First Bike Report- The A-bike Design
By Steve Robson
I am an avid cyclist that likes to ride a lot. There are times when a fulll sized non-folding bike like a road or mountain bike is just the bike needed to get in a good ride. However, there are times there are places that you can not take a normal sized bike. Travelling on a bus or train that lacks a baggage car means that you can no longer have a bike to use as a form of getting around. At other times, carrying a bike on a car rack can be done. However, the bikes could out in the open where the car is parked and with no safe spot to store the bikes at times. They could be stolen. Regular folding bikes work but take up a lot of space in a trunk of a car. In the late 1990s, a new type of bike has come into the mainstream of the cycling world. These are micro bikes. They are bikes that use very wheels, basicly 16" and under. There are a number of these bikes on the market at various price points. Although these bikes with small wheels look like a new idea, they have been tried in the past at various times. The A-bike design is one of these new generation style micro bikes. They are designed to fold down into a very small package that can be carried on to train and buses or be placed as baggage on a plane. The design was done in England by Sir Clive Sinclair, The bike I bought is a Chinese copy of the original model. The price of the bike was one of main reasons I bought it. The bike is a combination of scooter and bicycle design.
The original bike ueses 6" wheels. The main difference with the copy is the use of 8" wheels. After looking up how these bikes worked on the internet, I finally started to look for one at a cost I could afford. I found one at a hobby shop out in British Columbia, Canada. I ordered it on Oct. 20, 2009. It came to the door on Nov. 3, 2009. Now came the moment of truth, Did I get something that was worth the 124.00 dollars I spent on this bike. The bike came with a carrying bag and a small basic tool kit. Seeing that this bike is copy of the original, a number of things came up. The biggest thing I noted was the lack of any type of support for the product. Most items at least have some form of telephone support to help a customer out if they have problems with it. The small detail I also noted was the name printed top frame section. It has the name A-bicycle, not A-bike.
I noted a number of small problems with the build quality of the bike. There are a number of small fit problems on the plastic sections of the bike but given the price point of it, it is not too bad. The rear quick release assembly became loose when I unlocked the rear frame section after unpacking the bike from the box. The brakes needed some work to get them into good working order. The rear tube itself is very stiff to come in and out of the lower section. I makes for a very hard time to fold and unfold the bike. The seat design was on of the items I really was saw as a problem. Although it has been designed as a part of the bike so it can be folded into the bike, it lacked any type of comfort for the rider. The seat post was on the short side and for someone standing 5' 7" tall (that is how tall I am) in height and I am used to having a seat higher on my other bikes. Both the seat and seat post where replaced. The bike I bought uses a 25.4mm diameter seat post that was longer then the original. I had the post cut down in length so it could fit the bike better although it is still longer then the original one. I found the that I had to tighten the seat post clamp up to the point that the quick release lash could no longer up up. After getting the things needing fixed on the bike, I finally got it ready to ride.
The bike uses solid plastic wheels instead of the air-filled type I was expecting. I have mixed feelings about this. Although I no longer need to worry about flats, the ride quality is on the rough side with the ridden on rough paved surfaces. The small wheels give a very quick handling characteristic. I have used a number of bikes using smaller wheels so I was used to this transtion. For others used to mountain, hybrid or road bike sized wheels, this will be a big change for them. It will take a bit of time to get used to riding the A-bike design. The next item of note is the feel of the frame when it is ridden. Given the number of points that are needed to allow this bike to fold up, it surprizingly rigid. When compared to full sized non-folding bike, the frame does show signs of frame flexing. If you where to compare the two and use the same type of judgement on the folder as you would on the non-folder, you would be put off the A-bike right away. I had to judge the A-bicycle on it;s own terms. Once you ride it a bit, it feels overall solid with no creaking sounds. There is a bit of sway in the frame while the bike is ridden but I now feel comfortable on it. The stand over height on the bike when opened is a high 30" to 32" off the ground. For a person with small inseam measuerment, this will make standing over the bike difficult, if not impossible. It is just how the bike is set-up in it's design.
The next thing I did to place a number of safety items on the the bike. Seeing I bought this in October/ November, I added a rear and front lighting system on it for legal and personal safety. I also placed a cycling computer on the bike. I was interested how the bike was in terms of speed when compared a full sized non-folding bike. I was surprized at the results of the data I have gotten so far. Given the fact that the wheels are only 7.5 " (this is the masured size of the wheels) and the bike has only 42 gear inches, the following time and speed where recorded on it's first time out..
