gthomson

Hoping someone can recommend an easy fix for a 1990' Shimano 3X7 Altus thumb shifter I have that shifts down into the smaller cogs easily but then catches a little as I shift back up into the bigger cogs. I 've replaced the cassette, chain, shifter cable but still not super smooth.

Is it something to do with the shifter itself or the rear derailleur? there is no problem shifting with the front derailleur and I haven't made any changes to that.

vonfilm 

I have had success spraying a spray lubricant into the interior of the shifter and then working the levers.
Don’t use WD40 which will surely gum up in a matter of time.

dddd

If there is gumming of the pawl pivot lube, and if the shifter sometimes works but not always, then the correct diagnostic is to push the shift lever very slowly to see if it works reliably that way. Alternatively, test the shifter after warming it up slowly using a hair drier.

If so, it's good news, and vonfilm's recommendation should rectify the seasonal problem.
I say "seasonal" because this is the time of year that everyone's shifters act up for the same reason.

I settled on the very thin-bodied and foaming Liquid Wrench Lubricating Oil as my go-to for such re-lubrications of the shifter's pawl mechanisms, but any similar oil product should work as well if directed into the right places.

gthomson

And this answers my next question as to what lubricant to use so perfect. I should add that it will shift but sometimes you have to coax it. The original click won't work so then I gently push in the lever again until it shifts and this only happens going up into the bigger cogs as it shifts smoothly going down into the smaller cogs.

T-Mar

Alternately, it could be a case of not having quite enough tension on the gear cable. Trying increasing the tension by a 1/4 turn until it makes the desired shift, then see if it still shifts OK in the opposite direction. Another issue which can exhibit these symptoms is derailleur hanger misalignment.

Moe Zhoost

Have you disconnected the cable and then run the shifter up and down through the gears while keeping a bit of tension on the cable? If the shifter works ok while doing this, your problem is likely elsewhere. If you still feel the problem, then it probably is the shifter and a bit of lube/cleaner should correct it. At our local co-op, Seafoam DeepCreep is our go-to fix for problem shifters. Sprayed liberally into the shifter and then allowed to sit overnight brings most of them back to proper function.

Bianchigirll 

Personally I’d use that liquid wrench to get it loosy goosy then blow it really good and use some tri flow or other high nylon content lubricant. Liquid wrench might not play well with the plastic internals. But this is just my opinion.

100bikes

Shimano shifters are notorious for this behavior.
The lubricant (grease) congeals to a sticky and stiff consistancy.

I agree with the hairdryer trick as a first step.

I personally use a citrus degreaser, sprayed into the shifter body and let it sit for a while.
Blow out with compressed air while running through the gears and then a light spray of lubricant (NOT WD40!).

rusty

T-Mar

All brands of indexed shift levers can exhibit this behaviour. I've seen it on SunTour, Campagnolo and SRAM. While it surfaces far more often on Shimano units, this is because their production far outnumbers the competition. If Shimano has 1,000 times more units in the field than the competition, then they will also have a lot more failures. This will result in a perceived "notorious" problem, even though their overall failure rate might better than competition.

This issue is just the nature of the grease used as lubricant. All greases will eventually dry out and lose their lubricating properties. Some of these indexed shift levers are approaching 40 years age, so expecting the grease to still perform satisfactorily is asking a lot. Most members buying a C&V bicycle will routinely overhaul the hubs, bottom bracket, headset, pedals, etc. They'll even clean of the old grease from the stem and seat post and apply new grease, to mitigate binding issues. Indexed shift levers use grease too, so why should they be any different?

dddd

"Liquid Wrench" as it applies here is actually a brand, not a particular product. They offer many different aerosol sprays, I chose their "Lubricating Oil" product, it's just that.

Oil, to the extent that it (perhaps slowly) frees up stiff grease, is much longer-lasting than the more heavily-diluted (with kerosene or it's equivalent) WD-40.

Not unheard of though for old grease to thicken again after just one season, so flooding out a lever with WD-40 or a degreaser is a preferred first step for many.
Note that one can work the pawls through their full range of motion without swinging the levers through their full travel, and without even making the shifter click. Just pushing the lever (either one, actually) enough to first engage the pawl effects the needed pawl movement during a flush-out, sparing the lever return springs from a vigorous assault on their fatigue life!

Getting lubes between the lever and rubber hood is to be avoided at all costs, so I always position the bike tipped forward at least 30 degrees before spraying lubes into them.

