Shifting great on stand slow on road

[Richard Franklin]

I've recently been having some issues with my rear derailleur being slow to shift both up and down the cassette while riding. This seems to happens 20 percent of the time. Shifting is just fine when I have my bike on the stand. My chain seems to be in good shape and is about 2 years old. Any ideas on what to look for? I've tried barrel adjustments to play with cable tension.

 

[dhk2]

RD hangar bent? It doesn't take much on some bikes to bend the hanger just slightly out of vertical. You can carefully eyeball the alignment and try bending it yourself if it's out. (The RD axis should be parallel to the rear axle when sighting both from the back and from the top).

Or, better yet, take it to a good mechanic with a fancy alignment tool. You can also have the chain measured for wear, and the condition of the cassette and cables checked. New cables can often restore shifting.

 

[alfeng]

I've recently been having some issues with my rear derailleur being slow to shift both up and down the cassette while riding. This seems to happens 20 percent of the time. Shifting is just fine when I have my bike on the stand. My chain seems to be in good shape and is about 2 years old. Any ideas on what to look for? I've tried barrel adjustments to play with cable tension.

While dhk2 may be right that your bike may have a bent derailleur hanger, it is possible that you simply need to lube your derailleur cable(s) ...

EVEN pre-lubed cables and/or housings benefit from being lubed, IMO ...

You can use a dab of any light grease from Vaseline to White Lithium which you smear lightly along the entire length of the cable from shifter to derailleur where it interacts with the housing ...

BTW. YOU may be able to remedy the current problem by only lubing the short section of cable which passes through the section of housing that actually touches the rear derailleur ...

If the end of your cable is frayed, then depending on the amount of cable which extends beyond the rear derailleur cable's anchoring bolt, you may be able to introduce the grease to the relevant portion of housing by detaching the cable from the derailleur and simply putting a dab of grease on the cable at each end of the last section of housing & sliding the cable back-and-forth ...​

If you have some SLICK HONEY (in case you also are a MTBer), you can simply squirt a few drops into one end of an empty housing before sliding the cable through it ...
​

When in doubt, the cable AND housing could-or-should be replaced.

FWIW. I've said it before (and, some have disagreed for what I consider to be specious reasons), that I prefer to use brake cable housing which has a coiled core AND a larger inner diameter rather than I-thought-they-stopped-using-parallel-stranded-core-housing-in-the-70s housing which often has a plastic inner sheathing which results in zero clearance AND can introduce a rare-but-does-occur problem.

 

[maydog]

Remove the rear wheel and operate the derailleur. It should move without any stickiness or slowness in both directions. If it is sticky, replace or lube the cables and the derailleur pivots.

Two years on the the chain? It could be worn if you ride regularly. Check the chain and the cassette as well.

 

[CAMPYBOB]

"Shifting great on stand slow on road"

Are you reducing pedal pressure when trying to shift while riding? If the only change in shift quality/speed is the switch from rotating the cranks by hand on the repair stand to the feet while riding it may simply be due to poor technique.

As suggested above, you may need to lubricate or replace your derailleur cable and clean and lubricate your derailleur, but the fact that you have a repair stand kind of points to the direction that you already know how bicycles function and do your own maintenance as does your statement that you have tried adjusting the derailleur cable.

One thing I can tell you is the newer shift cables are prone to wear/damage at the shifter drum. This will cause erratic and slowed shifting so you might want to take a flashlight and have a look at the shifter end of your cable for frayed wires.

 

[dhk2]

Remove the rear wheel and operate the derailleur. It should move without any stickiness or slowness in both directions. If it is sticky, replace or lube the cables and the derailleur pivots.

Two years on the the chain? It could be worn if you ride regularly. Check the chain and the cassette as well.

That's a good basic check to do. Rather than working the shift lever to test for drag, I just pull the cable away from the downtube. Any drag or stiction will be obvious. If any drag is detected, and the cables are two years old or more, I'd say just replace them rather than try to clean and lube. I never lube cables or RD pivots, believing that surface lube only attracts dirt.

Agree checking the chain for wear should be a part of normal maintenance for all cyclists.

The two items mentioned above take about one minute each to check for an experienced mechanic. My LBS would check them for free, usually on the spot for riders rolling in.