So, on today’s ride, I had an issue with gear changes. The rear Derailleur would not shift down from one particular cog. So it was onto the repair stand when I got home.
I looked at the rear Derailleur, looked fine and moving fine. The hangar looked straight and true. So the process of elimination was almost complete and I moved on to cabling. I shifted to the highest gear and made some slack in the cable system. The rear housing looked fine, cleaned it off and applied some oil to the cable.
“When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking.” — Arthur Conan Doyle
The bike still did it. Would not shift down over the second highest cog. Thinking I’d checked almost everything, and it was down to a cable tension issue I was considering ripping out the whole system and re cabling. But before that I thought I’d just try adjusting the barrel adjuster at the top of the down tube. Low and behold, the bike shifted fine after slacking that off slightly. So with no cable tension, I removed the cable from the adjuster, and there was a shed load of grit in there. It must of been thrown up by the front wheel during a rather wet ride I had a couple of days back.
Sprayed a good helping of GT85 in the adjuster, oiled it over and reassembled. It was shifting like a dream again.
So the whole moral of the story, is one of trouble shooting the system, work backwards, don’t head down blind alleys and you’ll get there.