The Magura Marta SL is one of Magura's more lightweight brakes, being described as suitable for enduro, all-mountain and, confusingly, both cross-country and XC racing. The whole Marta line was redesigned for 2009, and while there's a clear family resemblance with Magura's more general-purpose Louise brakes the Marta is somewhat more stripped down in pursuit of low weight.
Reach adjust is by tiny Allen key in the traditional manner, and there's no adjustable bite point as found on Magura's own Louise BAT brakes, so you're stuck with the feel that you get out of the box. The Marta SL does get the EBP fluid port system for trouble-free bleeding, although with a five-year no leak guarantee you may never need to use it. As with all Magura brakes, the Marta SL uses paint-friendly mineral oil. The hoses are supplied at a generous length, but with care you can shorten them without having to rebleed - all the necessary bits are in the box. And of course there's the carbon fibre lever blade without which no lightweight brake can be.
The forged aluminium caliper is of the chunky style typical of Magura, with twin opposing pistons. The caliper is closed at the back, so you'll need to take a wheel out to replace the pads although a cutaway underneath lets you see how much is left reasonably easily. Something else that the Marta doesn't get is Magura's Heat Eater pivoting hose connection, although there is a choice of inline or 90° routing which should cover most requirements.
They're post-mount, with a range of adaptors available to suit different frames, forks and rotor sizes - 160, 180 and 203mm are your options there. The standard rotors are minimalist wavy items with slender spokes, but you can opt for heavier two-piece Ventidisc rotors if you feel the need for more heat dissipation. The stock SL rotors can be mounted to Centerlock hubs with the use of a Magura adaptor.
Claimed weight is 335g, although if you want to run the Ventidisc rotors you can add about 40g to that. If you want lighter, the Marta SL Magnesium uses the eponymous metal in the caliper (and a bunch of titanium fasteners) to shave 20g off. Or if you want to save a few notes, the regular Marta does without carbon fibre lever blades and is thus a trivial 5g heavier but £20 cheaper.
Out on the trail and there's certainly no shortage of power. Our test brakes came with 180mm rotors at both ends, and never felt lacking even on some pretty hairy descents. Under sustained heavy braking we started to detect a bit of pulsing from the wavy SL rotor, although it was mainly acoustic rather than haptic and didn't affect the predictability or power of the brakes.
With no bite point adjustment, you're stuck with the lever feel that Magura has deemed appropriate, which is either reassuringly positive or distractingly wooden, depending on your brake preferences. If you like lots of squoosh, shop elsewhere - the Martas are definitely on the firm side. There's actually pretty fine control available, though - you just have to recalibrate your hands.
Ups and downs
Positives: Light, reliable, powerful
Negatives: Pricey, firm feel won't be to all tastes
The Magura Marta SL brakes are solid performers in all senses. If you get on with the firm lever feel they won't let you down. At almost £200 the Marta SL makes Hope's 340g Tech X2 brake look like a steal for £35 less, although Magura's pricing is comparable to other similar brakes like Avid's Elixir CR. We'd be tempted to skip the carbon lever blade to save a few quid, although we're notorious cheapskates.