Saturday, August 29, 2009

sram i-motion 9 thoughts


D: I stand corrected.
The gears shift at a regular rate throughout most of its range.
The % change per gear is a bit more than the Rohloff.
D: I cannot figure out how that one store I mentioned can be so cheap.
I think they only have 3 in stock, and must be dumping it.

The fan sites say the chainring to cog tooth ratio must be 1.7-1.9

If I were to use this with an industrial belt, I'd want to keep the torque on the belt down.
However, with a fixed chainline and ? a series of track bike chains strung together ? the torque limit of the gear hub is the only issue.

IZUMI ECO Gold Track Chain. $23.95. Premium 1/8 " gold plated track chain. ... Weight: 277.0 g; Compatible with Shimano 10-speed drive trains [more] ..

D: OK so a chain of say 10' length on a 'bent would weigh, what, 3x that?
about a kg.

Recumbents use standard bicycle chain times two or three — sometimes more. ...
Hmm. narrow 1/2 weight nanodrive.

That was all back before anybody who matters was even born, and now it's time for the first 21st century drive train: "Nanodrive/Quarter-Twenty." This new modern universal standard cuts every dimension of a traditional chain in half! 1/4" (6.35 mm) pitch, with sprockets just 3/64" (1.19 mm) thick. In addition to cutting the weight of your chain and chainwheels in half, it also lets you fit twice as many sprockets as the old fashioned systems!

Mechanical Aspects

Although the new system has 20 rear sprockets instead of only 10, they fit in the same space, since everything is half the thickness of the old junk! Thus, they'll work with any standard frame.

The only parts you need to replace are the rear wheel, the front derailer, the rear derailer, the cassette, the crankset and chainrings, and the shifters! Nothing to it!


D: my lousy Paint pic is a revision.
Gawd I must learn Google Sketchup !

Anyway, as you can see, this addresses clearance on the front wheel with a series of cog adjustments to vary the belt line.
This is to address the idea of a one-size-fits-all industrial belt mod to work on 'bents.
It is a worth a pound or two in weight savings.

Friday, August 28, 2009

pic of proposed system for one-size-fits-all bent belt

D: this system would allow small to large riders to all use one standard size of belt.
For my purposes, it may allow me to adapt the bike to a pre-existing length of industrial toothed belt rated at least 1000 kgf.
Though this requires great care in gearing to avoid too much torque.
It probably favours a fast cadence of 100rpm or higher.

I don't think a front 26" wheel will play well with this.
I was already thinking 24" a the front.
I am unwilling to go down to 20" since the road bumps are felt severely.
Of course a 24"26" wheel layout pretty much requires alloy rims to keep the weighty feel of the spinning centrifugal momentum down.
I am not worried much about the gear and dynamo hubs since they are not at the rim.

I see that the adjustable point under the seat is also an ideal place to mount a motor assist. I was still pondering that Tetz 12V system.
I'd very much like mount a dynamo there instead of on the front wheel.

This layout precludes a chain-thru-frame layout, though, a la Green Machine.

As much as I'd dearly love a proper generator as opposed to just a dynamo, the weight penalty and complexity seem to preclude it.
The FreeCharge 12V Personal Energy Source is a lightweight, durable and efficient power source for mobile phones and other electronic devices. The self-charge system is powered entirely by winding a hand crank, so is independent of all conventional power supplies or batteries, enabling you to make and receive calls, or charge other personal electronic devices, at any time.

The FreeCharge 12V consists of a generic base unit and interfaces to the coupled device through a generic cigarette lighter socket.

