Sunday, July 23, 2017

Brompton M6R: Pentaclip Design and Saddle Change

The Brompton comes with its special saddle clamp, which is designed to shift the saddle position forward. This is to keep the folded package small, by tucking as much of the saddle as possible within the frame dimensions. Also, when the saddle is pushed all the way forward, it places it in the correct position for efficient pedaling. This is different from full sized bikes where there is usually a rear offset on the saddle clamp.

As much as I tried to like the Brompton stock saddle, I could not get comfortable on it. The saddle has a concave shape that makes it hard for me to find a good position on the saddle and maintain that position. Therefore, I decided to change the saddle to one that is more comfortable for me.

Stock Brompton saddle

Since I have spare saddles lying around, I looked to see if there is a suitable saddle. The stock saddle from the Merida Scultura 5000 is actually quite comfortable, and I changed it out only because it was heavy. Also, the colour matches the Lagoon Blue Brompton quite well!

Blue saddle from the Merida matches the Brompton quite closely! Not 100%, but close enough to look matching.

First, I have to remove the stock Brompton saddle from the saddle clamp.

The saddle clamp on the Brompton is called Pentaclip, and it is rather unique that I have not seen other brands use this design before. As shown below, it is made up of so many parts that it can be rather confusing to put everything back properly.

One side of the clamp disassembled. Made up of multiple copper washers and steel washers. Too many parts I feel...

The advantage of this Pentaclip is that it offers infinite angle adjustment, without any discrete steps of most other saddle clamps. I just wonder if they could have designed it so that it does not have so many separate parts...

Upon removing the Brompton saddle, I found a M5 threaded hole that can be useful for mounting a rear light. There are also two loops at the side for saddle bag straps.

Merida saddle installed! Flat top profile is what I prefer over the concave profile of the Brompton saddle.

Blue colour looks quite matching. Pushed all the way to the front for correct positioning and also compact folding.

From this picture, you can see why a saddle that is pushed all the way forward will make the whole folded package more compact.

This is a free upgrade since I am just using a spare part that I have lying around. Makes the ride more comfortable and also looks better in terms of colour matching. Many more upgrades to come!

Wednesday, July 19, 2017

Brompton M6R: DIY Front and Rear Light Mounts

Next, after upgrading the hinge clamps, the rear suspension, and the Eazy wheels, the next modification would be to fix front and rear lights onto the Brompton. Due to the nature of the folding, there are not many places on the frame where you can fix a light permanently and not affect the folding or folded size.

Most people install a light onto the rear of the seatpost, with the light sticking out at the rear. This means that when lowering the seatpost, care must be taken not to lower it all the way down and damage the light clamp. Also, depending on the rear light design, it may or may not interfere with the seat post clamp.

Instead of doing that, I decided to mount a rear light onto the rear rack, using the mounting used for the rear reflector. Of course, this only works for Bromptons that have a rear rack.

Original rear reflector on the Brompton rear rack

It took me quite some time, trying out different brackets and mounting positions before I could find a suitable place to mount the rear light. The main challenge is to mount the rear light without it getting in the way during folding, while still pointing at the correct angle. At the same time, the rear light should be easily removable for charging. The rear light that I want to use is the Moon Comet rear light, which is a compact and bright rear light.

After much trial and error, I finally managed to use the Cateye mount (for saddle rails), and combine it with the Moon Comet rear light mount. The Cateye mount is clamped onto the two original L-shaped brackets used to mount the rear reflector.

L-shaped brackets + Cateye saddle rail mount + Moon Comet mount

Moon Comet rear light mounted at the rear of the rack

At the same time, note that I have managed to reinstall the bungee cords onto the rear rack! Previously they were removed as I could not hook the bungee cords onto the bolt of the rear Eazy wheels, like in the stock condition. However, I realised that since the bungee cords end in a loop, I can just put it through the rear rack as shown. Simple solution!

The light is protected by the Eazy wheels, and also does not protrude out from the rack, making it possible to fold the bicycle without hitting the rear light.

Good clearance with the ground, will not hit objects when rolling the folded bike 

Rear light DIY installation completed!

Next, after installing the rear light, the front light also needs to be installed. The obvious solution is to install the front light on the front bracket, which comes stock with a front reflector.

Front bracket with original front reflector

Studying the position of the front bracket when folded, to see the clearance and space available for mounting a front light

Instead of making a complex bracket mounting due to lack of space, I decided to just bolt on a QR axle extender...

...and wrap the rubber strap of the Moon Comet front light onto it!

No interference with the frame or cables during folding

Compared to the rear DIY mounting, the front mounting is much easier and straightforward. I basically just placed some material on the front bracket for the rubber strap to wrap around.

With this, the DIY front and rear light mounts are completed! There are no protruding parts that will interfere or compromise the compact folding. These DIY mounts also allow me to use the existing spare lights that I have, instead of buying more lights.

Sunday, July 16, 2017

Brompton M6R: BikeFun Suspension Block

After upgrading the hinge clamps to the better looking and more well designed Imperium Cycle hinge clamps, and also upgrading the Eazy wheels, the next upgrade for the Brompton M6R would be the suspension.

