On Giatex folding bikes

[Shahmatt]

I came across this interesting folding bike in my search for a folding donor and thought I'd share. I don't believe it's suitable for my purpose but the concept is still interesting, and maybe future models may yield more suitable bikes.

http://www.giatex.com/Productshow.asp?id=519&mnid=110

The top tube of the bike shrinks, making the bike more compact. In the above link the rear wheel folds under in a Brompton like style, further improving compactness. Here is a demo of the fold (shrinking) minus the rear wheel folding underneath:

http://www.giatex.com/CONCEPT.asp?id=477

Some observations:

1. The Cruzbike seatpan would have to be fixed on to either the front or rear or portion of the shrinking top tube. Ideally it should fit on to the rear portion, as this would enable the most compact fold (or shrink rather) - but this length of top tube looks too short for the purpose. Maybe some measurements will help.

2. If folding is not intended, then the tube length can still help in improving the fit for riders with awkward leg lengths.

3. It doesn't look like the neatest fold, nor the most compact. On a completed Cruzbike conversion I guess the front wheel can be turned around to bring the Cruzbike frame alongside the rest of the frame thus reducing the overall length.

 

[Charles.Plager]

 i don't think your too far

i don't think your too far off in your observations. I don't think you could get the seat entirely mounted on the rear piece. A lot of bike Fridays fold only the rear wheel, so only having that fold wouldn't be bad and you wouldn't need to muck with the sear.


On my mantis, I have the sear pan quite forward. If you do take the seat apart, you might be able to compress the bike somewhat.

Not completely crazy.

 

[Eric Winn]

I wonder if some deformation

I wonder if some deformation of the slider sleeve will occur if the rider's weight is on the slider and/or sleeve all the time?

-Eric

 

[Kungfuguy]

It's a novel concept.  Not

It's a novel concept. Not the smallest of folds. Ideally a kid could grow with the bike. But manufacturers wouldn't like that as you only buy one bike. They also claim that it is cheaper than traditional folders because they don't a have an expensive hinge. I'd like to see their prices if that's true. Bring it on! They sure have a lot of models. But it seems like just a novelty. It doesn't take folding to the next level. Furthermore, the shaft of off center, making it look weird.

 

[Shahmatt]

They aren't new

It seems that they've been in business for a while. There are reviews of bikes from way back in 2004:

http://www.foldsoc.co.uk/giatex.html

Prices are not unreasonable either:

http://ridethisbike.com/folding_bicycle.htm

So maybe not really a novelty.

@ Eric Winn,

A good design would be a near uniform stiffness so that the stress on the tube is evenly distributed. My guess is that the sleeve and insert would be of similar stiffness.

 

[Shahmatt]

A really short wheelbase recumbent

@ cplager,

What if this bike is used to construct a really short wheelbase Cruzbike?

Compress the bike to as much as possible allowing enough length for a comfortable seating position and keep it at this length permanently. This would be the default unfolded configuration.

Folding would then simply be:

1. Putting that rear wheel under in the Bike Friday style and,
2. Turning the steerer around so that the Cruzbike triangle comes up along the side.

No messing around with the sliding top tube involved in the fold.

Edit: I've just realized that the shaft off-centre would result in a Cruzbike seat position out of alignment by a bit. Darn. How serious a problem would this be?

 

[Eric Winn]

I've just realized that the

I've just realized that the shaft off-centre would result in a Cruzbike seat position out of alignment by a bit. Darn. How serious a problem would this be?

I'm guessing you would probably would not want to ride very far or very much like that. I've felt some aches in my hips and ankles when I was just very slightly out of alignment when I was unconsciously avoiding knee contact with the Quest dual drive shifter housing. Once I realized what I was doing and adjusted the fit so I wasn't kinking myself a bit the problem evaporated.

-Eric

 

[John Tolhurst]

Bodies are not symmetrical

Bodies are not symmetrical really, some people ride a little off centre, half inch or so, on the seat, doesn't seem to matter.

 

[Eric Winn]

Trust me John, you start to

Trust me John, you start to notice it a bit more the older you get...

 

[Shahmatt]

Only the seat pan will be misaligned


Only the seat pan would be out of alignment. The back rest should rest straight on the seat post.

I wonder if it would be possible to rework the screws underneath the seat pan in order that the pan sits in-line with the steering column.

Interestingly, I've found another bicycle company from China doing the very same thing.
http://www.slidingbike.com/models-20.html

The top tube is in-line with the bike, but unfortunately there appears to be no model with rear suspension.