Shimano STI levers do indeed seem to be the ones most afflicted, due to their pawl-and-hair-spring internals, with relatively long pawl-pivot bores that trap a broad area layer of grease that is sheared by pawl movement and (relatively weak) spring force.

But all integrated levers rely on lubricants to give smooth shifting action.

Newer Shimano STI levers (having hidden shift cables) offer visible access to the pawls, allowing pin-point pawl pivot lubrication in lieu of messy flushing.

And SRAM's levers expose their release latch (that needs occasional lubrication to minimize the needed force at the lever when releasing cable).
I use a tiny spritz of heavy-duty PJ1 motorcycle chain lube there because it's designed to lubricate steel parts in a dirty environment.

Campagnolo's most-common Ultrashift mechanism (having replaceable indexing springs) needs to come apart to re-lubricate the indexing guts (with grease), and typically get new, inexpensive indexing springs installed at every infrequent overhaul.
Kind of unrelated to this discussion, but I do have the cringe-worthy habit of merely spraying lube into the greased indexing cavity of Campagnolo downtube Synchro levers in order to put an older bike back on the road, and which mostly restores their smooth, crisp "snap".

Chriscraft760 

I just went through this sticky shifter as you describe on my 1991 Trek 950. I ended up removing the thumb shifters ( including cables) and soaked them in purple degreaser overnight. Then I rinsed them with hot water, as hot as my kitchen faucet allows.

they ended up ratcheting very well after this. Reinstalled the shifters and now they shift up and down well.

gthomson

Great advice and I will go with the cleaning it out using a de greaser and then let it properly dry before testing again. Now I assume I need to apply some new grease after this? I'm guessing a synthetic grease would be best because of the plastic parts?

I also will admit I didn't replace the cable housing (shame, I know) but they had this nice Shimano writing embossed in gold so I really wanted to keep them.

cyccommute 

I know there is won’t be popular but there is a lot of misinformation in this thread.

WD-40 is just fine for this application. It has a high solvent to lubricant ratio which help flush the old sticky grease. The lubricating oil left behind is not going to gum up any more than other lubricants because it is very similar to most any lubricant you’d use on a shifter. It works to refresh old shifters just fine.

Neither Tri-flow nor any other bicycle lubricant…nor any lubricant for that matter…contains nylon. Nylon isn’t a lubricant. You may be thinking of Teflon but that really won’t do anything in the internals of a shifter. The oil in the Tri-flow, which is roughly the same concentration and make up as in WD-40, does the work. The solvent, which, again, is similar to WD-40 helps remove and refresh the existing lubricant in the shifter.

None of the plastic inside the shifter is damaged by the solvents used in Tri-Flow, WD-40, or Liquid Wrench. I probably wouldn’t use Liquid Wrench but that is for another reason…see below.

I would not suggest Liquid Wrench. While the oil in WD-40 and spray TriFlow is largely saturated hydrocarbons…and this stable to oxidation…, the same can’t be said of Liquid Wrench. The main component is 7,11-dimethyl-3-methylene-1,6,10-dodecatriene or, in a less jaw breaking, terms, farnesene. This means little to most every one but the lubricant is a unsaturated hydrocarbon (actually a terpene). Unsaturated hydrocarbons are more susceptible to oxidation than unsaturated hydrocarbons. That means that they are prone to gumming when exposed to air.


That probably won’t work. The problem is that the old lubricant causes the pawls in the shifter to not catch. Flushing it will usually solve that problem.

Only Shimano shifters of a certain era are notorious for this problem. 7, 8, and early 9 speed shifters will gum up. I’d say from mid 90s to late 90s are most likely to have this problem.

And, again, there is nothing wrong with using WD-40 to address this problem.

Bianchigirll 

cyccommute OH right sort of typo on my part.

dddd

You missed the details of what lubricant that I mentioned was what I used. A brand and a product are two different things (as I mentioned).

WD40 can work well, but unless the flushing and working of the shifter are adequately persistent (as with any other lubricating spray), the pawls can and often do begin sticking again after the fast-penetrating solvent dries. Actuating the pawls fully does not require full swings of the levers or even making the shifter click, which is important to know when the pawl needs to be actuated many, many times in order to thoroughly displace old grease in the pawl pivots.
Most mechanics will follow up a WD40 flush with real oil, but that oil will not readily displace the WD40 from the pawl pivot bores without a lot of pawl movement.

