As above, I’m fine at setting up an mtb drivetrain with 1x and have done recently (both lots sram gx but also done sram x9 with sunrace cassettes etc too).

I had a massive fight with internal cable routing on this setup but it doesn’t seem to have any stiction through the frame.

I’ve got a Cannondale Caad12 disc – it has a 36/52 double on the front and just fitted a new 11-32 cassette with a longer cage Shimano 105 r7000 rear mech. I can’t get the rear properly indexed right now.

I’ve set the low and high screws and had it shifting by hand but I can’t get it perfect. Either it’s ssjusted so it’ll go up he block smoothly or down but not at the same time.

I’m assuming it’s either b screw, cable routing or chain length to blame. The front mech seems broadly ok.

Just also to check – are 11 speed joining links different between sram mtb and Shimano road? I haven’t used one here as it had a press in joining pin but I’d like to potentially use powerlinks here in future.

Thoughts?

Pictures below:

Rear cable loop

B screw gap

Chain big/ big – 2x photos – 1 to show its not highly tight but has some slack if you move the mech by hand

Chain small / small – doesn’t rub against itself

My moneys on that horrid cable bend into the derailleur

That rear cable loop looks way too tight to me & you can see it trying to push out of the mech at an angle. That can’t be helping.

Yep, cable bend looks horrific.

Have you used the correct super flexible bit of outer cable for the rear mech?

Yes I’ve used the bit of cable that came with the mech. It was way too long so I chopped it down a bit. Maybe it needs chopping further so it’s just a short bend at less of an angle?

Also just realised it’s a directional chain and I might have joined it the wrong way round.

+1 on the cable bend being my first port of call…..

Cable bend too tight. The outer loop should be longer, needs to be a sweeping bend. You shouldn’t have cut it down.

I’m not sure going shorter is really going to help, worth a shot though as my next idea was to go back to a normal mech instead of shadow

Think you’re going to need something like a cable roller to cope with the severity of that cable bend. I’m presuming that it shifts OK going up the cassette – it’s excessive cable friction that stops it the other way. Wouldn’t worry about the chain direction and should be OK to use any 11 speed link.

outer cable length – Shimano mech are quite “fussy” about the curve ….

Mmmmn, tried cutting it down shorter so it has a less extreme bend and it’s a bit better – flies up to bigger cogs but a bit hesitant on the way down. In the middle of the block here’s a bit where it takes 2 shifts to make it go up.

I think I’m going to flip the chain so it is going in what I think is the right direction and try a longer / bigger loop of outer cable – I’ve got loads of new spare stuff lurking around. This Shimano bit doesn’t seem anymore flexible than anything else.

I can’t see longer cable helping, unless you routed it Millenium Falcon style (270 deg not 90) which might also be crap and would certainly look odd (sort of thing I’d try tho).

I’d go with a roller.

What kind of roller / where would you get one from? I’ve tried looking online and people seem to be running similar mechs on this bike without a roller. But the cable still looks wrong however it’s done!

Think I’m going to flip the chain just to fully rule that out.

Can anyone comment on the chain length – does that look ok – just to rule that out before I play with rollers /
Different length outer space?

cable too long, if you have routed through the frame check front mech cable isn’t wrapped under or over the rear one, this will affect tension on rear & front incidentally. easy to do. shift the rear with a hand on exposed front cable and check for movement

Might be worth trying a 5800 rear mech which has the cable coming in from the rear rather than the top, which is probably what the frame was designed for.

The 5800 was what I had on there before but it wouldn’t reach the 32t biggest cog on the new cassette!

But presumably a 5800 SS (short cage)? You need a 5800 GS (medium cage) for a 32T.

That’s a Di2 frame if ever I saw one. Rear cable loop needs to exit about three inches further down the chainstay to work properly. Even when you’ve set it up with a longer loop, I’d still expect it to shift poorly with dirt ingress and friction.

You’re right it was short cage. The 2019 caad12 105 is running the same mech as I’ve bought though, so it must be possible to make it work….

What kind of roller / where would you get one from? I’ve tried looking online and people seem to be running similar mechs on this bike without a roller. But the cable still looks wrong however it’s done!

Jtek shift mate

Shifting will be very sensitive to the angle of the cable. Have you used plastic ferrules? These can kink, and whilst looking fine externally, add some of that all important extra friction. How you cut the cable outer will also be important, I cut when bent into the angle needed – the outer run along the inner, so the top will be longer than the bottom.

I’m sure it will work, but this little cable outer is almost always the reason for poor road shifting in my experience. I’d go with a roller too based on that angle.

That’s a Di2 frame if ever I saw one.

Possibly, but that sort of cable routing works fine with older derailleurs.

