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suggestions to improve the shifting performance of a brand-new sunrace gripshift

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suggestions to improve the shifting performance of a brand-new sunrace gripshift

Old 09-14-20, 11:03 AM
  #1  
studbike1
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suggestions to improve the shifting performance of a brand-new sunrace gripshift

I have a new shifter that is performing poorly. The problem is that the shifter doesn't release all of the slack out of the cable on downshifts (to smaller cogs). Immediately following the shift, you can yank the extra bit of slack out of the housing and the derailleur will drop down to the correct position. I checked the basic stuff - my cables are friction-free and the b-screw on the derailleur is adjusted correctly.

I have figured out how to open the shifter by using credit card pieces to hold the retaining tabs and then sliding it apart. Zero internal lubrication from the factory. I put some of the white bearing grease I use on the sliding metal tab and this does not seem to have improved the performance at all - all I've accomplished is creating a dirt trap.

Does anyone here think there is something to be said for using a light lubricant instead? Perhaps whittling away some plastic material inside the shifter? Bending the metal spring? Using an ultra-narrow shift cable? Modifying the derailleur to have increased return-tension? I am open to any suggestions. The shifter works fine when you hold it in your hand and play with it, but then doesn't work when it's hooked up to the derailleur.

I do not want to try a different shifter and here is why: take a look at the picture below. I am married to this exact model because it has that gradual taper between the grip area and the collar instead of a raised edge. This is mounted on an extremely narrow handlebar and other shifters cause my thumb to sit in a bad position while I ride (I have humongous thumbs). This is the FOURTH shifter I have tried to fit on this bike and all of them have interfered with my thumb! If this doesn't work, I will need to get a shifter that mounts outside of the grip area, or change bars - I do not want to do either of these things, I just want a simple grip-shift setup that works!

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Old 09-14-20, 11:10 AM
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Iride01 
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How hard do you have to pull? Might it be that in the other direction your DR or the cable binding in a housing ever so slightly that it doesn't provide enough tension to pull on the shifter reel?

If this were a year or so old I might insist you check in the shifter for a frayed cable. But since new............. well you decide. I don't know how easy that is to get to on those type. And you didn't futch something up installing it? Maybe used the wrong cable?
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Old 09-14-20, 12:18 PM
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fietsbob
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Remotely Guessing, as I must, I'm wondering if it's your shifting technique at issue, not the gripshifter ..

When are you shifting ? forced or easy-pedaling to take strain off the chain, allowing it to move to the other gear??
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Old 09-14-20, 01:34 PM
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rosefarts
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Define friction free? It should be silky smooth.

The problem you have described is textbook cable friction. Kink in either or both of the cable or housing. Frayed cable. Something on the rear derailleur loop of housing causing friction.

My guess is it's the rear loop. Most people and even factory set it up too short. There won't be much friction when the cable is in your hands and disconnected from the rear derailleur. Once connected is when there is a problem.

Smooth flowing loops no tight angles.

Post a pic of your rear housing.
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Old 09-14-20, 01:45 PM
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If the SunRace grip shifter is like the Shimano RevoShift, lubrication won't help and might cause problems. They're very plasticky, essentially self-lubricating, with only a couple of metal springs or stiffeners. The RevoShift works fine until it breaks. Then the only recourse is to replace it. They aren't user serviceable. But for only $10-$15, including cables, it's worth buying a backup kit.

Check for a kink or fraying cable inside the shifters. Happens more often than I'd like to admit when I use cheap cables, like SunLite or other generic stuff rather than Shimano or Jagwire.

Double check the cable routing and clamps. With some front and rear derailleurs this can be really tricky. Some have two or more options and it's easy to get it wrong while it looks right and sorta functions.
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Old 09-14-20, 01:53 PM
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studbike1
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canklecat - do you think it's worth the effort to take it apart again and de-grease it?

thank you for the suggestions. the SRAM gripshift that was on here before (20 years old) was working perfectly with the same housing - but I did use a new cable - these things come pre-installed with a cable. i guess it's possible that the cable is a bit wider than the old one. Will post a pic of the rear loop - it's not beneath me to consider that maybe i've been stringing them too tight all these years.
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Old 09-14-20, 02:29 PM
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alcjphil
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20 year old cable housing should be replaced when installing a new shifter
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Old 09-14-20, 03:41 PM
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rosefarts
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Duuude! You can't ask about shifting problems without first replacing the 20 year old housing.

On the new stuff, check that it has no sharp bends and the plastic liner isn't all smooshed.
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Old 09-14-20, 04:33 PM
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studbike1
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Originally Posted by rosefarts
Duuude! You can't ask about shifting problems without first replacing the 20 year old housing.


On the new stuff, check that it has no sharp bends and the plastic liner isn't all smooshed.

Dudes! the housing is like a year old


I have taken a picture of the loop for everyone, and I guess it is a bit smaller than my other bikes.


In any event, the shifter is the issue. I triple-checked the cable and it's nice and smooth as it travels through the housing.


I compared to two other SRAM gripshifts I have lying around, one that's 20 years old and one that's 2 years old, and both of them have much less play between gears and a slight self-centering effect that nudges the shifter back to center under the force of its own internal spring. The sunrace shifter will gladly hang between gears unless I twist it back to center


I guess this product is just a piece of crap - anyone ever hacked these into working a bit better?? Maybe bending the spring a bit? if you're out there, please find this thread!


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Old 09-14-20, 05:20 PM
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Originally Posted by studbike1
I guess this product is just a piece of crap
Yep. I like their cassettes, but their shifters are about the worst.

John
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Old 09-14-20, 05:35 PM
  #11  
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I like the 3 speed Sturmey-Archer_Microshift_ Sun Race thumb shifter. (Sun Race is a big company with several divisions)
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