United Trifold: Brake System Upgrade

The stock brake system that comes with the United Trifold is not very good. It does not brake well, even when you apply a lot of force to the brake lever.

A bicycle braking system consists of many components. Brake lever, outer casing, inner cable, brake caliper, brake pad and the rim. Each one of these components must function optimally, to enable a smooth braking operation and strong braking effect.

Based on my plan, all the components will be changed.

Brake Lever: Change to Shimano SL-R780

Outer Casing and Inner Cable: Change to Shimano outer casing and inner cable

Brake Caliper: Change to Shimano brake caliper if possible

Brake Pad: Use the Shimano brake pad that comes with the brake caliper

Rim: New wheelset 

The challenging part is changing the brake caliper, all the other changes should be no issue. This is because the stock Tektro brake caliper is a long arm type, to allow the mudguards and wide tires (37-349) to fit inside. The reach is measured to be about 70 mm, which is very long.

Standard Shimano road brake calipers have a reach of around 51 mm, which is way too short. Even with a brake pad extender, it only adds 10 mm which is still insufficient.

Previously I have experimented with different brake calipers on the mini velos and folding bikes, you can read about it here.

Dahon Boardwalk Brake Caliper Part 1

Dahon Boardwalk Brake Caliper Part 2

Dahon Vitesse Brake Caliper

Wheelsport Brake Calipers Part 1

Wheelsport Brake Calipers Part 2

From all the prior experience, I know that the best braking performance can be achieved if you can use standard reach Shimano brake calipers, instead of resorting to long reach brake calipers or other adapters.

Stock Tektro brake caliper, which has a long reach to encompass the mudguards and wide tires.

My idea is to use the Elosix brake adapter for the front brake, like how I did many years ago. No idea for the rear brake yet.

The brake adapter does not fit well, as it sticks out too much from the fork and interferes with the tire.

Part of the reason that the brake adapter sticks out so much is due to the internal profile of the fork, where there are internal protrusions that prevents the adapter from resting properly.

Another reason is that the slot on the brake adapter is rather short, limiting its range of positions.

Old Elosix brake adapter on top, new one below. Note the longer slot on the new brake adapter.

New brake adapter on the right has a thinner wall at the larger diameter, where the brake caliper will be fixed to.

On the other hand, the new brake adapter on the right has a thicker wall at the smaller diameter, where it locks to the fork.

Even with the longer slot on the new brake adapter, I cannot push up the brake adapter all the way.

Time for some DIY, to grind a longer slot on the brake adapter, so that the brake adapter can be tucked into the fork as high as possible.

With a longer slot on the brake adapter, it can now go all the way up into the fork.

This is the new brake adapter, secured to the fork at its highest position for tire clearance.

The brake adapter is secured to the fork using the internal nut, and double secured with the external nut.

With the tire installed, there is enough clearance. Mudguards definitely have to be removed, as I already planned.

Here is the Shimano 105 BR-R7000 brake caliper, of the same generation as the Dura-Ace R9100 and Ultegra R8000 brake calipers.

Unfortunately, the 105 brake caliper is unable to fit, as it will interfere with the tire. The brake caliper is only designed for tires with maximum width of 28 mm, so the 35 mm width of the Schwalbe One tires is just too much. Previously on the Dahon Boardwalk, the brake calipers were able to fit over the 35 mm wide Kojak, only because the brake mounting point was a bit higher up.

In this case, the Elosix brake adapter puts the brake caliper too far down, and there is no way to reduce the amount of extension. Therefore, the Elosix brake adapter does not work for this bike, for me to install a standard Shimano brake caliper. In this case, I have to use the stock Tektro brake caliper, but I can still use new brake pads.

Separately, I got Ultegra caliper brake pads, so that I can replace the stock brake pads on the Tektro brake calipers. The stock brake pads are really bad, as they are very hard and not grippy at all. It goes right into the bin, no need to keep for future use.

Shimano Ultegra brake shoe set, with the brake pad holder and brake pads.

Each set of brake pads weigh 36 grams.

Each set of Tektro brake caliper weighs 173 grams, without brake pads.

I thought that the brake pads would be a straight swap, but it turned out to be a nasty surprise instead. Apparently the brake pads do not fit into the brake calipers directly.

The nut of the Shimano brake pad does not fit into the slot of the Tektro brake caliper.

Outer diameter of the nut on the Shimano brake pad is 6.4 mm.

Slot width on the Tektro brake caliper is only 6.1 mm.

I was surprised at this finding, as I always thought the slot width was a standard width. However, I realized that the stock Tektro brake pads are one-piece type, with the bolt molded into the brake pad. The bolt has an M6 thread, which means an external diameter of around 6 mm. That was why the Tektro slot width is 6.1 mm, to prevent too much free play with the M6 thread.