The stock suspension comes in two different hardness, the Standard type and the Firm type for those who are heavier or just want a more responsive ride. I opted for the Firm type, but I still felt that it was a bit soft, especially during hard pedaling when the bike will bob with every pedal stroke.

There are many aftermarket suspension blocks available for the Brompton, in different designs and many different colours. For me, the criteria is to get a suspension block that is more firm, and also in a colour that matches the Lagoon Blue frame colour.

Original Brompton Firm suspension block, which is basically just a rubber block for dampening the road vibrations. Picture taken before upgrading the Eazy wheels.

I came across the BikeFun suspension block, which has a rather nice looking external coil and comes in many colours to perfectly match all the available Brompton colours. Of course, I will need the Lagoon Blue suspension to match with my bike frame.

BikeFun suspension unit, with matching Lagoon Blue spring coil.

It comes with two rubber blocks of different hardness. The one with the white dot is the firmer block, which is what I will use.

BikeFun suspension unit weighs 70 grams, mainly due to the heavier steel spring coil.

Original rubber block only weighs 33 grams

Installation was quite easy, just need to follow the instructions to see which part goes where. For this Brompton, lightweight components are not necessary as no matter how many components I upgrade, the heavy steel frame will prevent any meaningful overall lightweight bike.

Blue suspension installed on the bike! The colour matches perfectly with the frame.

The suspension looks like it came stock with the bike. And it actually should, instead of just a rubber block.

With the new suspension, the ride feels more rigid and much more responsive. I can feel just a little bit of suspension, but not so much that it causes the bike to bob during pedaling. Some time ago, I had the Flamingo bike which is a replica of the Brompton, and it really bobbed quite a lot during pedaling, which makes it inefficient for faster rides.

Best of all, it looks good and matches perfectly with the Lagoon Blue colour of the Brompton frame!

Wednesday, July 12, 2017

Brompton M6R: Imperium Cycle Eazy Wheels

For a Brompton, one of the main advantage over other folding bikes is the ability to roll the bike easily when folded. The ability to roll the folded bike eliminates the need to carry a heavy bike when moving through the MRT station or into a shopping mall. This is especially important for a bike such as the Brompton, as the steel frame makes it heavier than many other folding bikes of equivalent specifications.

The "R" in the model type M6R refers to the inclusion of the rear rack, which has two more Eazy wheels (in addition to the two on the rear triangle), giving a total of four Eazy wheels for stable and easy rolling. The stock Eazy wheels (as the rolling wheels are called) seem to be made of a rubber outer ring fitted onto a plastic center core, which is then fixed to the frame or rear rack using a bushing type construction.

This bushing type construction is simple and cheap, but tends to have more friction when under rolling under load. There are many different types of aftermarket Eazy wheels for Bromptons, all of which claim to offer smoother rolling and better appearance. In the end, the main deciding factor is the appearance of the Eazy wheels.

Stock Brompton Eazy wheel

New Eazy wheels by Imperium Cycle. Uses sealed bearings which should be smoother than using bushings.

The wheels are sold in pairs. What I like about these set of wheels is the silver 5 arm design.

Comparing the width to the stock Eazy wheels, they are narrower by about one-third, which will be good for more heel clearance during pedaling.

As for the diameter, the new wheels are a bit larger. 60mm diameter vs the stock wheels which are 54mm in diameter. This will create an additional ground clearance of about 3mm.

New aluminium wheels weigh 61 grams...

...while the stock plastic wheels are a bit lighter at 55 grams.

Stock Brompton Eazy wheels have just a bolt, a bush and a washer through the center of the wheel.

New Eazy wheels installed onto the rear triangle! Installation is easy, as it is just a matter of removing the original ones and screwing in the new ones.

Looking good!

After that, the Eazy wheels on the rear rack will also need to be changed. This means that two pairs of Eazy wheels are required for the four wheels on a "R" type Brompton. However, the swapping of Eazy wheels on the rear rack is not so straightforward...

Comparing the bolt length. New bolt is much shorter than the original bolt on the rear rack, which also holds the roller for the bungee cord.

New bolt is about 10mm shorter than the original bolt.

Since the new bolt is shorter, it means that the bungee cord cannot be attached to the roller on the bolt any more. I tried using a generic M6 bolt to replace the bolt from Imperium Cycle, but it does not work as the diameter of the bolt head needs to be of a specific diameter to avoid pressing on the sealed bearing in the wrong place. If the wrong bolt head size is used, it just jams up the whole Eazy wheel. Therefore, I have no choice but to use the shorter bolt for the new Eazy wheel.

As the new Eazy wheel is slightly larger, it will touch the rear rack. A washer is needed to create clearance between the wheel and the rear rack.

With both Eazy wheels installed on the rear rack! Note that both wheels are supposed to be installed to the right side of the rack mounting.

Close up look of the bolt and the nylon locknut. The bolt is barely long enough to cover the locknut.

All four new Eazy wheels installed!

