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-   -   Front derailleur clearance issues (https://www.bikeforums.net/bicycle-mechanics/1160410-front-derailleur-clearance-issues.html)

sa513 11-16-18 08:33 PM

Front derailleur clearance issues
 
I purchased a new Cannondale Quick 3 last week and just noticed a scratch mark on the crank from brushing against the front derailleur. Following the guides on the parktool site, I got everything readjusted. The problem I'm having now is that when I'm in the highest gear, the derailleur has less than 1mm of clearance between having chain rub (I'm not cross chaining) and coming into contact with the crank. Are tight tolerances like this normal on my bike?

Andrew R Stewart 11-16-18 09:16 PM

As ft der cages became more and more sculpted to shift better the gap between the outer ring and the backside of the RH arm also grew. This increased the "Q" factor (sometimes called "tread") and some riders (like me) are sensitive to how wide apart their feet are when pedaling. So some cranksets are reducing this gap to lessen the Q. Matching a deeply sculpted cage with a narrow gap and you get the chance top rub or really tight clearances.

With out a visual that's all I got. Andy

sa513 11-16-18 09:31 PM

I'm unable to post a link to the picture until I have 10 posts.

Best I can do: imgur[dot]com/a/UWTMPdL

sa513 11-16-18 09:50 PM

Thank you for your reply. I'm unable to post a picture due to my post count at the moment.

Andrew R Stewart 11-18-18 10:42 PM

So looking at your photo I see what I was talking about. Cage plate with 3D sculpting and ring/arm gap not being very huge. In these cases very minor tweaking of der, on frame, angle and sometimes a cage manipulation can result in tiny but better results. Very hard to describe in a way to have your hands do it though. Andy


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