jgwilliams

I've been having a spot of bother with my gears (Force 22) not indexing quite as cleanly as they should. Mostly been working well but just occasionally being slow to engage.

I went for a ride today and everything was right back to how it should be. I was thinking back wondering what I'd done that made the difference and the only thing I can think of is this; I had the bike upside down and noticed that the cable guide under the bottom bracket was looking very grungy. So I cleaned it off and put a few drops of chain lubricant on.

So that's helped in the short term, it would seem, but given that it's steel cable running over a nylon guide I'm guessing there's something better I could be using. Any suggestions, please?

As an aside, I've often wondered why these guides are always left open to the elements, particularly given the location. Surely it would make sense to fit a weather seal on it?

Thanks

John

base2 

Nope. The exposed nature means that any gunk, junk, debris is also free to leave.

The steel on nylon is a very robust wear resistant system. You'd be hard pressed to find a nylon under bottom bracket cable guide that has actually worn through, much less worn at all, really.

The lubricant you added might actually attract dirt & grime. Not that it'd matter much. There just isn't much in the way of movement & pressure between the cable & the guide. Soap & water to clean the "lube" off the next time you wash your bike.

trailangel

What kind of chain lube was it?

Andrew R Stewart 

Independent of knowing about the durability and/or friction aspects of a steel wire on a plastic BB guide one only has to look at the millions of bikes with said guides to begin to think "maybe the plastic guide being out and in the open is not a generally problem".

Having said that shops do see worn out guides. Not commonly but we still do see them. Now what does bother me are the unique to a frame design guides. If they do become an issue then replacements can be unavailable (companies don't make these parts available for long when they have moved onto the next great design).

As base2 suggested it's more an issue of maintenance then design or material, keeping a shift cable freely moving through the guide (or casing for that mater). Andy

aggiegrads

As long as you keep sugary drink mix off of the guide, you will be in good shape.

cbrstar

In my own experience I have always found that dry cables work better and last longer because lube attracts dirt. But if the cable is a bit old and oxidized I've used tri-flow to get it working again for a while.

Shimagnolo

Been there; Done that.
I used to use homebrew maltodextrin/fructose on 3+ hour rides.
One morning I hopped on the bike, and the RD absolutely did not want to shift at all.
Put it up on the rack and found dried maltodextrin/fructose had "glued" the RD cable in place in the bottom bracket guide.

davidad

I have had the problem and found that cleaning the guide once in a while solves the problem.

jgwilliams

Fenwick's Professional. Very good on chains. Probably less ideal on plastic, but I happened to have it in my hand. I guess a silicone lubricant would have made more sense.

Jean_TX

First, clean/degrease the cable guide. Then rather than use chain lubricant or any type of oil, try using silicone spray - it will decrease the friction and it won't attract/hold dirt.

drlogik 

It's always best to use "dry" lubricants on cables and housing. Back in the day I used Phil's Tenacious Oil or TriFlow but "generally" stopped because it remained wet and attracted road grit. I sometimes still use them though. Graphite is good and so is moly powder (harder to come by). Puff some graphite into a towel and pull the cable through. Use the same towel each time and keep it in a Ziplock bag.

I have also used BoShield on my cables as a test and didn't see much difference between that and graphite though. Pulling the cable through a rag with graphite is a quickie.

Another option that some folks use, including a friend of mine on his own bikes, is Lock-Ease, the graphite lubricant for locks. My friend would attach the nozzle tube and spray it into the cable while the cable was pointing down onto a paper towel. Once it started coming out the end he would stop and let it drain. The liquid would eventually dry and leave behind a virtually permanent graphite lubricant impregnated inside the cable housing. He swore by this. I did it once but made a mess of it and dribbled the residual liquid all over the place. ...I'll stick with dry graphite.


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Ptcycles

Sounds to me that this a cold weather issue, and that the cable housings are stiff and slow and sluggish, due to lack of lubrication. The nylon guide I suspect has little to due with the sluggish nature of the shift. Lube the whole thing front to rear with something thin, like Tri Flow, and all should be smooth.

RGMN

Normally I don't lube the cables under the bottom bracket, but on the occasions when there is too much friction I use Drislide Bike-Aid on the cable. It is a dry moly lubricant and works quite well. On a couple of bikes with full housing I've dripped Drislide into the housing until it dripped out the other end and let it dry. Makes for a significant reduction in overall friction. Some friends that fat bike in the winter swear by it for their disc brake cables (they say hydraulics are too sluggish when it's -20ºF/-29ºC.) Just remember to shake the can extremely well before applying.