This is very often true in engineering and the apparent simplicity of bicycle mechanic hide a lot of difficulties, as I discovered making a bike prototype (which incidentally was the first bike I assembled, so there was some serious learning in the process).
There never was ‘official’ standards for bike mechanic, so the standardisation came from large adoption of equipment by bicycle manufacturers, often because a technology had some advantages over others, and stuff was designed in France, Italy, UK, Japan, USA so the origin are mixed and you will find dimensions in imperial or in metric or weirdly, as for steering bearing, a mix of the two.
1 inch = 25.4 mm: inches are symbolised by ". Sometimes for dimensions in millimetre, there is no unit at all (it is common practice to use mm in mechanic, but the official international length unit is the meter).
1/2" = 12.7 mm – Children pedal thread
9/16" = 14.29 mm - Adult pedal thread
7/8" = 22.22 mm – Handlebar ends – rarely seatpost diameter
1" = 25.4 mm – Steering tube – Handlebar attach – Seatpost diameter
1"1/8 = 28.6 mm – Steering tube
1"1/4 = 31.75 mm – Steering tube – Handlebar attach
1"1/2 = 38.1 mm – Steering tube
1"3/4 = 44.45 mm
1 foot (symbolized by ') is 12 inches, say 304.8 mm
Hopefully, this is mechanic and not piping and the tubes dimensions in inches are the REAL dimensions (beware if you buy piping tubes, they obey to another standard, e.g. 1" tube is effectively 1.33" say 33.7 mm, that is the fun of piping engineering…)
1 pound = 454 g or 1kg = 2.204 pound
1 psi (pound/square inch) = 0.0689 bar or 1 bar = 14.5 psi
Nowadays, most bike screws are ISO compliant but you will still find english threads on bottom brackets caps and steering tube.
ISO metric threads are standardised since 1947 but it exists coarse and fine threads. To qualify a coarse thread, you set an 'M' before the diameter in mm. So an M8 screw is 8mm external diameter, pitch 1.25mm and M10 screw is 10mm diameter, pitch 1.5 mm but you will find 10mm fine thread (1mm pitch) on dérailleur brackets. On a bike, you will mostly find M5 and M6 screws, with a few larger ones (e.g. for pedal crank).
To save weight, it was the tradition in bike mechanics that the bearings were integral parts of the mechanical elements (for steering, wheels and bottom brackets), so for minor wear, you just replace the balls, for higher wear, you replace the whole parts. You find nowadays more use of standard ball bearings which in theory ease replacement, e.g. to replace the bottom bracket bearings, you just change the cartridge bearings (often completely standard bearings) without replacing the shaft and caps. Such bearings are smaller and may theoretically be less strong but there was significant improvement in standard bearing manufacturing over the last decades which help compensate. The problem is that rust may lock bearings on shaft and replacement may in practice be more difficult than the old traditional system.
I choose to use a fork with a 1"1/8 tube, which is quite uncommon for 20" wheel unsuspended forks
It is stronger and I was afraid that fork with 1" tube, being built for small children bikes might not be sufficiently strong, because even on a LWB, front fork get a load two time higher than on a children bike.
This does allow to use semi-integrated bearings, which I feel preferable for load distribution on the wood frame and allow me to not use metallic insert to support the bearings.
I got (by luck) a steering bearing set with bearings on spherical support, which is ideal for my less than perfectly aligned wood frame. I discovered later that this is very difficult to get, especially for a threaded tube fork, but the low cost bearing set I get from the shop was having that.
A 1"1/8 fork tube (28.6 mm) does have the top tube of said diameter, but the low part of the tube is larger (to ease installation) and have a diameter of 30mm, mixing imperial and metric dimensions. I discovered it because the hole I did in my frame was just 30mm and so my steering had huge friction and the bike was very difficult to ride – and this was my first go on a recumbent!
Semi-integrated bearings are called ‘Zero Stack’, and the external bearing diameter may have different values, however by chance for 1"1/8 fork, it does only exist one external size, which is 44mm.
