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Suntour power ratchet stem shifters shifting like crud.

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Suntour power ratchet stem shifters shifting like crud.

Old 08-23-16, 03:58 PM
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Suntour power ratchet stem shifters shifting like crud.

I decided to replace the downtube shifters on a late-70s Dawes Galaxy with a Suntour VGT-Luxe RD and a 14-32 rear cluster with some stem shifters to make it more of a city bike. I found a used set of stem-mounted Power Ratchet shifters, and picked them up because I really like the power ratchet function on my old barcon bar-end shifters.

The problem is that since switching to these shifters, I skip gears a lot more and when I do find the right gear it sometimes "jumps" on the sprocket like it's trying to downshift but doesn't quite make it. I've got all new cables and housing, and I cut them nice and clean with no sharp bends, so I don't think that's the problem.

Do the stem shifters just not work as nice as the bar ends or downtube shifters? Could something else be the problem? Even with the down-tube shifters the bike only shifted into the 4th cog with very careful finagling, but now it's worse.
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Old 08-23-16, 04:35 PM
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...they will never work as smoothly as DT shifters, because there's more cable and housing between the shift lever and the derailleur.

Make certain they are firmly mounted on the stem, with no play or wiggle. Make certain that your transition at the down tube is firmly mounted and clear of any obstructions. If you did not use plastic lined, indexing compatible housings, and die drawn cables, this also makes them a little less accurate. Finally, make certain that your rear derailleur hanger is aligned, so that when you look at the derailleur pulleys, at eye level, from the rear, they appear to be on a parallel line with your rear cogs.
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Old 08-23-16, 04:44 PM
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Yeah, I understand that more cable = worse shifting, but at the same time my barcons shifted really well and had even more cable. The derailleur hanger is a "claw" type, so maybe I'll have a shop check the rear dropout alignment. It could also be the derailleur. I had a Cyclone on it previously and the cage was straight as an arrow, but perhaps this VG-T Luxe isn't in as good of shape.
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Old 08-23-16, 04:49 PM
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Best tool I ever bought was the Park Derailleur Hanger Alignment Gauge.....
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Old 08-23-16, 05:00 PM
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+1 to checking hanger alignment. That was going to be my first suggestion. Also I've found sometimes those claw mounts put the RD/upper jockey wheel quite far from the FW. If you are going from a hanger-mounted Cyclone to a claw-mounted VG-T Luxe, I suspect you also greatly increased the "chain gap" (the distance along the chain from where the chain contacts the cog to where the chain contacts the jockey pulley). Coincidentally, I was experimenting last night with a claw-mounted Vx RD last night and noticed this large chain gap. The greater the chain gap, the more sluggish a RD may feel and may require more overshift since the chain can bend slightly across that chain gap. This could be as much a reason for decline in shifting performance as the shifters.
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Old 08-23-16, 05:05 PM
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Originally Posted by gaucho777
+1 to checking hanger alignment. That was going to be my first suggestion. Also I've found sometimes those claw mounts put the RD/upper jockey wheel quite far from the FW. If you are going from a hanger-mounted Cyclone to a claw-mounted VG-T Luxe, I suspect you also greatly increased the "chain gap" (the distance along the chain from where the chain contacts the cog to where the chain contacts the jockey pulley). Coincidentally, I was experimenting last night with a claw-mounted Vx RD last night and noticed this large chain gap. The greater the chain gap, the more sluggish a RD may feel and may require more overshift since the chain can bend slightly across that chain gap. This could be as much a reason for decline in shifting performance as the shifters.
The Cyclone was mounted on the same claw, but I can try adjusting the b-limit screw out a bit and see if things improve.
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Old 08-23-16, 05:24 PM
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As an FYI, the shifter is this model:

VeloBase.com - Component: SunTour Seven

It feels different from other power shifters I've used because the ratcheting action is accompanied by the shift lever "flexing" around the pivot. Is this normal actuation for this style shifter, or is it not functioning correctly?
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Old 08-23-16, 05:25 PM
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Originally Posted by willydstyle
The Cyclone was mounted on the same claw, but I can try adjusting the b-limit screw out a bit and see if things improve.
The shifting on my suntour V-GT luxe improved after playing with the b-limit screw for a bit. Just riding it up and down the block in front of my house with a small screwdriver in my pocket for adjustments.
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Old 08-23-16, 05:25 PM
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Using the right width chain? Is the tension screw on the side of the lever tight (tight enough to hold the shift to bigger cog)?
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Old 08-23-16, 05:36 PM
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Chain jumping often indicates worn freewheel teeth and/or a worn chain. If these items are new than that obviously isn't it.
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Old 08-28-16, 08:05 PM
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Just as an FYI for everyone who gave me advice:

I tested out the same model stem shifters on someone else's bike, and didn't find the same play in the shifter body that my shifters had, so I replaced them with a later model Suntour Power Shifter stem shifters that did not have the same issue, and it's shifting beautifully now.
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Old 08-29-16, 06:10 AM
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Save the usable parts- Toss 'em before you tuck 'em away and forget how bad they are-
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Old 08-29-16, 11:12 AM
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Originally Posted by The Golden Boy
Save the usable parts- Toss 'em before you tuck 'em away and forget how bad they are-
Hah, yeah, I tossed 'em straight in the dumpster. They're old, entry-level stem shifters that you can find in the parts bin of any co-op in the world, so not really worth trying to save at all.

When my front derailleur cable clamp bolt sheared at the bolt head while I was re-installing my cables, I finally found a use for a Cyclone FD I'd had sitting around, though. I didn't use it after I won it on ebay because the cage was bent slightly upward and it wouldn't shift a triple, but it shifts a 52/42 double just fine, and has an integral cable stop. It was one of those components that I never thought I'd use, but couldn't quite bring myself to throw away.
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Old 08-29-16, 05:12 PM
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Just wait, you're going to need that little screw that holds on the little plate thing or something.

I have lost seemingly inconsequential screws...
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Old 08-29-16, 05:15 PM
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While you're at it, do a quick string test on the frame. It shifted poorly before so...
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