Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: Blodwyn Pig on 24 December, 2019, 02:30:48 pm
-
Its time Olive had new inner brake cables, for its TRP spyre calipers. After much salty water riding followed by daily rinse offs, the rear especially is a series of jerky movements, followed by ..not much at all really. So new pads, and inners. I'm getting the better 36 strand highly polished type, but what ,if any thing do folks use to lube the outer before the inner is shoved thro. GT85? Wilko bike lube? 3 in 1 ? i'm guessing a thin smear of grease is a nono. I've always used GT 85, but is this correct?
-
With the lined outers, you don't grease them anymore. It may even be detrimental to the outer.
-
With the lined outers, you don't grease them anymore. It may even be detrimental to the outer.
that's what I thought, but what about teflony stuff?
-
I find that dry is as good as lubed. Once the water gets in, you can usefully use lube to flush some of the crud out and prolong the life a bit, but ultimately you need new outer to restore full performance.
-
Would a bit of graphite be alright?
-
...ultimately you need new outer to restore full performance.
Thassaboutrite.
-
I presume you're using 'compressionless' outer?
Flush the outer with brake cleaner, you might be surprised at the gunge that comes out.
If the new cable doesn't feel smooth, replace the outer too.
-
I've used thin lithium grease until now - just a small amount. Seems to work ok. Then during servicing I'll drop a small amount of boeshield T9 inside the cables using gravity to make it flow inside the outer by leaving the bike upside down in the stand for a few minutes. It might be best to just use T9 for the whole exercise now if not just leaving the teflon coated cables bare.
-
If the new cable doesn't feel smooth, replace the outer too.
IME, if the (stainless) inner doesn't get chewed up by whatever it's attached to (usually shifters and front mechs), it will generally out-live the outer. At least for long runs of outer on recumbents and folders, and the loop to the rear mech on DFs; short runs at the handlebars have an easier life.
If I'm replacing a rear gear cable inner, I always fit a new loop of outer at the mech, seems like a false economy not to.
-
polished stainless steel inners and lined outers is the default setup. The main variation I'd suggest for spyres is using compressionless outer cable housing, e.g. from Jagwire. It will give a better feel to the brakes.
IMHO you are better off with some lubrication inside cables rather than none; with the right lubricant liner wear rates can be very low. Bike manufacturers think so too; hence they have been producing housings with with pre-applied silicone grease inside them and inner cables with coatings on them which do indeed make the cable run smoother for a while. However silicone grease is not a brilliant lubricant and IME all these different inner cable coatings don't persist for that long; most of them wear off and once that happens the coatings may do more harm than good, e.g. by accumulating at one point in the cable run and making the cable start to bind.
If you use no lubricant (BTW some folk who think they are using no lubricant are actually using housing with silicone grease inside it....) the liner wears and something similar may happen; the cables get more and more draggy as time goes on and sometimes worn liner debris can accumulate and start to impede inner cable motion.
The 'wrong lubricant' will not only fail to lower friction much, but it may even soften the liner material in the cable housing (again increasing wear rate). The liner materials commonly used vary somewhat and so does the nature of common lubricants that folk are liable to pick up and try and use. It is easy to do more harm than good, hence there are folk who have tried using grease (or something) and have found it better not to bother. The likelihood of softening with (say) a mineral oil based lithium grease is pretty high. The grease will probably be pretty crap as a lubricant inside a cable too.
I use a thin smear of finish line teflon grease mixed with some synthetic oil on polished stainless inner cables, and I don't have problems with liner softening or binding. Gear inner cables evetually wear out by fatigue, where they wrap round the cable drum in the shifter. The grease by itself is too thick and the oil by itself is too thin (it runs out the ends of the cable) but a mixture seems like a good compromise; the grease provides usefuk lubrication in its own right and helps stop the oil from running out. The synthetic base oil in the grease and the synthetic oil I add don't soften the liner in the cable housings I use. The grease is at least partly thickened by the PTFE in it, which is of course also a lubricant in its own right.
cheers
-
.... The main variation I'd suggest for spyres is using compressionless outer cable housing, e.g. from Jagwire. It will give a better feel to the brakes....
If I am using compressionless housing for the spyres does that mean the barrel adjuster thingy on the spyre won't do any adjusting? thanks
-
Won't make any difference. The barrel adjustor is for adjusting the angle of the caliper when you're tensioning the cable.
-
I use silicone grease on mine.
The first time I used it was on the Spyre's cables & it made quite a difference to them.