So a semi-integrated steering set for 1"1/8 fork will be named:
ZS44/28.6 – ZS44/30.
But you are not done with that, most of the sets are for plain tubes installed as ‘A-headset’, though in our case, we have a threaded tube so the top bearing support will be different and the mention ‘threaded set’ is imperative.
If you want (and you will if you are building a bike like mine in wood without inserts) a spherical support for bearings, this will be called ‘semi-cartridge’. You may find some info here:
When you are not that versed in bike mechanic you may assume that a brake lever can replace another and they are standard. They are somewhat standard, but there are TWO standards, one for road brakes, the other for V-brakes and they are totally incompatible as for the same lever movement, a V-brake pull twice the length compared to a road brake. It does exist costly accessories multiplying the pull to use V-brakes with Road levers but that add complexity and shall be avoided.
The advantage of the V-brake is that with twice the movement in the cable, the load is divided by two, so there is less loss due to elasticity of cable and housing and the feeling is better, less spongy and more precise. Less load means also less wear. You can have good road brakes but it need high quality costly equipment. It is always recommended to buy minimum quality equipment but cheap V-brake may work better than a lot of road brakes, especially if they are not carefully maintained.
V-brake are needed if you want to use large tires, as road brakes can’t open sufficiently to install the wheel. For comfort, you will prefer large tire and you shall not forget than on an LWB, the rear wheel take around 2/3 of the load. On a recumbent, you are on a seat and there is no possibility to rise on the pedal to avoid impact when crossing irregularities on the road, so a larger rear tire will protect your back from road impacts. And when you have no front suspension, a ‘balloon’ tire as I have used on the Velassi will do the job well due to the bike length and low front load.
Note that V-Brake boss spacing is normally 80mm+/-2 mm, and I choose to be on the larger side (82 mm +) to reduce width at the cable end (as the brakes goes between frame members).
I used V-brakes and ordered a complete brake kit. Commonly brake cable kit are supplied with two cables but only one housing to be cut to have one rear housing and one front housing. You bet it, with a LWB the available length is way insufficient to have both front and rear housing, so you have to supply at least one more housing and depending yout set, another cable. The most important brake on a LWB is the rear brake, as the front wheel tend to lock if braking hard. The rear brake housing is a bit longer than traditional front brake and so it is even more important that usual to use high quality cables and housing, either PTFE lined (cable or housing) or polished cables. And as always, ONLY stainless steel cables shall be used, forget those cheap galvanised cables and beware to the diameter as some manufacturers save marginal money by reducing cable diameter. A good cable set may cost three to five times more than a cheap one, but this is important. The particular position of my rised handlebar also make water ingress unavoidable. Lower force on V-Brake cable have advantages when new but that mean that they are more sensitive to cable and housing corrosion, friction and blockage.
Don’t forget than even if you are not much athletic, old and riding slowly and peacefully (me!), a recumbent is much more aerodynamic than an upright bike and you can reach speeds you never experienced before when going downhill, even for relatively moderate slopes. And you WILL do, because it’s fun on a recumbent! Think you’re on a roadster.
I replaced after six month use a supposedly good quality cable, but not stainless by a polished stainless steel cable from Jagwire and this made a quantum leap in brake efficiency.
The above drive us to have a close look to rims. If you use V-brakes on a recumbent, your rims may experience more energy dissipation than you may be used to, so even if that weight slightly more, double walled rims shall be preferred.
Also, wheels are generally supplied with some sort of cheap plastic rim tape, which stay not very well on the bottom of your rim by simple tension. No way! Send them in the bin where they belong and use glued cloth tape, their cost is very low but they will last the life of you rim and they may prevent flat and will help repair. Before gluing the tape, have a close look to the bottom of the rim to see if there is no remaining burrs, protruding spokes or anything aggressive. Start gluing by the valve hole.
I was willing to ride on non asphalted trails and also to have minimal comfort. Wide tires were so required. Also, the rear wheel carrying 70% of the weight, the rear tire is quite loaded.
I installed on the rear wheel a tire type Schwalbe 'Marathon'. These tires are relatively resisting to flats but less than the 'Marathon plus'. Their advantage is that their rolling resistance remains good and their weight is lower than for 'Marathon plus'.
On a recumbent, you can't lift yourself from the seat and so comfort is important, so I choose a quite wide size (47-559) which drive to a relatively heavy tire of 875 g. For comparison, a 'Marathon plus' tire of same size weight 995g. With a real pneumatic shock, a narrower tire may be sufficient and a size of 40-559 may save 140 g (making the pneumatic shock not heavier than the rubber blocks suspension).
Having no front suspension, I installed a front 'balloon' tire Schwalbe 'Big Ben' of 55mm. This is a tire similar to the famous 'Big Apple' but with more pronounced sculpture and a certification for 50 km/h (25 km/h for the Big Apple). These tires shall be inflated at 2.5 bar. Their design make them having a relatively good rolling resistance even with low pressure and wide size. Damping is quite good but they have less resistance to flats than the 'Marathon'. Indeed I got a 'slow flat' during the first 500 km, repaired with sealing product, this repair is yet still ok. Weight of size 55-406 is 575 g.
Dérailleur/chain tensioner installation.
Screws to attach dérailleur are metric, 10mm diameter but with fine thread, not standard M10 thread. Fine thread is very rare, so taps are only available from bicycle shops. But, as problems to attach a dérailleur are common, there is a simple solution, it does exist inserts which allow installing a dérailleur by simply drilling a hole diameter 12mm. Beware, theses inserts came in two widths, one for a 5mm thick support and the other for 6mm thick support. I bought mine for 7.5 Euros in a specialised shop which sent them through letter at very low shipping cost (2.5 euros).
I used a Shimano Alfine ct-s500 tensioner (devised to have double chainring on geared hub, capable of 11 teeth difference), but in order to have it not conflicting when folding the rear frame, I inverted the tension spring and the system is 'reverted' compared to similar dérailleur/tensioner. Due to to the spring reversion, there is some added friction but this works anyway. I disassembled the tensioner wheels and discovered that the top wheel and bottom wheel are built with bushings, not bearings and that for a very minor saving, only the top wheel bushing is reinforced with steel while the bottom is directly running in aluminium. So, my tensioner being reverted, I interchanged the wheels. But surprise, the tensioner is delivered with these wheels NOT lubricated - Seriously?? . I set grease under the shields. This noticeably improved the bike performance (not by a huge amount, but something I can notice - and I am a very casual low power old rider, not at all a performance rider).
Bottom bracket crank connexion
The cottered pedal connexion have hopefully disappeared (they were not reliable and tend to un-tighten with time)
There are other type of pedal connection for high end bikes but the most common standard is now based upon a square tapered connexion. But in fact there is TWO (+) standards which are very close but not always compatible, the ISO (international standard organisation) and the JIS (Japanese Industrial Standard) standard (say Asian suppliers, in fact). ISO is smaller and if you install ISO crank on JIS bottom bracket, crank will be set outward by 4.5mm. That will modify the chain line position by same displacement but on a recumbent, this is not very critical.
Painfully, the exact standard is often missing on specifications. Sometimes, square tapered connections are called 'Cotterless'.
Gear hub shifting
If we set apart electronic gear selection, on most geared hub gears are selected by pulling a cable of a given value, knowing that the pulling value difference between each gear varies with each gear and with the hub model, so the gear selector is specific for each hub gear. It is so imperative to have an indexation on the command. There is an exception to that, the Rohloff hub gears did have the indexation set on the hub itself and so the command is made by two pull-pull cables.
For Shimano hub gears which are by far the most common, you will find two types of command: Rotating select and lever selectors called ‘rapid shift’ (which allow up to two gear change at once). When you buy sets, typically the rotating selector is sold with the base models the ‘Nexus Inter’ and the rapid shift selectors are supplied with the higher quality ‘Alfine’ range. Some people prefers lever shifting and others prefer rotating shifting and in the Nexus gear hub series, they are interchangeable for the same gear number hubs (but you can’t use selector of another hub model, e.g. an Nexus Inter-8 selector won’t work on Nexus Inter-7). Except for Nexus/Alfine shifter interchangeability, there is absolutely no interchangeability between hub models and brands and wrong indexation may destroy the hub. Beware for recent geared hub, it seems Shimano have reversed the pull so there may be compatibility issues.
Due to the under-seat position of my handlebar, I choose to have the rotating shifter on top, with cable exiting on top and making a cable loop. There is no noticeable added friction and the thin gear cable can accept such curve (look the radius on the hub mechanism) but the housing was initially not very well maintained and was creating troubles. Gear cables are thin compared to brake cables and accept reduced radius bends without too much friction but it is anyway recommended to use low friction cables and housing (you can use polished cables and PTFE lined housing). To maintain the cable in proper position, I had to build a housing maintainer, done with an aluminium strip 20x2 mm with a handlebar tightening screw size M4.
I searched for a long time what I can use for handlebar. I finally decided for a 'U-bar' and bought the largest I found. It occurs this also is the one with the longer side arms which is quite practical for accessories mount (computer and phone support). It is very light, made in aluminium and came from Metabike. It doesn't look very sturdy. I thought initially that an under-seat handlebar not having to support rider weight will be submitted to very low loads. In practice, the loads may be higher than expected. You push it down when seating. When climbing, you tend to pull it strongly. You push it when doing hard brake. I also use it to lift the bike for manoeuvering. Metabike does not have the reputation to make strong parts and it may be the weakest part of the bike, which can be a problem for such a critical piece.
Another solution which I foresee was to use a beach cruiser handlebar. It may be less practical than the U-bar but you can find one in steel if strength is a concern (Ergotec sell one which weight 880g, this is really heavy. Width is 700mm). However, you may have to add small extensions to attach accessories.
A third option is to use a strong flat mountain bike handlebar with vertical aluminium extensions, but I did not find sufficiently long extensions, so you may have to build connections from aluminium block (a bit like what I did for the handlebar bracket (see below), but with bracket going inside the extension tube.
For ease of manufacturing the first bracket maintaining the handlebar and axis shaft was made from oak wood.
However, it was not sufficiently strong and the handlebar was rotating when pulling or pushing it, so I made a new bracket in 2017 Aluminium which work well though the screw shall be very firmly tightened.
When folding the rear frame, the chain is no longer tensioned. To maintain it on rear sprocket, you need to pull the chain by more than 180mm. I was not capable to devise a system to pull such chain length but with a geared hub (say single speed sprocket), there is in fact no need, you just shall retain the chain on the idler and on the sprocket, chain will remain in place on the chainring by gravity. Yet only the idler retainer is installed but the sprocket retainer will be done similarly with folded aluminium strip (25x2 or 30x3 mm).
Reversed brake lever ?
Due to the position of my handlebar, an ordinary brake lever will be reversed and I was very cautious about it and questioned myself if it will be a problem. I researched ‘reversed’ brake lever, they did exist but only for road bike brake, they are absolutely impossible to find with the ‘pull’ of a V-brake.
Practically, there is absolutely no problem, reversed levers are as practical as in standard position, maybe even better. Don’t forget that a lever rest position is adjustable with a screw, but as the available movement is then lower, your brakes shall be well adjusted (see above paragraph about cables and housing). With V-brakes, ‘three fingers’ levers are largely sufficient for a person without muscle problems and it is NOT recommended to use ‘four fingers’ levers. Remember: on a LWB, your front wheel will lock if braking too hard.
Cable guiding wire
Due to the possibility to fold the rear wheel frame, it is not possible to attach the brake and gearhub cable housing, so they move and tend to touch the chain idler. So I made a wire loop in 2mm diameter stainless steel wire to avoid contact with the idler.
There are two types of seats, the rigid ones and the meshed seats. Rigid seats tend to have the user sweat when weather is hot, while mesh seat breathe more. However, you can install breathing "pads" sold under the name 'Ventisit' which are originally made to be set under mattress in boats. They are a bit aggressive for clothing and may drive to quick wear of your shirts and pants. Rigid seats made in carbon fiber can be very light.
For mesh seat, you find two types, the one with a meshed base built like the back part and the others with rigid bottom with a cushion set on a pan. Generally speaking, the rigid based seat are installed on relatively vertical seat with the bottom bracket located well below the seat base. However, this is not always the case and you can find seats with meshed base on vertical seats, like on the Hase Lepus.
On recumbent forums, some people explained that even in quite upright position, they do prefer fully meshed seat built by Recycled Recumbent, so your mileage may vary. Unfortunately, it seems that like for saddles, seat comfort is something very personal but it is much more difficult to swap seat than saddles and that can be fairly costly tests. The best is to test seats if you have opportunity to do so, understanding a comfortable seat is not the one which is comfortable when you seat in, but the one which is comfortable after hours of riding.
The typical rigid based seat are the one sold by Rans, but it is very costly (500 USD) and Rans have no representative in Europe. Another one is the Bachetta 'Recurve' for 275 USD and may be a bit easier to import in Europe. Both seats looks very similar but you find on forum a lot of people who much prefer one or the other and you may organise an exchange fair...
In Europe, you can relatively easily supply fully meshed seats built by ICE, the standard seat being sold for 200 Euros but they have now a supposedly higher grade seat for 300 Euros. They are reputed but designed for trikes with bottom bracket at same level as the seat base.
I got the opportunity to buy a used Rans seat, but with a too thin cushion. The former owner did add 'ventisit' pads which improves the situation, but that is not sufficient for my taste. I did experienced some 'Recumbutt' at the beginning but this seems to reduce as I became more experienced (overall 800 km at time of writing).
I contemplated the idea to import the thick cushion but the shipping price to Europe were very high (much higher than the cushion cost) for an unguaranteed result, so I abandoned. I did buy an 'ergonomic' cushion for people with seating problems with the idea to cut it to adapt to the rans bottom, but I never did it.
The seat is an old Rans model for Stratus LWB bicycle.
The seat base is attached with clamps done with folded aluminium strips 40x3 mm (folded with a vice and hammer). These clamps are screwed on a half plumbing collar (grinded) to a 16mm diameter aluminium tube screwed on the carbon fiber seat base. The countersunk screws are M5 and the tube was stamped for the screw head (else the screw head will contact the support instead of the aluminium tube). However original thread was not metric but UNF 3/16"x 32 TPI (say diam 4.8mm, thread 0.76 mm) and it was required to tap with M5 (thread 0.8mm) (that is less than 0.1 mm removed).
The seat back is maintained by supports done with aluminium angles screwed on the back of the frame.
Seat tend to slide on its support when pushing hard and the clamps shall be firmly screwed. You need to write position marks on the frame (beware, if your clamps are not perfectly symetrical, the marks are not at the same position on right and left). Gluing a rubber strip may help to have a better grip and protect the frame.
It is not very practical to remove the seat from its support for transport because when reinstalling it, nothing maintain the clamps and you need to guide them by hand. A maintaining spring may help to retain in place the clamps when the seat is removed.
I was willing to have a seat with a foldable back but this is quite complex to devise with the Rans seat as it does only have on attach on the bottom plate. So I am thinking to a wood frame based seat.
Because they are reliable and the battery last for years, I prefer wired computers. However, the wiring length for most brand is typically 80 cm (31") , which was insufficient for my handlebar mount. With below seat handlebar, the sensor shall be installed on the rear wheel.
A known supplier is SIGMA sport and I bought an ultra-simple BC 5.16 (too simple, you may prefer the BC 7.16).
So I searched a support with longer wires. Sigma sells ‘universal’ supports with wires of 1.5m for cargo bikes but they are quite difficult to find. But they also sell standard ‘universal’ support and this is undocumented but the wires are 1,2m long and this is sufficient for an USS LWB.
However, don’t be fooled by the denomination ‘Universal’ which is abusive. In fact, there was a change in the mechanical connection for the range issued in 2016 (BC nn.16) which is not compatible with the former ranges (BC nn.09 and BC nn.12), so in fact there are TWO ‘universal mounts’ which are not compatible. In fact the new range computers can be installed on the old support (while perpendicularly) but they don’t lock properly and the connection points are not perfectly aligned. Note that with the new range, there is no wired computer which can display the cadence (whatever the brand). I did replaced this too basic computer by a Sigma BC 16.12 (no longer produced, but it could be in stock in some shops, I bought mine on Amazon market place) which I equipped with a low cost wired cadence sensor (sold separately). Don’t be fooled by the novelty, the old Sigma series are of same quality, and maybe better than the new one. On a wired computer, it is very important to firmly lock the wire to the handlebar before it enter the support, as the junction between wire and support will break over time is there is frequent pulls on the wire (that is the reason why you find supports as spare). Cadence sensor wires are too short and as they don't exist as spare with longer wires, I will lengthen them.
I was warned by forum threads that on a recumbent, mirrors are required because it is too difficult to rotate your body. No problem, I have a mirror on my upright bike so I am used to, while I still rotate head and body when possible.
Though, where to install the mirror? Some say that this is not OK on handlebar because it rotates. This argument doesn’t hold much value, this is the same on any upright bike.
There was some suggestions to use a helmet mirror. The mirror is very near your head and as I have not much optic knowledge, I was thinking the focus distance was the distance of the reflected objects, not the mirror distance. Though, it seems it doesn’t work like that and that you shall focus on the mirror, at less than 20cm, this is only for young people. For those over 40, have no hope, it will absolutely be impossible to focus and the image will be very fuzzy. Plus changing focus from 100m to 0.2m quickly is not that easy and create a significant and lengthy distraction. Maybe the problem is elsewhere and the brain is troubled between the mirror frame and the mirror glass but in any case, that simply absolutely don't work (for me, at least).
Then I installed a Busch and Muller Cyclestar mirror on the top of my left handlebar (for right riding). This is a sturdy mirror with many mounting options. The mirror is small (65mm) but is is convex and the covered field is larger than you may think at first. It worked but I bought another one of the same model with a larger mirror of 80mm diameter. This is really much much better and I am now happy with this mirror (this mirror is also convex). The small mirror was not a loss, it changed place from the left to the right of the handlebar.
The only problem is that very significantly increase the bike width and mirror always get pushed when passing doors or motorist filters or when parking. Their tightening shall be finely tuned for them to move when impacting stuff but staying in place with the bike vibrations. They somewhat tend to move on rough roads. Also, your handlebar shall be firmly locked as mine was somewhat rotating in its support on my first trials and that was also dis-aligning mirrors. This make the bike larger than my pedestrian home gate (which is fairly narrow). I broke the right mirror while loading the bike in my car and I will not replace it, the bike being narrower without right mirror and the experience telling that left mirror alone is sufficient for all uses.
It is really needed to use a chain guard if you want to avoid trousers being catch in your chain-ring. Note that on a recumbent due to the horizontal position of your legs exposing them directly to sun, you may wear trousers instead of shorts more often than on an upright bike to limit sunburns.
For a hub gear transmission, you shall be aware that there is two widths for chain transmission 1/8" and 3/32" and the width of chain-ring and sprocket shall be attuned with the chain width. The most common (stronger) width is 1/8" and such chain is too large to go through a chain guide tube, they don’t even enter in. But if you have a simple chain-ring without a front dérailleur, it is relatively simple to use traditional town bike chain guard which are maintained by a support locked by the right bottom bracket cap. Chain ring protector helps but are not sufficient to avoid trousers catch which can be dangerous in some situations as they can pull your foot off the pedal - and incidentally destroy the trousers.
Crank and pedals
On recumbent, it is preferable to use shorter crank arms. Typically, the crank length is around 150mm, but can be lower if you have short legs.
Short cranks are not easy to found and what you can find is often children cranks. Children cranks are often low quality steel but it is doable to get better quality aluminium cranks. There is a small problem though, some children cranks have a lower diameter thread diameter for the pedals attach, say 1/2" while most adults cranks have pedal attach thread of 9/16" (with rare exceptions for some BMX). And as usual, this is not always documented when you want to buy online. You shall avoid 1/2" pedal attach as they will be less strong and they will dramatically reduce your choices in pedals, notably preventing the use of clipless pedals.
Excluding high end mountain bike standard, there are fundamentally three standard on traditional bottom Bracket, The French, Italian and British. Nowadays, The British standard have became the norm and we are referring to it as BSA (British standard association) threaded bottom bracket. Most common width is 68mm (could be larger for mountain bike), the thread of the right cap is left-handed, 24 TPI (thread per inch) with an internal diameter of 1.37", say 0.945 thread per mm, internal diameter 34.8 mm. The thread of the left cap is right-handed.
For the Velassi, I escaped all the trouble by using an unthreaded ‘repair’ bottom bracket which is centered by its end cones and screwed on itself. These ‘repair’ bottom bracket use standard cartridge bearings.
Due to the width of my wood frame, I choose to use the largest bottom bracket shaft available, say 127.5mm (that will be reduced on new design frame). By prudence I bought the bottom bracket before building my frame, and that was a good idea because the bottom bracket was asymmetric, with the right shaft 5mm more outward than the left shaft, supposedly to left room for the chain-ring. This was not documented on the online shop and not even indicated on the box which had a drawing showing a perfectly symmetric BB. I then built the bottom bracket holder to compensate this asymmetry (shifted on left by 2.5 mm). I ignore if all large bottom bracket did have the same asymmetry. After much thought, this asymetry may be related to the possibility to use this 'repair' shafts on 73mm wide BB (on mountain bikes), where they became symetric as shaft will be shifted by 2.5mm on left compared to a 68mm BB.
Because they are unthreaded, it is difficult to disassemble bottom bracket caps, so I made a ejecting tool with a splitted tube. You also may need two bottom bracket tools instead of only one to disassemble because the BB may turn freely in its support.
To stabilize my steering and improve low speed handling, I installed a fork spring.
I choose a model made by Hebie, a German accessory manufacturer, mostly known for kicktands.
I choose the 695 Universal model.
There is two angle brackets supplied with the 'Universal' model but only one spring size (78 mm eye to eye), and I installed the small bracket. With this spring highly tensioned, the system work but have a quite high return force when the steering is at its maximum angle (which help tight radius handling). I think the larger bracket may be a better solution with higher initial spring force but you need a longer spring, which is sold separately, but you have to select the longest spring.
To be able to attach parts, luggage rack and other stuff, I used M5 wood insert. The cheapest model made in zinc alloy which can be screwed with an 'Allen' key is the most practical because it is easier to be maintained perpendicularly to the wood part when screwing it. All these inserts are first installed before part or frame assembly to create the wood thread, then removed and finally installed when the resin is still liquid and the holes are impregnated with resin prior to insert screwing.
Rear wheel frame retainer
I quickly discovered that it might be useful to lift the bike to displace it, but with the folding rear frame, the rear wheel remains on ground till a very high lift. So I made a rear frame retainer in 2mm diameter stainless steel wire.
On a recumbent, you can't use a backpack to carry stuff as I do when I use an upright bike.
I had since years a 10 liters handlebar bag which was never used (this is the largest size for handlebar bags).
While it was equipped with a CTS quick attach, I found simpler to add hooks made with aluminium strip 20x2mm to be hanged on the seat top bar. These hooks allow easy removal and are screwed in the back plastic reinforcing sheet. I may remove the quick attach but as is, the bag can still be used on my upright bike equipped with CTS support. The hooks are also used to store the bag in house (wall support made with IKEA kitchen accessory). A messenger bag might be more practical, easier to use outside the bike for visits or else, but you shall design a seat support.
This is not the best solution because this sort of bag is a bit heavy (800g~900g) and a specialized seat bag may save you a few hundred grams for a larger volume.
To have a larger bag (18 liters to 25 liters), you need to buy a specialized seat bag for recumbent at a larger cost. However, all these bags are don on the back top which in my case might be conflicting with the rear light also located on top of seat back.
Three suppliers for recumbent seat bag:
My seat (Rans) don’t have a flag support and I initially devised a system based on folded aluminium flat bar pinched on seat side tube. Unfortunately this was not sufficiently strong and I lost (and never recovered) my whole flag installation the first time I used it. I then bought a Burley trailer flag bracket and a standard bike flag (most bike flags are all identical with plain glass fibre pole 6mm diameter and plastic junctions). You also can find flags for children bikes with pole made with tube and an inside rubber, but they are too flexible.
I screwed the Burley bracket on left seat stay. This bracket is of too large diameter for my 6mm pole (probably 6.35mm-1/4 "), so I use aluminium tape around the pole to have proper locking. With this new installation I then lost the flag in forest on trees lower branches as flag was only pinched with a weak plastic collar (and never recovered it).
I replaced this flag with reflective strips (50mm-2" width) that I sewed then glued with polyurethane sealant on the pole.
For festive rides I bought a nice Weather vane (brand HQ) which have some success. Beware, it is even more sensitive to lower branches than a flag.
I lack easily accessible room in my house and garage and it is not very thinkable to left such bike outside like I do for my rugged town bike. So I built a shelter to protect the bike from weather and vandalism (while there is a gate to access my home). There is a wall anchor and the bike is always attached. Till this was built and the anchor set up, the Velassi was sitting in my living room, which was not much practical...
Rear light attach
The ideal place for a rear light is on the top of the seat, unfortunately this did escape to all recumbent seat manufacturers. In addition, my folding rear frame prevent installation of the light on the rear fender. On my seat (Rans), there is a top bar covered by fabric, so if you don't want to damage the fabric, you have to 'pinch' the bar and fabric. I did fold aluminium strips (22x2mm) to make the light brackets. They are strong and not easily removed. It shall be noted that on the light (a Trelock LS615), once the attach nuts are screwed, they cannot be removed as the rod turn freely, I suppose this is done to avoid having your light stolen, so be sure that your brackets are ok before tightening. Another point is that you may need to remove the seat for transport, so a plug is required for unwiring the seat. It is a good idea to add a second plug in order to be able to add a mast light later. I also discovered that the rear light support makes a very useful hook for a grocery bag set atop the handlebar bag.
Shimano plug for hub dynamo
Shimano hub dynamo was delivered with the wheel with an installed plug and no manual.
The plug is made of two parts which shall be disassembled to insert and then pinch cable between these two parts, that I did't initially understood and I simply pinched the cable between the plug and the dynamo male part but that did'nt last for long and I finally understood the mechanism on further inspection.
To navigate with a smartphone, I initially installed a German made Busch and Muller plastic phone support. It was slipping in rotation on the handlebar so I added rubber but I finally replaced this plastic support by a very sturdy aluminium one (Chinese made...), though this new one does have less flexibility for positioning. I had to file the right bottom support to be able to plug a charger wire in the phone (I produce electricity from the hub dynamo and use a 5 Volt converter USB2BYK).
Many things on such prototype bike are difficult to find and you have not many options to buy stuff but go online. The big problem is the online documentation is often scarce and very basic information is missing. By example, for more than 2/3 of the product proposed on online shops, you will not find the weight which is a bit insane for bicycle parts. Even for a utility bike, you shall be cautious of the weight. An utility bike is heavier than a road bike, but that does not mean that you shall not take care of the weight.
You will end up asking simple questions (mostly on dimensions) which may or may not be answered (often not). A few shops set online the questions and answers and this is a good thing.
A very typical example of question:
I was needing a front light support attached on the top of fork tube (on 20" fork, low attach is too low). This does exist but all these supports are for 1" tube only, but in most cases this is not mentioned. One shop did proposed multiple references for such support so I assumed the maybe one could be in 1"1/8. My question about that was never answered and I ended up building a light support in folded aluminium flat strip. No big deal, but that need time and tools. No name here because the problem is universal.
Sheldon brown The world universal reference site for bike mechanics, the site of the late Sheldon Brown (still maintained by friends)