One of my last projects at ENVE was helping to develop the In-Route (hidden cable) System. During the development process I compiled a list of all products that support full internal cable routing and have continued to add to it. After consulting with many builders about the subject I wanted to share it here.
HIDDEN CABLE SYSTEMS - Here’s the complete list of every internal routing product available to builders. This includes proprietary headset/stem compatibility. Please comment here or in the sheet if I missed any!
ROUTING
There are two methods of routing for aftermarket products.
Oversized Upper Bearing - Utilizing a standard 1 1/2" (52x40) upper bearing allows the cables to pass between the bearing and a standard 1 1/8" Steerer tube with adequate clearance. This is far and away the dominant standard and has been adopted by most large brands as well. The Downside? There is no standardization of the stem/headset interface so stems and headsets need to be purchased within the same design ecosystem.
D Shaped / Custom Shaped Steerer Tubes - These designs remove material from the steerer tube in order to make room for the cables. This allows for full internal routing while maintaining the compatibility with MANY standard 1 1/8" headset and stem. What’s the Catch? This design has less surface area for for both the stem and upper bearing race making it incredibly difficult to design a fork that maintains the strength and safety of a proven 1 1/8" steerer tube. Additionally these designs are limited to electronic drivetrains only. Columbus new Trefoil fork (pictures below) looks really promising and they have done extensive testing to ensure safety.
Note: Both these systems require forks specifically designed for internal routing and will feature a hole in the steerer above the crown race for front brake routing.
HEADSET/STEM INTERFACE
As mentioned above, the oversized upper bearing design lacks standardization of the headset/stem interface. This requires the stem and headset be purchased within the same design ecosystem. Pictured below are the ENVE In-Route, Deda DCR and FSA ACR Interfaces. Reference the Hidden Cable Systems doc for a complete list of compatible headset and stems.
EC44/EC44
I want to make sure everyone is aware the ENVE EC44/EC44 Cups Only (without bearings) can be purchased separately and be paired with any IS52/IS52 headset from Deda, FSA, Token etc. to make a complete EC44/EC44 system. When creating skus for the headset I made sure the cups were sold separately for this very reason. (See below for an example of the ENVE EC44 Cups paired with a Deda IS52/IS52 headset and stem) White Industries has also made some prototype cups for use with IS52/IS52 headsets.
IS52/IS52 Spec - 8.7mm Upper bearing Drop
If you’re looking to make a custom Headtube then it’s important to note the unique 8.7mm upper bearing drop used for all these full internal headsets. FSA led the charge with this spec and luckily all full internal headsets have followed suit.
FRAME REQUIREMENTS / RETROFIT POSSIBILITIES
In some cases older frames can be converted from semi internal to full internal with the products listed above. Rob English did an amazing job converting a semi internal frame he build in 2016 to full internal.
I wanted to create this as a resource but there has been some great discussion on The Great Internal Cable Routing Debate Topic already. If you have opinions on full internal routing that’s a great place to keep the conversation going.
Wolftooth has entered the chat with a EC44/EC44 Headset!
It’s designed around the ENVE Stem Interface and it looks like they prioritized the EC44 design to make it as low stack as possible. Other options like the ENVE and FSA Headset use a taller stack so the cover is compatible with both IS52 (8.7mm) and EC34.
“HIDDEN CABLE SYSTEMS” google sheet above has been updated along with some of the new swath of bar/stem options
New Fork
The all new EXS FK-00 fork has been added to the HIDDEN CABLE SYSTEMS link above! This fork introduces a third method for internal routing 1 1/4" D Shaped so I thought it warranted it’s own post.
Steerer - D shaped 1 1/4" to 1 1/5" Tapered
It uniquely uses a 1 1/4" upper with a d shape. Their claim is that bumping up the diameter from 1 1/8" to 1 1/4" creates more surface area for the stem clamp and headset and makes the D shaped interface safer and stronger than 1 1/8" D shaped options.
