Saturday, September 30, 2017

Brompton M6R: DIY Lezyne Pump Mount and Tool Bag

One interesting thing about getting a Brompton is that most of them come with a hand pump included on the frame. As far as I know (correct me if I am wrong), only the E version (no mudguards) and titanium type do not include the pump.

The included pump is a Zefal branded hand pump, made specially for Brompton. It fits into a specially designed mounting area on the non-drive side rear triangle. The end with the handle has a hole, which goes onto a metal rod on the frame. The pump is then compressed slightly, and the pump head is then slotted into the holding frame at the other end. The spring inside the pump tends to extend the pump, keeping it tight within the frame.

Mounting of Zefal pump in the Brompton frame

This method of holding the pump is quite OK, however the pump itself is quite lousy. First, the pump head does not have a flexible hose, which means that during inflation of the tube, the pump has to be maintained at 90 degrees to the valve, to prevent damaging the valve. This makes efficient and ergonomic pumping quite impossible. Also, the construction and design is such that it is difficult to achieve a high inflation pressure with this pump. Brompton tires have a recommended inflation pressure of 100 PSI, which is impossible to achieve on this pump unless you have a lot of patience and strength.

As such, I have no confidence in using this pump to reliably fix a puncture if required. My preference would be to use a better pump such as a Topeak or Lezyne hand pump that has a flexible hose for ease of use. However, this also means that I will have to find an alternative way to bring the pump along, as it cannot be mounted like the Zefal pump.

I believe that most Brompton riders either use the stock Zefal pump, or bring a separate pump in a front carrier bag or in the jersey pocket. I would prefer to fix the pump to the bike itself if possible, so that I don't forget to bring it along.

The underside of the rear rack can be a useful place to store a separate hand pump, as shown in the picture below. However, you will need a way to mount it securely, so that the pump does not drop off or get lodged in the rear wheel. I imagine that it would be possible to secure it to the rear rack if you use velcro to tie the pump around the rear rack, or get creative with the use of rubber bands.

Simplest way to mount a pump to the rear rack would be to tie or velcro it at the area shown here.

After some tinkering and experimenting, I found that it may be possible to mount a pump to the frame, near the original Zefal pump mounting. What I would need would be a way to mount the pump bracket that is included with every Lezyne hand pump.

Objective is to mount the Lezyne pump in this manner, using the space left behind after removing the stock Zefal pump.

Looking through my box of spare clamps, I found a pair of seat stay clamps used for rear lights. I cannot remember which lights these clamps come from, but that does not matter. The Lezyne pump bracket usually mounts to the frame using the bottle cage bolts, but I will be using this pair of clamps instead.

Pair of clamps originally designed for mounting a rear light onto the seat stay. Rubber shim required to get the correct inner diameter.

After mounting the Lezyne pump bracket to the Brompton, using the pair of seat stay clamps.

Lezyne pump mounted onto the bike. Not as neat as the Zefal pump mounting, but this pump works better.

This is an S sized Lezyne Pressure Drive, which is shorter than the M sized pumps. From what I see, only S sized pumps will fit within the rear triangle, as the M sized pumps are too long. I like this DIY method of mounting a hand pump onto the Brompton, as it does not interfere with riding or folding, and allows me to bring along a better quality hand pump.

For puncture repair, there are three things that you need. The first is the hand pump as shown above. The next essential item is the spare tube or patch for the tube. I prefer to bring along a spare tube instead of relying on the patch, as it can be difficult to patch the tube while on the road. The faster and easier way is to swap in a fresh tube, and patch the punctured tube at home during your free time.

Lastly, you will also need a pair of tire levers to remove the tires from the rims. With these three items, you will be able to repair a puncture. Miss out any one of these items and you might as well not bring the other two.

How do we bring along the spare tube and tire levers? Once again, most riders who bring out these items either store it in the front carrier bag or in the saddle bag. I cannot mount a front bag on the front carrier block as I will be using the Bobike Mini child seat, which will interfere with a front carrier bag. As for using a saddle bag, I don't want to use it on the Brompton as it will prevent the seatpost from being lowered all the way. As the saddle bag sticks out from the back of the saddle, it will also make the folded size larger.

