Repair

[Tanner]

Hi I’m a beginner and I just bought a road bike. The bike stays in 6th gear and only goes to 5th when I hold on the shifter it returns to 6th when I let go. I attempted to tune the back derailleur but nothing worked. Ps the derailleur is a shimano rx100

[Jesper]

(10-11-2022, 01:40 PM)Tanner Wrote:  Hi I’m a beginner and I just bought a road bike. The bike stays in 6th gear and only goes to 5th when I hold on the shifter it returns to 6th when I let go. I attempted to tune the back derailleur but nothing worked. Ps the derailleur is a shimano rx100

Hi Tanner,

If it is a friction shifting system then the shift lever adjustment may need to be tightened up. Usually a thumb nut, "D" ring, or screw head to tighten it. A photo might help us to get an idea of what you have. I am not familiar with that Shimano derailleur, but I will look it up to see if I can help you more.

[ReapThaWhirlwind]

Try this first.

Shift the gear into the smallest cog if possible. Do as many clicks as it takes. Undo the cable on the rear derailleur. Dial the barrel adjuster in all the way, turning it clockwise. Pull the cable just so slightly to remove the slack and refasten the cable. Note if you pull the cable too hard, you will have too much pretension on the cable and it won't shift properly. Now, begin to dial the barrel adjuster out, turning it counter-clockwise, and every few turns check the shift. If it doesn't shift into the next gear, undo the shift back down and dial the barrel adjuster out some more. If shifting eventually restores, then indexing is complete and that was the problem.

Otherwise, you may have a bent derailleur hanger. You'll need to go to a shop to check it.

You may also need a new shifter.

And also, your limit screws might be tightened in too far. Undo them entirely in their respective highest and lowest gear, then peek inside the mech and dial them in until you just begin to lightly press the ridge against the mech (which is intended only to prevent overshifting). When the limit screw is dialed in too far, it can totally prevent shifting into the highest and lowest gears. You could even try this step first, but re-indexing your entire derailleur is still the best method overall.

[Talha]

I think it's a derailleur issue. It's actually really common to have problems with the derailleurs given how exposed they are.

1. I recommend you give the derailleur a thorough inspection. Look for any bends on the mech hanger or cassette. You can easily align it back with an alignment gear or take it to the bike shop.

2. Lift your bike up or get it on a rack and adjust the limit screws. (I think this is the case with your bike) Put your chain in the highest gear and adjust the limit screw (turn it clock/anticlockwise) depending on your alignment. If the derailleur is too far out (twist the screw counter-clockwise).

Hope you sort it out and get riding again