Friday, June 22, 2012

Modifications to Flamingo London NX7: Brompton Firm Suspension Block + Riser Bar

What suspension block does your Brompton or Flamingo use? If you have not changed the suspension block on the bike before, most likely it will be the stock suspension block with standard hardness. This is good for most people on leisurely rides, where the pedaling is smooth with low torque. 

However, some people do use their Brompton for fast rides and they do pedal hard in order to go fast. In this case, the standard suspension block may not be suitable for this type of riding. This is because when you push down on the pedals hard with high torque, the chain tension tends to pull the rear triangle forward/upward and compress the suspension block. When this happens, the bike will start bobbing up and down in sync with your pedaling motion. Not only is this motion uncomfortable, it actually saps a lot of your energy by repeatedly compressing the suspension block instead of powering the bike forward.

The rear suspension block and the rear triangle on the Flamingo

For myself, I have been quite happy with the original suspension block on my Flamingo. Just as an experiment, I got the standard Brompton suspension block and installed it on the Flamingo a few months back. After quite a bit of riding, there does not seem to be any noticeable difference between these two suspension blocks. Both work well, but are also soft enough that bobbing occurs during hard pedaling.

My recent riding style on my Flamingo has changed, from a more casual riding style to a slightly more sporty style. I used to only use my Flamingo for mixed mode commuting to work, riding from my house to the MRT, and then riding from the MRT station to my workplace. After work, I will ride to the nearest MRT station again and take the MRT home with the bike.

 Size of the folded Flamingo that goes onto the MRT

This used to work very well, until the MRT timings in the morning changed. The trains used to arrive every 2-3 mins at 630am in the morning, which means that there is no problem for me to get on the train with the bike. However, a couple of months back, the train frequency decreased for some reason, and the wait stretches to 4 mins or more half the time. This means a very crowded train that makes it difficult and inconsiderate for me to squeeze the bike onto the MRT.

That was when I decided to just try riding my Flamingo directly to work. It is about 12km one way, and it takes me 40 mins to ride to work, door to door, on my Dahon Boardwalk, including grabbing the newspapers along the way. With the Flamingo, it takes longer even though I have to ride harder, because the Flamingo is not built for speed. 

To solve the bike bobbing issue, I decided to try out the firm suspension block that is used on the Brompton. It is said to be designed for use for heavier riders or for riders with a strong pedaling style. 

Swapping out the block is easy, as I was already using the Brompton standard suspension block. After installing the firm suspension block, I did some riding to test it out by cycling all the way home, riding reasonable hard. I found that there is actually a lot of difference! Not only does the bobbing problem disappear, the bike also feels more rigid overall. When you lay down the power on the pedals, more of the energy goes to driving the bike forward and not to compress the suspension block. 

Brompton firm suspension block shown on the right

I do not have any numerical data to say how much more efficient it is, but the pedaling feeling has been greatly improved. At the same time, the comfort level of the bike has not been affected significantly. Theoretically speaking, the ride should be harsher due to the harder suspension, but it does not feel that way. The ride is still very comfortable, even though the suspension block is now much firmer. This may be due to the fact that I am still using the original Flamingo tires, which has a max PSI rating of 55, giving some degree of suspension. Another reason may be because there was too much suspension in the first place!

My initial aim to convert the Flamingo into a sportier ride was to change out the suspension block AND also change the handlebars. The stock M handlebars are a bit too tall for faster riding, with a grip height of 1080mm. For comparison, my Dahon Boardwalk has a grip height of 1000mm on the flat portion, and it is already considered higher than average for a drop bar.

To lower the body posture and to reduce the flex on the handlebars, I bought a 60mm riser bar to lower the handlebar height. Since it is a MTB handlebar, it is very wide at 680mm, it needed to be cut down to an appropriate width. For comparison, the stock M handlebar has a rise of almost 160mm, and are about 580mm wide.

The new riser bar would have lowered the grip height by this much

Comparing the handlebar widths

About 80mm difference in grip height 

After removing the shifter and brake levers and grips from the handlebar, I took out the M handlebar from the handlepost clamp. This is actually quite difficult due to the bends in the handlebar. I managed to hold the clamps open by using a bolt to help push open the clamp and hold it open, while I wriggled out the handlebar.
Inserting the original bolt from the other direction. By placing a metal plate in the opening, tightening the bolt will push open the clamp, making it easier to insert or remove the handlebar

Upon inserting the new MTB handlebar, I realized that there was a big problem! The handlebar can’t fit in the C shaped clamp. Only upon closer inspection I found that the reason the original handlebars could fit, was that only the handlebar centre clamp area is 25.4mm diameter, the rest of the handlebar is a smaller 22.2mm diameter. This was how the bends of the handlebar can be wriggled through the clamp.

But for this new MTB riser bar, the diameter starts to increase from 22.2mm to 25.4mm at the bends, making it impossible to squeeze it through the clamp. The increased diameter together with the bends means that the clamp would probably have to be at least 30mm wide in order to put the handlebar through.
This was something that I overlooked when I bought the new handlebar. There is no way the clamp can be opened this wide without breaking it. The only consolation for this error is that the new MTB riser handlebar is a relatively cheap one. 

