[SupremeDork]

Or perhaps it's the front derailleur? I dunno. I've only used index shifters before, so my thumb shifter ignorance will probably show.

Build:

• 2012 Surly Moonlander
• Stock Microshift SA-109 thumb shifter (3 speed)
• Stock Shimano SLX FD

What's happening:
Sometimes when I shift onto the big ring the Microshift lever will lock just enough to hold the derailleur in place, but is easily released when barely tapped.
Sometimes it won't lock at all and just slides back to a resting position. The tension of the FD is obviously forcing the shifter out of position.
This is a big problem when I'm banging around the trails and it unexpectedly drops to the granny gear, not to mention just plain irritating!

I've googled the crap out of this one. Searched MTBR too and found nothing. I may just not know how to describe the problem to a search engine.

Any help is much appreciated! Thanks!

 

[Fat Bob]

Not sure if this is any help to you or not, but there should be a small allen bolt on the top of the shifter, at least there should be. If not an allen bolt, some sort of mechanical fastener, tighten it and you should be find... thumb shifters are basic and simple, don't overthink it. If you decide you don't like them, I'll gladly trade you for some SLX rapid fires... just say'n

 

[SupremeDork]

Not sure if this is any help to you or not, but there should be a small allen bolt on the top of the shifter, at least there should be. If not an allen bolt, some sort of mechanical fastener, tighten it and you should be find... thumb shifters are basic and simple, don't overthink it. If you decide you don't like them, I'll gladly trade you for some SLX rapid fires... just say'n

SupremeDork confirmed for complete n00b here. I think reading the instructions would have saved us all the trouble.

There's a cap on the shifter that reads "ADJUSTMENT" with + and -. Well, the HEX HOLE facilitates an Allen key quite nicely! All I had to do was tighten it. The lever stays put now. Don't overthink it is right!

Thanks for the reply! Can we delete this thread now? lol

 

[rumblestrip]

FYI - the same thing happened on my Moonie. Got loose out on a ride. Didn't want to stay in the big ring, I tightened the allen bolt in the center, easy peasy and all is well.

 

[Fat Bob]

FatBob is an old fart and remembers a time when your only choice was thumb shifters

 

[Joshua_B]

I had the same problem with the ones on my necro.

 

[SupremeDork]

FatBob is an old fart and remembers a time when your only choice was thumb shifters

Your wisdom is appreciated, old fart!

I remember switching from a POS Huffy MTB with thumb shifters I had in the late 80s to my Giant Iguana a few years later. It had index shifters with convenient little numbers and I was like "WHAT IS THIS I DON'T EVEN".

 

[robselina]

Figure I'll post this here instead of starting a new thread. I'm having issues with the microshift thumbies.

Front is OK, but the rear is a bit of a PITA. The problem I have is that it seems to let the rear derailleur drift out of alignment, so if I leave it in a gear (especially a smaller sprocket) for a few minutes on bumpy terrain, the chain inevitably starts to chatter and try to jump to another gear. I then have to readjust the thumb shifter position. I often can't find the sweet spot without jumping a gear up or down. This is especially frustrating while climbing.

I've cranked up the tension on the top cap allen screw, but still get erratic behavior.

Any tips/advice for setup + use?

Assuming I get tired of them, anything I'd need to know about putting some Shimano 3x9 shifters on there? How do you lock out the granny gear position on the front shifter? Or is the adjustment all in the limit screws of the front derailleur?

 

[boogman]

How do you lock out the granny gear position on the front shifter? Or is the adjustment all in the limit screws of the front derailleur?

Yep.. limit screw..

 

[DubzOxford]

Figure I'll post this here instead of starting a new thread. I'm having issues with the microshift thumbies.

Front is OK, but the rear is a bit of a PITA. The problem I have is that it seems to let the rear derailleur drift out of alignment, so if I leave it in a gear (especially a smaller sprocket) for a few minutes on bumpy terrain, the chain inevitably starts to chatter and try to jump to another gear. I then have to readjust the thumb shifter position. I often can't find the sweet spot without jumping a gear up or down. This is especially frustrating while climbing.

