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Myotragus, an rising Mallorcan mountain bike model named after an extinct mammal identified solely to have inhabited the Balearic Islands of Mallorca and Menorca, may be very near releasing its debut framesets; the Dorothea 20 DH Bike, and the Dorothea 17 Enduro Bike. Reasonably appropriately, the Myotragus Bikes are named after Dorothea Bate, the Welsh paleontologist who unearthed the creature in 1909. Historic references apart, the Dorothea DH prototype stole our consideration with its uncommon execution of a digital high-pivot twin-link suspension platform that delivers an virtually straight-line rearward axle path.
Roger Pisà, a Mallorcan DH and Enduro Rider, is the thoughts behind the patented OLS Suspension Linkage. He labored intently with Barcelona-based engineer, Joan Bujosa, to execute his concepts and produce his dream bikes to actuality. The frameset continues to be below improvement because the group await their first samples of the V4 prototype. Although gearbox framesets are proven all through, ultimate manufacturing will carry a conventional drivetrain choice to market additionally. We hopped on a name with Joan Bujosa to be taught extra about these thrilling new bikes.
Myotragus Dorothea
The thought of the Myotragus Dorothea was born over 10 yr in the past when founder, Roger Pisà, launched into an exploratory journey to design a mountain bike suspension platform that might ship a straight-line axle path, by way of a twin-link association whereby the decrease hyperlink rotated anti-clockwise because the rear wheel was displaced by a bump. Not solely that, however he wished that straight-line axle path to maneuver rearward solely.
Noting {that a} rearward axle path would end in a rising rear-center size and thus, chain progress, Roger realized the usage of an loafer pulley can be essential to handle anti-squat and pedal kickback. He reasoned the most effective place to find the loafer pulley can be on the decrease hyperlink, such that its place would transfer in live performance with the motion of the swingarm because the bike was pushed into compression.
At this level, together with his concepts having not but materialized past his personal ideas, Roger determined he wanted the recommendation of an engineer who would have the ability to mathematically clarify why the theoretical straight-line rearward axle path would provide efficiency benefits on the path. It’s intuitive that an axle path that strikes according to the route of the forces utilized to the rear wheel, slightly than in opposition to them (assume low single-pivot), can be best at absorbing and damping these forces, however Roger wished to depend on one thing greater than easy instinct.
Enter Joan Bujosa, a buddy of Roger’s who had just lately accomplished a Diploma in Engineering. Whereas not a rider himself, Joan tells us that “Roger’s thought made actual sense, actual bodily sense; the issues he was saying, I discovered they may very well be supported by physics or mechanics”. From that time on (round 2015), Joan started working with Roger to make his dream bike a actuality.
Early on, the 2 thought of manufacturing the Myotragus bikes with titanium lugs and carbon tubing, very similar to the bikes of Robotic Bike Co, however had been postpone by the extremely excessive worth of manufacture. They wished to supply extra reasonably priced framesets, so have as an alternative partnered with aluminum body producer, Campmajó Bikes (identified for his or her full suspension tandems), a Catalonian bicycle model working out of Tarragona.
OLS Suspension
Having produced, validated and patented his suspension design, Roger’s OLS Suspension Platform has come to fruition on the Myotragus Dorothea 17 Enduro Bike (V3) the place it delivers 175mm of rear wheel journey (200mm on the DH Bike). It sees a excessive digital pivot twin-link format, however its execution is slightly out of the unusual. What drew our consideration to this bike within the first place was the eccentric axle about which the higher portion of the swingarm articulates. Whereas it might look complicated, it features very similar to a really short-link.
Because the rear wheel is displaced, the decrease hyperlink rotates anti-clockwise to drive shock compression, whereas the higher hyperlink pivots eccentrically a few very giant bearing housed between the seat tube and the highest tube. The higher pivot on the swingarm strikes ahead and up initially, after which down and rearward once more because the shock is pushed deeper into compression. On this approach, Joan and Roger had been in a position to management the arc of the rear axle path such that it is rather near a straight-line.
The end result? The rear axle solely ever strikes rearward. The appreciable chain progress related to such a design necessitates not solely an loafer pulley on the decrease hyperlink, but in addition, on condition that this bike runs a Pinion Gearbox drivetrain, a really long-arm chain tensioner aft of the chainring.
I hear you. You need a slow-motion video of the suspension articulating. Right here it’s!
