STI Trouble

[chicagorider]

Hi all,

I lack the vocabulary to describe this problem well... I'm having an issue where if I try and shift up the rear cassette (on a DA9100 shifter), then the metal lever that is actuated by the shifter would get stuck... I've made a video of it (please excuse the background noise).

https://photos.app.goo.gl/mm9ntT1MPhEwY7bo7

Before I start taking it apart etc. wondered if someone knows what's going on. I've had similar problems before when the hoods were not on properly but I don't think that's the issue here.

Thanks PL!

[mass_biker]

Could not open video but I had problems with my STI right (rear) shift lever getting stuck on occasion.

One time I managed to “unstick” it by spraying the (shift) interface with lube. There was some gunk stuck in there.

The other time, it was revealed on an overhaul that the cable had become frayed and some burrs were sticking in the housing.

MB

[John H.]

Check the rear cable. This shifters are know to eat/fray the derailleur cable up at the shifter.

[oldpotatoe]

Originally Posted by chicagorider

Hi all,

I lack the vocabulary to describe this problem well... I'm having an issue where if I try and shift up the rear cassette (on a DA9100 shifter), then the metal lever that is actuated by the shifter would get stuck... I've made a video of it (please excuse the background noise).

https://photos.app.goo.gl/mm9ntT1MPhEwY7bo7

Before I start taking it apart etc. wondered if someone knows what's going on. I've had similar problems before when the hoods were not on properly but I don't think that's the issue here.

Thanks PL!

Remove the inner wire, check for broken strands.

Spray the innards liberally while shifting it...then spray some lube in there.

WD-40 followed by some lube.

DON'T take it apart, you'll never get it back together.

[herb5998]

Agreed with Oldpotatoe, Check your cable first.

Pull back the hood, and open the small plastic tab that helps the cable with the steep 90deg turn into the housing. If any of the teflon coating, or wire appears rough, change it. You do NOT want to be fishing for the head of the cable when it breaks (very common from Shimano 7900 and up).

If cable appears fine, cleaning and lubricating best you can with it on the bike should help.

[saab2000]

Originally Posted by oldpotatoe

Remove the inner wire, check for broken strands.

Spray the innards liberally while shifting it...then spray some lube in there.

WD-40 followed by some lube.

DON'T take it apart, you'll never get it back together.

Agree with this. Check cable first. They are a wear item, especially in modern Shimano cable systems. Second, a bit of WD-40 or a very light spray oil up into the mechanism will loosen things up. I don’t think huge amounts are needed but make sure it gets into the moving parts.

Use a bit of caution with the rubber hoods while doing this and wipe down everything as well as possible afterwards, while leaving the WD-40 other light oil to do its work. The hoods and these lubes or solvents aren’t good for the rubber pieces, so be careful. I use a can of spray WD-40 and just short bursts into the shifter from the bottom.