Therefore, I decided to do some DIY again and try to mount the spare tube and tire levers to the rear rack. The rear rack is very useful for mounting stuff at the sides, as the sides are unused and it will also not interfere with the folding.

The small bag that I found is a Schwalbe Race Saddle Bag, originally designed to mount under the saddle. I don't have a concrete idea on how to fix this saddle bag to the rear rack, I will just have to experiment with the actual bag after I get it.

Schwalbe Race Saddle Bag can fit a spare tube and tire levers, but not much more. I added a tire boot for good measure.

After testing out many different configurations, I finally settled on a mounting method that is secure, unobtrusive, and not too difficult to access.

The bag is mounted this way, so that it is wedged between two beams of the rear rack. The velcro straps will then wrap around the rear rack.

The top velcro strap is first wrapped around the top beam of the rear rack, followed by the wide grey velcro to secure everything in place.

It is very important to mount the bag securely. First, it needs to be secure so that it cannot drop off during the ride, even when riding over bumpy roads. Secondly and more importantly, for safety, it cannot dangle or lodge itself in the rear wheel, which will be very dangerous if you are riding and it jams the wheel. Same requirements needed for the DIY pump mount installed earlier.

View of the DIY pump mounting and bag, which carries the spare tube and tire levers.

With these puncture repair tools mounted to the Brompton, I will be able to repair any puncture on the roads, without needing to remember to bring out any spares or tools separately. Best of all, these DIY mountings do not make the folded package any larger, which is the main advantage of the Brompton.

Hopefully this can inspire some of you to do the same DIY mounting, which I feel is very useful and does not compromise the folding size or speed of the Brompton.

Saturday, September 23, 2017

Brompton M6R: Bobike Mini Child Seat with Bryan Adapter and X Bar

Why did I get a Brompton? Definitely not because I need another folding bike, as I already have so many other bikes of various designs and purposes. The main reason for me getting a Brompton is to be able to mount a Bobike mini child seat, so that I can bring my kid along for a ride. When he outgrows the Bobike child seat, I can then install a Pere child seat onto the same Brompton.

After making various modifications to the Brompton to make it more comfortable to ride, easier to fold and roll, it is finally time to install the Bobike mini child seat. I know that this child seat can be installed on other types of bikes, but since most of my bikes are equipped with a drop bar, they are not suitable for mounting a child seat. It is better to have a dedicated bike for cycling with the kid as the saddle needs to be set at a lower height, which is not suitable when I ride myself.

For installation of a Bobike mini to the Brompton, an adapter called the Bryan Adapter will need to be used. This will be shown later on. Before that, let's take a look at how the Bobike mini child seat will position the kid on the Brompton.

How it looks when mounted on the Brompton. I got the child seat plus Bryan adapter at a really good price on the second hand market.

An example of how the kid will look when seated on the Bobike mini that is mounted on the Brompton.

One advantage of mounting the Bobike mini on the Brompton is that the child seat can be mounted further in front and lower than on a normal bike. This is because the Brompton does not have a top tube that will affect the placement of the child seat. Not only is this more stable due to the lower centre of gravity, it also allows the adult rider to pedal more efficiently as the knees do not have to open so widely during pedaling.

As you may have noticed in the pictures above, there is a cross bar that links the two sides of the M handlebar together. This gives the child an alternative place to hold, and also stiffens up the handlebar for more rigid steering, which is an advantage when trying to steer with a load on the front.

Note that the Bobike mini child seat is not suitable for S type flat handlebar, as the child will block the adult rider from accessing the handlebar. As for P type handlebar, I think it can still be mounted but you will not be able to install the cross bar.

Cross bar by Brompton, not necessarily a part of the Bobike mini child seat package. Good to have but not essential.

Parts of the cross bar. Note that the cross bar is made of plastic and not metal.