All that stated, Joan tells us that Myotragus will cast off this higher pivot design on the V4 for ease of fabrication, and to make it possible for it will likely be extra easy to service and discover alternative elements when the time comes to alter the body bearings. The render under reveals the shape that the manufacturing Dorothea will probably take, with a short-link changing the eccentric axle pivot on the entrance triangle. Joan says the axle path is barely affected by this variation, however not considerably so.
The Dorothea’s axle path is actually fairly totally different to the rearward axle paths we’ve seen on different, extra mainstream high-pivot bikes. These are extra arced, such that the rear-center size grows extra early on within the stroke, however begins to arc ahead once more towards bottom-out. A notable exception can be the Forbidden Dreadnought. Because the axle path is nearer to that of a straight line, the Dorothea’s rear-center size grows extra progressively, however the very shallow arc implies that it by no means begins to trace ahead. On the 200mm journey DH bike, the rear-center size grows by an enormous 57mm.
In actual fact, the trail taken by the rear axle is extra much like the trail taken by the entrance axle of a daily telescopic fork, as proven within the above graph supplied by Joan. The bike’s wheelbase nonetheless shortens throughout compressions that contain the entrance and rear wheels concurrently, because the 62° head tube angle on the DH bike is way slacker than the efficient ~74° angle of rear axle displacement.
As you may think, such an axle path leads to some uncommon anti-rise and anti-squat plots.
Specifically, whereas the anti-rise begins out at a reasonably customary 130% (for high-pivot bikes) across the sag zone, it really will increase the additional the rear wheel is displaced into its journey. That’s the precise reverse of what we see on different high-pivot bikes the place anti-rise falls off as you go deeper into the journey.
What does that imply for the Dorothea’s efficiency on the path? Theoretically, the bike could have a larger tendency to compress into its suspension journey throughout braking occasions that happen deeper within the stroke. Arguably, it’s not so related, since most of riders are doing most of their significant braking across the sag zone anyway.
Anti-squat values are extra constant all through the 200mm journey on the Dorothea DH body, sitting at round 100% by way of the sag zone, then reducing thereafter. Thus, round sag, pedal kickback ought to be stored to a minimal.
What concerning the leverage curve?
Providing up extra perception into how the bike might carry out on the path is the leverage curve. The Myotragus Dorothea’s OLS Suspension Platform has a 58% general development. It is vitally progressive early on within the stroke till it hits a ratio of three.05-2.66 across the sag zone. From right here, the mid-stroke help sits round 2.55 till it turns into very progressive once more towards bottom-out. Joan tells us they don’t thoughts the bike by no means utilizing, for instance, the final 3mm of journey, if which means the rider by no means experiences a harsh bottom-out occasion.
The above leverage curve pertains to the Dorothea 20 DH Bike. The 175mm journey Dorothea 17 Enduro Bike leverage curve is not going to be dissimilar in form; Joan says the extremely progressive preliminary stroke and end-stroke will probably be decreased to supply a curve with a lot much less general development (41%).
All that stated, Myotragus plan to make development adjustable on the V4 with two potential shock mounting places on the decrease hyperlink. As in comparison with the leverage curve seen above, the alternate shock mounting place will ship a curve with decrease general development. The group can also be contemplating two potential mounting positions for the higher shock.
Myotragus Dorothea Geometry
Myotragus plans to supply two customary sizes for the Dorothea; a ~450mm attain, and a ~480mm attain. That stated, the two-man model is keen to work with every buyer and a motorbike fitter to ship a custom-sizing possibility for many who want it. Additionally, depending on the client’s weight, driving model, and intention for the Dorothea (DH or Enduro), Myotragus can tailor a lighter, extra compliant tubeset, or a heavier, stiffer tubeset. Joan tells us the manufacturing bike will have the ability to run a 29″ or 27.5″ rear wheel, with changes accessible to negate its impression on the geometry.
4 chainstay positions will probably be provided; two for a 29″ rear wheel and two for a 27.5″ rear wheel. For the previous, chainstay lengths of 435mm and 450mm can be found. For the latter, chainstay lengths of 435mm and 420mm can be found. It’s price mentioning once more that the rear-center size will develop by 57mm all through of the complete stroke of the suspension, if solely to appreciate that the 450mm chainstay will develop to an efficient 507mm at bottom-out!
When can I purchase one?
Joan and Roger are uncertain on timescales in the mean time, on condition that they’ll nonetheless want to check and validate the Myotragus Dorothea V4 presently being fabricated by Campmajó Bikes. Thereafter, it would go to ISO testing earlier than it will likely be accessible for pre-order. The pair are aiming to promote the Dorothea at round 2,700-3,000 € for a body with out shock.
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