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.

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