Birzman Internal Cable Routing Kit

The Birzman Internal Cable Routing Kit is a sleek and well-executed package that has pretty much everything you need to manage internal routing jobs. However, Unlike the Park Tool equivalent, it doesn't include any sort of flexible lead cable.

A few years back Liam rated the £70 Park Tool 1.2 Internal Cable Routing Kit very highly, praising its ability to make otherwise fiddly internal cable routing jobs quick and easy.

Yes, the comments attracted the requisite 'I do this with a shoelace, paperclip and blob of Blu Tack' responses, but having owned the Park Tool kit for a few years, I agree with Liam that Park created a winner. So I was very interested to see what Birzman could do to improve the routing experience with a product at two thirds of the price.

The first major difference is that Park gives you a bunch of thin, strong, flexible cables, each with a different interface on the end, such as Di2, a threaded barb, a magnet and the like. Birzman doesn't give you any lead wire – so you need to use the existing cable/outer/hose to draw the new one through. However, if the routing is particularly torturous (I'm looking at you, Giant Propel front mech) then you might not be able to meet your needs in one go.

One end of the sleek alloy tube contains a strong magnet. There's a fluffy pad on the outside of the threaded cap that prevents you from scratching your frame as you run the magnet along the surface, drawing the desired cable along inside. Inside the cap there are five holes, one for each of the kit's adaptors.

Two of these adaptors – for Di2 and shift/brake hoses – screw into a short lead wire that ends in a magnet. A third and fourth adaptor thread together to clamp on the end of a metal 1.2/1.5mm gear or brake inner cable, while the fifth adaptor is a double-ended conically threaded joiner that screws into a gear or brake outer.

This is the really interesting – and frustrating – one for me. If you have an outer – whether shift, brake or hydraulic hose – already in your frame, it's perfect for drawing the new outer or hose through the frame. Of course, silicone spray or grease is handy on the new outer/hose to help it draw through nicely, but just how do you join the old and the new?

In-the-know mechanics have long been aware that Rock Shox makes a £3 hydraulic hose joiner that makes replacing a dropper post hose easier. Birzman has used that idea here but frustratingly, and possibly for legal reasons, Birzman has omitted the key feature.

The Rock Shox joiner has opposing threads, so when you hold the old and new outers together on each end, turning the joint threads into both outers at once – it's easy. The Birzman has matching threads, so you need to thread it fully into the old cable, then twist the new one around and around it to thread it on. Doing this with a 50m boxed reel of outer weighing five kilos is a faff.

That said, once the old and new outers are joined up, you can haul along with a fair bit of force. Again, lubing the new section makes your life easier, as does pushing and pulling simultaneously. It's eminently satisfying to replace the outer or hose quickly and painlessly without having to dissemble a bottom bracket or – worse still – remove an e-bike motor to achieve this. It's still not a total guarantee of success though, as some routings are just too tortuous.

The adaptors that screw over the end of a shift or brake inner wire are steel, so don't need a magnet to be attracted through the frame. I found threaded them successfully on the first attempt most of the time, only occasionally needing a second or third go. And while the magnet isn't quite as strong as the one in the Park kit, it does the job.

> How to replace a gear cable

To thread a new outer or hose through your frame without one to act as a lead wire, you thread the single-ended adaptor into the new outer and thread that into the flexible short magnet-ended lead wire.

There's a few centimetres of flex, which is enough to bend around things inside the frame.

There's a matching flexible opposing-magnet-ended gooseneck section that you can poke into the destination port to help attract the new end that you're threading through the frame.

The opposite end of the Birzman tube contains an awl that you can use to splay the end of any outer. In practice this worked well to tidy up cut housing ends.

Value

During the few months I used the Birzman kit I sometimes found it easier to use than the Park Tool that Liam liked – but not always. The 1.2-1.5mm inner cable clamp that is unique to Birzman does work very well, but if the frame is particularly challenging and you need a very thin lead wire to start, the Park is the way to go.

The £22 LifeLine Internal Cable Routing Tool looks a strong contender for value, as it includes a lead hose, but it does lack an inner-cable lead or outer jointer.

Hollis was impressed with the KranX Internal Cable Routing Tool when he tested it recently. This costs £27.99 and while there's no attachment for regular inner cables, he found the included magnet guide tool would do the job.

For around £15-16 Amazon has numerous routing kits, with or without lead wires, such as this Besnin cable routing kit for £16.45, or this £12.44 model also from Besnin.

Overall, for £46.99 the Birzman Internal Cable Routing Kit is a tidy bit of kit. The absence of lead wires means it won't solve all your internal routing challenges, but it will work in many workshop situations.

Verdict

Chances are the Birzman kit will sort nearly all your routing needs, but as with all kits of its type it's not perfect