We have a one tool and one design but that does not limit us to one bike.  This is a rethink on how bikes are manufactured without big brand marketing.  A bike is a bike and we should all remember what has been ridden in the past - before marketing.  Tour de France was ridden on gravel roads on fixed gears until after WW2.  Mountain bikes had a total 1 inch front suspension for XC and DH in the 1990's.  John Tomac won both DH and XC on the same bike.  With respect we are not all Sam Hill.

This bike will run derailleur, however it has been designed to accommodate the Pinion gearbox and Gates Carbon Drive.  This means that you can change your drive system without changing your frame.

My concept was to create a versatile frame that could be built into many different bikes.  Options options...what to design... how to combine everything and get something??  There are several points on a bicycle that needed to be changed to accommodate different fork geometries. Forks and tyre choices have changed over the decades.  Long travel forks with 120-150mm travel suiting slack head angles and short chainstays.  100mm short travel or Rigid forks suiting steeper head angles and longer chainstays for Bikepacking adventures.  29 & 27.5" tyres have relegated 26inch tyres to being fat.  There have been some good developments, like the clipless pedal and the dropper post.  And tapered headsets have helped the bottom bearings last more than a few seasons....

So to combine it all....


At OLSEN Bicycles we believe in versatility so we have designed a do-it-all chassis that can change with you. It is not actually one chassis but, one design platform that allows us to change the following:

  • Head angle
  • Reach (top tube geometry)
  • Bottom bracket
  • Chainstay length.

While the outside shape stays the same, we can lay-up the frame to suit the task that it is meant for.  

  • Long-Travel, Enduro hardtail - 1.4Kg - Long reach - Short chainstays- Slack head angle - High BB 
  • Short-Travel. Bikepacking / Endurance XC - 1.2Kg - Long reach - Long chainstay - Low BB
  • Med-Travel. E-Bike - 1.5Kg - Long chainstay - stable ride for commuting and trails

This website tries to explain how we make the changes to each frame.   


Frame sizing has changed.  MTBs were always sized on seat posts, however stack and reach are a much better method. With the invention of the dropper post this has be come more important. If you are tall in the torso then you need a longer reach. If you like to sit up a little then a taller stack and shorter reach is more important.  The dropper post means that the seat tube length is less important as the seat post can be dailed in at your handlebars.  This is why I have gone for a set seat tube length.

By adjusting the Reach, and head-angle.  I can create a geometry with 66 deg to suit Long Travel forks or 70 deg to suit Rigid forks.

The "swing-plates" tension the belt, but they also sling the gearbox under the frame.  This allows the carbon to be almost continuous from head-tube to dropouts.  The swing-plates can also be swapped out to adjust the bottom bracket height.

All of this means that we can create the following geometries for you;

With a 430mm chainstay, 65mm BB drop and 65 to 68 degree slack head angle, this frame can handle 140mm forks with 29er tyres or 150mm forks with 27.5" tyres.  This makes the riding style aggressive and perfect for jumps, burms and table tops at Trail centres.

With 68 or 70 degree head angle this from feels balanced with 470mm Axle to Crown rigid fork.  This make the bike ideal for bike packing and long distance cycling.  The bottom bracket drop can also be changed by changing to the +5mm "swing plate".

semi-custom geometry:  MODIFIED for your type of riding:

This frame uses the benefits of carbon monocoque construction.  However the "reach" (top tube) can be changed from between 400 - 455mm.  The head angle can be anything from 66 to 70 degrees.  Bottom bracket drop can be changed by changing the mounting plates.

With low-maintenance at the heart of the design, lets break down some of the frames unique features:  Elevated chainstays allow the frame design to use continuous runs of uni-directional (UD) carbon from the axles to the head tube. Elevated chainstays also gives the frame large tyre clearance around the chainstays and chainring. The gearbox is suspended from this structure on some adjustable "swing plates" that also tension the belt. 
This frame will also fit two different wheel sizes, both 29 x 2.4" and 27.5 x 3.0" (plus sized) tyres without affecting the handling.


The derailleur drivetrain was invented in 1928 and works perfectly fine for road bikes where precision shifting is not impaired by mud sand and more mud.  A lot of design and engineering has gone into improving the rear derailleur, but this system is still exposed to the elements and mud. The derailleur has become the mechanical Achilles heel when long distances and trail conditions turn bad. 

Gearboxes have more long-term benefits for mountain biking than an exposed rear derailleur system. Years of maintenance free cycling. 10000 quiet belt drive miles.  At Olsen Bicycles, I have designed a frame around the Pinion gearbox based on UK hardtail geometry. With the Pinion gearbox and Gates Carbon-drive belts, this frame has both low maintenance and ride versatility. 

OLSEN BICYCLES offers a semi-custom geometry tailored precisely to the customer.  OLSEN Carbon frames are monocoque and are all hand laid.   Each frame uses a combination of 3K weave & UD Carbon laid into a tool.   I offer advice on geometry options to suit your forks and type of riding that you do.