The long awaited gap transportation Raw Review Roundup is finally here! We've been piling up the miles on these machines for the last several months and there are a few clear winners.

Gap transportation usually serves to get a commuter from mass transit to their destination. Since gap transportation machines often need to be carried onto trains and buses, they should be light and compact. Typically, there are some trade-offs to make something both fun to ride and easy to carry.

Without further ado, here are the contenders and their rankings.

Top Tier:
Dahon Jetstream P8 folding bike
Riese und Muller Birdy 2 Monocoque folding bike
Dahon Mu P8 folding bike

Middle Tier:
Riese und Muller Frog folding bike
Ross Motors 2000XR electric scooter
REI Novara Buzz FlyBy folding bike

Bottom Tier:
Schwinn Stealth R electric scooter
Bladez 450 electric scooter

The rides were compared to non-folding reference bikes and used on surfaces including gravel paths, suburban streets, and pothole-infested urban pavement.

Dahon Jetstream P8: The Dahon surprised us here at RawEco by scoring solidly into the top tier with a great combination of performance, comfort, portability, and style. Why were we surprised? Typically in large cities, the folding bikes you see are of the "hardtail" variety: utilitarian machines that get you there with minimum impact on your wallet... and maximum impact on your spine.

The Dahon, equipped with a good elastomer front suspension and an excellent air shock rear suspension, gets you there with tailbone intact and ready for a day's worth of work. It's not designed for off-road use, but we couldn't help ourselves and took it for some light trail work. While the Schwalbe Marathon Racer tires on the Jetstream are definitely optimized for road use, the bike itself did admirably well on dirt and gravel.

The Jetstream is fairly priced and relatively lightweight at ready-to-ride 25.5 lbs on our scales. Twenty-five pounds may seem like a decent load to carry, but it's quite reasonable for a full-suspension bike, and this one happens to fold to a compact package that easily fits in the trunk or back seat of a typical sedan.

We found folding the Jetstream to be intuitive and the easiest of all the frame-hinged bikes. We definitely liked the frame hinge design compared to the Mu and FlyBy.

Frame hinges are located in the middle of a bike frame and allow the bike to literally be folded in half. The advantage of a frame hinge is that it allows for design flexibility and simple folding. It also has the distinct advantage of leaving the bicycle's drivetrain unmolested during the folding process. We'll revisit that in more detail in the Birdy review.

The disadvantage of a frame hinge is the vague concept that having a hinge in a structurally important part of the bike may lead to potential failures down the line. On one hand, this makes sense to some of us here at RawEco, especially the engineers. The hinge folds the bike sideways, but your weight is trying to crack the hinge downwards.

That being said, it seems quite feasible to design a hinge and frame that is strong enough to withstand the relatively puny forces that a human can exert jumping off curbs and hitting potholes. Furthermore, research here at RawEco has only located a handful of individuals who have reported hinge failures on frame-hinged bikes, and those are typically on low-end steel framed bikes, some of which may have been exposed to saltwater corrosion. The Dahon representative we spoke with noted that hinges, like many mechanical parts on a bicycle, should be inspected and adjusted over the years.

Of all the folding bikes, the Jetstream rode most like our reference bikes. That's quite a compliment, given that our reference bikes include high-end XTR equipped Specialized Stumpjumper FSR full-suspension mountain bikes and the same carbon-fiber Trek model that Lance Armstrong rode to victory in the Tour de France. We love our bikes here at RawEco, and we definitely love the Jetstream.

Pros:
Plush, adjustable rear suspension
Great brakes
Good SRAM drivetrain and gear range
Intuitive folding

Cons:
Non-adjustable front suspension is too firm for riders under 130 lbs

Other observations:
Retails for around $999
Feels more stable/less nimble than the Birdy
Geometry and components make it feel like a big, full-sized bike
Small magnets hold the bike folded shut, but when they accidentally detach, the bike can feel like a limp noodle
Can roll when folded, but the magnets will sometimes detach. Bring a small bungee cord if you plan on rolling it a lot while folded.
Invest in a shock pump (~$15 and up) to tailor the rear shock to your weight and riding style
Pump the tires up to their maximum pressure and enjoy the benefits of ultra-low rolling resistance and the comfortable, full suspension ride. Those same pressures on the FlyBy and Lance's Trek sometimes make our teeth rattle

Riese und Muller Birdy 2 Monocoque: The Birdy looks amazing in specs. Award-winning design designed by award-winning designers. Hand-welded, ultra-stiff, one-piece aluminum alloy frame suspended on dual, customizable, elastomer springs. Amazing, almost artistic folds using the suspension swing-arms to enable compact storage without frame hinges. Legendary stories of people riding thousands of miles on their Birdy bikes through cross-country tours. A cult-like following in Germany and Japan. 25 year warranty.

The reality is still impressive, but it's nearly impossible to live up to the high expectations. That 25 year warranty appears to only be honored in some countries. That beautiful folding act requires smaller wheels and also requires that you to shift to high gear in order to fit the rear drivetrain in. And that elastomer suspension works well, but probably isn't going to deliver the plush ride that some people associate with full-suspension.

Our test ride was finished in a badass matte titanium gray paint job with black handlebars, seatpost and stem. In many ways, it looks like a futuristic, high-tech BMX bike sized for adults. Although there are quite a few stories of people slapping on BMX knobbies and taking their Birdies off-road, like the Jetstream, it's intended as a road bike. Conversely, there are Birdy fanatics around the world who mod the bike to be as light as possible. The current record is at 18 pounds, which is quite impressive for any bike, let alone a folding one with full suspension.

Like most folding bikes, the Birdy arrives in a folded state. As you unfold it for the first time, you appreciate the incredible design of the bike. Folding is equally cool: the rear suspension swingarm folds forwards nearly automatically as you lift up the bike. As it approaches the front of the bike, the swingarm's hinge tilts slightly to the side, and somehow the rear tire, which was perfectly behind you while you were riding, is now tucked slightly to the left of the frame. The seatpost, when retracted into the body, perfectly blocks the swingarm and locks it into place.

The ride on the Birdy is firm, but absorbent. For some people, this is the ideal type of suspension: you only notice it when you're riding a bike that doesn't have it. We wouldn't mind a little more plushness, but it definitely does the job with the stock elastomers. R&M sell several versions of the elastomer and let you choose the ride quality tradeoff that you prefer, but we're not sure even the softest elastomer can provide the travel and plushness that a good air shock can.

The Birdy's Shimano Capreo drivetrain is competent and shifts reliably, and the gear choices are appropriate for a road bike. The v-brakes, while solid, are not as grabby as the Jetstream's set; this can be altered, of course, by using a different set of brake pads.

Folding the Birdy is actually incredibly fast: after the first few times we've been able to fold it in twelve seconds without rushing. You can even fold it without getting your hands dirty by using your foot for the front wheel fold.

There is one issue with the way the Birdy folds, however. You need to put it into the highest gear before you fold it. We've found that putting it into the second-highest gear works even better as the derailleur is more tucked-in, but either one works. The problem is that the highest gear is most likely the gear you don't want when you arrive at your destination and start riding from a standstill. As a result, there's a lot of pointless shifting up and down as you fold and unfold the bike. It's not a dealbreaker, but there are definitely days when you're late for the train and you forget to put it in high gear as you approach the station.

Life is full of tradeoffs, and this is the Birdy's tradeoff. By avoiding a frame hinge like the plague, Riese and Muller (the German design duo) did an amazing job in re-using the suspension hinges of the bike to allow folding. The bike, of course, still has pivots for the suspension, but the weight of the rider is exerted in the same plane as the pivot's folding plane. In the words of some Birdy owners, the forces exerted by the rider help hold the bike together rather than try to tear it apart as with a frame hinge bike.

Over the years, Riese und Muller (the company) have sold tens of thousands of Birdies, and reports of catastrophic Birdy frame failure are extremely rare. That's a reassuring thing, but the tradeoff of having no frame hinge is that the drivetrain takes part when the thing folds. As a result, you need to remember to shift the damn thing to high gear before you fold. The bike won't explode or burst into flames if you don't, but there's a higher chance of minor annoyances like the chain falling off if you forget to do it.

Overall, we love the Birdy. It's like owning a piece of art, and the performance is excellent, as well. We actually prefer the unfolding process of the Birdy to the Dahons as it uses gravity to help you unfold, but the requisite gear-change is a bit unfortunate.

Given a choice of all the bikes we've reviewed, it would come down to the Jetstream or the Birdy. The Birdy is an exceptional bike, but at nearly twice the price of the Jetstream, it really depends on how it fits into a particular budget. There is a more affordable Birdy 1 which does not use the Monocoque frame and starts at a very reasonable $999, but the component choice is somewhat inferior and the older tubular frame design, while solid and proven, is not quite as stiff nor as awe-inspiring as the Monocoque frame.

In the end, $999 for a Jetstream or $1700 for a Birdy is probably money well spent if you're going to ride it instead of driving a pollution-spewing car or truck. You'll be doing your part for the ecosystem, and getting exercise at the same time. Considering that opting for an in-dash GPS system, moonroof, or leather interior for your car will often cost you as much as one of these bikes, the bike sure seems to be the better option to stash in your car (or home).

Pros:
Peerless design and construction quality
Excellent performance, on and off-road
Stiff, no-excuses frame
Interchangeable elastomers allow adjustment for both front and rear suspension
Nimble and light at 24 lbs

Cons:
$1700
Suspension has shorter travel and is not as plush as the Jetstream's
Requires shifting into high gear before folding

Other observations:
Try shifting into the second-highest gear for a slightly smaller fold
The Expedition Rack for the Birdy is solid and folds automatically with the bike
Birdy bikes with hub gears, sold in some regions, do not need to be shifted before folding; in general, we prefer the performance of cog gears over hub gears
With the adjustable-height handlebars, make sure to tighten the quick releases sufficiently

Coming soon: The best of the rest.

It's no secret that coal-fired power plants, along with other human activities, emit an enormous amount of mercury into the air.

This map shows where much of the mercury rains down on the US. It's too bad it doesn't cover Alaska and Hawaii, as well, not to mention the rest of the world.

On the right side of the page, you can select specific states and see various food-related warnings. Though it's largely limited to fish that are not recommended for consumption, mercury content has a host of negative health effects for all living things.

As an editorial note, the authors of this map were very careful to state that mercury in the air can be from natural causes like volcanic eruptions. This is true, but it seems highly unlikely that the skyrocketing levels are due to natural causes if the levels are 10-20 times higher than "pre-industrial" levels. For example, there haven't been 10-20 times more volcanic eruptions in the 1900's compared to the 1800's.

In other words, our industrial civilization is to blame.

http://www.usatoday.com/news/health/2007-10-30-where-mercury-falls_N.htm

There's been some talk lately of toxic compounds in plastics that are often used for drinking and baby bottles. We'll keep this page updated with new information as it becomes available.

Several people have been asking us what we recommend as reusable drinking bottles, and there are good choices depending on what you need. Glass bottles have always been our favorite for pure, unflavored water. Re-using a purchased bottle of mineral water means that it also costs less than $4. Being made for retail shipping and handling, they are surprisingly durable, but of course they will shatter if you drop them on concrete or hard tile.

That being said, we can't remember the last time we've dropped a plastic bottle from height, either. The caps of glass bottles are often made of plastic or aluminum, which isn't ideal, but at least the water usually doesn't sit around in contact with the cap. There are also stainless canteens made by several companies; they seem decent choices, as well, but we definitely prefer the taste of glass-bottled water. For infants, a stainless bottle, or at least a glass bottle with some cushioning around it, may be a better bet.

Here is the list of household plastics:

Commonly known as: PC, Lexan, Polycarbonate, Nalgene (misnomer) Properties: Rigid, can be transparent, melts at higher temperatures, used for sunglasses, CDs, re-usable drinking bottles, water cooler bottles Known risks: BPA: carciogen, endocrine disruptor

Commonly known as: Polyethylene, HDPE, PETE Properties: Can be flexible or rigid, depending on thickness and type Known risks: Antimony: PETE leaches this highly toxic compound into water, especially in hot weather.

Commonly known as: Polypropylene, PP Properties: Opaque plastic, sometimes used for cutting boards and water filter vessels. Known risks: We're having difficulty finding specific information. Contact us if you have research links in peer-reviewed publications.

Commonly known as: Copolyester, Tritan Properties: Rigid, can be transparent, used for re-usable drinking bottles Known risks: This is the new kid on the block, and the reusable water bottle makers, finally acknowledging the toxic effects of polycarbonate, are jumping all over it. It's specifically advertised as "bisphenol-A free", but you can bet it contains a boatload of other chemicals with side effects that are yet unknown. Remember, it took decades to uncover the toxic effects of polycarbonate/Lexan.

We find it a bit amusing, and probably more the work of Eastman's marketing department, that its main claim to fame is being free of a specific chemical, bisphenol-A. It's a bit like saying "this gasoline is lead-free!" Even being lead-free, gasoline is still one of the nastiest concoctions around, and just saying it's lead free doesn't mean we're ready to go and drink it or pour it into the earth.

Howdy folks, we've been gearing up and accumulating test miles on our fleet of "gap transportation" in preparation for the good weather up here in the northern hemisphere.

The review is looking pretty complete: we have our trademark and extremely detailed raw reviews on rides like the new Dahon Mu P8, the REI Novara Buzz Flyby folding bike, the high-tech Ross Motors 2000XR, the elite Riese und Muller Birdy 2 Monocoque, the affordable Schwinn Stealth scooter, the Bladez 450 electric scooter and a very rare appearance from the endangered Riese und Muller Frog.

Dahon is a big name in folding bikes, and we're very happy to report that they will be participating with the new Mu P8. As far as we know, this will be the first official review of the hot new ride. We'll update here when it arrives. We'll also be reviewing the new Jetstream P8 when it's available later this year.

Brompton is across the pond, so we'll need to give them some time. We'll update here as things change. Stay tuned for the review this Spring!