Stem Options
There are a number of good 1 1/4" stem options available but you are somewhat limited. Both Giant and Canyon use 1 1/4" Steerers and stems on most of their drop bar bikes so availability will be good for the foreseeable future. All the 1 1/4" stems that allow for the full pass through routing have been added to the sheet.
Headtubes (requires at least a 42mm OD upper bearing)
̶E̶C̶44̶/̶̶E̶C̶44̶ - Edit* After some consideration I don’t think a 44mm Headtube will be compatible. The larger 31.8mm steerer only leaves about 6mm inside the headtube for the rear brake cable which is too close for comfort.
Headsets
This is where things get weird. Conventional wisdom tells us that IS41 and IS42 upper standards are for 1 1/8" only. HOWEVER, Both Giant and Canyon use IS42 Headtubes and 1 1/4" steerers with custom FSA IS42/31.8 Headsets.
IS42/IS52
– Upper - FSA No.54 Upper Assembly
– @opticspen pointed out that this headset cover is designed around giant’s non-standard 47.6mm OD and 6.5mm bearing drop (vs standard 46.5mm OD / 3mm Bearing Drop) so a custom 3D printed bearing cap/cover will be REQUIRED.
Aesthetics This is purely subjective but I think this will be the best looking full internal system available. Compared to 1 1/8" D shaped steerers like Columbus, the larger 1 1/4" steerer and spacers will be much more proportional to the headtube. Compared to Oversized Upper Bearing systems like ENVE with the 44mm wide (profile view) headset spacers, it’ll be a huge improvement. (speaking purely about aesthetics)
Justin from Speeder Cycling have bunch of great fork, great build quality, ISO test, 2 years warranty, and reasonable price point. I’ve use their fork for all my base/default build.
Also seen their fork in some builder/brands bike such as Triton, TrueLove, and Stinner.
The bars require internal routing with an exit hole at the stem similar to below. Most brands are good about calling out internal routing in their descriptions but the hole in the back of the bar is the easy indicator.
I’m leaning towards 44mm straight head tube now, seems an obvious choice for metal frame.
for upper headset, seems M Part is the obvious choice. however lower headset, I can use any EC44/40? saw wolf tooth have a good one, and enve? or any other brand?
one final question, if I go with EXS FK-01 fork, I noticed the bottom size of the steerer tube is different than FK-00? what type of lower headset that requires?
the only reason I’m thinking FK-01 is tyre clearance, FK-00 is 30mm which is not bad, but worried about what if I want a 32mm tyre?
thank you so much
Hi Kevin, thank you so much for the list, very helpful!
BMC has its own system (in collaboration with FSA) and they have a very cool internal cable stem (made with Redshift) BMC Stem ICS2 MTT Black – BMC Switzerland. I am not sure what headset system works with it but it looks like IS42/IS52, but please double check as I am not an expert (FSA, HS-B-13P, upper bearing 30.5 x 41.8 x 7.5 ; 45x45°; lower bearing 40.0 x 51.8 x 7.5 ; 45x36°)
Hi Lorenzo, Yeah that’s a really cool stem! I didn’t add it because there isn’t a universal headset available to use it with non BMC Bikes.
That said there are many companies and individuals 3D printing “transfer spacers / transition spacers” allowing you to match a stem and headset from different interfaces.
Bike Tester James Huang printed a FSA ACR To BMC MTT spacer so he could use that stem on his Framework Bike! I would first reach out to him and if you can’t get your hands on that spacer, one the companies below will get you sorted!
New to the forum! This is the first time i’ve seen someone mention this. I’m sort of looking to internally route my custom steel CX bike for aesthetic reasons. The headset is EC34/44 which sort of complicates things. Would it be possible (ignoring adviseable) to internally route with a D shaped steerer?
Im fine with cutting things close and having them be janky, having dimpled chainstays and drilled holes for cables post hoc.
Just want to know: is it technically possible at all?
Hi Metallfisk, That comment is referring specifically and exclusively to the EXS FK-00 Fork from that individual Sep 2024 Post.
