Know Your Brake Lines...................
You’ve probably bled your brakes or changed your pads in a bid to up your bike’s anchorage, but what about changing your lines? Venhill’s Max Adam talks us through the virtues...
FB: What is the role of a brake line?
MA: These days most bikes come fitted with disc brakes and a hydraulic braking system. The way the system operates is that when you squeeze the brake lever, brake fluid is forced through a hose until it reaches the calliper, where a piston pushes the brake pad against the brake disc, creating friction for braking force which in turn slows the bike down. Essentially, brake lines create the vessel to get the fluid to the caliper.
FB: So cable operated brakes are no good?
MA: It is possible to use a cable operated system on a bike, as was done over time for generations, but these would struggle to cope with the pressure required to slow down 200kg of bike at speed. Admittedly, cable operated brakes are much simpler and easier to maintain, but they can’t facilitate anywhere near the same performance as a hydraulic option. The fluid is pumped by a master cylinder’s piston to accentuate the pressure applied to a caliper’s piston and allow for much more stopping power. FB: How good are standard lines?
MA: Rubber brake hoses are typically standard fitment on most motorcycles and they’re okay when new but become prone to expansion under pressure with age, which means you need to pull the lever in further to achieve the same amount of pressure. Over time, rubber will perish, harden and crack, which can allow water to seep into the brake fluid. When the fluid heats up during operation, water in the system turns to gas, creating the air pockets that make the brakes feel ‘spongy’. Not good for anyone.
FB: What’s the main benefit of steel braided lines?
MA: Braided hoses are made up of a flexible Teflon tube, which is heat resistant and won’t perish for a very long time. It’s wrapped in a stainless steel over-braid, which prevents expansion under pressure unlike their rubber counterparts. Due to their construction, braided lines completely eliminate swelling under heavy braking, even when the brake fluid reaches the extremely high temperatures experienced during racing, as there’s no room for expansion. So what you squeeze is what you get, in essence. That’s why race teams fit them – their riders need reliability and consistency throughout the whole race distance.
FB: Why are they made from stainless steel?
MA: Quite simply it’s just way more resistant to corrosion. That’s important, not only for appearance, but also to maintain the integrity and the longevity of the line.
FB: Would you get any advantages on the road from aftermarket brake lines?
MA: Braided brake lines are a practical upgrade for road riders – not only will they improve performance even on general braking, but they should literally ‘last a lifetime’. Apart from bleeding occasionally, they won’t require any maintenance or need replacing, unlike the standard components.
FB: What’s the difference between stainless steel and zinc fittings?
MA: In performance terms, absolutely nothing at all. In the long term however, stainless steel
fittings will stay looking good for longer which is always a bonus. In price terms, stainless steel is more expensive though.
FB: Are there any advantages of making lines specifically to order?
MA: If you’re simply replacing a standard set-up, then an off-the-shelf kit is probably best as the whole configuration is still similar. However, if you’ve modified the set-up (higher/ lower bars, changed the forks, etc. like you would on a race bike) then it’s always worth going made to measure, just like you would with a set of leathers if you were searching for that perfect fit. Custom lines aren’t always necessary, but they’re there to ensure your bike is as safe and functional as possible. If your hoses are too short they could restrict the degree of movement from the bars, and being too long might risk them snagging on something.
Cable operated lines are best kept in museums.
Braided lines don’t flex or perish like rubber hoses. Pick a colour, any colour... If your hoses are crap, your braking will be crap.