Fixed Gear Airnimal Chameleon
1 - Introduction
My search for the ideal fixed gear bike took me over a year. Online articles and reviews were very useful, so I am keen to repay the favour and provide details of my quest for a folding fix.
I only got into cycling in July 2005 when I bought a Dahon Speed Pro. I wanted to go fast and my wife would not allow a non-folded bike into the flat. I really liked the Dahon and fell in love with the feeling of riding a nimble small-wheeled bike. However, I had many problems, I do not want to put people off Dahons, but I basically wore out two frames in 9 months. The main hinge on the cross tube wore out on the first bike, the bike was replaced, but then the same hinge wore out, the joint where the stem folds broke and the Pantour suspension hub broke so that the axle was locked in the most depressed state. I don't want to put people off as I not heard of anyone else having these problems with a Speed Pro, it must be that I have a very intensive riding style that wore out the bikes (I don't understand how I do it though). I only mention this as it had a big influence on my choice of bike. Also, I was never able to getting into the ideal riding position on the Dahon, I would have liked to have the handle bars about 15 cm lower and 8 cm further forward and to have the saddle about 4 cm higher. I am 188 cm (6' 3") and really like a quite aggressive riding position.
Over the first winter riding the Dahon I wore thick gloves that meant that I couldn't easily change gear. I also noticed that there were all of these couriers that were constantly passing me on single speed/fixed bikes. I started riding single speed (i.e. not changing gear) and got hooked. I realised with practice you can accelerate away from traffic lights quicker than with gears and there is a real freedom that comes without always having to think about when to change gear. I could see the next logical step was to go fixed, I tried a few fixed bikes and really liked the extra control and connection with the road (I did nearly kill myself though the first few times I tried).
I test-rode many 700C and 650C bikes including some very expensive all carbon bikes with all the trimmings, but after the Dahon, they felt like knives cutting into the road that didn't want to turn so I decided to search for something else with smaller wheels.
There are two things that are quite important when looking for a folding fixed gear. First, having either track ends (rear facing dropouts) or at least horizontal dropouts, but not vertical dropouts, this is to be able to adjust the chain tension (very important on a fixed). Second, is a unified rear triangle so that when the bike folds or any rear suspension moves, the distance between the bottom bracket and the rear axle does not change. You can get around the first issue by changing the dropouts (a very serious undertaking) or by using an eccentric bottom bracket or eccentric hub (eccentric means that the axle can rotate around the mounting). Some people say that you can find a 'magic gear'; the two cogs that fit perfectly into your frame so the chain is tight even with vertical dropouts, but I have had to re-tighten my chain about once a month as the chain stretched so I would not recommend the magic gear solution. The only way that I know of to get around not having a unified rear triangle is to undo the rear axle each time you fold the bike.
Looking at the folding bikes commonly available, I decided that I would dismiss bikes with both vertical dropouts and a non-unified rear triangle i.e. Bromptons and Birdys. Also, after my experience with the Dahon, I decided to rule all of them out as they all have the same kind of hinge in the cross tube. This left the following bikes:
Moulton - some AM frames have a unified rear triangle and horizontal dropouts
Bike Friday Pocket Rocket - without a unified rear triangle, but available as a custom build with track ends
Swift Folder - with track ends and a unified rear triangle
Airnimal Chameleon - with a unified rear triangle, but vertical dropouts
I test rode some Moultons at the Moulton workshop in Bradford Upon Avon which were great bikes, but I found the suspension so soft that I was too disconnected from the road. I can imagine that there could be nothing better for a long distance ride, but most of my rides are between 5-10 miles. Also the high price, relatively heavy frame and the inability to fold easily put me off.
I really liked the fixed Bike Fridays I saw online, but the idea of having to re-set the chain tension every time I folded the bike seemed like too much hassle.
I was really set on getting a Swift Folder, all the reviews I found said the frame was light, stiff and responsive. Peter Reich, who custom builds Swifts in New York, was very helpful and I got as far as ordering a bike, but then there was a serious delay with shipping and in that time I test rode a Chameleon and loved it. I had not had a chance to ride a swift and Peter suggested that the delay would be so long that I should probably look for another bike.
I originally dismissed the Chameleon as I thought the bike would be too big and it would take too long to fold. However, I moved to a new flat where the space for keeping bikes is bigger. I test rode one just for fun and fell in love with the handling, it felt as nimble as the 20" bikes I was used to, but much much quicker and stiffer.
The photo above shows the bike when I first got it with MKS pedals and powergrips.
