ScubaGearhead85

Hey everyone:

I need some help with getting the shifting on my bike dialed in after replacing the rear derailleur and rear shift cable.

I commute with my bike daily year around and put a lot of miles on it. This past weekend, I serviced my bike to get it ready for spring/summer. I cleaned/re-greased the hubs and replaced most of the drivetrain including the rear derailleur and rear shifter cable. I have never replaced these things before. My bike has a Shimano Tourney 7-speed rear gear and 3-speed front gear. Even though I was successful in installing these components and have the bike back together, I'm having a hard time with getting everything adjusted and shifting correctly.

I tightened the shifter cable first since that made the most sense to me. For the shifter cable, I moved the rear shifter to 7th gear, pulled the cable taut with my fingers, and tightened the cable anchor down on the derailleur. After doing this, I could only go as low as 2nd gear. I could get the shifter into 1st, but it took a lot more force and the derailleur still didn't move the gear into 1st (stays in 2nd gear).

I then tried to adjust the rear derailleur as per the Park Tool video on youtube. However, this didn't improve the shifting either. At this point, I threw my hands up into the air and walked away in frustration.

What am I doing wrong here? I don't think the rear derailleur hanger is the issue because I replaced that last year and still looks straight.

Thanks!

Bill Kapaun

It sounds like the H screw needs to be turned out a bit.
Try a 1/4 turn at a time and test.
Keep track of turns in case that wasn't it.

EDIT- OOPS- I was thinking backwards.

KCT1986

If your issue is getting to the innermost sprocket (closest to the spokes), it may be the 'L' screw that may need to be loosened.

As a test, pull on an exposed part of the inner cable (along the frame with no cable housing over it) while in the lowest gear. If it doesn't move enough to shift to the innermost sprocket, then it is the 'L' screw.

ScubaGearhead85

I'm guessing it's the L-screw. I did this the other day while troubleshooting. The cable was so tight in low gear that I couldn't move it by hand. So, I'll give the L screw a try and see if there is any improvement there.

rccardr 

The Park Tool web site is your good friend.
Visit it, listen to it, read it.

smd4

Don’t tighten the cable first.

grumpus

Before attaching the cable, push the derailleur onto low gear by hand, adjust the low limit screw so it shifts easily onto the inner sprocket but with no sign of wanting to go further. Repeat with the small sprocket and high limit screw. Now attach the cable as you did, with shifter and derailleur in high gear, the cable adjuster(s) wound in and minimal cable slack. Run through the gears, probably wind a cable adjuster out slightly so they index correctly in both directions.

ScottCommutes

My experience is similar to yours as far as the 3x7 drivetrain and the Shimano Tourney and the daily commuting. I replace rear derailleurs every so often because a pulley wears out or a spring breaks. I also change my cables about once a year and have to re-adjust the derailleurs. I'm no expert. My technique is to put the Park video on my laptop next to the bike and literally go one step at a time with lots of pausing. This has worked well for me.

Iride01 

Probably didn't set your limit's correctly. Which is usually done with the chain off and one of the first things done after mounting the RD on the bike. Second thing is not getting the cable correctly in the pinch bolt with the shifter in the proper gear.

This is the general DM for most everything Shimano on a typical bike.

https://si.shimano.com/en/pdfs/dm/GN...001-27-ENG.pdf

Make sure your top and low adjustment are correct first. Pages 14 or 27. One is the section for mountain bikes and trekking bikes and the other for road bikes. But the limit settings are the same for both. Other things might be different later.

smd4

Afte an initial setup, the final adjustment of the limits should be verified with the chain ON.

Iride01 

Initially, I find it works better to do it with the chain off as Shimano shows in all their initial setups for RD's after installation. Then if the chain isn't shifting correctly into that high or low sprocket, it can be tweaked afterward.

But I'm okay if you prefer to do it the other way. But for someone that isn't experienced and is having issues, then taking the chain off and setting them where they show in the DM might work better. Especially if they don't really understand what the limit screws do and when to use them.

smd4

Agreed. I edited my response accordingly.

grumpus

​​​​​​That's a good ballpark method on a new build, but if the chain is already on you can still check it with your thumb, while pedalling with the other hand. Even if you go into the spokes you'll not cause damage or get stuck, because you're pedaling slowly by hand.

wheelreason

I do the above with a twist. Before installing the cable, screw the adjust knob all the way down, then back off 2 turns, shift to the highest gear (smallest cog) now manually place the chain on the second smallest cog, and attach cable with medium finger tension on the cable. Most times, you'll be done at this point, but if not, a couple of turns of the dlr adj knob and voila.

Jeff Wills

This is what I do also and my initial adjustment is usually very close. Many times I don’t have to touch the cable adjustment afterwards.

I think Shimano derailleurs “like” a little bit of preload on the cable when in high gear (small cog). If the cable is loose in high gear it’s likely that the adjustment is off by one cog.

cyccommute 

*****Don’t go messing with limit screws!******

If the limit screws were set properly before you adjusted the cable, the limit screws are set properly now…unless you went messing with them. This is a cable problem (which is usually what shifting problems are). It sounds like you pulled the cable too tight. Release the anchor and try again. This time pull the cable up so that it is taut but not super tight. If you strum it with your finger it will vibrate a little but it shouldn’t be like a guitar string. It would be better if it were a little too loose because you can fine tune with the cable adjustment barrel easier than adjusting the cable anchor bolt.

KCT1986

In the OP's case it probably needs a little loosening of the L screw. He states that the shifter goes into L gear with force applied. Probably caused by the RD hitting the L limit, and cable having to stretch to enable the shifter to get to the L position.

With most shifters, there also needs to be a little additional 'allowable movement' in the derailleur 'beyond the last click' to allow the shifter's pawl to disengage from the ratchet. If the cable is in an 'over-stretched' position the shifter won't release properly.

smd4

He said he replaced the derailleur. What makes you think the limit screws were properly set at the factory, or if used, by the previous owner?