The Velassi, a not so reclined recumbent (but more than a ‘semi-recumbent’).
Build a recumbent
Why a recumbent ?
This, finally allow larger range of bike rides (increased by 40–50 %).
Why a not so reclined bike ?
Why a wooden bike ?
Is there a motor?
On a long chain line, you can set up a motor in diverse places. A side mount motor with incorporated freewheel of this kind is really easy to install but they are very low quality equipment and to be legal in my country, you shall install a command by pedal switch only.
A mid-drive motor like the Tongsheng TSDZ2 (with torque sensor) or a Bafang BBS-01 (with pedal sensor) might be better but they cannot be installed on the present wooden frame because there is no sufficent bottom clearance, but the future wood frame have been redesigned to allow a mid-drive motor.
Specification of built bike (small size, for inseam between 73 and 80 cm):
Transmission with geared hub (Nexus 8) with simple chainring. Very short gear-inch: 196” in 8th gear (=development 5 m), I did not pedal while descending.
I did modeled multiple frame types and among them a monobeam frame but pratically two scissor trellis frames, one in wood and the other in steel looks preferable while remaining reasonnably light. Loads on a long wheelbase bike are not negligible and I did not trust much a monobeam frame while this was already done.
As for some of my other projects, I have the intention to publish the model (made with OpenSCAD) and information about building. The bike is at its beginning (first run in may 2019) and there are modifications to do, I feel I am still in debugging phase and I am still modifying the model, so you will have to wait and came back from time to time if you are interested. There will also be development of the Internet pages which also are at their beginning. I shall make a preliminary evaluation of the building and handling and practically my intent is to rebuild a new frame. Model will incorporate steel frame, however I have not yet any intention to build a steel frame.
Building in wood
Building in wood:
Welding/Brazing steel structure
Brazing shall always be preferred to stick welding or flux-core wire welding for resistance and metallurgic quality. When it is well done (no excess heat), a brazing have the advantage to not drive to thermal modification of base steel. TIG welding allow high quality welds but you need argon gaz (and it is also required to inject argon inside tubes). To have quality MIG weld you need BOTH gas and flux-cored wires because gas only creates inclusions. Beware, the rod metal for brazing steel is different from the one used for copper welding, you need specific rods which is not always well explained.
As all my projects since four years, this was developed on OpenSCAD and is entirely parametric, but yet there is only one pre-defined dataset for small size, the one built. It is relatively complex to develop a dataset and you have sometime to dive in the program to chack what the data is modifying.
2D projection (drawings) and cuts
On this model, I did more than a simple computer mock-up and also created a module projecting the beam shapes on drawings. I then use a CAD program to add dimensions. I then printed beam shapes on paper, cut the shapes with scissors and glued the paper on may wood planks. I cut the beams with a track saw with the help of a jigsaw for contoured elements. A track saw is very precise and you have no need to rework the straight cuts. After drilling, I did a pre-assembly to control structure. The rounded edges were sandeed by hand which is quite long with oak hardwood. A table tank and disk sander is required but I did’nt have one when I started the manufacturing.
Transport the bike
Velassi can be installed on a typical cantilever rear bike rack with the rear wheel frame folded, which was one of the main design requirements. Rack is locked on the trailer 50mm hitch ball with no other attach but load is limited to 45 kg.
Waiting the development of a foldable back seat, to transport the bike, it is required to remove the seat. This is not very long, a bit more than one minute but you will need three to four minutes to reinstall it. To remove the seat, you need to disconnect the rear light. Without a plug (bought, but not yet installed), I used screw connectors for re-connection.
Is it reliable and durable ?
Even if I made some design mistakes that I explain in the details page, this bike has proven to be comfortable and reliable and it has covered (in February 2021) nearly 4300 km (including 400 km on a home-trainer during the first confinement) without having spared it (I do a large part of my mileage on unpaved surfaces or trails). The seat cover (bought second hand) is very tired and as it is a seat made in the USA, it is a bit complicated and expensive to replace it. The handlebar pivot bearings are the big mechanical weakness and would need reinforcement. Also, depending on the ambiant humidity, they either jam or have too much play. My fears about the fragility of the handlebar proved unfounded when I cut it to change its shape. The braking needs to be reviewed, I replaced the rear brake cable by a polished one but I should install better quality sheaths and review the front braking as well. After a stupid maneuver, I fell in a drainage ditch and had to replace some spokes. The chain tensioner had to be modified after 2000km and I finally built an external spring that lacks some strength. Even if it’s clearly a prototype to be replaced, I’m glad because it’s often the case that home-made bikes don’t last much compared to commercial bikes.
On this forum the Velassi thread
Atomic zombie diffuse many recumbent drawings, including the WildKat USS that I did buy. I was not really convinced by these plans as they are relatively general and focus more on the manufacturing than on design details and neglect important elements. They recommend a given head angle without taking into account fork offset (rake) which varies significantly from one fork to another in 20” wheel size (typically from 30 mm to 50 mm), which will make a trail with significant variation depending fork parameters, so the handling will be somewhat random. Handling of recumbent is a complex problem where you can write a book, which was indeed done:The lord of the chainring I did bought (after building and some handling problems) the kindle version of this book but there is a big problem in the kindle version and formulas are not understandable. However, the book author (William Patterson) defined an equation advising a trail for a recumbent which can be found here. The recommendation of Atomic Zombie will give a trail notably lower than what recommand Bill Patterson, though the ‘wheel flop’ will be lower, which is more benefitting for low speed handling.
On the other hand, Atomic Zombie publish a book:Bicycle builder bonanza that I bought used and that I recommend if you want to build a steel frame bike.
Long wheelbase similar bikes
There was Lightfoot mountain long wheelbase recumbent but they are no longer produced.
An amateur (Richard Ehrlich) had remarkable mountain recumbents built for him, first built in aluminium then carbon fibre. He race with these bikes. Vidéos: 1, 2, 3, 4. He is quite active on the BentRideronline forum.
Long wheelbase bikes for touring are mainly diffused in the USA, by opposition to short wheel base bikes, often more sport oriented which are monopolising European market. In Europe, touring demand for recumbent often drive to choose ‘tadpole’ tricycles, which may be easier to transport with good stability and good performances.
Recumbent sector is relatively confidential, and among them long wheelbase bikes are fairly rare in Europe. We are there is the ‘niche of the niche area’.
One main problem of recumbent bikes is that they are relatively costly which may be one reason why their diffusion remains limited. Conservatism also maintain this situation.
It shall be noted that these US bikes costing more than 2000 to 3000 USD are delivered in standard without lighting nor mudguards, you still shall add some money for this basic equipment… This sort of thing makes me cringe.