The riser bar cannot fit through the clamp!

 Reason is because the riser bar starts to increase its diameter at the bends

A straight handlebar will work, but it will be too low for comfort. The only way a riser bar will work is if the handlebar is narrow all the way, and only widens to 25.4mm at the middle clamp area. Otherwise, if the diameter at the bends are more than 22.2mm, it will not fit.

So, the only change that was made to the Flamingo is the new firm suspension block. I’m really happy with the firm suspension block, as it enables more efficient pedaling without energy loss, while at the same time the comfort level is hardly reduced!

Tuesday, June 12, 2012

Bicycle Lights for Night Riding

For night riding, it is always a good idea to be well lighted. The more lights the better, as you can be seen more clearly by other vehicles on the road. There are two main types of lights for bicycles:

1) To See
This will refer to lights that you mount on your bike/helmet, for the purpose of enabling you to see the road clearly. These type of lights will have powerful beams, with spot lighting to light up the path ahead. For on-road riding in Singapore, these are usually not necessary as the roads are generally well lighted.

For off-road riding at night, these are essential. You will need a light that is powerful with a good spread to see the terrain ahead. The drawback for these type of lights is that it usually requires a separate lithium battery pack for the power, and the runtime is usually limited to only a few hours at the highest setting.

2) To Be Seen
It is very important to be well lighted during night rides. The aim of being well lighted is so that the drivers can see you and your bike. To be seen clearly is not that easy, as there are a lot of other distractions and lighting on the road, such as from traffic lights, street lights, other cars' lights etc.

A good blinker will be able to draw the attention of road users and announce your presence. The brighter the blinker, the better. If you have a bright flashing light, drivers will be able to spot you from further away, giving them more time to avoid you. No point having a weak blinker that can only be seen when the driver is 50 metres behind you. This gives them too little time to change lanes completely, and indirectly contributes to close encounters.

Front Lights
For me, I have many many lights on my bike. At the front, I have two lights, a S-Sun 1 watt blinker and a powerful headlight in the form of a Busch & Muller IXON IQ light.

S-Sun 1 Watt light

Busch & Muller IXON IQ mounted at front of frame.

The IXON IQ light serves as a dual purpose light. On dark roads, it will be used to light up the path. On well-lit roads, I also turn on the light, as it becomes a steady headlight that can be seen from a good distance. A steady front light plus a front blinker makes you very visible from the front.

Rear Lights
As for rear lighting, it is even more important as you cannot see what is coming up behind you. Therefore you will need to make doubly sure that you are seen and highly visible from the back.

The main rear light I have is the Bontrager Flare 3, which has two 0.5 watt LEDs flashing alternately. This is a good bright light with an attention-grabbing flashing pattern. It is fixed onto the hook on my Topeak saddle bag.

Bontrager Flare 3

Supporting the red rear light is a blue rear light that also flashes to catch attention. This is a Cateye-lookalike light, and is mounted on the light bracket on my rear rack.

Blue coloured rear light fixed onto the rear rack

Additionally, I also have an Infini helmet light to improve visibility. This light has an elastic strap which can be used to fit on almost all helmets.

Infini helmet light

With these 3 lights, I have lighting at my head height, saddle height and wheel height. This should make me quite visible from far.

In order to further improve night visibility, I recently added two more lights at the end of my drop bars. Since these lights are further apart left and right, it will give me more width and make me and my bike even more visible.

Q-Lite Bar End Light

These are actually bar end lights meant for flat handlebars. The design is such that there will be bright beams coming out from the side of the bar end, such that when installed on a flat handlebar, the lights shine backwards like a rear light. It happened that this model has a transparent tip that also glows red, although it is not as bright as the main beam.

Another point to note is that MTB flat handlebars have a slightly narrower internal diameter compared to road drop bars, and thus does not fit snugly on my drop bars. However, with the bar tape on my drop bars, the lights fit nicely. Although they are not tight, it is sufficient to ensure that it will not drop out easily.

Bar End light fitted at the end of my drop bars

Glowing bar ends!

The main beam is rotated such that it points downwards towards the ground

Main beam creates a bright spot on the ground, while from the back, the bar ends glow red.

As an added advantage, the main beams point to the ground and creates a bright spot, which is actually quite visible even on well-lit roads. Not too sure about the visibility from a greater distance, but is an added advantage nontheless.

I prefer my lights to use rechargeable batteries, so that I can recharge the batteries whenever they start to get dim. I don't have to get stuck in the dilemma of throwing away half-used batteries, or continue riding with dim lights. Apart from the small helmet light which uses 2 x CR2032 batteries, my other lights uses standard AA or AAA batteries.

S-Sun: 3 x AAA
IXON IQ: 4 x AA (comes with built in charger)
Bontrager Flare 3: 2 x AAA
Blue rear light: 2 x AAA
Q-Lite Bar End Lights: 1 x AAA each

Overall view of my lighted bike from the back