Here you can find
|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|
|Bottom Bracket||Steel - adjustable|
|Crank||Aluminium - 53 / (39 not used for the moment)|
|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]|
|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]|
- LOSNA model "alpha"
Here after you can find some details about this model, the first "serious" recumbent 100% designed and produced by us.
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.
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:|
|What solutions I'm going to choose (specifications):|
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.
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).
About the material, even if I'm not able to weld at all, steel seems to be still the best solution.
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:
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:
for ideas about various kinds of solutions, I took in consideration many
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):
|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.|
fork is a reinforced BMX front fork (20" wheel) with an off-set of
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.
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.
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:|
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:
round section is better than square.
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:
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:|
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.
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:|
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 ):
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).