This is Evil Bikes’s new Revolt downhill frame, which represents a departure for the Seattle-based company in all sorts of ways. It’s not steel, it’s not a hardtail and it’s not all straight lines, for starters.

Thomas Vanderham has been riding various incarnations of the 203mm travel Revolt for a couple of months now. The frame seen here is actually an earlier (but considerably less battered) prototype, which is partly why you’re seeing it from a less-than-informative angle – most of the back end will be considerably different, and Evil’s Gabe Fox quite justifiably asked that we didn’t show too much of it, because, well, it’s wrong.

The suspension design is by Dave Weagle, but it’s not DW-Link. The Revolt uses a new Weagle system called Delta, which features a floating shock mounted between the single-pivot swingarm at the back and a small rocker and linkage at the front. Cleverly, the shock passes straight through the main pivot, which is actually two pivots side by side with a shock-sized gap between them. The Delta system has two main characteristics – highly-tunable ramp-up at the end of the stroke (which is where, we’d guess, the name comes from, as the Greek letter delta is used by clever numbery types to symbolise changes in values) and infinitely adjustable frame geometry without affecting the characteristics of the suspension. The shock is mounted using reversible “chips” at both ends – flip the chips and the frame sits lower, but the rate curves and all that stuff stay the same.

Adding to the adjustability is the split headtube, allowing the head angle to be tweaked between 64 and 66°. The frame is also said to be impressively light by DH standards, with a 38lb build perfectly possible “without going stupid”. The Revolt should be available around May in a choice of painted or anodised finishes, with shorter-travel all-mountain models based on the same design rolling around a little later.

On the subject of Evil, the company’s infamous Sovereign hardtail has been revised for 2009. As well as details like the profiled headtube and logo stamped into the end of the top tube, the original Sovereign’s 853 tubeset has been replaced by Japanese-made Tange plumbing. The main effect of that will be a considerable drop in price, from a pretty chewy £850 to a more accessible £595.

Evil Bikes come to the UK via Silverfish – have a look at www.evil-bikes.com or www.silverfish-uk.com for more details.