I've cranked up the tension on the top cap allen screw, but still get erratic behavior.

Any tips/advice for setup + use?
Try to turn the cable adjuster out 1/2 turn at the rear derailleur. Maybe the cable has stretched a little.

 

[juandoe]

Are you sure the wheel is aligned straight in the dropouts? I had my quick release a little loose and my wheel moved a bit. I had a similar problem as yours. Once I squared up the wheel, it was fixed.

 

[robselina]

Are you sure the wheel is aligned straight in the dropouts? I had my quick release a little loose and my wheel moved a bit. I had a similar problem as yours. Once I squared up the wheel, it was fixed.

Good point. I'm running Lou out back, so I can't put the tire all the way forward in the dropout. It's currently aligned by eye and spaced back 1/2", but I'm not positive it's aligned. I'll have to check that!

I'll also try to put the shifter dead-on a detent and triple-check cable tension....

 

[robselina]

(Tentatively) Fixed!

Just had a good ride with a well behaved derailleur! :thumbsup:

Double checked the wheel alignment, tweaked the cable tension on the derailleur side 1/2 turn, and took a little tension out of the allen adjustment on the shifter. Its not perfect, but it's not acting erratic either. Shifts to smaller sprockets work perfectly. Shifts to larger sprockets stick a bit - I tend to overshoot a little and then gently shift the lever back to the detent. I'll try with less tension on the shifter, I think that'll help too.

A few notes for anyone else who's struggling with these:
1) The rear track fork end (dropout) adds an extra complexity compared to most bikes. Make sure the wheel is centered before adjusting.
2) Before adjusting cable tension, release some pre-tension on the shifter itself so you can feel the detent positions crisply. This ensures you're adjusting to the correct shifter position.
3) Don't try to use the cable tension adjustment on the shifter since it doesn't hold well and will drift out of adjustment. Use the cable tension adjustment on the derailleur instead since it's indented at 1/4 turn intervals and holds position better.

Thanks for the help guys.

Rob

 

[GTscoob]

3) Don't try to use the cable tension adjustment on the shifter since it doesn't hold well and will drift out of adjustment. Use the cable tension adjustment on the derailleur instead since it's indented at 1/4 turn intervals and holds position better

Good advice on all bikes. Use the barrel adjuster on the rear derailleur (if it's there) for the initial setup and then use the barrel adjuster on the shifter for future tuneups.

 

[singlefin]

Gonna bump this back up and see if anyone has had issues with the rear shifter detents having differences in slack (w/ the shifter) when shifting up vs shifting down. I'm getting some jumping of gears going up to low gears, and jumping down going to high gears. If I tune one out the other stays. Rear derailleur high and low limits are set, b-tension seems okay (adjustment isn't as visible as a SRAM).

Usually I just set limits, reset the cable, put chain back on and tune the shift of 2-3 and all is good.

 

[brebla]

I was having trouble with the rear shifter over-shifting when going for a larger cog and then trying to grab the next larger cog. I found that if the shifter adjustment was set too tight, the shift lever moved into the new index detent, but didn't spring back slightly so that the the derailleur was aligned with the cog. I had to adjust the shifter tension (using the top cap allen screw) so that it was just tight enough to stay in the selected position, but loose enough so that the shift lever sprung back slightly from the position that it clicked into when selecting a larger cog.

 

[singlefin]

I'll give that a go. I feel like I've narrowed it down to the shifter...almost put it on friction mode, as that is a simple fix.

 

[singlefin]

What a frustrating shifter...have the same one on the Necro and it's non-issue. Maybe I should just be SS for the summer or drop the coin on the IGH.

Just seems like the indexing side has slop in it. I got the downshifts OKAY but up shifts are finicky. Tried various tensions on the adjustment cap to no avail.

On another note found one thing I like about offset wheels...

 

[mochunk]

I've found that a tight link in a chain can have some issues with the indexing on mine. Clean and relube and it goes away for awhile until I get it dusty and dirty again.