The 2019 caad12 105 is running the same mech as I’ve bought though, so it must be possible to make it work

You’d think, but I suspect it would be very sensitive to dirt and cable wear. It wouldn’t be the first time that internal cable routing was fatally flawed. The original rear brake cable routing on my wife’s Cube simply didn’t work. It was so sensitive to cable length that you couldn’t adjust for pad wear (see https://singletrackworld.com/forum/topic/brake-cable-routing-problem/)

I’d love Di2 or eTap given the budget 😝

I’ve just redone the cable with metal ferrules on the end instead of plastic ones to see if that makes a difference.

The internal routing seems to just leave the cable loose in the downtube – it has a cable stop for outer by the headtube, and then at the underneath of the BB there is a guide there for the front mech / rear mech / rear hydro disc hose. I wonder if I’ve messed up as there was a little white plastic pipe floating around and I assumed the cable went through that in the Guide – but wondering if it was meant to just sit round the cable in the chainstay. Could be causing extra friction. Such a **** design!

I have the same routing on my Supersix and have just rewired it and fitted a new R8000 rear mech. I didn’t cut down the rear outer supplied with the mech. It’s working really nicely with the long loop slow bend.

I would run a new cable and a longer rear mech final outer loop if I were you.

PS there is a straw under the spindle at the BB. Take the cranks off and you will see it. That saves the cable getting worn against the spindle.

I could see that straw up the downtube but can see how I can get the cable through it from the port at the top.

I’ve got it sort of acceptable shifting for now with the last few changes.

I need to invest in the tools for the cranks / BB, plus get a new super flexible rear pipe (and not cut it down this time) and have another go to try and get it perfect. Or pay Mud Dock to do it 😝

I’d easy sort it for you if your near Aberdeen

Unfortunately I can’t get much further away from Aberdeen whilst in the U.K. down in Bristol 🙁

But appreciate the offer!

On internally routed frames I always drill out the cable stops for the rear mech & run full outer from shifter to mech. I’ve had Ultegra 6800 & now R8050 on my winter bike & I think the shifting is slicker than Di2 on the summer bike.

Top jockey wheel looks miles away from the cassette. I’m not sure you need that goat link alike bit.

The instructions do say you can remove that extra link for direct mount frames and go straight into the mech hanger. When looking online it looks like the link has been kept on the 2019 caad12’s though.

I think it could make the cable routing even worse if I remove it!

In terms of running full outer I don’t think I can bring myself to take a drill to my Cannondale 😱

Why would you need to take a drill to it to run a full length outer? Just run it and cable tie to frame.

Have you got eyes though? Can’t do that to my beautiful Cannondale……

Not too bad on the 8.5 mile commute this morning. Ironically I think the front mech is setup worse than the rear as I had to loosen the cable when getting the rear internal cabling routed. Not good at front mech setup!

The root cuause of the issue seem sto be the fact Shmano have turned the part where the cable enters the mech through 90 degrees making the approach angle for the cable loop all wrong which is why it works on the older style mech in the lower photo…i have no idea why shimano did this it seems a bit of a daft design. That pulley wheel widget seems to me to be what you need to resolve the issue…bit like the pulley wheel SRAM have included on their MTB mechs.

Another option is, of course, to ditch the new style mech and go with an older style mech…they’re cheap and work just as well.

i have no idea why shimano did this it seems a bit of a daft design.

It’s a copy and paste from mtb Shadow mechs, where i’ve never heard of it being an issue. The only time I could ever see it being an issue is when the cable comes horizontally out of the chainstay…..which is unfortunately what’s going on here. It’ also just made me put the idea of getting an Ultegra RX mech on the back burner as my bike has very similar routing

As it’s a new mech I’m determined to try everything to make it work properly – I don’t want to take a loss selling it and buy yet another rear mech!

I’m going to get a new flexy length of rear outer and have a play with it all on the weekend. Might have another look at the routing through the Bb area and check that’s not causing loads of drag.

Makes me crave di2 or eTap – but it would be much cheaper just to take it to my lbs and pay them to fix it!

I went out at lunchtime to the lbs to see how they’re caad12’s are setup with the same mech as mine. They have a cable outer run a bit longer than my chopped down one but shorter than my original run pictured above. Probably about a 9” degree bend.

The lbs person also wasn’t aware the outer that comes on their bikes / with rear mechs is any different to normal cable – so I’m going to have another go this weekend with a longer piece of cable and see if that makes any different. I’m hoping I can get away with the existing inner otherwise it’s a fight with internal routing again which I don’t relish!

Don’t go for a longer bit of outer cable, make it shorter. On that design of rear mech, the point the cable outer stops doesn’t move relative to the frame (well, not very much, there _is_ a pivot there). So a big length of outer will just add more friction.

It should look more like this: