Here you can find details about
LOSNA model "alpha"

the first recumbent 100% designed and produced by us.
This bike is really fast and runs like lightning ! But it's easy to ride too.Take it easy and have fun !!!

( other LOSNA models )

Turin, 3rd March 2007

First ride test with the new
finished LOSNA - model "alpha"

More WILL come ...
... for the moment, at least,
a preliminary album
and a short video (9'390 KB)

2007 - LOSNA model "alpha" specification

Drive Front Wheel
Steering Over Seat


Wheelbase 1160 [mm] - 45.67 [inch]
Steering Axle Angle 70 [deg]
Trail 72 [mm] - 2.83 [inch]
Seat Height 560 [mm] - 22.05 [inch]
Bottom Bracket Height 705 [mm] - 27.75 [inch]
Fork Steel - Trevi-bike - FWD special
Handlebar Steel - Dechatlon Cycle - handlebar for city bike
Stem Steel
Bottom Bracket Steel - adjustable
Crank Aluminium - 53 / (39 not used for the moment)
Chain ---
Front Derailleur n.a. (for the moment)
Rear Derailleur Sram 5.0 - 9 speed
Cassette 9 speed, 11-12-14-16-18-21-24-28-32, gears ratio graphic
Shifters Sram X-7 - 9 speed grip shifter
Brakes Disk: front 160 [mm] - 6.30 [inch] - rear 140 [mm] - 5.51 [inch]
Brake Levers Aluminium
Front Wheel 406 Malvestiti Vega - 36 spokes
Rear Wheel 406 Malvestiti Vega - 36 spokes
Front Tire Schwalbe Marathon 40-406
Front Tire Schwalbe Marathon 40-406
Pedals Aluminium - Dechatlon Cycle
Seat Glass Fiber - Trevi-bike - Small
Seat Options Trevi-bike Mesh
Color Mono-boom frame: Orange (RAL 2004)- Fork: Black
Sizes Cyclist height from 1.6 [m] - 5.25 [feet] to 1.8 [m] - 5.90 [feet]
Weight 16.2 [kg] - 35.7 [lbs]

2007 - LOSNA model "alpha"
Here after you can find some details about this model, the first "serious" recumbent 100% designed and produced by us.
My first recumbent was a Flevo Racer.
My Flevo Racer is home-build using plans I found in Internet. It took me around one year to be ready to use this bike (mainly because I have not so much spare time for building) and many hours to be able to ride it for some metres.
I'm not a fanatic cyclist, but I love recumbent concept for many of the usual reasons everyone can read in several web sites.
As an home-builder, I like the thinking and design phases behind the final result: a ready to be ridden recumbent bike.
With these pages I would like to give some general information about the process followed to design and build this new home-made recumbent .
As I'll repeat here after, benchmarking is the key of the success: before to think about a new "toy", it's really important to have a look to other bike that follow concepts close to what we have in mind; this in order to have new suggestions, ideas and to avoid big mistakes.
Building a bike it's not so difficult if you think in advance about what you are going to do … and it means a lot of fun!
What I'm looking for (requirements):
At the beginning of a new project it's important to write down the main requirements and only after this step to try to find solution to satisfy them (with as less compromise as possible). My goals:
  • the bike has to be fast
    I'm thinking to use the bike on-road
  • I want to be visible in traffic
    I can't consider "low" solution "safe" as in my area there are not so many streets dedicate to bicycling
  • easy to find commercial components
    it means components used mainly on standard bicycles
  • easy to build
    frame with less parts as possible and without curves
    - take in consideration the use of front and rear fork from conventional bikes
  • easy to transport
    I just want to be able to put it easily inside my car; I don't want to consider foldable bikes
  • riding must be easy to learn and not so much challenging
    the Flevo Racer experience teaches that only very motivated people can learn to ride this very unique kind of bent; you need a lot of time (months); this reduces a lot the possibility to involve sceptical people giving them the opportunity for an occasional riding test
    - in other words: I would like to involve other people to this different & clever way to pedal
What solutions I'm going to choose (specifications):
Considering the 1st requirement, a "racer" bent will be the solution, but in order to be visible in traffic (2nd requirement) it will be at least a "medium racer" if not an "high racer".

The 3rd requirement depends a lot from how much it's easy to find special components for bent; living not so far from a "recumbent guru", this could be not a big problem; in other words: I could accept to only partially follow this requirement if the solution I'll prefer needs special components.

Straight, mono-boom frame seems to be the best choice to respect the 4th requirement; fortunately there are so many blazoned bents to drawn inspiration from. In order to improve torsion stiffness, a round section tube will be used (here after consideration about this topic).
Shock absorber will be not considered due to the consequent complication in the frame construction, not forgetting weight & cost; even if it's really simple, the rubber cylinder used on the Flevo Racer is not the best solution, due to undesired damping effects.

About the material, even if I'm not able to weld at all, steel seems to be still the best solution.

The 5th requirement depends a lot from the kind and size of your car.
The FWD (Front Wheel Drive) choice could be helpful as it will be possible to easily disassemble the rear wheel; FWD is a good choice for weight-saving and simplicity too.

Even if I'm really fascinated by the centre steering bent concept with front wheel drive, to satisfy the 6th requirement I'll follow a more conventional steering solution.

Having these specifications in mind, it's almost defined that the new "monster" will be:

  • SWB (Short Wheel Base)
  • FWD (Front Wheel Drive)
  • Medium Racer (2 x 20" wheels)
  • Straight mono-boom (circular section)
  • Steel frame
  • No front and rear suspension
  • Dimensions good also for a twelve years old kid, like my first son
In order to define the general dimensions of the new bike, benchmarking trough the web sites of the "blazoned" commercial (and not) recumbent is a good starting point.
You can find some useful information inside the general specifications, but other can be detected printing a picture of the bike and measuring them (for example steering angle).
For the general dimension, I took in consideration the following example:
  • Fig.1 - Bacchetta (models Aero, Corsa, Giro)
  • Fig.2 - CarBent (model Dual 650)
  • Fig.3 - Velokraft (model VK Highracer)
  • Fig.4 - Volae (model Team)
  • Fig.5 - Rans (model Force 5 XP)
Looking for ideas about various kinds of solutions, I took in consideration many other examples.
Mainly I looked for ideas about: FWD, handlebar position / adjustment, seat position / adjustment, ... In these cases, pictures and owner manuals can be very useful!
I strongly suggest to have a look at least at these interesting links (but you can find many, many others surfing in the web):
  • Toxy ZR
  • ZOX
  • XPORT 4
  • Dragon Bike CTZ
  • Fast FWD
  • HHS/1 (download .pdf manual)
Here after the general LOSNA dimensions as a combined result of the analysis of several bents plus consideration related to the component I'm going to use.
The rear fork is a reinforced BMX front fork (20" wheel) with an off-set of ~32.5 mm.
The front fork is a special fork designed to accept a 20" wheel with 9 gears, exactly the same of the Dragon Bike CTZ .

For a simple frame construction, the headset is perpendicular to the mono-boom main frame.
The pivot angle (20 deg) is the result of some geometric constrains due to the mono-boom diameter (50 mm), the headset and the rear & front fork dimensions. The adjustable bottom bracket position comes from my experience on a FWD kid-recumbent.
Finally, the feed-back from the benchmarking gives the necessary confidence about these choices.
In order to have a general overview of the new recumbent I did some simple 3D CAD sketch without the claim to reproduce everything. Here after some views


Mono-boom section choice:
If you look at the different solution of the commercial bents using a mono-boom frame, you'll find different approaches. My choice to use a round tube with o.d. = 50 [mm] and wall thickness of 1.5 [mm] is due to the following comparison vs. a 40x40x1.5 [mm] square tube (40x40x1.5 [mm] square tube is the same used in the Flevoracer frame as in many other bents: the first version of the very famous RANS Rocket used this kind of tube too, the ZOX bent range is based on square section tube frames).
Of course a square section helps a lot in the alignment phases, but, if with the same weight it's possible to reach higher stiffness, may be this is something to take in consideration in order to have an easy and safe to ride bent, isn't it?
Some formulas for the bending and some for the torsion:
Here after the results of the comparison round section vs. square section:

As you can see from the data on the left, the round section has:

  • almost the same weight (a little bit lighter): -1%
  • an higher bending stiffness: + 15%
  • a very considerable higher torsion stiffness: +55%

(Obvious) conclusion: round section is better than square.

Construction Details
Rear fork:
As written above this component is a reinforced BMX front fork with a dedicated plate welded as disk-brake attach.
In order to align and secure it to the mono-boom main frame, I follow the solutions showed by the pictures on the right:
  • two "bushes" (machined with a lathe) are welded (just three stitches each side of both bush) to the original headset tube of the fork

  • the inner diameter of each bush is slightly smaller then the outer diameter of the headset tube in order to have a sort of shrink-connection and a precise fitting; ~0.02÷0.05 [mm] are more than enough; heating the bush on a camping-gas enable to insert it very easily, then you have to keep it in position till the temperature will go down (be careful, use thick gloves!)