2 - Building the bike
Rob at Ben Hayward Cycles, Cambridge was very helpful with choosing the parts and building the bike. At first we considered an eccentric bottom bracket as this would mean that the chain tension would not have to be set each time I took the wheel off to fix a puncture etc. However, the bearings on eccentric bottom brackets are smaller than on a regular bottom bracket and are prone to wear out quite easily. Then I was able to have a look at a wheel built up with a White Industries ENO hub and decided it was a really impressive way to create fixed gear. You can see in the photo below how the chain tension is adjusted by rotating the wheel axle around the bolts that attaches the wheel to the dropout. I have found it very easy to set the chain tension, it is actually easier and quicker to put the wheel back on with the ENO hub that it is with normal track ends and bolts. All you have to do is tighten the bolts almost all the way, then take a spanner and rotate the hub around the bolts until the chain is at the correct tension, then tighten the bolts completely. The ENO hub is also a flip-flop hub, which means that you can put a fixed cog on one side and a free-cog on the other so you can change from fixed to single speed by flipping the wheel over. As this was my first fixed gear bike I wanted to keep the option of going back to single speed just in case.
The chain ring is 53t which is the second largest commonly available in 1/8" track size. I needed to have a big chain wheel because the 24" wheels are smaller than the more common 700C the 53/16 set up gives 74.5 gear inches. There are two chain widths available; 1/8" made for fixed gear track bikes and 3/32" used for everything else. If I had gone with a 20" wheel bike with a 1/8" chain then it would have caused problems as I would have used a 54t 1/8" chain ring, and could have gone down to a 12t fixed cog giving as much as 91 gear inches. However, the smallest free cog you can get for a flip-flop hub is 15t which would give only 73 gear inches. Lots of people believe that 3/32" chains are fine, but I wanted to over-engineer as much as possible with this bike after breaking the Dahons. I have heard no stories of a well-maintained chain breaking, no matter what the width, they only break if they are rusty/un-oiled etc. A 1/8" chain is definitely stronger so it stretches less, lasts longer and you don't have to adjust the chain tension as frequently. To over-engineer some more, I went with 3-cross 32 spoke wheels and a steel steerer.
Complete spec as follows:
Frame: Airnimal Chameleon Aluminium
Fork: Carbon forks/steel steerer
Headset: Crane Creek S2
Bottom Bracket: Race Face XC Taperlock steel 110mm
Cranks: Dura-Ace Track
Chain Ring: 53t Dura-Ace Track
Fixed Cog: 16t Dura-Ace 1/8"
Free Cog: 16t Shimano
Chain: Sram nickel plated 1/8"
Front Hub: White Industries RacerX
Rear Hub: White Industries ENO eccentric hub
Rims: Airnimal 32h 24"
Tyres: Schwalbe Stelvio
Brake: Ultegra
Brake Lever: Crane Creek 200TT
Handlebar: Profile Airwing
Stem: Deda
Saddle: Specialised Alias 143
Seatpin: Race Face XY 400mm
Mudguards: SKS Quick Release Race Blades
Original Pedals: MKS AR-2 Quick Release with Powergrips
Current Pedals: Crank Brothers Egg Beaters C
Weight: 9.2 kg / 20lb (with mudguards and pedals)
Price: £1480 inc. MKS pedals and mudguards
3 - Ride
This bike is so fast and accurate, it goes wherever I want it to go and always feels steady and safe. On average, the bike is about 2-5 mph faster than the Dahon - the difference between 30 minutes and 24 minutes to do the 5.6 miles from Brick Lane to Imperial College, London (but with some training at the velodrome, I got that down to 21 minutes). I regularly hit 35 mph going through underpasses and the bike could go faster, I am only limited by being able to pedal at about 160 rpm. I could change the gearing of the bike to go faster, but that would affect my acceleration.
The suspension is great, a lot stiffer than on a Moulton or a mountain bike. It gives a lot of feedback from the road, but with the carbon fork, the ride is quite comfortable.
There is some debate about if the smaller wheels are an advantage when riding fixed. They are lighter than 700C wheels so you think that they should accelerate faster, but they have to rotate quicker. Overall I think it is a much of a muchness personally I prefer the feeling of the smaller wheels and it is by far the fastest thing I have ridden.