It can be useful to try to locate where the afflicted pawls are in the shifter, unless one doesn't mind removing and soaking the shifter, or flooding it out.
MTB STI's offer access via removable covers, but different models require quite different approaches to gaining access to the pawls. Some can be pin-point lubricated in minutes after swinging the shifter upside down on the bar, then removing the cover. However, some retain the cover with the central bolt holding things together, and others require cable removal to remove the cover. Still others have gear indicators needing removal, and that need to line up to top gear (smallest cog) position upon reassembly. It is quite useful (speeds up the oil's penetration) to be able to work the pawl(s) on their pivot pins using the tip of a screwdriver in the axial direction, to free up stubborn pawls. Touching the tip of a soldering iron to a stuck pawl has also been useful for me in severe cases of dried pawl-pivot grease (when I was readying a box full of old MTB STI's for sale).

Tri-Flow contains a far-higher concentration of lubricating oil than WD40, opposite ends of the spectrum! The WD40 is more like a degreaser than a lubricant in this sense, and I've had shifters quick-lubed with Tri-Flo or WD40 start missing gears less than a year later. So after a few years of using Tri-Flo I switched to the Liquid Wrench Lubricating Oil for it's seemingly longer-lasting effect as it seems to have a thinner base oil in it(?).
Shifters that are gummed up so dry as to not shift (even after heating) can be rescued using a petro-based (smelly, flammable) degreaser like Finish Line Citrus Bike Chain Degreaser, but you must apply it before applying another spray or it will take much longer to work. It's an aggressive solvent so perhaps not the best thing for the shifter's various polymers, but it rescued some truly glued STI pawls in a hurry when I was flipping bikes poste haste two summers ago.

It can be a challenge to prevent having lubes drip out of a shifter that has been blasted with a substantial lubricant. At least the Liquid Wrench Lubricating Oil is very thin-bodied so as to flow out of the shifter to a good degree, with it's meager solvent content then evaporating to leave substantial real oil behind (of the sort that may keep old grease from re-thickening in a few months). I tuck a strip of paper towel between the levers on road STI's so as to wick any oil out of installed levers after lubing. Levers off of the bike can be whirled on a bungee cord to force out the excess oil.

I'll mention again that the (road) bike or handlebar must be pointed sharply downhill when blasting out installed road STI levers, else there will be oil flowing down into the rubber hood's interface with the lever (to be avoided at all costs).

dddd

Yeah, Teflon is trademarked, so we got Cerflon, Ny-Tech, Polygon (kidding)

cyccommute 

My mistake. I looked at the penetrating oil. That said, Liquid Wrench Lubricating oil isn’t that different from WD-40 in terms of composition. Both use the same solvent in roughly the same proportions. The oil used is in the same family which means that both work the same way. The solvent ratio also means that they work similarly. In other words, one product is not vastly superior to the other.

Again, the products are significantly different and would act the same way. WD40 has a similar range of solvent as the Liquid Wrench product.

That’s because most mechanics are not aware of what is in the product nor how it works. There is a whole lot of snobbery when it comes to use WD-40 that is undeserved. I’ve used lots of different products to fix this problem and WD-40 works just as well as does other products. Finishline makes a similar product which works about the same as WD-40. About the only thing that doesn’t work is a soy based oil that my co-op got. It has too little solvent in it to help refresh the oil grease.

In my experience, there are few Shimano shifters that have easy access to the guts of the shifter. Yes, you can remove the levers but that is often not worth the effort. SRAM paddle shifters are far easier to work on but I’ve never had one with a stuck pawl.

Nope. Look at the SDS for the liquid and the aerosol. The liquid actually has less (about 10% heavy naphtha) than WD-40 (about 35%). The aerosol Tri-Flow has a similar content of heavy naphtha (25 to 50%) to that of WD-40. Frankly I was surprised when I found this information.

Sorry but I don’t agree. Citrus degreaser is not more aggressive, nor more effective, than mineral spirits which is what the “aliphatic hydrocarbon” (CAS# 64742-47-8) is. Generally speaking, you have to use more citrus degreaser to do the same degreasing as mineral spirits does. There is a limit to how much grease citrus degreasers can dissolve while there is no limit to how much grease (and oil) can be dissolved in mineral spirits. You can have a mixture of mostly grease and little mineral oil without that mixture separating.

