Headset cable routing is a divisive topic, with some riders and manufacturers quickly getting on board with the trend for integration, while others have been hostile and remained loyal to routing cables in a more traditional manner.
Cast your mind back a few years, and some bright spark decided it was a good idea to start routing cables through the top headset bearing.
Bring things forward to today, and almost every road bike is fully integrated – to varying degrees of complexity, because there’s no unified standard for front-end integration – and an increasing number of mountain bikes have followed suit.
It’s a topic we’ve explored before – first through the point of view of bike shop mechanics, and then from the perspective of bike fitters.
However, as BikeRadar’s resident workshop manager, charged with looking after the test bikes that arrive with us, I wanted to share my hands-on experience of working on an integrated MTB for the first time, for a video shot for MBUK’s YouTube channel.
You can watch that video below for a full account of the process, and go and subscribe to the channel while you’re at it.
To find out what impact integrated cable routing has on bike maintenance, whether you’re a pro like me or a home mechanic, I set about changing the headset bearing on a Scott Voltage eMTB. Usually, this is a 10-minute job for a competent mechanic, but add a snakes' wedding of cables and who knew what challenges I faced?
- Read more like this: Opinion | Internal cable routing has gone too far
What’s the point of integrated cable routing?
But let’s back up a bit. The typical options when it comes to cable routing on a bike are:
- Fully external (pictured above): with the gear and rear brake cables running along the outside of the down tube. This used to be the go-to method for routing, but is much rarer these days.
- Internal routing (above): with the gear and rear brake cables staying external at the front end of the bike, before being fed inside the down tube to make their way to the rear of the bike.
- Integrated routing (sometimes called headset cable routing, above): where everything is hidden and typically routed through the headset – that’s what we’re talking about here.
So why have so many bike manufacturers adopted the trend for integration?
When it comes to road and gravel bikes, there can be a small aero benefit to tucking the cables into the frame right below the stem. However, in a mountain bike application with a wide bar, a more upright riding position, baggier kit and large tyres, any aero benefit is unlikely to be noticeable, if relevant at all.
When it comes to the aesthetics of modern bikes, visually the clean lines of a bike with headset cable routing are impressive, without flapping cables sprouting from the down tube. I’ll admit to that.
There’s extra protection from damage, too; hoses and gear cables are better protected from rock strikes and crash damage – and less likely to be impinged or severed if they’re encased inside the frame tubes.
And, finally, as a more oblique benefit for the rider, engineering a bike with holes in it, to run more conventional internal cable routing, is more difficult.
Manufacturers can choose between making a weaker frame, or adding material around the routing holes to maintain the same level of strength. Bikes with headset cable routing can, therefore, be lighter and/or stronger than bikes with internal routing, some manufacturers claim.
But do these potential benefits outweigh the difficulty of working on such a convoluted system?
Putting my patient under the knife
As I’ve already alluded to, the Scott Voltage – introduced a year ago as Scott’s answer to the lightweight electric mountain bike – is far from the only mountain bike (let alone road or gravel bike) with an integrated front end, but it’s my patient for today.
The Voltage in question has four cables that must travel through the upper headset bearing:
- The cable-actuated dropper post (SRAM’s electronic gears are wireless)
- The electric wire to control the TQ motor
- A cable for the twin-position shock-lockout system
- The brake hose for the rear hydraulic disc brake (the front brake hose runs outside the headset down to the fork leg)
Typically, changing a headset bearing would simply mean removing the stem and the fork, and sliding in the fresh bearing before reassembling everything, with no cause to mess with any of the cables. In the case of the Voltage, however, all of the above come into play.
Stripping the bike, I found myself calling upon the skills I’ve picked up from 23 years as a mechanic – but that’s not the kind of knowledge the average home mechanic would necessarily have or be able to find in an instruction manual.
Starting with the brake lever, it wouldn’t fit through the upper headset bearing, so I had to disconnect it and prepare to bleed it after changing the bearing.
However, the TQ ebike controller was easy to disconnect, and the electrical plug was tiny and easy to fit through the bearing.
The dropper post, meanwhile, should have been straightforward to change, but unfortunately, as I removed the remote from the cable, the end of the cable turned out to be badly frayed. This meant I needed to shorten the inner and outer cable to make rethreading it into the remote possible on reassembly.
The lockout was the hardest part of the process to tackle. Complicating matters, the Scott Voltage has a hidden shock and the lockout cable attaches to the shock way down inside the tubes of the frame. This leaves a nipple with no method for removal at the handlebar lever end.
I elected to take apart the remote lever, with the cable still attached, in order to fit the various pieces of the remote through the inside of the bearing. This was nerve-wracking, but thankfully there were no coiled springs or detent balls to explode and it was straightforward.
Reassembly, however, was more challenging. I had the distinct impression that I wasn’t supposed to disassemble the remote without relieving the tension from the cable, but with careful surgery, I managed to put the remote lockout lever back together in working order.
Ninety minutes later, the bearing was changed.
What did I learn from all of this?
With the bike back together, it was time to reflect on the process. Bikes with headset cable routing look great, but is it worth the extra effort when working on your bike?
In terms of changing the Voltage’s headset bearing, this relatively simple process became much more challenging, both in terms of time and complexity.
In reality, this isn’t a job that needs doing more than once a year or so, but it’s still important to bear in mind when deciding if you want a bike with headset cable routing or – if you have the option – a more traditional system.
On bikes with headset routing (and arguably some older bikes with internal routing where the cables run through the head tube), the cables run very close to the soft material of the steerer tube, which means a poorly routed cable or an extreme steering angle could cause them to rub.
While this isn’t a problem in small doses, it’s possible that in extreme cases, this rubbing could weaken the steerer tube as material is removed. Thankfully Scott has included a plastic mesh cuff over the steerer tube to protect it from cable rub, so top marks on that front.
It’s also worth mentioning that integrated cable routing can create a path for water and dirt to enter your bike. Again, Scott has looked to deal with this problem with two extra, external dust shields under each bearing, but it shows how brands are having to find solutions to these problems.
This is just my viewpoint from tackling one maintenance job on one bike, so I’m really interested to hear where you stand. Are you all-in on integration or loyal to external routing? Do you work on your own bikes or do you phone your local mechanic at the first opportunity, credit card in hand? Let me know in the comments below.