First measured run on A-bicycle
- Distance travelled- 4.6 km
- Recorded riding time- 20 minutes, 47 seconds
- Average speed- 13.3 kp
- Maximum speed reached- 18.9 kph
As a control, I rode my 14 speed around town as well, following the same type of riding mode of stops and starts. The distance was shorter but it gives you some idea of a comparison of how the two types of bikes compare.
Vision Orion 14 speed road bike data
- Distance travelled- 3.39 km
- Recorded riding time- 12 minutes, 31 seconds
- Average speed- 16.33 kph
- Maximum speed reached- 23.8 kph
The A-bicycle gives you 82 per cent of the speed of the road bike using a wheel size 3.55 times smaller. The dual enclosed chain drive system gives the folder a 5.6 to 1 final gear ratio. For every one pedal stroke one that done with the crank arms, the drive wheel is turned 5.6 times.
Given the fact that a higher gear ratio relative to tire size is used on the road bike, it works out to be that the same RPM is going being used with both bikes to attain the speeds each bike reaches. I used the 42 low gear on the front gear ring while the18 and 16 rear gears used to get the 4th and 5th gear settings. In 4th, 62 gear inches is the set number. In 5th gear you get 69.8 gear inches.
I looked at a gear/ speed chart, comparing the RPM in relation to gear inch number to see the speed you get. First look at the average speed of the folding bike. It has a speed of 13.3 kph. Next take the gear inch number, that being 42 gear inches. Based on these two number, you get an RPM range in the 65 to 70. Next, I looked at the road bike gearing doing the same thing. Take the same two base numbers, the average speed (16.33) and 69.8 gear inch number and looked at the chart again. The RPM you get is around the 60 range. Given small changes in the length of the crank arms (170mm on the road bike vs. the 140 crank arms on the A-bike design), the rider is within the same pedalling speed range. Therefore, the rider is putting out about the same amount of efford in terms of RPM to attain the speeds that each bike gets. The gearing range determines the speed. The wheel size also helps determine the overall gear inch. The larger the wheel, the lower the gear ratio has to be to maintain an overall higher gear inch rating. The dual chain drive set-up on the A-bike design makes the smaller wheel act like a larger sized wheel. Given the small size of the A-bike design, I would not want it geared up too much more.
On a run with the A-bicycle I did in London, Ontario I rode on both the bike path and roads. I was maintaining a cruising speed of 18 to 20 kph with no problems. At this, I was keeping a RPM range of about 80 to 90 on smooth paved road ways.
I really like this design of bike. It makes for a great mobile travel bike or just to do runs around town. It is small, light weight and so far holding up. I do have a number of concerns with the design. Over the long term, I am wondering how well the various fold points and the fastners that hold then will hold up to the bumpy ride this bikes gives. The rear quick release assembly could be better thought out. When the bike is unfolded, it comes up with the up rear frame section allowing two nylon bushings to come out if the quick release assembly is a little loose. I would like to see a secondary lock nut and bolt to lock this assembly on the place it is meant to be. This would allow the quick release function to just lock the frame in the open and closed positions without worring about the tighten of the lock colar the frame release is mounted on. I have a tripod that uses this type of assembly and it works great. The handle bars are a little off centre when the bike is unfolded. It would be nice to see this fixed so they are straight to the front wheel. Overall, the bike works out to be a nice short range commuter. It does what the designers set out to do, creating a basic portable, light weight bike. It makes for either a second travel bike or a primery bike that is stored in an apartment for short trips. It would nice to see something like this in more stores where the market is ready for it. People can see and feel what a bike like this can do. For many, this could a bike for the little trips they do.
Dimensions (LxWxH) 100 x 70 x 16 mm (39" x 28" x 17")
Folded size 67x30x16cm (26" x 12" x 6")
Weight- 14.6 lbs (6.7 kgs.)
Folding 3 click telescopic mechanism
Dual Chain ratios- 14:8 and 35:9
Max. weight tolerance 85kgs / 185lbs
Polymer Composite 30% GF PA66 Aluminium Heat treated 6061T6
Tire Size- 8" Solid plastic wheels on plastic rims
Max saddle height 90 cm Min saddle height 82cm
A-bike design pictures
A-bike test ride.
Video details of A-bike design.
More by this Author
The Dwarf community lacks some of the products that others take for granted. The bicycle is one of these items. Getting a good high quality bike is very difficult. This article looks at the design process of creating a...
A review of the Schwinn Tango folding bike. It shows how I feel it works out.
A look at a low cost digital camera design. This model is the Vibe Digital camera. It goes under the name of the Jazz DV14 as well.