Look at the SDS of the Liquid Wrench Lubricating oil again. The solvent to oil ratio isn’t a “meager solvent content”. It can be 50 to 60% solvent. WD-40 is up to 70%. That’s not really a large difference. Nor is the oil significantly different.

dddd

I don't study the chemical makeup spec's on different lubes, but the Tri-Flow seems much thicker than WD40 after application. Have you tried both products on a chain for example?
I would say that the difference is dramatic in terms of how much lube reappears on the outside of the chain after wiping it down and then riding 100 miles.
The WD40 doesn't leave much lube behind after wiping the chain down, seemingly because it's thinner and it's greater volatility leaves far less lubricating product behind.

The ingredient naptha is a solvent, not a lube. Quoting Brittanica, "naphtha, any of various volatile, highly flammable liquid hydrocarbon mixtures used chiefly as solvents and diluents".

If you've used Finish Line Citrus Degreaser, you'd know that it cuts old crusty grease much faster than other solvents or degreasers. It's much more aggressive on hardened grease, with fumes to match, and is proportionally bad in terms of de-fatting one's skin.

I would say that the constituent descriptions you've mentioned are quite vague in terms of the specific molecule sizes and properties. Those are just families of hydrocarbons, not specific molecule descriptions. As such, the properties of the compounds can vary tremendously.

As I mentioned earlier, visible access to the pawls is a feature of the Shimano road STI levers having hidden shift cables.
I've had a go at the internals of many variations of Shimano's Rapidfire-Plus levers, and as I said there is a range of difficulty but most are quick and easy to look inside.

cyccommute 

I don’t…and wouldn’t…use WD-40 on a chain because it is in an aerosol form…usually. But I don’t use Tri-Flow either because it is an oil and I don’t use oil lubricants on chains. Neither is particularly viscous. Only the solvent is volatile and both contain solvent. For flushing and lubrication, aerosol works very well but from a composition standpoint, any of these would work similarly.


No, naphtha is often shorthand for any liquid distilled from petroleum. “Heavy naphthenic petroleum oil”, “naphtha, hydrotreated heavy”, “hydrotreated heavy naphthenic distillates” all refer to oils which are related to solvent naphtha but are thicker. The CAS# 64742-52-5 compound is described as

In chemistry, we often refer to such material as heavy naphtha, along with a whole host of synonyms. Understanding what chemists mean takes some understanding of the context as well.

No, it really isn’t what you are describing. I should have looked up the SDS before but the main ingredient in the Finish Line product is similar to mineral spirits and that is what does the major work. The d-limonene, which is the “citrus” part, is there only in 4-8%. The petroleum solvent does allheavy lifting. The citrus oil is pretty much along for the ride. And, yet again, the proportion of solvent to active ingredient isn’t that much different from WD-40 although WD-40 does contain mineral oil (another way to describe the heavy naphtha).

I’ll admit that the descriptions can seem vague to the uninitiated. You have to dig deeper and go look up the Chemical Abstract Service (CAS) number and even then the descriptions are somewhat vague. But, with experience (and not a small amount of education), the descriptions are clearer. These are all mixtures and we really don’t need to know the specific molecular size nor even the specific chemical composition to know what a class of compounds will do. Generally, these are all chemically related with very similar properties. From the solvent to the oil, they are much the same molecule with longer carbon backbones. The longer the carbon backbone, the thicker the material gets but their properties are predictable and don’t vary as much as you might think. There can be some viscosity variance but it’s not as large as you might think.

dddd

LOL, we agree on at least one thing, that is that chain and many other lubes are best not dispensed directly from aerosol cans, to the extent possible.

That said, I do sometimes put aerosol products into small squeeze bottles, so convenient with a tapered applicator tube installed!
And the better for comparing the observed differences between various "lube" products without prejudice as to their "mode de dispensation" if you will.
The flat-sided, clear squeeze bottles are my favorite, make the entire chain lubing task a 90-second affair.

For chain lube, I add ~20% "thick" chain lube to a squeeze bottle containing a fast-drying DRY lubricant (from an aerosol can) having only hexane solvent, PTFE or ceramic particulate and propellant in it's ingredient list.
WD40 proved short-lasting and relatively noisy on my chains, and it's solvents didn't seem to evaporate quickly, so there was still some fling-off getting on my rear wheel (even as the chain itself stayed relatively clean).


These aerosols get lots of use around here, the Silicone Lubricant is for cables/housings/guides, and the Dry Film Lubricant is what I often use as the base solvent in my chain lube blend.
The Silicone is best for plastic-lined cable paths. It's special in that it never evaporates or thickens.