STI shifter sometimes doesn't catch in cooler weather

Question

I've got a road bike with brake lever shifters, and it's developed a small problem with age: sometimes, the shifter doesn't catch the first time or two I push it. It'll move easily, with no resistance, since it's not actually pulling on the cable, then after a few tries, catch and work normally. The colder the temperature, the more often this happens.

I don't know how the mechanism works internally, so I'm curious what would cause this, and also whether it's (as I suspect) gradual wear of some part of the mechanism, and if it's likely to fail catastrophically, or gradually worsen.

Answer 1

WD40 will work, for awhile, but in the longer term it'll work against you since it's a poor lubricant and will work to prevent future lubing. Spraying some penetrating oil into the ratcheting mechanism is the way to go, long and short term. Gaining access by working the brake on the shifter and spraying, using a long neck attachment for better aim, into the little hole, opposite the cable side, that you can see when applying the brake, leading to the gear ratchet will do the job. Zimm's confirms this, as does my local bicycle shop.

I just did this on an Ultegra gear shifter, using "Super Lube", and now the shifter works like new. After it evaporates it leaves a extremely thin layer that is highly slick.

Answer 2

The problem is dirt in the mechanism. A blast of WD40 in there should clear matters up and get your shifting working properly.

Whatever you do, don't pull apart the mechanism, also try to avoid getting WD40 on the cable/inside the cable outer as that tends to increase cable friction by pushing dirt in and you do not want that.

The WD40 product is not recommended for the chain on a bicycle, but for STI shifters it does a good job of getting them lightly lubricated.

Answer 3

Here is what I did that resolves the issue of "WD40 is not a lub" My problem was RX shifters that did not work at all after a few of years of storage - They were throw-away if I could not get them working, so I considered that WD40 was acceptable.

WD40 - did not work. After 2 days still got no movement, so pulled out the big guns

Aerosol Engine degrease - can be anything that dissolves the dried and ineffective grease, toyed with using brake cleaner (I had a can on the shelf). It does not need to be a lube - the idea here is to get ride of the stuff that does not work anymore.

Cleanup with lot's of hot soapy water. No cleaning residues left inside the shifter. Now working but obviously metal one metal...

Aerosol Grease. This is magic - it has a light carrier that gets it to places you cannot normally get grease - which then evaporates away, but being a grease, is the right stuff for the shifter. It's better than oils and teflon lubes etc, as it's a higher pressure lube than those, and the shifter has very high pressure contact points.

You will get away with WD40 and oils, but this will cause the shifter components to wear out faster (and probably won't be a smooth). The wear issue may or may not be a problem you are concerned with.

Answer 4

WD40 fixed my shifters, but it wasn't the best solution. The proper solution is to clean out the old grease and replace it with new grease. The reasons cited above don't properly explain the problem with WD40.

Here is my experience: This problem occurred on three of my bike shifter levers (multiple bikes obviously). To fix them, I removed the shifter dust caps and hosed the shifter innards with copious amounts of WD40. The WD40 washed away the problem grease, and then my shifters worked. However, the shifters did not operate quietly and smoothly. Each time I shifted up or down, there was a loud and sudden SNAP and Jolt. Here is the problem: WD40 is indeed a great lubricant in certain applications, but not in a shifter lever. It is much more viscous than the grease that is packed into new shifter levers. I suspect that any kind of penetrating oil will have the same problem as WD40. To get my shifters working like new (with quite and smooth action), I used kerosene to wash out all the old grease and WD40. Then I repacked the lever with new grease. Now all is well.

Some bloggers have claimed that WD40 leaves a gummy residue. This is false. WD40 does not leave a gummy residue and this is exactly why WD40 isn't good in a shifter leaver. The shifter lever needs a sticky, buttery, gummy grease--not the super smooth (too smooth) WD40.

Answer 5

I've got these shifters on an old 1998 Mongoose bike. They were kinda okay after a burst of spray lube but not great.

Some Previous Owner had use the wrong length of gear outers on the front so I changed the gear cable inners and outers, but I fitted the inner wire wrong, and it got caught in the gear mechanism.

I watched this video

and it was really obvious how to open and close the mech.

Approximate outline of how I did it on the right hand brifter - some steps may not be required, and swap left for right if working on the LHS brifter.

1. Remove bar tape
2. Remove brake inner cable
3. Remove gear cable inner and disconnect gear outer from brifter
4. Use the 5mm hex key on the big front bolt - there is a round spring on the inside that will ping, and one or two rings, and a crinkle washer. Put aside.
5. Use 5mm hex key on single bolt inside the rubber hood - this holds the mech to the handlebars. It should now be off the bike.
6. Use 2mm hex key to remove grub screw under brake handle.
7. Use 4mm hex key as a pusher to drive the axle out. Note position of two bushings and a round spring.
8. Push the gear-down lever to one side and you'll see a Phillips screw. Unto that and the front cover will come off; may need some gentle prying.
9. Now you can see the gubbins. Soak it in 1/4 cup of petrol and use a small art paint brush to dissolve the hardened yellow lube.
10. Work the mech and clean the new bits you can now see.
11. Let it dry and test if its working better. If so, lube. I used white lithium grease in a spraycan.
12. Then reassemble in the reverse order.

The gotchas are refitting the springs. For the top cap the two tags must sit in the holes, so put the cap on 90degrees back and rotate into place. Took me 5 goes.

The other gotcha is the round spring around the axle. Shimano have a special tool that looks like a small short pipe that goes over the end of the spring while reassembling. I used a lollipop stick with a 1mm hole up the end. I also had to use a couple taps of a hammer (PIKEY TOOL ALERT!) to get the axle fully home.

Watch the video if you can, it worked fine for me, and nothing more than basic bike tools.

Answer 6

WD40 works well as a solvent, but not as a long term lubricant. It will evaporate fairly quickly, leaving a gummy residue. Remove the cable from the shifter. This will allow you to get the housing out of the way as well as make it much easier to get at everything. Flush the shifter with solvent and actuate it several times, both up and down, and if possible spray it out with an air compressor. I've used a lubricant called "Bike Aid" with good results, just drip a bunch in and actuate the shifter again. It is a dry lubricant (graphite based I belive) so it shouldn't attract grime like an oil-based lube will.

Answer 7

I've used the wd40 method myself on my old RSX shifters. I noticed the same thing where it wouldn't catch while trying to shift, so I removed the levers (didn't take them apart mind you) and sprayed wd40 into them while continually shifting up and down. After shifting up a down a few times they worked brand new, or as great as the RSX shifters ever have. I think I replaced the cables at that point too but that was only because I was trying to be nice to my bike.