My design goal was around 100 input watts to the motor and less than 10 pounds total system weight. It came in at 4.2 pounds, 1.9kg ! -- That’s every thing – motor/gearbox/freewheel/mounting bracket assembly, battery, electronic controls.


standard chainline causes grief on Cruzbike

Gah.It did it again!
I was going uphill. Switching to easier and easier granny gear.
I left the front chainring on the biggest ring - again.
With moderate force on chain, as it reached the biggest cog, the chain had least play for the tensioner, and also the most severe sideways bend.
And... jammed solid. Again.
I think maybe I need a longer chain. Another 30 bux.
I think either a smaller largest cog or a longer chain may be desirable for a Cruzbike.
This is making me fond of the idea of a straight chain line and gear hubs.
I think the 1/8" track chain has bushes that keep it from falling off sideways or flexing enough for a standard bike system.


"There are two common widths of single speed and fixed gear bicycle chains: 1/8 inch and 3/32 inch. The chainring, sprocket and chain should all be the same width. Although an 1/8-inch chain will work on a 3/32-inch chainring or sprocket, it is not ideal. A 3/32-inch chain will not work on a 1/8-inch chainring or sprocket. Because they do not need to shift from sprocket to sprocket, track chains use a full bushing to allow little flex and to be stronger. All bicycles with derailleur gears use bushingless chains which flex, making gear changing possible."

D: though a belt system would be sooo much lighter for a RWD recumbent.

Hmm. OK, the idea of getting a single custom toothed belt rated at at least 1000kpf made sounds... difficult AND expensive.
I know recumbent SWB RWD bikes are pretty niche.
But the weight savings of a toothed belt/ gear hub arrangement would be great.
I wonder what the smallest limited production run would be for this?
Of course, investing in this could result in me retiring with crates of the things in the basement still, LOL.

D: this would require a conversion kit that interacts with standard bicycle components.

As always, I doubt a big company rep will talk to a lone innovator, but I'll try.
Gates company seems promising...

Thursday, August 20, 2009

# of gears in i-motion 9, thoughts

Make & Model Range 1st 2nd 3rd 4th 5th 6th 7th 8th 9th

Sram i-Motion 9 340% 0.54 0.62 0.73 0.85 1 1.17 1.38 1.61 1.84
D: THAT'S the secret the SRAM rep wouldn't tell me?!
It's what I thought it'd be.

The percent hop between gears is pretty choppy.
Compare to the Rohloff, with uniform steps.
plus .09, plus .11, plus .15, plus .15...
Not ideal, but likely tolerable.
It does mean going above/below personal preference on cadence.
It means mid-range, one must spin-out with too high a cadence for comfort prior to switching.


I probably listed this last year, but this is a frickin' terrific article!

Point is that the devil is in the details.
If yer out of yer cadence but in an ideal gear, the result is similar to in yer cadence but in a less-than-ideal gear.

Weight versus Drag.
A fairing pays for itself- at speed.
Uphill it is a bugger.
Then there is cross-wind.

If I build a fairing-less cycle with commuting in mind, the gearing simply will NOT be what I need for a road tour with a fairing.
The gearing for commuting can be midrange, and mid-level gear hub will suffice.
I don't have alotta weight or severe hills for low gearing.
I will just coast downhill, and won't be racing, so no high gearing either.
BUT put this cycle on a road tour with a ruck sack, after a day (or week) of steady cycling, and the demands are extreme.

I mentioned my Mark I, and contrasted it with the FB Green Machine.
Well oddly I can make up the weight penalty of the Schlumf Mountaindrive.
(I'd go to a larger chaingring for the default gear hub arrangement on the road tour.)
I can offset the weight via an industrial toothed belt.
The whole thing is sealed, so other than ambient humidity, there are no environmental considerations.

D: basic primer on gear hubs.


OK just one question.
Why for the love of god?
This is a damn penny-and-farthing.
It'd creep along at, what, 10kph tops?

Now tack a Rohloff hub where the pedals go, and Bob's yer uncle!
No idea how to attach it.

You listening, big impersonal unreactive corporation?

Wednesday, August 19, 2009

im9 vs nuvinci gear hub

Amendment: yesterday's dream bike has an issue.
It shows rear steering.
This has NEVER worked.
I just assumed it used a Python mid-steer layout, which CAN work.

I do like the Triton-trike style steering handles.

I pondered an around-the cyclist version, versus underneath.


D: Niagara Cycle Works seems to have both good variety and great prices.

Let's put the Nuvinci and I-motion 9 head to head:
IM9, 270 bux, c. 2kg.
NV, 350, TWICE the weight.
As intrigued as I am by the continuous variable drive, I just gotta say no.
Plus changing the tire becomes a huge task.
Meaning monofork.
Meaning theft issue of very expensive wheel.

The Rohloff also weighs 2kg.
Meaning with Schlumf Drive, the 350% range hub plus .4x option of the Schlumf will weigh more.
However, it STILL costs less than the Rohloff at $1400.
Schlumf Drive 400-500 bux.

Obviously, if price is an issue, the R-hub is plain out.
But if weight is at a premium, it's the winner.

I can buy a 250 buck IM9 at first for commuting, then for touring get a Mountaindrive for the partial-fairing/rucksack payload.
I'll need a granny gear from hell, particularly after protracted multi-day cycling.

Again, the internal single chain of the Mark I means no frame-embedded hub drive.
It will be on the rear tire.
Changing tires on the road means the IM9 too.
And anti-theft precludes monofork, or else a long cable (the siren one is long).

D: Dualdrive costs 450 bux.
Just by way of comparison.

Does anybody know of an industrial belt that could be modified to drive a SWB recumbent/ RWD?

nice fold down bike design.
Also nice.
I cannot imagine those lil' wheels on potholes...


Tuesday, August 18, 2009

sexiest bike concept EVER

D: fuzed some upright designs into 'bent bike.

1) that style of upright
2) steering from Triton trike
3) mid steer from Python DIY

But mixed together, man, that would be one sweet ride!

This design can go with 20" wheels where my concept cannot.
I was just gonna put the pedal crank thru the front wheel axle.
Sufficient road clearance pretty much dictates 24-26" wheels.
And that pretty much precludes a lowracer, if only to see over one's own knees.

A problem with 26" wheels is for people with short stature to stop and steady the bike.
The Orca is a good example of this problem.

D: note how the body suspension pivot point pretty much cries out 'internal gear hub'.
Leaving the wheel hubs naked, or for...
The right hub depends on the rider, his planned type of ride, and the bike gearing.

I'm pondering chain efficiency.
This favours the largest chainring possible.
But then we face a weight penalty.
Having 2 medium sized toothed chainrings/cogs is likely a decent compromise.

Keeping the chain taut is tricky if the front boom is not adjustable.
A slight pivot, even with an internal-in-frame chainline is doable.
You'd wanna switch from square to rectangular tubing for that.
And it still works better with a frame pivot point and embedded gear hub.

A taut chain is important for effiency.

I was pondering how a FB GM (Flevobike Green machine) layout could be made at home.
I think the frame will try to twist sideways.
The front and rear parts are both off-centre, to work around wheels.
In my case, the front boom is on say the left, and rear the right.

I looked at Fuller's 'octet truss'.
This can be simulated somewhat by welding triangular cross struts in a left-right layout.

I'm sure a weight sweet spot exists.

D: I had the chance to try an electrical power assist last weekend.
It was a lithium bionx unit.
Nice assist, but wow does full assist ever drain the battery fast.

D: a bike frame starts running out of places to attach widgets in a hurry.
I'm all about the fold out baskets.
Even so, they preclude use of a luggage unit - a pannier.
A bent bike might favour some attached under the seat and beside the rear tire.

Monday, August 17, 2009

thoughts on DIY mod to house wheel dynamo hub in a bottom bracket

D: I would like a dynamo in the bottom bracket.
However, Shimano controls the patent and shows no signs of making this product.
They do make wheel hubs though.
Well... I *could* make a custom bottom bracket.
It could be big enough to accomodate a wheel hub.
I suspect there will be issues with diameter difference between a pedal crank axle and a wheel axle.
This is not insurmountable, though I may require expensive high-end metal.

As an aside, one could also place gears here in lieu of a wheel gear hub.
The benefit would be
1) harder to steal
2) less in way for tire changes
3) no mass to accelerate on the wheel, which deals with centrifugal force too.

D: OK it's called a spindle and not axle.

I had endless grief with terminology building the Cruzbike.
The instruction used on set of terms.
The bike shop didn't even know what they were talking about.
I.e. Threadless or not front steering tube.

There are so many bottom bracket arrangements!

"Ashtabula (One-Piece)

With an Ashtabula crank and bottom bracket, the spindle and crank arms are a single piece. The bottom bracket shell is large..."
D: maybe I don't need to go custom.
D: here's a pic.
Nice overview of brackets, various pics.

D: I guess a dynamo is not a true electrical generator somehow.
My bud Ryan is intriged by the idea of regenerative braking on a bicycle.
I suspect the weight penalty is prohibitive.
I think the lightest I found would be electromagnetic, which would involve elaborate and demand power control.
D: I suppose yer suspension could power a battery or capacitor too.
Why waste all that energy?
The bumpier the road, the better the energy harvest.

Any talented electrical engies out there?
What is the weight a bicycle -ready electromagnetic generator?
It is estimated that regenerative braking systems currently see 31.3% efficiency;

D: a strong enough setup would remove the need for a mechanical brake.
This implies the front wheel because
1) it works better for regenerative braking and
2) not locking up the front brake is actually desirable to avoid losing control.
Energy efficiency potential for single vehicle: 5 - 10% ...
Sweet! Why waste all that energy with a stationary bike rig?
Even charging USB devices and cell phones is pretty brilliant.

I refer again back to Tetz's awesome setup.
D: I suppose it could be mod'd to double as a generator.
You could listen to tunes or chat on a (hand free) cell phone without draining batteries.
I'd recommend helmet-mounted speakers to allow listening for traffic.

D: the FWD Cruzbike layour encourages:
1) extra weight at the front end - like a battery and
2) dual drive wheels, with a power assist on the rear wheel, to deal with steep hills.

A commuter bike can use lotsa torque at slow speeds for red lights and hills.
But a touring bike could use much less torque but at medium speeds.
You can have two wheels with motors mounted, or you could swap out motors on the bike frame.

Again, I'm intrigued by the idea of a partial fairing with solar panels.
It could assist you all day and/or charge yer electronics.
But given the measly power offered by the sun, maybe charging commuter batteries during the day for the return trip home is desirable.
This would allows 2x the power to be used as assist, since half does not need to be saved for the return trip home.
A simple wall-plug arrangement could also work.

While we're at it, the motor assist could also be housed in the bottom bracket.

A poor man's Greenmachine could involve a Nuvinci or IM9 hub drive mounted in the frame at the pivot point for the suspension.
Then or later, one could add a Schlumpf bottom bracket drive.
The price still comes in wayyy below a Rohloff.
Though if they ever release the 580% range version, I might not care.

I do think my Mark I, with its single enclosed in-the-tube-frame chain is elegant.
Such an arrangment DOES mean a gear hub must occupy the rear wheel.
I don't like this from the point of view of theft risk.
The dual parallel bike frame is very easy to secure with a bike lock.

I'm tempted to try an industrial drive belt in lieu of a chain, with potentially pounds of savings, plus less noise.
I imagine torque would cause it to slip.
You'd need very good granny gearing for hills.
A Schlumpf drive would address that.

The many benefits of a belt – nearly impossible to break or cut, long life, no grease, easier on pants legs, no rust, no stretching, low maintenance – are offset to a great extent by the current lack of a derailleur design that can handle a belt

D: a belted design pretty much demands a gear hub.

D: maybe I'll try to modify some industrial belt for the Mark I GM-homage bike.
It would be one of the few mods that would improve the already terrific Flevobike!

