First Look: BTR’s Brazed-on Steel Brake Lines. Taking Integration To Another Level.

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Michael Braybrook caught up with Tam from BTR to quiz him about his prototype, integrated brake line, hardtail.

Tam and Burf of BTR Fabrications quickly made a name for themselves in 2012 with the release of their bold genre-busting Belter frame featuring some pretty outrageous geometry figures, even to contemporary standards. Six years on and it seems the fire inside that drove them to push boundaries still hasn’t gone out with the first test prototype of their hardline rear brake. We managed to hold Tam down for five minutes to find out more.

So, let’s get right into it. What is it?

It’s a piece of stainless steel tube brazed onto the frame, to replace the majority of the rear brake hose.

Looks like a normal hardtail, eh? But look closer…

Any particular reason? I’m presuming there’s an advantage to doing this?

Yeah, so we’re often looking for greater integration between components and the frame – if it results in better performance. Our internal cable routing goes a little way towards this, where we brazed in a thin tube to guide the rear brake hose through the frame, but with no performance gain. Using a rigid steel tube instead of a plastic, or even braided, flexible hose should give a definite increase in stiffness of the hose, therefore a firmer lever, more like you get from the short hose on a front brake.

And does it work?

Hard to say so far. It seems like the connectors that join the flexi hose to the solid line trap a bit of air, so I haven’t managed to properly bleed the system yet. I’ve had it feeling at least as good as the front brake, but it didn’t stay like that for long during testing at Bike Park Wales. It lasted the day with no leaks, but I did have to pump the lever a bit to keep the bite point away from the bar in my last couple of runs. It would be easy to sort the connectors so that they at least trap a lot less air – this bike just has ones that I machined up quickly, so aren’t particularly accurate.

See, under the top tube? That’s a brake line, that is… Neat internal dropper routing by the way…

So this one’s quite an early test model at this stage then – did you find any downsides so far?

In use, none other than the bleeding woes. However there’s clearly some possible issues that we’d want to work on; any failure of the welded part of the system requires metalwork on the frame, as well as the initial brown-trouser moment if the worst happens. Failure is arguably more likely since there are twice as many joins in the hose, and there are even questions around fatigue life of the hard line, since it’s rigidly attached to the frame, but that’s the point of testing it so we can work out these kinks before releasing it.

Threaded mounts on the top tube take the flexible hose, just like in a car.

Is it something you’re hoping to offer on future bikes? Can we expect to see it on the BTR spec sheet any time soon?
If it works well – makes a worthwhile difference to the performance of the bike, and can be proven to be extremely reliable and durable, then we’ll try and bring it into production. A lot of ‘ifs’ there though.

Stand here and look awkward will you?

Has anyone tried anything like this before then or are you guys the first?

I’ve seen it once before, on a Titchmarsh custom frame. That said, every car on the road has a similar layout of flexible hose and steel lines, so it’s clearly a sensible move. The main issue is miniaturising the automotive system for bike use, and assembling it in a way that’s reliable.

Is this the longest brazed joint in the UK?

What’s the plan for the future with it? Can we expect to see other manufacturers having a go?
For now, I think we’ll just run it on our own personal bikes. There are too many unknowns to build a customer’s bike with it. Maybe some other small manufacturers might give it a try, but I doubt any of the larger guys will bother themselves with the risks involved, not yet anyway.

So flowy. It’s like a bodybuilder’s arm vein…

Can we expect to see anything else from the BTR workshop soon then?
Ranger Plus is the next announcement I guess… or the Roamer fat bike. They’re pretty much ready to go, so it shouldn’t be long for either of them! We’re always working on ideas, so it’s worth keeping an eye on our Instagram or Facebook. New stuff tends to appear there before anywhere else!

Check out: for more gossip.

Chipps Chippendale

Singletrackworld's Editor At Large

With 23 years as Editor of Singletrack World Magazine, Chipps is the longest-running mountain bike magazine editor in the world. He started in the bike trade in 1990 and became a full time mountain bike journalist at the start of 1994. Over the last 30 years as a bike writer and photographer, he has seen mountain bike culture flourish, strengthen and diversify and bike technology go from rigid steel frames to fully suspended carbon fibre (and sometimes back to rigid steel as well.)

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Comments (7)

    Vertigo did similar with internally routed Ti tubing. Worth checking with Sean how he got on with it?

    video on sean’s bike. the brake worked extremely well – and to my knowledge still is. doing it internally was pretty hard work and I don’t think he ever wanted to do it again! but the hard line concept is pretty cool.

    I can only applaud these kind of innovations and testing them before releasing to market.

    It has the potential to be very neat, sleek, and free of cable rub.

    However part of me is concerned at the exposed nature of the brake pipes on the concept – take a tumble or flick a rick up and you’ve potentially dinged or broken your brake pipe. I’d suspect a hose would have more ability to absorb an impact or deflect from damage. Of course damage to the hose is still a possibility.

    Would they consider routing the pipe internally to improve aesthetics and to mitigate this? But you then have the pipe in a position you can’t inspect it!

    And swapping brakes over has now become a much more complex job.

    My personal preference is tidy external routing for full-length cable and hoses – but i’m sure just as many would want everything internal.

    Photos on their facebook look like silver soldering rather than brazed 🙂

    My concern would be dealing with internal contamination after “brazing”. The flux is on the outside to keep the hot surface clean but the unprotected inside might get a bit cruddy and oxidised. Could flux internally I guess might still be a pain to clean out.

    Otherwise a nice idea. I’ve done twin 12.5mm top tubes before (one piece from head tube to dropout). I vaguely considered putting a brake hose fitting each end and just filling one with fluid!

    Is there a sensible method for flushing the hardline if you were to switch from brakes that use DOT brake fluid to brakes that use mineral oil or vice versa? Or does simply draining the line leave everything clean enough to avoid any fluid contamination?

    @hopkinsgm Erm, I think you may have just described a suitable method? (it’s flush the lines btw…)

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