>>1900227I though that this plastic guide at the bottom of the frame might be worn out, but it doesn't look to bad. I'd replace it, but it's not available.
I think the derailleur itself is the problem here. Shifting became problematic after dirty, wet rides. It actually froze solid during one winter ride, I guess the expanding water might have damaged it a bit.
I'll give it a go with wd40/lot's of movement/lubrication. Ultrasonic is the next step. After that I'll just get a new one.
