Planning Ahead

[JonB]

Lets daisy chain the bikes and put a 3. cruzbike behind, or a 4, or ...

If we are smart we might make it like this.

Take 2 normal cruzbikes. Remove the rear wheel from the 1. bike, and attach the 2. bike complete with frontwheel to the 1. bike. Then you end up with a 3 wheeled bike that can pivot in the middle.

 

[Mark B]

JonB wrote: Lets daisy chain the bikes and put a 3. cruzbike behind, or a 4, or ...

If we are smart we might make it like this.

Take 2 normal cruzbikes. Remove the rear wheel from the 1. bike, and attach the 2. bike complete with frontwheel to the 1. bike. Then you end up with a 3 wheeled bike that can pivot in the middle.

That's sorta weird, but I like it! Talk about something that would get stares!

Mark

 

[defjack]

A leaning delta trike back end would be nice. Jack

 

[John Tolhurst]

The rear question in a one + one cruzbike tandem is the connection between the frames and the actual detailed positioning of the stoker seat and crank. Here is a attempt I made in 2005:

 

[Mark B]

OK, it looks like a tandem, but you said "attempt". What happened? How did it ride?

Mark

 

[John Tolhurst]

I wanted know whether such an extension could be provided as a kit. I concluded that the variance between frames was too much and that the positioning of the stoker seat and crank presented too much complexity for a universal kit to succeed. So we disassembled it and made the bikes into regular conversion cruzbikes.

 

[Mark B]

johntolhurst wrote: I wanted know whether such an extension could be provided as a kit. I concluded that the variance between frames was too much and that the positioning of the stoker seat and crank presented too much complexity for a universal kit to succeed. So we disassembled it and made the bikes into regular conversion cruzbikes.

You got that close and you didn't build/ride it? Man.... I mean, I understand you were looking to maybe build a kit, but I can't believe you didn't give riding it a go!

Mark

 

[John Tolhurst]

Any time that is available goes into the Cruzbike business, and is married up against what the essential next steps for the business might be. The tandem was either a goer, or not; as soon as I knew I switched focus to something else more important. But that approach is not the end of the line, as I said, there is sure to be a neat way of doing and extra cycle type of thing, a spreader structure spanning between the swingarm and the main frame to allow goods and/or a stoker. That is the direction of effort on this line, the frame + frame approach has been tested and is not viable in my assessment, so it was not like a project that led nowhere. This is the difference between building for fun, and building to identify workable systems- as well as have fun. I have sure not been done out of any fun. :mrgreen: What I did after ruling out the frame plus frame approach was to develop the sofrider frameset and fork. I think that was worthwhile.

 

[JonB]

johntolhurst wrote: What I did after ruling out the frame plus frame approach was to develop the sofrider frameset and fork. I think that was worthwhile.

Yeah, developing the Sofrider was surely usefull. I love my Freerider. When ever i see "other" recumbent bikes with their long complicated chainlines, chaintubes, no real cargo space and no possibility of a child seat, the more i like the cruzbike design. I also like that i sit so high up such that i can see arround me, and people can see me.

On the way home yesterday after the recumbent club meeting i was thinking about seating reposition systems. So you can have a much more reclined seat when driving, and as you pull up to the street lights the seat can be more upright.

I have 3 ideas to make the seat move and keep it in place.

1) a spring loaded that pushes the seat forward, and something that clicks into place with regular intervals preventing the seat from being pushed further back. Then you have to lean all the way forward until you can again push the seat all the way back to the most reclined position. To raise the seat, lean a little forward and let the spring push against your back. Stop leaning forward when the seat is in the requested position, and the click system prevents pushing the seat back. Lean VERY much forward to be able to push the seat back again.

2) a gas driven system like an office chair. The only problem is that you have to remove one hand from the seat in order to press a leaver to allow the gas to flow. Maybe you can have a lever at the handlebar, or maybe a pneumatic switch? or an electric that allows the gas to flow.

3) all electric that uses a motor to push the raise or lower the seat.

 

[kling]

Hi JonB,
happened to see this on TV recently- uses the office chair hydraulics
http://www.abc.net.au/tv/newinventors/txt/s2206272.htm
Australian inventor...

regards
Kendrick

JonB wrote: I have 3 ideas to make the seat move and keep it in place.

1) a spring loaded that pushes the seat forward, and something that clicks into place with regular intervals preventing the seat from being pushed further back. Then you have to lean all the way forward until you can again push the seat all the way back to the most reclined position. To raise the seat, lean a little forward and let the spring push against your back. Stop leaning forward when the seat is in the requested position, and the click system prevents pushing the seat back. Lean VERY much forward to be able to push the seat back again.

2) a gas driven system like an office chair. The only problem is that you have to remove one hand from the seat in order to press a leaver to allow the gas to flow. Maybe you can have a lever at the handlebar, or maybe a pneumatic switch? or an electric that allows the gas to flow.

3) all electric that uses a motor to push the raise or lower the seat.

 

[JonB]

kling wrote: Hi JonB,
happened to see this on TV recently- uses the office chair hydraulics
http://www.abc.net.au/tv/newinventors/txt/s2206272.htm
Australian inventor...

They are crazy those australian inventors, what will they think of next, hot water?

Seriously, i think something like that would work fine for pushing the seat back and forth.

 

[Mark B]

Hmmm, I guess I don't see the need for the seat repositioning feature. It would be a nice gadget, I guess, but would add weight to the bike. I'm not against adding useful weight, but like I said, I don't see the need.