  • the outer diameter of the bushes is machined in order to fit the inner diameter of the mono-boom tube

  • the bushes total length is ~20 [mm] in order to avoid stress concentrations on the headset tube of the fork

  • in order to reduce the weight (some grams!), the bushes are machined keeping ~10 [mm] for the centring between the bush itself and the inner diameter of the mono-boom tube

  • the rear tip of the mono-boom tube is then shaped with a Dremel to fit with the fork

  • after this fitting, it will possible to define the precise position of the 10 [mm] centring band of both bushes where to drill three 5 [mm] holes [*] at 120° around the outer diameter

  • [*] in order to keep the fork in position for welding, one hole for each bush can be treated M5 (different hole!) ; two screws will complete the job

  • these 3 + 3 holes will permit "welding spots" to fix the bushes to the mono-boom tube (here after detailed pictures of the welded frame)

  • then the rear fork will definitely fixed with a continuos welding around the two arms of the fork


Front fork:

This is a special fork designed to accept a 20" wheel with 9 gears. I decided to use a disk-brake for the front wheel too; this is not the best solution to reduce weight, I know, but disk-brakes are really cool and my children love them ...

In order to drill an hole perpendicular to the mono-boom main frame and to keep everything in position during the drilling operation, I find "pipe-clamps" very useful. I used a level temporary fixed to the rear fork to define the right mono-boom orientation. Now a column-drill is the best tool to finish the job!

Adjustable bottom bracket:
The choice to use an adjustable bottom bracket is due to the necessity to have a bicycle that "will groove" with the owner and/or that will adapt different owner's sizes. Varying together the seat position, an adjustable bottom bracket could be useful to test different riding posture too. Of course, after these tests, for the second LOSNA bike, it could be possible to define a specific frame size and use only the seat position for fine adjustments. This solution will save considerable weight.
As it's possible to see from the pictures, the clamping solution is quite simple and standard: two screws with bolts trough two small metal plates welded on the left and right of a cut done on the tip of the mono-boom frame. Here, as on all the other parts of the bike, I prefer to use self locking nuts.
If more than one gear is used, on the bottom bracket support it will be necessary to weld an additional tube to support the front shifter.
For the moment, I decided to use only one front gear together with the nine gears on the wheel. This solution gives an acceptable range of gears (here after more about this topics). May be in the future I'll take in consideration the possibility to add another front gear.
Gear ratio:
As written above, for the moment I decided to use only one front gear.
Even if I have "on the shelf" a special 76 teeth gear, I'll start with a more standard 53 teeth that give a good compromise between speed and climbing.
Front Wheel Drive System:
As defined in the "specification", this bicycle is a FWD recumbent.
There are advantages and disadvantages related to this choice, but, at least for me, the firsts are enough "strong" to accept the few "bad points" (all my recumbent bicycle are front wheel driven … ):


  • chain is shorter than standard rear driven systems ' lighter and cheaper (anyway at least 2 std. chain are needed)
  • no undesired effects due to forces coming from chain tension along the bike frame
  • rear wheel can be easily disassembled giving transport advantage (reducing length)
  • lay-out design is easier as it's not necessary to take in consideration the chain path from the bottom bracket to the rear wheel


  • a special front fork is necessary (but a std. front fork can be used for the rear wheel)
  • steering angle is a little bit limited (you could feel this limitation only at low speed)

Here after some pictures that show the solution used on LOSNA. As you can see two pulley are necessary. The position of the rear one is a little bit critical in order to reduce at the minimum the limitation of the steering angle; the best position depends on the number and size of gears and on the shape and geometry of the front fork; generally speaking, the best position is the one that keep the chain as close as possible to the steering axle, but the chain must not hit the front fork arm. Some practical lay-out test moving the chain on all the gears will permit to easily define the rear pulley position. Usually the rear pulley has a bigger diameter than the front one, but the front pulley can have the same "big" diameter. Once defined the rear pulley position, the position of the front pulley will be easily found: as close as possible to the rear pulley, a little bit lower to avoid interference and with space enough to enable to mount the chain.

The first test were done with a preliminary version of pulleys; this to check if they worked properly.

Then I decided to move to a solution based on a M10 bolt welded trough the mono-boom for the main pulley (as close as possible to the steering axle), plus a carbon fiber support plate for the second pulley (same item used on the shifter).