4 - Frame
Overall I am really pleased with the frame, I have had to make a small modification with the elastomer (see below). Also, the joint where the seat post attaches to the cross bar creaked from time to time, but some grease soon sorted that out. I have a theory that (at least when I ride a bike in my clearly abusive way) there is lots of stress on junctions where metal meets hard metal, (i.e. the hinges on the Dahons I broke and the seat post hinge on the Chameleon). If you compare the amount of engineering that goes into headsets, bottom brackets and the joints on most folding bikes, maybe it is not surprising that folding bikes are breakable. The Chameleon eliminates a hard metal junction at the back of the bike by using the suspension hinge as the main folding hinge. This means the junction is soft rubber pressing against metal. The hinge used on the Chameleon is far bigger and beefy than hinges I have seen on other folding bikes and I believe the suspension also removes quite a bit of stress from the seat post joint. The contact area of the seat post joint is twice the size of most joints on folding bikes. There is also no folding joint at the front of the bike, instead the Chameleon becomes smaller by removing the front wheel. In comparison, both the Swift and the Bike Friday Pocket Rocket have three hard metal junctions with quick releases (seat post, rear triangle and steerer). Considering that I can still make the over-engineered Chameleon squeak a bit from my riding (I have no idea how I do it though) I am very pleased that I went with the really strong frame with only one metal/metal junction.
5 - Accessories
The MKS quick release pedals that I originally had, were a nice idea, but I never had to get the bike small enough that I needed to take them off. They are tapered which improves ground clearance when cornering (important on fixed gear when you can't coast through corners). However, there is a bit of play in the joint so they can wiggle about in the housing (see what I was saying about joints where metal meets metal). I think I noticed this more because when riding fixed I often have to pull back on the pedals and I could feel the pedals moving in the mountings. Also the bearings in one of the pedals have started to catch a little, so I changed after 3 months to egg beaters. The bearings don't seem as smooth as the MKS, but I did notice an improvement in speed after the first week or so. However, the improvement may just be because of the stiffer shoes that I have to wear with the egg beaters. I also had powergrips on the MKS pedals, they give more connection with the pedals than straps and clips, almost as much connection as cleats, but you can wear any shoes you like with them. - A really great invention. However, with intensive use, they can really cut into soft shoes which was getting a bit painful.
I built a compass mount from a reflector mounting, cable ties and super glue. The steel in the bike and the vibrations from the road made it not all that effective so I took it off. I use tiny LED lights mounted to the steerer (one on each side) that leave more space on the handle bars for my hands. You can also see in this picture (and the picture at the very top) the lower handle bar position that I experimented for a while. It was very aero, but it became a bit too uncomfortable in the saddle on longer rides - I was a bit confused about why bar position would affect pains in my behind.
SKS quick release mudguards are useful as the front wheel and mudguard need to be removed to fold the bike (see below for details of folding the bike). Putting the front mudguard back on can be a bit of a hassle. The rear one is not ideal either, I used to get mud sprayed all over by back so I added a little extension to it. I cut a bit of plastic from the top of a Evian water bottle, glued it to the mudguard, then drilled a hole through each side and looped a cable tie through each hole to secure it in place (I really like cable ties and glue - very quick and effective fabrication). Finally I used the touch-up paint that came with the bike to paint the extension black. Not very pretty, but prettier than having a muddy back.
6 - Modifications:
I found that after a few weeks, the elastomer compressed by about 2.5 mm (the manual says this is normal). This meant that the frame geometry changed slightly which changed the feel of the bike and I didn't like it. Also, when I lifted the bike, the rear triangle would fall back slightly which was annoying. I went to my local friendly acrylic machinists and got a little yellow disk made that spaces out the elastomer slightly (for only £5). The spacer is slightly too big (they only go down to 3 mm in yellow acrylic) so it puts a bit of stress on the catch that holds the frame together, but it has made the ride quite a bit firmer and I like it. It also raises the bottom bracket slightly which improves ground clearance for cornering. However, the pressure on the catch means that to release it, I have to lean over the bike, pressing my chest down onto the saddle, to compress the elastomer, then reach in and release the catch. This is not ideal, but I fold the bike very rarely and I prefer the firmer ride.
I discussed this issue over e-mail with Richard Loke from Airnimal, he said that most customers prefer to be able to operate the folding catch easily so they designed the elastomer to have a few millimetres tolerance in it.
7 - Folding
I have only folded the bike 5 times, once to go into a friends house, once to go on a very crowded train, once when I got a puncture in the rain I hoped on a bus home, once to take the photo to the left and once to show someone how the bike folded. Every time it was really great to be able to fold the bike (especially when I was not in the mood to be fixing a flat on a cold, dark and rainy night with muddy hands). I now realise that because I fold the bike so infrequently it would probably have been not much hassle to get the Bike Friday which would require me to release the chain tension each time I folded the bike. This would also mean that I would have more options for hubs and wheel rims etc. and produced a lighter, more foldable bike. However, there is the issue of the metal junctions in the frame that I mentioned above and the feel of the Chameleon is just about perfect for me so I have no regrets at all.
