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2 speed chain rings think they are a 3 speed?

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hostage

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Discussion starter · #1 ·
I got a 2016 Trek Super Fly 5 a couple of months ago new from my LBS. Either I am crazy and I never noticed this or something is wrong. It is a 2x10, though the front shifter has 3 index positions. My chain doesn't come off when I shift to the lowest position, though I don't think it was intended to operate this way.

Indexes 3 and 2 are the only ones that work. #1 doesn't down shift, thankfully. Though it does have me worried.

It hasn't caused any problems, but it is annoying. This isn't the first time I have had issues with the front derailleur, with this new bike.
 
#3 ·
It's worth a check under the shifter so see if they are switchable between 2x and 3x.

Like this:

Image


or this:

If they are, the shifter needs to be in a certain position before you flip the 2x/3x adjuster - I can't remember what it is off the top of my head, but I've heard you can damage the shifter if you get it wrong, so best check!

(Edit: Yeah, what Harold said! :D )
 
#5 ·
It looks like A=3X and B=2X (Page 26/27 of the manual )

If I interpret the instructions correctly, you need to shift into the smallest ring before flipping the switch. (If it doesn't want to move, don't force it).

You may need to adjust the cable if it is currently shifting between 2 and 3, as I believe you would only get 1 and 2 positions with the switch flipped. (Maybe LBS will do this for you if needed?).

(I only know about the switch because I crashed my first real MTB on the first visit to a trail centre, and the front triple became a double for no reason. The workshop there coudn't understand what had happened, and told me I had a faulty shifter. It was only later, back at home, that I spotted the switch - must have got caught on something when I crashed.)
 
Discussion starter · #6 ·
On further research, the switch is in "A" position, which corresponds to the 3x of Mist's first picture. I also noticed on the bottom it says SL-M610 on the shifter. When I bought the bike it would shift between 3 and 2, though I couldn't switch it to one. I did bring it in for a front derailleur readjustment a couple weeks after I bought as the front derailleur was having issues. I think the LBS for some reason switched it from 3 to 2 for some unknown reason. I guess I never noticed it, until a couple weeks ago when I got on the bike and noticed I couldn't up shift, as I was shifting between 1 and 2. Shifting between 1 and 2 does nothing. I noticed the cable was loose when it was in 1.

I think I will bring it back to my local LBS to fix it. IT doesn't look to hard to fix, though I worry that I might do something and break it, then it would be "my fault", instead of the LBS. Granted according to the document I will have to put it into 2nd and then flip the switch: file:///D:/users/E602190/Downloads/DM-SL0001-03-ENG.pdf (page 12).

I do not want to DIY adjust the derailleur on my bike.

Another question, why would a LBS switch a 2 speed into a 3 speed? I certainly didn't do it.
 
Discussion starter · #7 ·
Misterg said:
It looks like A=3X and B=2X (Page 26/27 of the manual )

If I interpret the instructions correctly, you need to shift into the smallest ring before flipping the switch. (If it doesn't want to move, don't force it).

You may need to adjust the cable if it is currently shifting between 2 and 3, as I believe you would only get 1 and 2 positions with the switch flipped. (Maybe LBS will do this for you if needed?).

(I only know about the switch because I crashed my first real MTB on the first visit to a trail centre, and the front triple became a double for no reason. The workshop there coudn't understand what had happened, and told me I had a faulty shifter. It was only later, back at home, that I spotted the switch - must have got caught on something when I crashed.)
Click to expand...
I agree, though I haven't laid my bike down. Granted I have "bailed", but my bike never crashed I still held it up right, so I think they must have switched it, when they were working/adjusting the front derailleur. Unless there is a defect, I can't see any other way it got switched. In any case thanks for the pointer, I can walk into the LBS w/o feeling like a complete idiot.
 
#8 ·
hostage said:
Another question, why would a LBS switch a 2 speed into a 3 speed? I certainly didn't do it.
Click to expand...
Because the unknowing high school student didn't know what the switch does, so they just moved it. Same reason you or I would move it.

I will say, I use my 3-speed SLX shifter on my 2-speed SRAM crankset with no problems. It's not like the derailure cares if you're in 1/2 or 2/3. It goes from the lower limit stop in the small ring, up to the 2nd ring when the gear is shifted, and prevents enough cable pull stopping the shifter from going to the 3rd shifter position by the upper limit stop.
 
Discussion starter · #9 ·
watts888 said:
Because the unknowing high school student didn't know what the switch does, so they just moved it. Same reason you or I would move it.

I will say, I use my 3-speed SLX shifter on my 2-speed SRAM crankset with no problems. It's not like the derailure cares if you're in 1/2 or 2/3. It goes from the lower limit stop in the small ring, up to the 2nd ring when the gear is shifted, and prevents enough cable pull stopping the shifter from going to the 3rd shifter position by the upper limit stop.
Click to expand...
Watts, I guess that is good enough for me. I just don't want to spend hours of research to make sure I don't brake something on such a new bike. When technically they are the ones who made the mistake.
 
#10 ·
watts888 said:
...It's not like the derailure cares if you're in 1/2 or 2/3...
Click to expand...
Getting geeky, it is my understanding that Shimano front shifters pull 11mm on the first shift (granny to middle) and 7mm on the second shift (middle to big). Newer Shimano 2X 10 front derailleurs expect a 7mm pull, older 2X9 ones, 11mm. I think that setting the shifter to 2X locks it into the 2-3 shift (despite what I wrote above) which suits the 2X 10 front mech. It does sound like it could be made to work either way, though.

/geek

I doubt that the switch has been changed deliberately - it could have been caught when moving the bike about, snagged with a cleaning cloth, etc. etc...

Actually, it would be worth seeing if the switch will flip with the shifter in position 2. If it will, it may be that the shifter will operate as a 2X again, without further adjustment. (Don't force it, though).

Whatever, it sounds like Hostage is on the way to getting the issue resolved :)
 
Discussion starter · #11 ·
Misterg said:
Getting geeky, it is my understanding that Shimano front shifters pull 11mm on the first shift (granny to middle) and 7mm on the second shift (middle to big). Newer Shimano 2X 10 front derailleurs expect a 7mm pull, older 2X9 ones, 11mm. I think that setting the shifter to 2X locks it into the 2-3 shift (despite what I wrote above) which suits the 2X 10 front mech. It does sound like it could be made to work either way, though.

/geek

I doubt that the switch has been changed deliberately - it could have been caught when moving the bike about, snagged with a cleaning cloth, etc. etc...

Actually, it would be worth seeing if the switch will flip with the shifter in position 2. If it will, it may be that the shifter will operate as a 2X again, without further adjustment. (Don't force it, though).

Whatever, it sounds like Hostage is on the way to getting the issue resolved :)
Click to expand...
The issue has been resolved, rode it up and down the street, after adjusting the switch. All is well for now. At least if it some how moves on it own in the future, I will know how to resolve the issue.
 
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