Reference the initial Dec 2023 post for everything you need to know about all other Internal / Hidden Cable Stems, Headsets and Forks Compatibilities.
EC44/EC44 is without doubt one of the most common headtube styles for full internal routing and will work with every other internally routed fork on the market. Feel free to DM me with specific questions.
I’m in the process of purchasing a new OEM-built titanium frame from Wittson, and I would appreciate some guidance regarding fully integrated cable routing for a Rohloff Speedhub setup using GEBLA and SRAM shifters.
My main question is whether standard wired brake and shifting cables can be routed internally through a cockpit such as ENVE In-Route, and what frame or fork provisions the builder would need to include to accommodate this.
Key points:
Standard mechanical brake and shift cables (no wireless)
Rohloff Speedhub with GEBLA SRAM shifter system
Three cables need to be routed internally and exit at the rear of the frame, near the usual disc-brake exit point
Priority is a clean, fully integrated appearance
Specifically, I’m interested in:
What internal routing channels or guides need to be added to the frame
Whether additional space or access ports are required in the head tube or down tube
Any known limitations with ENVE In-Route for this type of setup
I’d appreciate any feedback or recommendations, as I want to ensure the final build is as clean and well-executed as possible.
As I’ve never worked with Enve In-Route systems, I can’t say with certainty whether all four cable housings will pass through the stem and headset.
A key consideration with any mechanical brakes and gears is that you want to minimise the total direction change in the cables, and keep radii as big as practically possible. Each bend adds friction, and a tight bend increases the friction significantly. Aiming for a few big sweeping loops in the housing is preferable to several tight bends, and this will not be possible when considering a fully internal configuration. You’re essentially compounding the negative effects of the two things shift and brake housing do not handle very well - many bends AND tight bends.
For the brake housing, you’re probably also going to want to use high-quality compressionless housing. Something like Yokozuna Reaction Compressionless Housing. It made a night and day difference on my mechanical setup.
The downside is that this housing is quite stiff, and may not like the tight bends that are likely to be required in order to run the brake housing internally.
I’ve built and serviced a couple of bikes with a Rohloff/GEBLA/SRAM Force configuration. From experience, the operation of the Roholff shifting via the GEBLA unit, is already quite tight - even with externally routed cables with nice big bends.
Part of this is the force needed to get the shift mechanism in the Rohloff hub to turn. The customer who’s running this setup has snapped his shift cables multiple times. Part of the problem may be his shifting technique, but the fact that quite a bit of force is needed does not help. I personally think that the added friction from introducing a few more tight bends in the housing will make things a fair bit worse.
From a practical point of view, as far as the construction of the frame goes, you’re going to have to make sure that the vent hole from the TT to the DT is as big as possible. You’re also going to have to consider how you’re going to fit all three cable housings through the BB and into the chainstay without interfering with the crank spindle. This operation is already quite tight in a standard T47 BB when routing only a single, more flexible, hydraulic brake hose into the chainstay - so I can only imagine how tricky it will be to get three pieces of stiff mechanical brake and shift housing through the BB and into the chainstay.
Thank you for your feedback. Based on the response from Framebilder, we’d like to propose the following solution:
Headset and Stem:
We recommend the ENVE In-Route stem paired with the Wolf Tooth EC44 In-Route headset. This headset design provides superior cable capacity (4 cables) compared to the FSA ACR or Deda DCR alternatives.
Cable Routing:
∙ Rohloff cables: Full internal routing from cockpit through the downtube, with an exit port positioned near the bottom bracket. From there, external routing via the chainstay.
∙ Disc brake: Fully integrated internal routing with chainstay exit.
Technical Note:
Drilling three exit ports on the chainstay (2× Rohloff + 1× disc brake) would significantly compromise structural integrity and risk cracking. The proposed configuration avoids this issue while maintaining clean routing.
Yup.
That seems to be the way to go if hidden cables are a requirement.
I would personally avoid this setup as I believe it’s asking for trouble - especially considering the Rohloff & GEBLA shifting stiffness that may mean you’ll have to replace cables a lot.
