Longtime readers will know that with Hyro, my 2014 Giant TCX SLR 2, I had a couple of trepidations. First, it was designed around press-fit bottom bracket bearings, and second, it routes all but one of its cables internally. After two sets of cranks and bottom brackets, my fears of the former were allayed…but I did not know what to expect from the latter.
Seeing how the LifeCycle mechanics used to wince when I sent Hyro in for replacement of a frayed and broken rear shift cable…I went through the process of discovery in a rather tentative manner. The LifeCycle guys never even touched Hyro’s cable housings, and they stayed in place for almost four years, with only the inner cables being swapped out. I found out for myself the aggravation of swapping Hyro’s rear shift cable for the first time as it ran through the drive-side chainstay. Subsequent inner cable swaps went smoother, but when horror stories abound about how it takes many professional bike shop mechanics at least 45 minutes fishing a cable out of a frame’s routing holes, I was dreading the prospect of having to perform a full cable replacement a little.
While looking for anything to help my odds of a successful DIY cable replacement operation, I came across the Park Tool IR-1, which was launched at the 2014 Eurobike trade show…and I just knew I had to get it for myself someday.
- Three guide cables, each 250 cm long, all with magnets at one end
- Threaded barb adapter
- Rubber sleeve adapter
- Bare guide cable
- One guide magnet
- Plastic carrying case
The IR-1 is the logical extension of bike mechanics’ tips and hacks when dealing with running cables through a bike frame with internal cable routing: tying cotton thread to an inner cable and using that to pull the cable through, or taking a more direct approach with a strong rare-earth magnet. What Park Tool did is to incorporate these tricks and build them into a dedicated tool.
All the guide cables have a magnet at one end. At the other end awaits either a rubber sleeve, a threaded barb, or nothing at all (just the bare guide cable). You can use the rubber sleeve to grip electronic shift wire or cable housing from outside, or screw the threaded barb into the cable housing’s inner lining and grip it that way, which is my preferred method. These should also work with hydraulic brake hose. The adapter-less guide cable is meant for use in places where the cable routing holes are just too small for anything else to work.
The fourth item is an anodized blue handheld “guide magnet” about 5 cm long…and this thing is pretty strong. The way it attracts itself to anything made of iron or steel, I’d guess it’s made out of some rare-earth metal such as neodymium – traditionally used for applications that require strong magnetic attraction properties.
Generally, Park Tool recommends the IR-1’s guide magnet to do most of the work of routing and navigating either the guide cables or bare inner cable through the frame. Best results involve a push-pull motion, pulling with the guide magnet while feeding the guide cable in. Once that’s through, any cable housing attached to the guide cable can follow suit.
The guide cables are all strong enough under tension. While pulling cable housings through the routing holes of a frame, they were in no danger of snapping…even when you’re negotiating stubborn compressionless brake housing out of a tight cable routing hole.
When I replaced all of Hyro’s cables by myself for the first time, it took me about three and a half hours for the whole job – and this is with the IR-1 helping me out. Imagine how much longer it might have taken me had I not had this tool at my side. Six cable routing holes, three sections of cable housing, 45 minutes spent fishing housing from each hole…you can do the math. Had I not had this tool, I may have been permanently put off from performing DIY cable replacement altogether. I can only imagine how much of an investment this tool can be if part of your everyday job requires that you re-cable other people’s bikes with internal routing.
The video below is the final persuasion I needed to buy the IR-1, as the second demonstration bike featured is a 2014 TCX SLR 1 – an identical frameset to Hyro in everything save for the 15 mm through-axle fork.
As Park Tool themselves will tell you, you can’t actually buy the original IR-1 brand-new any more. They’ve replaced it with the IR-1.2, adding a fourth guide cable that they say is better meant for the wires of either a Shimano Di2 or Campagnolo EPS electric-shifting groupset. It also adds around US$10 to the original US$60 price. Frankly, I’m not sure it needed the upgrade, as the IR-1 was already capable of dragging Di2 or EPS wiring through a frame.
If it’s not already obvious, I highly recommend this tool if you’ve got a bike frame with any internal cable routing at all. If you run a local bike shop, and you believe that time is money, not availing of a couple IR-1s is the equivalent of leaving money on the table. I liken the IR-1 to a torque wrench: it can feel expensive at the outset, but it’s so essential at what it does and has very little in competition that it’s easily worth its price.