Also, if you look at the photo you can see adding the left brake lever housing means the handlebars sit flatter on the ground.
8 - Track Riding
I recently started taking my chameleon to Herne Hill Velodrome. I get some strange looks from the hard core track cyclists, but it has been a lot of fun. For the first couple of sessions it was a bit embarrassing always coming last in the training races and generally not being able to keep up. Just this morning I managed to improve from last place to 5th out of 20 so the training seems to be working and now strange looks from other riders have changed from slight indignation and scepticisim to interest.
To ride on the track I have to swap the bullhorns for drop bars and remove the brake and the mudguards. I also moved the cycle computer to the stem so that it stays there when I switch the bars over. I think it looks quite sexy like this, but not very practical for the streets.
Another track-modification was to replace the free-wheel on the flip-flop hub with a 14t fixed cog which gives me 86 gear inches. Because the ENO is a fixed/free hub it only has threads for a lock ring on the fixed side. A lock-ring is a threaded ring that has a reverse thread and goes on over the cog and stops you unscrewing the cog when you back-peadal. In general, it is quite a bad idea to ride without a lock-ring (sometimes this is called a suicide fixed) but on the track if you tried to brake hard enough that you would start unscrewing the cog, chances are that the guy riding 2 cm behind your real wheel will crash into you. To change between the two cogs, I just need to take the wheel out and flip it over (hence the name flip-flop). To get the right chain length that would work with both cogs I also changed the chain to a half-link bmx chain.
On www.bikeforums.net there have been many self-righteous track riders that have been slating me for riding my bike on the track. It is almost like they take it as a personal insult that I would take a non-700C bike near a track. Lots of them don't believe that it is possible even to ride such a bike on a track, so here is a photo to prove that I do. Sorry about the out-of-focus-ness, my brother took it on his mobile phone, will try to get a better picture sometime.
9 - Future Plans
I am not quite satisfied with the handle bars. They are comfortable and can get me into an aerodynamic position, but they are a little too wide to do some of the traffic acrobatics necessary to go fast in London. I would like a sub 35 cm bull horn, but I think they would have to be a custom build. I have considered a 28 cm flat bar with bar ends, but then I would not have the rounded corners that give more hand positions.
I am keen to look at wheels, I am getting better at city riding on a fixed and often spend long periods cruising through traffic at over 20 mph so I think better wheel aerodynamics could make a difference. HED and Velocity make some interesting 24" wheels, but the unconventional size does restrict my choice of manufactures. I still want to keep the wheels very strong and with quick acceleration, but more importantly I have to get some extra cash first. When I contacted Richard Loke at Airnimal, he told me that the Airnimal rims are probably the lightest available, the velocity wheel-set is lighter mainly because of a lower (20) spoke count. The HED rims have only a slight aerodynamic advantage but the weight is significantly more. So, if anyone out there knows of some amazingly obscure 24" rims, please let me know (e-mail: minty at minty-ai dot net).
10 - Conclusion
In case you haven't guessed, I think this is a really great bike.
11 - Reference
Airnimal's web-site:
www.airnimal.com
Ben Hayward's bike shop, Cambrdge, UK:
www.benhaywardscycles.com
for your daily dose of bike porn:
www.fixedgeargallery.com
check out bikes 757, 793, 897, 1251, 1452, 1566, 1608, 1851, 2164, 2337, 2373, 2790, 2772, 3028, 4261, 4355, and many more.
great tutorial on how to ride fixed:
www.63xc.com/gregg/101_1.htm
very funny, but critical blog, I fear he may not aprove of my bike:
bikesnobnyc.blogspot.com
custom built fixed bike fridays:
http://bikefridaywalter.wordpress.com/2006/10/01/fixing-a-friday/
www.monkeyview.net/id/990/bikes/fixed/friday/
a fixed swift:
http://james.architectureburger.com/swift.html
UK fixed gear road racing:
www.fixedwheel.co.uk
NYC couriers using track bikes on the road:
www.oldskooltrack.com
great reference site about fixed gear bikes:
www.sheldonbrown.com/fixed.html
folding society:
www.foldsoc.co.uk
Bike Bought: 11th Oct 2006
Last Update: 28th Sep 2007
Total Miles: 3058.7
© Andrew Stewart: near Brick Lane, London, UK
e-mail: minty at minty-ai dot net