My conversion sits up probably a little higher than the sofrider / freerider and as I roll up to a stop, sitting up is not a problem. As soon as I'm at a stop, I sit right back in the seat. On my Silvio, I rarely sit up because there is no need at all. When I do sit up and back, it happens so quickly that fussing with a switch, lever, or other mechanism while trying to downshift and brake seems as though it would be way beyond the realm of practicality. Everybody is different, though.

Mark

 

[Rick Harker]

Hmmmm!

Just what I've always wanted...

Hot water!

Good to see someone catering for all kinds of people who want to cycle too.

As for hot water, hmm! Let me think... :?:


Rick

 

[JonB]

what about putting a spring or some other suspension system between the seat and the frame?

 

[Mark B]

JonB wrote: what about putting a spring or some other suspension system between the seat and the frame?

Hmmm, that's a thought..

Speaking solely on the Silvio; the seat is fixed and an integral part of the frame, a lot like a Velokraft. So, I'm not sure that a seat suspension would be doable.

Not being an engineer, I'm not sure how it would work suspending the seat on an already full suspension bike. My thinking, though, is that one suspension would negate the other? I would think it could bob a little, too, when you pedal. Not sure, though, like I said.

Mark

 

[jeebus]

I finally made it to the same ride that Brian Lewis goes to in plano and got to see his silvio in person. I was very impressed; that is one sharp looking bike. At the start of the ride I made a brief attempt at riding it and only managed about 20 feet in a straight line. Then after the ride was over I tried again and successfully made a couple laps around the parking lot. I love the crisp feel, very responsive.

The seat is very hard and rigid compared to my strada with euromesh, but I think it's a good seating position and is part of what gives the bike a precise and very non-mushy feel.

But I'm posting this in the "planning ahead" section because I'm wondering if it could be made lighter.

I'm sure everybody has different interests for the bike, like touring, commuting, etc. My interest is in the light weight side oriented toward sport riding. I guess I'm lucky to have a good route between me and work so a "commuting" version for me is identical to what I would want in a sport version.

Anyway I'm afraid the frame is paying a heavy price to have that rear suspension. Not that the suspension itself is heavy, but it forces you into a frame design that is.

The part I'm suspicious of is the metal that curves in front under and behind the seat. Correct me if I'm wrong, but most recumbents have seat stays running from some point on the seat down to the rear wheel making a triangle that's strong without being massive, and without those bars the seat would have very little rigidity of its own. But in the silvio you could remove the rear half of the bike and still have a solid seat because of the strength built into that part of the frame.

The downside to the triangle would be no rear suspension, and my test ride didn't involve hitting any bumps at high speed so I'm really not sure how critical that is. I do recognize that the seat's hardness may make that suspension more valuable than I'm thinking.

I really don't consider the weight excessive; the bike felt very good, and I may well end up buying a silvio exactly as is. But I still think a lighter version could be made (without switching to any exotic materials I mean). And surely it could still be made comfortable.. maybe a few inches more wheelbase and some passive suspension back there?

- Mark

 

[John Tolhurst]

It would be nice for the Silvio to be even lighter. The overall bike is exactly as it needs to be I believe. changes to wheelbase, seat height and so on will through up other issues and take it away from the concept that makes it work, which is as an alternative frame to a road bike. Perhaps the seat back and pan can be perforated, those double curved shells in 7005 T6 2mm alloy are amazingly strong. Then many of the small CNC parts might be shaved a bit more here and there, and later if we got strong sales volumes, forged parts would reduce weight. There may be a way to lighted the rear suspension a bit. These are all at the margin type improvements.

 

[MrSteve]

If I had a Silvio, I'd want it light as well.
Carefully choosing light components would be a start, of course.

There's another route to lightness.
Removing stuff.

The retro look appeals to me.
Hand-formed aluminum fuel tanks,
hand-hammered dustbin fairings;
aluminum frames - all hand polished to a fine, liquid luster.
Polishing the bright aluminium pieces is an easy way to keep track
of the mechanical health of the bike...and part of the fun of ownership
for anal-retentive gear-heads like myself.

I'd remove the paint.

The beauty and uniqueness of the bike would be blindingly obvious
and a few grams of weight would be deleted.

My point:
offer the Silvio frame set finished in primer, so the customer
can paint/finish the frame to their taste.
(And removing primer would be way easier, psychologically, than removing the factory paint.)

-Steve

 

[JonB]

yakmurph wrote: If I had a Silvio, I'd want it light as well.
Carefully choosing light components would be a start, of course.

For some of us, the weightloss will come automaticaly and be significant if we just started biking enough.

 

[JonB]

Mark B wrote:

JonB wrote: what about putting a spring or some other suspension system between the seat and the frame?

Hmmm, that's a thought..

Speaking solely on the Silvio; the seat is fixed and an integral part of the frame, a lot like a Velokraft. So, I'm not sure that a seat suspension would be doable.

Not being an engineer, I'm not sure how it would work suspending the seat on an already full suspension bike. My thinking, though, is that one suspension would negate the other? I would think it could bob a little, too, when you pedal. Not sure, though, like I said.

I wasnt speaking about the Silvio, not having one i dont know enough about it.

I am also not an engineer, but i was thinking about taking a somewhat thick U steel thingy and mount it on the side with the curve in the front. One side to the frame and the other side to the seat. That should give some suspension too. If you do it right, it might even be done on the silvio.