dglevy

Hi all,
I have to replace my shifter cable TODAY in order to be able to ride in 4 hours. (Sorry for the last minute query but I didn't realize it would get complicated.)
(1) Should I lube the cable housing before installing the new shifter cable and, if so...
(2) Does it matter which lube I use? I have Finish Line Dry teflon lube, but the description on the can talks only about using it for chains...
Thanks in advance for well-informed replies from the community!
--David

cny-bikeman

The dry lube should work. The thing to avoid with modern plastic lined cables is any grease or thick oil, as it can actual increase resistance.

wphamilton

No reason "why not" so I say "yes". I oil the cable though, not the housing, figuring that I'm guaranteed to get the whole surface lubed that way.

dglevy

Thanks, y'all, for your quick replies! I read them, then decided to take a look on the big ol' Web with a search, "bicycle cable housing lubrication". This thread was interesting:
https://bicycles.stackexchange.com/q...bricate-cables

Looks like there's no consensus, and 3 routes: 1) no lube at all (because modern cable housings are reportedly designed for no lube). 2) any dry lube will do. 3) use a lube specifically designed for it, like Triflow.

I also went down to my LBS (local bike shop) and asked. He recommended Triflow but, at $10 for a lousy little 2 oz bottle, I balked. The mechanic was a young guy who I hadn't seen before, not sure whether to trust his opinion...

blamester

Try it with no lube see how it goes.
It's not going to wear out in a week.
If your not happy lube it.

TimothyH

I can't remember ever using lube on a cable.

Maybe I put a few drops of transmission fluid in the cable back in the 70's or 80's. I've lubed automotive emergency brake cables with the stuff but can't think of a reason why modern PTFE coated cables would need lube of any kind.

dglevy

Thanks for the 2 latest posts!
I've decided to go with NO lube. I can always add lube later. I'm also going to ask my LBS mechanic maven, in a day or two. He wasn't in the shop today, unfortunately. (He's been doing mechanic work for at least 10 years, probably longer, and is a no nonsense kind of guy--good as gold for an amateur mechanic like me who takes care of 4 bikes...)

WizardOfBoz

For their Dura Ace and Ultegra shifters, Shimano recommends:
1) NO lube for their PTFE coated brake cable
2) A special grease made from an extract from the belly fat of hummingbirds (to judge by the cost*) on their shifter cables.

I grew up working in a machine shop and worked 7 years in a bike shop. I have four degrees in engineering. (this doesn't make me right, just saying I have some credibility here). Barring contrary information from the mfr's instructions, I'd lube, using grease.

*SIS SP41/BC-9000.

dglevy

$28 for less than 2 oz of grease? I think an expletive would be appropriate, here. No wonder Shimano's stock price has more than quadrupled...

But thanks for posting. More information--reliable and credible--is always better. I am still curious to know what my local ace mechanic has to say. Will post when I talk to him.

TimothyH

This is really interesting.

Not trying to challenge but where is that in the docs? I assume it is in the dealer manual for the shifters?

Four degrees is impressive.


-Tim-

TimothyH

Well, here it is...

The dealer manual for the BR-9100 and similar dual pivot caliper brake is at https://si.shimano.com/pdfs/dm/DM-RACBR01-02-ENG.pdf. It says...





The dealer manual for the latest model shifters at https://si.shimano.com/pdfs/dm/DM-ST0002-05-ENG.pdf says...





-Tim-

WizardOfBoz

You got it, Timothy. I actually used that stupid 20 dollar grease.

Regarding degrees, I got a bachelors (Chem E.) then a Masters (EE), and then a PhD (Chem E.). The MS in Chem. E. they kind of throw in once you've made enough progress towards your PhD. It was a lot of work, but it was a lot of fun, too.

Paul Barnard

Christ, it gave me a headache just reading that.

csport

Rock N Roll Cable Magic is another lubricant formulated specifically for the cables. Never tried it.
I normally use Boeshield for shifter and brake cables.

wschruba

I'm willing to bet some people's heads would explode if they found out that SP-41/BR-8xx+ hosting already has lubricant (grease) in it. Some levels of Jagwire, too.

WizardOfBoz

Timothy, I worked at the local Schwinn shop in my hometown when I was a young fella. I set up hundreds of bikes. EVERY bike with a brake or derailleur cable got grease on the cable. But I'd bet non of those cable outers were lined with PTFE.

I actually worked at the factory were DuPont made most of the Teflon(R) fluoropolymers. PTFE is pretty slippery, but lubricating it DOES make it slipperier. So again, I'd lube unless the mfr said no. I'd probably use my fancy Shimano cable lubricant. Need to get more mileage out of that 20 bucks.

TimothyH

Maybe that's my problem then...?

wschruba

Couple of things immediately come to mind:

-The cable was clamped too tight/re-tightened too many times. The new clamping system for Shimano is much more aggressive than the old ones, and has a tendency to break cable strands if over-tightened.

-See the little black plastic nose? It's there to protect the PTFE wrapped cables from rubbing directly on the metal bushing insert in the derailleur body. It is possible that your issues started there, with the cable rubbing on the bushing/wearing out a strand or two. Unlikely, but possible if the above explanation isn't the cause.

Of course, with all cables/ropes, once one strand is damaged, the rest follow in short order.

JonathanGennick 

Is the recommendation against grease on brake cable for performance reasons, or to protect Shimano from liability? Sounds like it might be the latter.

gregf83 

wphamilton

Except when you buy SP-41 and get SP-40 which doesn't. Like this https://www.amazon.com/gp/product/B004XUQ1UQ

TimothyH

I thought the same thing Jonathan.

Sounds like liability rather than engineering or mechanics.


-Tim-

dglevy

I can understand the logic in supposing that Shimano is just trying cut down on potential lawsuits by claiming an unapproved lubricant was used. But there *does* seem to also be some logic in recommending no lubricant. See post #6 here above. And it does make some sense to me that grease would only attract dirt and dust. The mechanic at my LBS recommended against grease, recommended Triflow but, as I said, he is young and I don't know how much experience/expertise he has. But, also, see the link I mentioned earlier:
https://bicycles.stackexchange.com/q...bricate-cables
which, among other things, includes a link to this:
https://www.sheldonbrown.com/cables.html#lubrication
which says "Modern plastic-lined cables have made the use of grease inappropriate, because the viscosity of the grease makes for sluggish cable movement. This is a more critical concern with modern brake and gear systems that use weaker return springs, and with indexed shifting in general." But he also goes on to note a few exceptions.

JonathanGennick 

Right. It was more the seeming inconsistency of Shimano's recommendations that had me wondering: no grease for brake cables, but do put grease on shifter cables. Shifting is a picky thing though, so I can see where Shimano might choose to fuss more and put grease in their shift housing.

wschruba

Grease IS intended for their brake cables. It comes in their higher level housing (both kinds...). They want you to wipe it thoroughly off the clamp area. As someone pointed out already, clamping something designed to slip is not a great idea, and Shimano knows it. While a slipping derailleur cable is irritating, it's unlikely to cause a crash...the same cannot be said of a brake.