Originally Posted by
San Rensho
I would check your shifter. Something is going on there. I have never had a cable, either shifter or brake cable break. It is by far the strongest component of a brake or shifting mechanist. You will break a brake mechanism or the shifter before you break a properly installed cable. The very light loads that modern brifters put on cables will not break them.
I have had cables last for years of average use with no problems whatever.
If one shifts frequently the cable just wears out where it goes around the small diameter corner in the shifting drum in about 7,000 or 6,000 miles. It just bends sharply too many times and the strands start to break from flexing, not a hard pulling force. This is were it bends much more than any other place.
Originally Posted by operator
The doc specifically says ONLY use SIS-SP41 and warns against using dura-ace grease. I've never seen this grease before - can anyone comment if shimano is just b.s'ing this requirement (e.g you can substitute anything) or is it really a requirement for proper shifting.
Can you get a Shimano "2006 Bicycle components trade sales & support manual" ? The grey soft cover book. I know this is not an answer but, it's all I have right now.
page 129 says
"SIS-SP41 cable housing--- The cable housing with silicone grease reduces the cable friction by 10%"
It says use this for Dura-Ace, Ultegra, and 105 doubles and triples. It does not mention it for Sora or Tiagra.
Page 125 has a cut away drawing and a few "benefits" (claims?) about the pre greased cables. It says--
"Special silicon based grease is injected into the shifting outer casing to significantly decrease cable resistance. Combined with the wide link derailleur designs (RD-7800/6600/5600) ads key advantages: crisp instantanious shifts that are 10% more efficent from lever to derailleur"
my words- the wider derailleur links make the derailleur stiffer and makes for better shifting. It's in other places in the book.
I think the silicone grease keeps a more even viscosity in a wider range of temperatures. Maybe the silicone grease does not mix well with other grease? My memory is a little fuzzy on that detail, but I think that's right. I think it's not absolutly needed, but it is an improvement.
That's just a guess.
They show the pre greased cables and "special grease" next to the "dura ace grease' and the"special freehub body grease" - not the same as either of the other two.