Tuesday, August 11, 2009

olympic cyclist dream bike, cruzbike continued

D: other than the electronics, this is a mishmash of various existing conceptual bikes.

"The new bike design has a built-in locking system that can only be activated and opened by the owner's fingerprint. The computer-equipped machine can also monitor the amount of calories burned. Made of carbon fiber, it will even have a battery that will assist you when going up a steep hill, as well as puncture-proof, self-inflating tires."
D: I have a 120db siren alarm cable lock on my Cruzbike.
I am not particularly impressed with the package though.
I suspect the plastic joint could be broken with a hit.
Also, all it takes is two pointed items to pop the case open.
Using the key as the basis to open it would address that.
Also, I bought 3, and 1 siren didn't work. The quality control is meh.

D: I think I mashed the chain guide on my Cruzbike.
They took off the guard to fit the aluminum cranks.
Unfortunately, the front end of the CB is massive and has a habit of swinging around.

I went to the shop to ask for better gearing at the high end.
It is a standard 21 gear mountain bike arrangement, Shimano, freewheel.
The 48 vs 42 tooth chainring would cost about 300 bux !!! nope.
But a 13 vs 14 tooth swap would only cost 30 bux.
This gives me about 10 vs 15% increase in range at high speed. I find a CB bike favours less granny gear and more high speed gearing.
High cadence seems to introduce instability, whereas more slow-but-strong pedalling is very stable.
My youth frame 'spins out' around 20-25kph. If I can stably ride at cadence at 30kph, then I'll be happy.
The 60 pound beast (with accessories) favours just coasting downhill anyway.

In the shop...
I asked them to take off the biggest gear - that's the one that caused the chain jam.
I don't use it anyway.
I DO wish to place some additional padding at my lower back. Pushing hard while applying torque, I bruised my lower back. It was tender for a few days.
I think I'll hafta add the padding above the seat. The tape-and-velcro affair underneath does not lend itself to modification. I'm looking for some mid-resistance foam for that.
I do wish the screws for the seat mount had been recessed.
As it is, the seat padding has 2 layers of foam- very rigid and very soft.
Without screw heads sticking in yer back, perhaps a more layered foam layout involving ? 3 layers would be more comfortable. The rigid foam could be thinner.

Aside - I'm curious why the factory does not attach the metal seat edge trim with silicone.

Seat idea - a seat back with some flex to it, attached to a frame, could allow for custom lower back curvature for any rider, of any height.
Maybe I'll try that on the Mark I.

One more thing. I installed that kickstand thru the unused bottom bracket.
It worked well enough- except the front boom would pivot and pull over the bike.
So I need an additional kickstand on the front boom.
A small latch for the boom would hold it in line with the bike frame.

Thinking about the CB conversion kit, I think:
1) the tube diameters they selected feel like a road bike motif.
2) the tubes should be large aluminum ones for a mountain bike frame.
3) the bottom bracket needs a plug of some kind to look finished.
4) the chopper handlebars should be an option in the basic kit
This would mean swapping parts. Ditto the superman bars from Silvio, if a kit mod can be made.
5) multiple kits of parts and instructions are redundant and confusing
6) instead, include the aftermarket different-size steering tube I needed to order
7) make a DVD!!! With a tutorial, this is a DIY project.

I'm curious how light a CB layout can be made.
I think I'll grab a coupla beater hardtails and have my pal Fern weld them.
I'll just chop off the redundant pedal axle.
I think the seat should be the part that adjusts for rider height.
Might need to modify one tube for the seat position.
Instead of rear suspension, I can test my dual-'bent-Thudbuster layout.
I *could* use the CB bike, but would need to make a faux-seat-post for that.
Hmm, thinking about that, finding some square tubing for the top tube might be easier.
No chance for the seat to rotate sideways and fall down.
I guess that could be tacked onto a round tube on top.
(Image won't load.)

This woman's frame seems adequate too.

That is something an upright bike has going for it - the diamond frame dual triangle layout is as strong and light as possible.
A lot of LWB 'bents attempt to emulate this geometry as best they can.

The SWB lot seems to gravitate toward one rigid tube.
The Bacchetta series, for example.
One hi-end frame weighs in at only 23 pounds!
(see pic)
I understand why they prop up the seat back on the frame - it's light.
But my suspended-seat concept requires a free-floating seat.
It needs its own rail mount.
For that matter, a rail could in theory allow more range of motion, with the seat extending rearwards past the frame itself, towards the rear tire.
The idea is use the simple no-suspension frame geometry.
Then get fancy with the seat mount.
It has potential as an aftermarket accessory on, say, the Bacchetta series.
But I fear one-size-fits-all would be too much to hope for.

Thursday, August 6, 2009

Cruzbike tweaks continued

Well, I think I need more chain length.
I think 2 gears that both use the most chain pull the um tensioner derailleur things together and they jam.
So, really, nothing to do with Cruzbike.
One cable does hang low to ground, could get caught in rough terrain.
I'll likely tie that off to be higher.

I bought some spare used bottom bracket threaded bits.
Threading in a bit to the thicker portion, then I'm chopping off excess with grinder.
I should have drilled a wider hole in the kickstand, so a bolt would be flush with the axle hole size.
I'm drilling an off-centre hole for where the little nub inserts, to keep the kickstand from shifting.

D: the trim on the edge of the seat pulls off nearly constantly.
I used some tape.
A better solution would be use some silicone caulking to attach it.

To reiterate, a kit part that mounts an axle-type kickstand thru the old bottom bracket would create a nice, finished look.
The empty bottom bracket is an eyesore.

Even the short wheelbase for the youth frame is actually good at speed.
I find a high cadence is less stable.
A slow steady cadence with constant pressure is ideal.
I'm thinking about losing the one gear that caused the jam.
I'd like to add a higher ratio one at the bottom, for high speed.
Not sure how few teeth are available.
Would be easier than an even larger largest chainring. And lighter.

I finally like a mirror on a bike.
On a chopper-steering CB 'bent, it is at comfy eye level.
It doesn't vibrate much.

I think aluminum tubing on the Cruzbike conversion kit might be desirable.
The front end is frickin' HEAVY, even with aluminum cranks.
And it flops around a lot.
After all, with a mountain bike Y-frame backing it, motif-wise, a thick tube visually looks better. The joint pieces could still be steel.

I'd highly recommend standard round tubing frames for Cruzbikes.
Mine has a lot of odd geometry, and finding places to anchor accessories is a problem.

My thoughts turn to the Mark I.
That is, the DIY Greenmachine knockoff.
Will measure, get square stainless tubing for frame welded this summer by pal Fern.
I won't likely really seal the chain inside.
I can do so later.
The bike will test:
1) variant thudbuster suspension on seat
2) test a backpack /rucksack mount system. Though the CB can do that now.

I'll likely start with a NuVinci hub drive, followed by a Schlumph Hyperdrive later.
Of course, I'd LIKE one of those new 580% Rholoffs but $$$.

Sunday, August 2, 2009

cruzbike malfunction, idea for another item in the kit

Disaster strikes!

I had put a coupla hours on the Cruzbike.

I was on the other side of town.
I was going uphill.
There was a fair bit of torque on the gears.
I tried switching down the gear, to increase my cadence.
Somehow, the whole chain derailleur affair ended up in this jammed bunch.
No more pedal power.
Since I could not recall the initial layout of the parts, I could not begin to guess how to fix it.
I'll try to find some earlier pics for the details.

I wonder if these bikes are prone to this, or if my rebuild was not laid out properly.
There had been a bit of grinding on those gear changes earlier in the ride.

