Support road.cc

Like this site? Help us to make it better.

Cannondale synapse front mech touching crank.

See image (not sure if will work) 

Out on first ride and front mech design has changed so not sure how to trim it  but mech cage is just touching crank arm each rotation 

https://i.ibb.co/wQZDfRG/2-F01-AC76-5-C7-B-4879-8265-0-D6-C65024-FAE.jpg

<a href="https://ibb.co/qgLbvdq"><img src="https://i.ibb.co/wQZDfRG/2-F01-AC76-5-C7-B-4879-8265-0-D6-C65024-FAE.jpg" alt="2-F01-AC76-5-C7-B-4879-8265-0-D6-C65024-FAE" border="0"></a>

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

Add new comment

6 comments

Avatar
andystow | 2 years ago
0 likes

Shimano's instructions are quite good. Are you sure the outer plate is absolutely parallel to the big ring? I used two steel rulers to set mine up.

https://si.shimano.com/pdfs/dm/DM-RAFD001-05-ENG.pdf

Avatar
Sniffer | 2 years ago
0 likes

I had a similar problem with a Cannondale crank.  My front mech is a SRAM Red.  It took a trip to the bike shop to get it right so there was just sufficient clearance and the mech worked well.  The tolerance is actually quite small and I couldn't get it right.

I have a Supersix not a Synapse, but the problem is the same.  What mech are you using?

Avatar
SimonS replied to Sniffer | 2 years ago
3 likes

Shimano 105.  I think i've got it now by fiddling with the limit adjust but seems to be a tiny fraction of a turn between rubbing on chain and rubbing on crank.  

https://dassets.shimano.com/content/dam/global/cg1SHICCycling/final/ev/e...

Interesting that there is now cable tension adjust on an allen bolt.  I finally get around to buying a JIS screwdriver for adjusting shimano mechs and they change all the adjustment to allen bolt....

Avatar
emjay49 replied to SimonS | 2 years ago
1 like

It shouldn't be as fine as that Simon. Difficult to judge by the angle of the pic but for me, the 2mm hidden trim screw is right out against the frame plate causing the cage to stick outside of the big ring.

Avatar
Wingguy replied to SimonS | 2 years ago
2 likes

SimonS wrote:

Shimano 105.  I think i've got it now by fiddling with the limit adjust but seems to be a tiny fraction of a turn between rubbing on chain and rubbing on crank.  

That's not right. Simon, it looks pretty clear that your front mech cage is significantly tailed out. This means it needs a complete reset from the ground up. Back out the limits, bracing screw and tension bolt, undo the cable fixing bolt and start from scratch according to the SI.Shimano instructions linked above, beginning with attaching it to the braze on tab in the correct position and angle.

Avatar
thax1 replied to Wingguy | 2 years ago
1 like

Yep.

Both the GCN and Park Tools videos on YouTube go through this 're-install' very clearly and simply if you prefer that to the written Shimano instructions.

Certainly helps to get the bike in a workstand and lift it up to eye-level.

Latest Comments