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Front derailleur cable pulley on seatpost

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Front derailleur cable pulley on seatpost

Old 11-25-23, 08:35 PM
  #26  
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Originally Posted by Kontact
GRX is the new long throw type while the CX70 has the pre-11 throw.
That is good to know on the GRX front derailleur. I'd still have to use that seat tube pulley, but once I get that running smoother I doubt it'll be an issue.
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Old 11-25-23, 10:15 PM
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Two thoughts. You could probably get that miserable pulley to work just fine for a long time just by reassembling with plenty of marine grease between pulley and pin. Clean and repeat say every two years. (The stuff is so thick that grit cannot get in and it doesn't break down.)

Or - slide one of those cable inner sleeves over a new cable and run it under the bottom bracket and up between the chainstays. (I don't remember what they are called but there was a thread about them going around a few days ago. Heat shrink tubing might also work.) It will wear off the paint and keep the immediate "channel" it forms rust free by polishing the bare metal every shift. (I saw after I wrote this that the Jamis is aluminum. That will accelerate the wear a lot but BB shells are thick, With plastic liner over the wire you will still have plenty of time.) Crude, yes. Ultimately it will saw the BB shell in half but you will have plenty of time to rig something protective.

Or- spend the $70. (My bet? If you own this a while, that $70 spent will not get you an additional $70 for selling the bike with a more pristine bottom bracket bottom.)
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Old 11-26-23, 09:20 AM
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The pulley system was used on cx bikes in international competition for about a bazillion years. Still in use on the Fantom CX out in the garage. Works just fine
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Old 11-26-23, 03:46 PM
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Doubt it's the pulley itself causing the issue. Maybe check which direction the cable is coming off of the pulley wheel? It should be obvious but there's always a chance it was routed and clamped incorrectly during assembly.
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Old 11-26-23, 08:04 PM
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Originally Posted by tFUnK
Doubt it's the pulley itself causing the issue. Maybe check which direction the cable is coming off of the pulley wheel? It should be obvious but there's always a chance it was routed and clamped incorrectly during assembly.
I know that was the guess of several people, but I took apart the entire front derailleur system and checked it out as I went. It was probably 80% caused by the pulley.

Without the pulley, there's almost no resistance on the shift levers. With it, it was nearly immovable. The pulley spinning on the bushing was extremely rough, and is still not all that smooth even after cleaning and lubricating it. Even though the cable & housing didn't seem to need it, I replaced them with higher quality housing and a new cable. After replacing the cable & housing and lubricating the pulley/bushing, it now works pretty well, but not perfect. There's still a fair amount of friction between the pulley and the bushing because neither are smooth. I will be replacing the pulley with a higher quality one, probably the Specialty Retro Products pulley that uses a sealed ball bearing.
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Old 11-26-23, 09:02 PM
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Gotcha. Not trying to discount what you're reporting - thinking back to when I had a frame with such a system, even if the pulley was completely non-spinning, the cable should just slide within that groove - just as it would through an under-BB cable guide. That's why I suggested perhaps it could be a routing issue that's introducing friction. Good luck with the new pulley kit, hopefully that resolves it.
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