Product idea: A centrally located kickstand makes the most sense for a Cruzbike.
Some way to lock the front wheel straight would be nice too.
Anyway, the kit leaves an ugly empty bottom bracket on the original bike frame.
This is a PERFECT place to put the kickstand!
I'll be using a couple big washers, some smaller ones, and a fat bolt that spans the width.
I'll use these to attach a standard kickstand.

Once again, if Cruzbike would stop throwing all parts for all kits together, the savings could be applied to the nonstandard front steering tube *thingie* I needed to order aftermarket.
Plus the above suggested layout for the kickstand in the bottom bracket could be made much more slick in the kit.
I don't think this would cost more!
I had more redundant (and misleading/confusing) parts from the kit I received...

I'd really like to see an adaptor for the kit that allows the 'Superman' steering from their other bike.

I solicit feedback from other Cruzbike owners.

Saturday, August 1, 2009

cruzbike, amended. back from shop.

Well, I had my pal Sanjay over.
We tried to sort through the parts for the two kits thrown together.
After hours, we concluded we were simply missing a part we needed.
We needed an aftermarket ... um the thing inside the steering tube.
The diameter was wrong.
I took it to the shop - McPhail's - Sanjay swore by Jamie the mechanic's prowess.
Anyway, a few weeks later I got my bike back.
I guess the wrong sleeve to adjust spacing had been ordered.
But it is WORKING now.

I foolishly tried to replace the kickstand on the rear axle.
I had forgotten that Mike needed to place the whole thing in a clamp to put the rear tire on.
Much jumping on the bike frame later, I managed to re-attach the rear tire, sans new longer kickstand.
This turned out OK.
I plan to use the now-empty old bottom bracket with some bolt and washer affair to mount the kickstand more centrally.
A Cruzbike has a whole lot of front to it.
The alternative would have been to mount a kickstand fore and aft.
OR get one of the heavier bike types, with dual ground points, mounted centrally and underneath.
They are all but impossible to find now.

I weighed the bike.
Keep in mind, it IS based on an all-steel youth frame.
It does have a pannier mount and 2 side baskets mounted.
It came to... 55 pounds. OM- F- G.

I'm not sure how much instability was removed from the bike by a proper and professional front fork construction, instead of the improv job I used.
I HAVE been balancing by walking on railroad track rails all year.
I am so good that I need to put my hands in my pocket to make it challenging.
Plus my yoga routine helps.
I took it to work and let the coworkers try it.
They looked like a bunch of drunks, LOL!
I do think a standard non front-boom SWB 'bent is easier to ride.

So here is a thought.
Instead of confusingly cobbling together parts for two kits, instead include the aftermarket front-tube insert that will be required on many bikes.
I'm sure the cost would be about the same.

And for the love of all things holy, include a DVD on how-to!!!

With the youth wheelbase (coupla inches less) and gearing, the bike is pretty much capped at 20-25kph.
It is a fine workhorse of a commuter bike.
Until my steering skill improves, I would not want to go faster anyway.
Poor handling introduces some instability around 20kph.

Nobody has made oval chainrings help much.
I suspect this is due to pursuit of efficiency in the layout rather than ergonomic considerations.
Having said that, a few modifications to standard pedalling technique suffice.

I.e. a GreenMachine knockoff.
To test my suspended-seat suspension system on rigid frames.
And a backpack/rucksack luggage mount system.
My pal Fern is a genius welding stainless steel (and titanium even).
So it'll be stainless steel tubing, burnished.
Borrowed from the Python mid-steer DIY design.

While the initial Thudbuster-derived suspension system will be a dual arrangement, the final version could be off-centre, one-side-only elastomer.
I'll just go very light on the elastomer.
That is, I'll have TWO very lightweight elastomer pads in lieu of one heavy one.
A very interesting product.
I'll likely buy one to try it out.
NOT cheap...]

I've been using my roomie's bike.
It has a seat post suspension mount. The seat is gel-filled but narrow.
I STILL bruise my seat bones when at all off road!
Those old spring-mounted fat-ass wide granny seats are wayyyyy better.
Just not fashionable.