The Aeris Mk1/Mk1.5

Please note that the Mk1/Mk1.5 Aeris below has been replaced by newer versions. Please visit our homepage for the latest bikes!


The Aeris 140/150mm adjustable travel trail bike has landed. Sleek lines, bob-free pedalling and progressive shock curve combines to make the hardest hitting yet pedal friendly 150mm travel bike around.  Shimano XT 11 Speed and SRAM GX 11 Speed is now also available on the Aeris.

Read about the Aeris in What Mountain Bike

The Aeris has been designed for UK mountain riding, taking in trail centres and back-country riding.  Please visit the shop to configure your Aeris.

Geometry and Information

Geometry is the secret sauce that makes an Aeris so good. Its the often overlooked basis for any great bike. The Aeris is long, slack, and low. It’s not one of these on its own that makes the Aeris so special though, its bringing them together in a single package, adding progressive, poppy suspension with custom tuned shocks, and of course the amazing value of frame only or full bikes that makes the Bird Aeris the most exciting bike to come out of the UK for some time!


Here’s the top six things you probably didn’t know about an Aeris

  1. The Aeris Frame runs on a full complement of Enduro Max bearings. Exceptionally well sealed and running maximum balls in the race for better load distribution, Enduro Max are the bearings of choice, and easily found online.
  2. The Aeris frame offers 2 travel positions, 140 and 150mm but the same geo in both. What changes is the progression of the shock. 140mm is less progressive for an improved trail feel – supple traction across the whole travel, with just enough progression to prevent wallowing, while the 150mm mode adds progression to resist bottom out and prevent wallowing even further. We don’t change the geo on the different settings as its perfect just how it is.
  3. Aeris frames are not tall. The biggest is 19.5 – thats still plenty big enough for even the tallest of riders, as a 150mm Reverb needs at least 7″ of seatpost showing (with another 7″ on tap!), and the reach and ETT are perfect for big riders. By keeping the frames low, we reduce weight, and improve handling. Simple really.
  4. The shock position and top tube on each size is in the same place. We designed a great linkage system, and we want to keep it that way. By using the same dropped TT and increasing seat tube brace size we ensure that the perfect shock curve of the Aeris is the same on every bike.
  5. The Aeris runs external full hose routing. We don’t like internal routing because we’re British, and it rains. Alot. Internal routing is the bane of mechanics everywhere. We also offer dual routing on the downtube so left or right reverb, UK or rest-of-the-world brakes, there’s a perfect cable and hose routing for your set up on the Aeris.