Internal routing causing poor shifting?

After some idea. I’ve got an Orbea Alma as a second mtb. Bought cheap second hand for when I don’t want to get my full suss out.

The shifting on it has always been a bit off. It shifts at the bottom (smaller) end of the cassette ok but get’s really stiff at the top end. At the start of the year I replaced the inners and outers. Clearly the engineer who designed it thought we should all be riding wireless as it was a pain – more so than any other bike I’ve done.

When I did this I checked everything out and ran it in the garage externally routed just to make sure the shifter and mech weren’t the cause. It worked fine. SLX mech and XT shifter.  However, the problem persists and is a bit annoying – I have some time now and was thinking about trying to fix it before winter.

I think it is something to do with the routing. Most likely between the BB, chain stay and mech as that was particularly convoluted and awkward I wonder if the loop out the chainstay to the mech is too tight but what I have is similar to the pictures online.  I used standard Shimano cables. They’ve always been fine in the past. But would more expensive versions actually be any better? Open to idea, I’m not buying AXS, probably cost more than the bike.

Open to other ideas. Ideally that don’t involve redoing the outers either!

Try it routed externally to check the function of the mech and after shifter properly.

Is there any way that you can dr the end caps to allow a full run of outer?

I had similar issues on a Pivot Firebird which I think I’ve sorted.

Did 2 things

(a) Ran a longer outer casing, the loop at the deraileur \ chainstay was too short (as you suggested might be the issue for you)

(b) I used a SRAM road gear cable. They’re a fractionally smaller diameter than other brands apparently.

I only made these changes last weekend so can’t say if it’s a long term solution but I had smooth easy shifting all the way up the cassette on last weekend’s spin.

P.S. I also use a tandem bike gear cable to assist changing the internally routed cable outers. Makes it an easy 10 min job rather than an annoying 1hr+ job.

(i) Cut the new outer to the required length (helps if you’ve made a note of the required length, otherwise estimate and add surplus).

(ii) run the tandem cable through the new cable casing,

(ii) Remove the old cable (leave the casing in the frame).

(ii) Run the tandem cable through the old cable casing (from the derailleur end). Note: It won’t go all the way through.

(iii) Push the new cable casing through the frame while gently pulling the old outer through (the old outer casing will guide the new outer casing through the frame)

Check strands from the outer’s ends haven’t dug in to the caps if they’re plastic – this will introduce friction. Check the mech hanger alignment.

The routing thing is hard to explain. There are three internal carbon guides. 2 at the BB and one at the head tube. There is also an internal clamp in the down tube. There’s no way to change the outer without taking off the forks and removing the BB. Even then it is fiddly. Other bikes I have done it has been straight forward using the outer/inner as a guide methodically.

I might try the SRAM stuff. I was wondering if something less stiff might be better. I know Jagwire used to be more flexible than Shimano. Or using posher PTFE coated inners if they still exist.

The smoothest inner is Jagwire’s slick polished, machined surface so it’s nice n smooth, 1.1mm instead of 1.2mm, recently fitted one in a new XTR shifter after it’s original fancy inner’s coating started coming away as it exited the rear mech, I usually use Optislick without issue, I think it’s Shimano”s best inner but the Jagwire polished is better, if a little pricey, I wouldn’t touch Shimano”s top tier polymer coated ones again.
I’ve always disliked the cable routing on the chainstay, it’s causes a crappy tight loop, some frame designers need shooting for their internal routing choices, imagine how smooth shifting would be if the cable went down the top tube and seatstay, designing it to go around the BB internally is just dumb.

It was much quicker to do the cables this time. Mostly because I knew I had to drop the forks and take out the BB straight away! Still cost me a press fit BB as it came out in bits. Probably a sign it needed to be replaced anyway.

Put in the Jagwire stuff above. Massive improvement. Last time it didn’t feel great immediately after new cables. Now it seems to work normally, just slightly heavier than my other bike. Both times I did the inner and outer.

I suppose the answer with internal gear cables is fit expensive ones that will last. It’s not like it is something I want to be doing regularly. Hopefully I can do a simple refresh with just an inner at least once. I like internal cables for looks and keeping things clean (during and after a ride) but they are a faff. My next expensive mountain bike will almost certainly be wireless sram!