How it looks when the rear triangle is folded down

Just a bit more clearance between the rear rack and the ground, due to the larger Eazy wheels.

Brompton fully folded. The silver wheels seem to fit the overall look of the bike quite well.

Clearance with the stock foam grips. Just a bit more clearance than the stock condition.

Rolling the folded bike around with the new Eazy wheels is definitely smoother than using the stock Eazy wheels, although the stock Eazy wheels are not too bad in the first place. I would say that this is more of a cosmetic upgrade than any functional (performance?) upgrade.

Thursday, July 6, 2017

Brompton M6R: Imperium Cycle Hinge Clamps

After getting a Brompton M6R for myself, my upgrading instinct has kicked in. As with all bikes, I will identify areas that are not up to my standard and see if it can be upgraded. On the Brompton, there are a few areas that do not seem to belong on a premium bike. The parts that I am referring to are the injection molded resin parts that belong more to a supermarket bike than a bike that has a starting price of around $1800.

There are a few of these parts around, such as the shifters, the chain tensioner, the hinge clamp knobs, the roller wheels, and a few clips here and there. Although they function well, they do not provide the premium feeling that a Brompton should have. Imagine a premium Mercedes car with plasticky interior trimmings, that is the feeling I got.

The very first component that I want to upgrade are the hinge clamps. I have always been a fan of Dahon's folding clamp mechanisms, which are well engineered, easy to operate and nicely designed. If the Brompton has Dahon's clamp mechanism, that would be the best of both worlds.

Brompton uses a very simple clamp that basically holds both sides of the hinge together, using a simple but cumbersome rotating knob to press the clamp against the tapered surfaces of the frame. This removes any free play between the joints and does not need any adjustment over time, since you are basically adjusting it every time you use the clamp.

One annoying aspect of this hinge clamp design is that when you loosen the knob, you have no idea how far you need to rotate to loosen it sufficiently to free up the joint. Loosening it generously only encourages the clamp to rotate after becoming loose, causing it to be misaligned against the frame. All this creates the cumbersome feeling as I always need to fiddle with the clamp position to align it, before tightening the knob.

After loosening, the clamp will rotate and not be lined up with the frame. Also, there is no stopper to let you know when the clamp is loose.

Plastic knobs on a premium bike? Rather disappointing...embarrassing even.

Same for the hinge clamp on the handlepost

I wanted to get rid of the plastic knobs which do not belong on a premium bike such as the Brompton. After looking at a few aftermarket hinge clamps, I found that there is actually a solution to prevent the self rotation of the hinge clamp after loosening. This is exactly what I am looking for.

One downside of upgrading a Brompton is that the components cannot be found cheaply on Taobao, unlike those for Dahon or other folding bikes. Seems that the supply of these aftermarket parts are strictly controlled to maintain the higher prices that Brompton owners are willing to pay.

Anyway, I found the hinge clamp set from Imperium Cycle that look good and has the self aligning function.

Hinge clamp set in all black colour, made of aluminium

The various parts of the hinge clamp set and what they do

The pair of hinge clamps, for the frame and also the handlepost

They are virtually identical, except for the silver bolt at the end which has slightly different lengths. The silver bolt with the step is for the handlepost.

Machined lever for lightweight image. Feels much better than the plastic knobs.

One side of the clamp is longer than the other, and this is what keeps the clamp aligned after loosening the knob.

Comparing the new clamp with the stock clamp. The clamp plate on the stock clamp looks quite a bit thicker.

New hinge clamps weigh 62 grams a pair

Stock Brompton hinge clamps weigh 105 grams a pair

The silver bolt at the end is reversed (left hand) threaded, to prevent self loosening when operating the clamp.

Using a size 4 Allen key to tighten the silver bolt into the black bolt.

One problem I found during installation is that the frame hinge will get in the way of the Allen key when I am tightening the silver bolt. Even with the ball end of the Allen key, I am not able to engage the silver bolt properly to tighten it. To solve this, the next version should have 2 flats on the silver bolt, so that we can use a wrench to tighten it instead of an Allen key.

The silver bolt acts as a stopper during loosening, which is designed to stop when the clamp has retreated far enough to free up the joint.

At this point, the shorter side of the clamp has cleared the frame, while the longer side is still engaged to prevent self rotation of the clamp. Ingenious design!

Both hinge clamps installed!

All black aluminium hinge clamps and levers look more befitting of the Brompton

This upgrade is a must for me, as it solves the two main issues of the stock hinge clamps. First, there is a stopper which stops the knob when the clamp has been fully loosened. This makes it easy as I just need to twirl the lever until it stops, without thinking how many turns is required.

Second, the long-short clamp design ensures that the clamp is aligned with the frame or handlepost at all times. When I need to tighten the joint, I just close the joint and tighten the knob. No need to fiddle with the clamp to align it. Much faster and fuss free than the stock design.

If you are a Brompton owner who folds and unfolds the bike a few times a day, this is a highly recommended upgrade as it makes operating the hinge clamps much easier, and you will wonder why did you put up with the original clamp design for so long.