP are there any ring spacers on the hub?
02-18-11, 10:59 AM
#5
Steel80's
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Same wheel, didn't change spacing. The 6 speed is a narrower stack. The Cyclone has only 3 screws, L, H, and the chain wrap, which I dialed all the way in. The chain just doesn't make enough of an angle going in to pick up the sprocket, just chatters.
02-18-11, 11:31 AM
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Sorry but it's not clear that you did try the limit screw? As mentioned, the freewheel body may have a different relative position. If your freewheel is a Suntour Ultra, they have a history of being fussy with some chains.
02-18-11, 11:41 AM
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Sounds like chain is too flexible for the increased chain gap caused by the smaller large cog. B-screw should be dialed out, as opposed to in, for this problem.
02-18-11, 12:01 PM
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02-18-11, 12:35 PM
#9
Unique Vintage Steel
Yeah, that was going to be my next suggestion - taking a link or two out of the chain. if you've got it on a stand, you could manually push back on the derailleur to mimic adding tension / adjusting the B-limit while turning the cranks to see if that solves the problem, or slide the wheel forward in the dropouts to do roughly the same.
02-18-11, 02:43 PM
#10
Steel80's
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Thanks,I'll try the B-limit the other way (vertical drop-out on this bike, no adjustment). I already have the L limit fully out. The purpose of the experiment is to see if I can eliminate auto-shifting I get under certain conditions. The narrower, 6 speed looks like it will have a straighter chain line, which should help. I also have a wider Nashbar 6 speed freewheel to try.
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