First off, I'm fairly inexperienced with adjusting derailleurs. We recently bought my son his first bike with multiple gears, so I followed a great YouTube video from Park Tool to adjust his derailleurs because they were a little off. Everything went smoothly and his gears are working well.
With that success under my belt, I decided to take a look at my own bike. It's fairly old, a hand-me-down from my dad that I've had for many years. The gears have been a little off for a long time. I usually need to nudge the shifter up or down a little for them to land on the intended gear. It's a "twist style" shifter where you have to rotate forward or backward around the axis of the handlebar. I'm not sure what the proper name is for this kind of shifter.
I started going through the process of adjusting my bike by setting the high and low limit screws. Once I tried to adjust the shifting within that range, things started to behave a little different than I expected. The general tactic is to turn the barrel adjuster to adjust the tension up and down. However, when I turn the adjuster (at the handlebars) the derailleur doesn't seem to move. If I turn the adjuster too far, the shifter actually clicks into one of the neighboring positions. In the end, I'm kind of stuck where I started. The lower two to three gears and the upper two to three gears seem to shift just fine. It's the gears in the middle that are a bit sloppy. I usually have to shift through two larger gears and then back down one gear to get it to land where I want it.
So to those of you who have more experience with derailleurs, do you recognize this behavior? Any advice would be appreciated. Thank you.
Rear derailleur trouble for middle gears
byu/benbrandt22 inbikewrench
by benbrandt22
4 Comments
That derailuer is mounted in a place I’ve never seen before. Is it firmly attached to the frame? Looks like it may have broken off the traditional mount
I had to watch this a couple of times. I have worked on hundreds and hundreds of bikes and have never seen a derailleur set up like this.
Is there something unique about this bike make and model where the derailleur sits under the chain stay instead of towards the rear where I see the derailleur hanger?
Sound like friction in the system. It could be friction in the cable. You could try undoing the cable clamp bolt at the derailleur and pulling the cable out. Then spraying some TriFlow or equivalent aerosol lubricant into the housing. The housing has a plastic liner which is where you want the lubricant to go. It should drip out of the other end of the housing when you’ve done it right. Then wipe off the cable with the same lubricant and thread it through the housing again. Note that this only works if the end of the cable is not damaged or frayed in any way. Otherwise you won’t be able to get the cable back in the housing. Other areas that could need a little lube are the derailleur pivot points on the derailleur body, the pulley cage pivot, and at the point where the derailleur bolts to the frame.
The way I usually start off adjusting a derailleur is I move the shifter to the smallest cog position. Then I undo the cable clamp bolt on the derailleur. I adjust the barrel adjuster to the halfway point so I have room to increase or decrease tension. I then adjust the high limit screw so the derailleur aligns with the smallest cog. Then I grab the cable with pliers, pull it tight and simultaneously tighten the clamp bolt. It should be tight enough to vibrate when plucked. Now you can adjust the low limit screw and fine tune the tension to get all the gears to index perfectly.
While you are at it you may want to take the outer twist shifter off to expose the mechanism, clean up any old grease or crud and relube it.
1993 Schwinn Crisscross?
Interesting SunTour take on the on a 1930’s derailleur design. The indexing is built into a cam on the derailleur and not in the shift lever (I wouldn’t disassemble the lever unless it doesn’t turn).
Carefully pull the cable from the housing and lube … also lube the pivots and the cam.
Edit: Derailleur, for those that care is a SunTour S-1 7spd index
If it is a Crisscross… Schwinn catalog is here.
https://waterfordbikes.com/SchwinnCat/flschwinn_1991_2000/1993_Cnsmr_18.html
Edit 2: Nothing beats having an original setup guide to work on a dead end derailleur design.
https://www.disraeligears.co.uk/site/suntour_s-1_derailleur_s100_-_instructions.html
Thank you Disraeli Gears.