Instruction manual for installing the cross bar

Quite complicated instructions and method for installing the cross bar...

All ready to be installed! I wonder if there is a simpler design for a cross bar, this seems too complicated.

After a bit of difficulty, the cross bar has been installed.

No interference issue with the front hub axle if you have managed to set the position of the cross bar properly.

With the cross bar done, the next step is to install the Bryan adapter, before the Bobike mini child seat can be mounted. Although there are other clamps that can be used to mount the child seat, this design is the best, as I will explain in a while.

Bryan adapter, used to mount Bobike mini child seat on a Brompton.

The various bolts, nuts and rubber shims on the Bryan adapter.

This adapter that is made out of sheet steel is heavy at 452 grams. But when you are adding a child of 10kg onto the bike, this does not matter.

Just hook the adapter onto the handlebar, and clamp it around the handlepost

The design of this Bryan adapter is superior to other types that just clamp onto the handlepost, as it is much more stable. With the two hooks on top, it prevents the adapter from slipping downwards under load. Also, the two hooks prevent the whole adapter from rotating around the handlepost. A very robust design which I like.

The shifter and brake outer casings are routed around the side of the adapter

The adapter sticks out from the side of the bike when folded, which is a downside.

This adapter can be left on the bike permanently, as the Bobike mini just slots into the adapter without any tools. However, when folded, the adapter sticks out quite a bit which can be annoying. At least the child seat can be removed easily when you are not using it, and it does not affect normal pedaling.

Now, let's take a look at the Bobike mini child seat!

The Bobike Mini child seat. Still in good condition for a second hand product. 

The safety belt goes over both shoulders and clips in between the legs. The clip has a safety feature that requires two hands to open. 

Foot rests, and straps to prevent the legs from swinging around.

The height of the foot rests can be adjusted by moving the fixing bolt. This is more troublesome but also stronger and more secure. 

These two steel rods on the underside of the child seat will be inserted into the Bryan adapter to hold it

How it looks when the child seat is installed onto the adapter 

For additional safety, I added a ring at the end of the rod to prevent the seat from being lifted off the adapter accidentally, although it is difficult and very unlikely to happen.

Final view of the Bobike Mini child seat installed on the Bryan adapter, on the Brompton!

This child seat is located quite high on the handlepost, which is not so good for stability as the centre of gravity is higher. However, this also prevents the adult's knees from hitting the back of the child seat during pedaling, as there is more clearance.

For me, I only have to widen my knees slightly for sufficient clearance during pedaling. However, since I usually step forward, over the top tube when I come to a stop, this child seat prevents me from doing that. The solution is to lower my saddle for riding, so that when I stop, I can just put my feet down at the sides and touch the ground. Not ideal for pedaling efficiency, but necessary for safety.

With the additional weight on the front, the bike is actually quite stable, since the weight balance over the front and rear wheels are now more balanced. However, steering is also heavier due to the extra mass over the front wheel. It takes some getting used to, and strains the arms more than usual.

Perhaps there are better solutions for bicycle child seats out there, but I think it is hard to beat this combination for compactness, as the child seat can be removed easily, while the Brompton can be folded down to a small size. Together, they will fit in a car boot easily.

Tuesday, September 19, 2017

Brompton M6R: Ergon GP1 Grips

Not many bike brands in the world can claim to be made in London or a major city. Brompton is one of the few brands that still makes its own frames and is assembled in a major city. As such, it commands a higher price than many other bikes, due to its manufacturing location and premium image.

Even though Brompton portrays itself as a premium bike, there are some components on the bike that are not premium at all. Earlier on, I upgraded the hinge clamps, due to the outdated clamp design and plastic knobs. The other component that I feel does not belong on the Brompton are the stock grips.

The stock grips are made of foam that are glued onto the handlebars. Although they are lightweight, they are not comfortable or ergonomic, and are difficult to remove and change. Credit to Brompton, they have already made the changes in their 2017 models, which are equipped with lock on type foam grips that are at least easy to upgrade.

