Having to "pump" shifter before it will downshift, baffled!

[lucklesspedestrian]

Hi

I have a Raleigh Motus ebike (mid motor) with pretty standard gears, 9 speed cassette and low end Shimano shifters (Altus) and mech (Deore).

I developed a problem where I was having to pump the downsifter with my thumb about a dozen times when first starting out on a ride before it would shift and then once out on the run just the one extra "pump" before shifting. The actual shifts are fine. Tried the barrel adjuster myself but just made things worse. Took it to my local bike tech yesterday, he checked it over put in a new derailleur cable and pronounced it good to go. It seemed okay on the 10 mile ride home, left it overnight (you can guess what's coming) just back from a run there and I still have to do the initial dozen thumb pumps before my first change and the double pumps thereafter.

6 months ago another bike tech put on a new chain, mech and cassette for a different problem (it was skipping gears under load) and that solved that, so it's now had cable, mech, cassette and chain. I'm just wondering if anyone here has an idea what the problem might be. About the only original component left seems to be the shifter (Shimano altus) itself. Do they go wrong (bike's only done 2500 miles) maybe time for an upgrade? I know they're not expensive.

As always any thoughts/suggestions most welcome

 

[C R]

Hi

I have a Raleigh Motus ebike (mid motor) with pretty standard gears, 9 speed cassette and low end Shimano shifters (Altus) and mech (Deore).

I developed a problem where I was having to pump the downsifter with my thumb about a dozen times when first starting out on a ride before it would shift and then once out on the run just the one extra "pump" before shifting. The actual shifts are fine. Tried the barrel adjuster myself but just made things worse. Took it to my local bike tech yesterday, he checked it over put in a new derailleur cable and pronounced it good to go. It seemed okay on the 10 mile ride home, left it overnight (you can guess what's coming) just back from a run there and I still have to do the initial dozen thumb pumps before my first change and the double pumps thereafter.

6 months ago another bike tech put on a new chain, mech and cassette for a different problem (it was skipping gears under load) and that solved that, so it's now had cable, mech, cassette and chain. I'm just wondering if anyone here has an idea what the problem might be. About the only original component left seems to be the shifter (Shimano altus) itself. Do they go wrong (bike's only done 2500 miles) maybe time for an upgrade? I know they're not expensive.

As always any thoughts/suggestions most welcome

It sounds like the ratchet in the shifter is not catching consistently. It could be that the reel does not turn fully so it doesn't catch, maybe it needs some lubrication.

 

[lucklesspedestrian]

That makes a lot of sense. Thanks

 

[vt2]

It's a common problem with these trigger shifters. The grease on the pawls thickens with age and the pawl return spring is too weak to overcome the resistance. The quick fix is to inject some GT85 into the shifter through the cable port. That usually this the grease enough for it to work again. If still reluctant to shift, you can take the underside cover off and inject the GT85 in directly. Hold some kitchen towel under the shifter to catch any that leaks out when spraying.

 

[HLaB]

Did you replace the outer cable as well as the inner; if not the new inner cable could be snagging.

 

[Rhythm Thief]

Flood the thing with penetrating oil. There isn't much that goes wrong with cheap (or early) Shimano shifters that can't be fixed with a dose of thin oil.