The Kevlar Debate For Brake Lines

Many of our customers ask us why we will not sell Kevlar® reinforced brake lines for the motorcycle or performance/racing marketplace and the answers are simple.

For a start, it is extremely hard for Kevlar® Hoses to pass the strenuent FMVSS-106 Tests. Although our original hoses have passed, this was only with the Stainless Steel reinforced Teflon Hose. If we were to change, that would mean submitting the same again for seperate certification based on materials used in the original assembly when tested for compliance. But thats not all.....

Kevlar® is an Aramid fiber introduced by DuPont® in 1971. Kevlar has become a predominant fiber in the high performance racing sector for many parts such as body armour and fairings. It is stronger than steel for its weight and has a modulus that is five times greater than polyester. When Kevlar® was first introduced there were two types: Type 29 and Type 49 (High Modulus). Type 49 has a 50% higher initial modulus than Type 29 and lower flex strength. Other Kevlar® styles (Types 129, 149 and 159) have also been developed but are less used since the higher strength goes hand in hand with lower flex strength.

 But....

Additional drawbacks of Kevlar® include poor UV resistance (Kevlar® loses strength roughly twice as quickly in sunlight as polyester and, when affected, the gold Kevlar® fibers turn brown) and rapid loss of strength with flexing, folding and flogging.

As you can see this product needs to be covered so that UV sunlight does not effect it's strength and reliability. Therefore all brake lines which are sold as a Kevlar® (or Aramid if the company does not use the original DuPont® designed Kevlar® and only a copy) must have a pvc cover on the outside to protect the Kevlar® from UV rays.

This also means that if a stone flicks up, which when riding a bike is quite likely, and cuts or removes some of the outer protective cover the Kevlar® braid will be exposed to UV and lose strength. This fact coupled with the fact that Kevlar® has rapid loss of strength with flexing (and how many times will your brake lines flex with the movement of suspension) make this, in our opinion, an inferior and dangerous choice when considering the best materials for use in brake lines - After all this is what makes your motorcycle stop...

You have been warned and the choice is yours but we will NOT sell Kevlar® or the unbranded 'Aramid' hoses for your motorcycles or any vehicular brake lines. We repeat the following statement again:

'Additional drawbacks of Kevlar® include poor UV resistance (Kevlar® loses strength roughly twice as quickly in sunlight as polyester and, when affected, the gold Kevlar® fibers turn brown) and rapid loss of strength with flexing'.

Kevlar® is great in the correct environment but not as a cover or reinforcement for motorcycle brake lines - You have been warned. They may offer you a few grams of weight saving but is it really worth it ? The few race teams who use Kevlar replace every line after each event so the flexing / UV issues are not valid but do you want to replace your lines every month?

HEL and ALERT only ever use stainless steel or Titanium fittings on stainless steel hose with stainless steel or Titanium bolts offering no loss of strength when subjected to UV. So Ride the best you can - Fit HEL / ALERT Performance Brake Lines.

nb. Kevlar® is also used in the manufacture of the Aeroquip StartLite® Hose. This is then covered by Nomex® braiding to add additional shielding. That on top of the fact that normally these performance hoses are NOT subject to flexing as severe as Brake Hoses, nor normally exposed to UV. For further advise please contact our Technical Staff.

return to brake line page

return to home page

Kevlar® and Nomex® are registered trademarks of DuPont®

StartLite® is a registered Trademark of Eaton / Aeroquip