As this is a pre-2017 Brompton, it is still using the glued on foam grips. I tried to get used to the grips, but it was just not comfortable to hold onto for longer rides. Therefore, I wanted to change to more ergonomic Ergon grips that provide support for the palm.

Similar to most Brompton parts, upgrading or modification is not straightforward. First, I had to select the correct type of Ergon grips to match the handlebar.

Ergon grips come in two different lengths, the standard length being 130mm, and the shorter 95mm type for Gripshift or Rohloff shifters. With the shorter type, part of the resting surface for the hand will be on the rubber grip of the Gripshift.

Comparing the length of the shorter Ergon grip with the stock foam grips. Shorter by about 10mm.

The length of the Brompton foam grips are about 100mm in length, and are only just sufficient for my hands to grip properly. If I change to shorter Ergon grips, without a Gripshifter, the gripping length will be too short for proper and comfortable gripping. As such, I cannot do a straightforward swap to the shorter type of Ergon grips.

On the other hand, I also cannot make a direct swap to the standard 130mm Ergon grips, as it is too long. There is not enough handlebar length to move the brake lever or shifters inwards, as they are already close to the bend of the M type handlebar. With a S type flat handlebar, a straightforward swap should be possible.

As many people have already done previously, one of the solutions is to cut the standard length Ergon grips to your preferred length. This is quite troublesome, which is why I stated earlier that upgrading the Brompton grips is not a straightforward matter. The Ergon grip that I will be using is the simple Ergon GP1 grips, without bar ends. Bar ends will complicate the folding and may touch the ground when the bike is folded.

After measurement and comparison, I need to cut about 20mm off the standard length Ergon grip, as shown by the cutting line marked on the grip above.

I used a sharp pen knife to cut the rubber along the cutting line, then peeled it off the plastic inner shell.

After that, a cutter is used to cut the plastic inner shell, enabling it to be broken off and removed.

Finally, some slight filing is done to give a relatively smooth cut edge. I think this method of cutting the Ergon grip is better than using a hand saw, which may tear the rubber.

Final length is about 111mm, quite close to my target of 110mm.

This new length is just nice for me to grip comfortably.

This new length is also about the same as the original foam grips.

The modified Ergon grips weigh about 152 grams per pair.

With the new pair of Ergon grips prepared, it is now time to remove the original foam grips from the handlebar. I did not remove it beforehand as I was not sure how the Ergon grips will turn out after cutting, so I left it on first.

It is not possible to remove the foam grips neatly, as they are glued on and so will definitely be damaged during removal. Therefore this is a non-reversible modification, so you need to be confident that you will like the new grips.

Cutting open the foam grips with a pen knife. Cut it at an angle so as to minimise any scratching of the handlebar.

Peeling off the foam grips. It is starting to get really messy here.

There is still a thick layer of glue on the handlebar, which need to be removed before the new grips can be installed.

I tried using a strong solvent to remove the glue, but it did not work. Using a sanding block also did not work as the glue was stuck on like glue onto the handlebar. Finally, I discovered that the fastest and cleanest method was to use a pen knife to scrape off the glue.

Using a pen knife to scrap off the thick layer of glue

Took quite a while to scrap the glue cleanly off the handlebar. Now to repeat this for the other side...

Finally, the stock foam grips have been removed. You can see that for the second grip, it is done more neatly as I had practice and experience from removing the first one.

The foam grips weigh only 12 grams! Best for weight weenies.

New Ergon grips installed! The brake levers had to be re-positioned a little bit to fit neatly against the grips.

Both the Ergon grips installed! It already looks more comfortable...

About 10mm of clearance with the ground when folded, helped by the larger Eazy wheels.

The Ergon GP1 grips are so much more comfortable than the stock foam grips, and it is an upgrade that is definitely worth the effort. Some shops may offer to install the grips onto the bike for you when you buy the grips from them, and you should take up that offer as it is quite a lot of work to remove the original foam grips and also cut the Ergon grips.

If you decide to buy the grips online and install it yourself, you can refer to the steps above as a guide for installing new grips.