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DOROTHEA, the mother of

Dorothea? Why this name for our first bicycle?

Dorothea Bate was a palaeontologist, pioneer and ahead of her time. She is believed to have been the first woman to work as a scientist at the Natural History Museum in London, although without an official contract. Later, thanks to her studies and publications, she became the first woman to obtain a professorship at the University of Cambridge in 1937.

In the early 20th century, Dorothea undertook multiple expeditions to explore the Mediterranean in search of fossils. Among many other discoveries, in 1909 she discovered the Myotragus balearicus on the island of Mallorca.

In tribute and admiration of her, we have decided to name our first model Dorothea.

 

We have designed and tested up to five iterations of the most radical version of the OLS system

DOROTHEA V1 prototype

2020

Although we first designed and attempted to manufacture other enduro versions, in the end, the first design to become a reality was the downhill version. Downhill is the F1 of MTB, and our favourite discipline, so it made sense for us to start here.

  • Upper shock mount, pulley and modular rear dropouts.
  • Pinion gearbox. Why?
  • Very good absorption but a slight lack of ‘pop’ due to the linear section of the leverage curve.
  • The pulley mount and swingarm were not rigid enough.
  • Due to the opposing forces between the two pivot points of the main triangle, the tube connecting these points ended up breaking.

 

Very happy with the result for our first bike!

  • We refined the aesthetics
  • We designed a system to modify the angle of the seat tube, but due to its complexity and lack of time, we were unable to manufacture it.
  • We joined the two lower cranks at the rear to reduce the flexing of the pulley support and the swing arm.
  • We changed the design of the eccentric, but we were not convinced.
  • We designed the main triangle area where the axles are located, with two CNC parts to better withstand the forces.

 

It worked well, but some cracks appeared and there was still much room for improvement. 

DOROTHEA V2 prototype

2021

DOROTHEA V3 prototype
2022

In this iteration, in addition to the descent model, we modified the geometry and, with a modular shock absorber mount, we installed a 230x65mm shock absorber to create an Enduro version with 180mm rear travel. 

  • Larger diameter pulley to reduce friction.
  • Return to an eccentric design similar to the V1.
  • Reinforced swingarm with larger lower chainstay and welded dropouts.
  • Return to the upper modular shock absorber mount.
  • The lower link connection is moved to the front.
  • The bearings on the lower shock absorber shaft are removed.
  • We incorporate an eccentric shaft design to support the pulley, which allows us to gain rigidity in a small space.

 

They held up well and the Enduro version climbed very well.

The objectives were: to reduce weight and facilitate manufacturing, assembly and maintenance.

  • The upper eccentric is replaced by two connecting rods that are as short as possible. This change increased progressiveness in the middle section.
  • We installed all the same bearings and shafts (20x37x9mm) except for the eccentric shaft of the pulley (which was impossible to install due to the design).
  • Use of standard M6 and M8 screws, always with Allen 5 and always accessible. Except for the 3 screws on the pulley shaft, which are M4 with Allen 4.
  • The central part was replaced in two CNC parts with welded tubes, which turned out to be a mistake. There were misalignments and cracks in the welds on some units.
  • The modular shock absorber support was removed to simplify the design.
  • We reincorporated modular rear dropouts.
  • We manufactured two downhill units and one enduro unit without a gearbox. And two enduro units with gearboxes.

DOROTHEA V4 prototype
2023

DOROTHEA V5 prototype

2025

This is the version available for purchase at Campmajó Bikes. The result of everything we have learned throughout previous iterations

  • We lowered the entire suspension system by 1 cm to slightly verticalise the wheel trajectory and lower the centre of gravity a little. 
  • The central body of the main triangle where the pivots are located is once again manufactured in two parts using CNC.
  • Triangular pressed top tube to improve rigidity and aesthetics.
  • We return to the modular shock upper mount.
  • Direct access to all hardware except for two bolts that remain behind the pulley.
  • The CNC plates that form the swingarm are narrowed to improve comfort and traction as well as eliminate weight.
  • Modular upper chainstay connection.
  • Decreased progressivity.
  • ZS56 semi-integrated headset – ZS56 to modify reach or head angle.

DOROTHEA V5 KINEMATICS

The rear wheel axle follows a virtually linear trajectory that is tilted backwards. This results in: 

  • Better shock absorption and less loss of momentum, as the wheel moves in the same direction as the impacts = more speed on broken sections. 
  • The wheelbase is not shortened as much as on bikes with a more neutral or forward trajectory = the bike maintains greater stability.

It has been designed with three clearly distinct sections to better adapt to different impact sizes. 

  • First section: with a high ratio to promote initial sensitivity to small bumps.
  • Middle section: with a smoother progression for absorbent and predictable behaviour. 
  • Final section: more progressive to avoid sudden bumps that can cause you to lose control during big landings. In the case of the electric enduro model, we eliminated it as it is not designed for big jumps, thus making better use of the entire travel range.

Values above 100% indicate that the suspension will contract, in this case slightly, thus compensating for the compression that inevitably also occurs in the front suspension, maintaining the geometry during braking.


Given that the suspension system has been designed with a less progressive middle section and that the wheel trajectory describes a straight line inclined backwards, we have not noticed that having values above 100% has a significantly negative effect on absorption capacity.

The values increase from start to finish and, from the SAG zone onwards, are slightly above 100%. The aim was to have firm suspension when accelerating while pedalling and maximum stability in all gears. 

At the end of the travel they are too high, but we will never be pedalling in that zone.

This is a fundamental parameter for comfort when cycling on uneven terrain.

The values in the SAG zone show that the PK is zero with downhill gears and low with high gears. This means that the movement of the suspension will not cause the pedals to kick back significantly.

DOROTHEA V6 2025

With the V5 now complete, we began experimenting with other design and manufacturing possibilities while maintaining the essence of Dorothea’s kinematics.

  • The linkages are now a single piece and are hidden inside the frame to improve rigidity. 
  • The shock absorber is also hidden and anchored to the down tube to lower the centre of gravity and achieve a cleaner aesthetic. However, its adjustment dials remain accessible.
  • The entire suspension system is lowered slightly, resulting in greater sloping and a slightly more vertical wheel trajectory.

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Dorothea