However, the Shimano brake pad uses a M5 bolt and nut, and thus the external diameter of 6.4 mm on the nut is just to ensure sufficient wall thickness on the nut. The slot width thus needs to be wider to fit the nut.

In this case, the width difference is only about 0.3 mm, so it is safe and not too difficult to widen the slot width on the Tektro brake caliper. Using a hand file, it will take quite some time. I used an electric grinder and it was done quite easily.

Grinding off some material from the slot of the Tektro brake caliper, so as to fit in Shimano brake pads.

Now it fits!

Since I have removed the brake calipers from the frame, this is the best chance to condition the brake calipers, so that they move as smoothly as possible. After all, I don't have any other solution to change the brake calipers.

The Tektro brake calipers does not operate smoothly, as there is quite a lot of friction in the pivots and joints. I added some grease to the sliding areas, and oil to the pivots. After conditioning it, the brake calipers are able to operate more efficiently. This ensures that more of your hand input force goes to press the brake pad against the rim, instead of working against friction.

Front Tektro brake caliper with Ultegra brake pads weigh 207 grams.

Rear Tektro brake caliper with Ultegra brake pads weigh 209 grams.

Ultimately, I was not able to change the brake caliper, but I was able to improve the efficiency of the Tektro brake caliper by applying grease and oil to the moving areas. The brake pads were changed to Ultegra brake pads, which should be better than the stock brake pads.

Whether all these improvements are able to provide a good braking performance will be confirmed after the whole bike is set up.

Fnhon DB11: Elosix 29 cm 2 Bolt Handlepost

My latest folding bike project is the Fnhon DB11, which is a 1x11 speed folding bike with 451 wheels, premium XTR brakes and some other goodies.

Among the new components that I used was the latest Fnhon handlepost, which has a smooth joint like Tern Physis handleposts. This gives it a better appearance and also looks more high-end. However, after using it, I found that it seems to be slanted to one side.

What I mean by slanted is that the handlepost is not perfectly vertical, when the front wheel is perfectly vertical. There is a sideways tilt of the handlepost, which causes the handlebar to be tilted as well. The end result is that one side of the handlebar will be higher than the other, when riding straight. This effect is not much, but it is enough that I can feel the difference.

When the front wheel is vertical, the top of the handlepost can be seen offset to the right side, due to the tilt of the handlepost. This offset also causes the handlebar to be higher on the left side than the right side.

Although riding and folding the bike is normal, this tilting of the handlebar gives me a weird sensation that I cannot get used to. I am probably more sensitive to these kind of non-symmetrical effects, as I always set up my components to be as perfectly symmetrical as possible.

Examples: height and angle of road shifter hoods needs to be the same on left and right side, handlebar needs to be perfectly perpendicular to front wheel, saddle needs to be pointed perfectly straight, etc.

Other than the handlepost tilt, I also found that the handlebar height is a little higher than what I prefer. It is VERY difficult to find a handlepost height that is shorter than the common 31.5 cm Fnhon handlepost, as most other handleposts are taller. I used to have a shorter 27 cm handlepost, but I can't find it on Taobao any more.

After much searching, I finally managed to find a seller who has a shorter handlepost available. It also needs to be the 2 bolt or 4 bolt kind (not QR or T-shaped type), and also inward folding. Apparently the brand is Elosix, but it could be anything actually.

New shorter Elosix handlepost on the left, versus the common 31.5 cm Fnhon handlepost on the right. Both of these are the traditional Dahon/Fnhon design, not the new smooth type from Tern/Fnhon.

New handlepost has a rhino logo printed on the top clamp, and uses a bolt with a different head.

Base of the handlepost looks almost the same, but with a different clamp bolt.

Looks almost the same from the bottom.

The lever looks the same, but the plastic safety catch is different.

As mentioned, the lever looks to be from the same mold. Even the circular debossed feature is there.

Internal clamp design is different. Shown on the left is the new Elosix handlepost.

Elosix design is simpler, with no frame to hold the sliding bolt. This allows the internal space of the handlepost to be seen.

Fnhon 31.5 cm handlepost has an actual height of about 33.8 cm. The difference is due to how the height is defined (from clamp joint) vs how it is measured (from base). Strange but true.

New Elosix handlepost (claimed height 29 cm) has an actual height of 31 cm. About 2.8 cm shorter than the Fnhon handlepost.

Traditional Fnhon 31.5 cm handlepost weighs 565 grams

New Elosix 29 cm handlepost weighs 518 grams, a difference of about 47 grams.

However, note that this comparison above is between the traditional construction of the Fnhon handlebar and the Elosix handlepost, which look almost similar. The handlepost that I installed on the Fnhon DB11 is the new type of Fnhon handlepost, which requires a longer compression bolt.

Therefore, a more complete weight comparison is as shown:

Weight comparison of handlepost + compression bolt:
Traditional Elosix 2 bolt type (29 cm) + compression bolt = 518 + 45 = 563 grams
Traditional Fnhon 2 bolt type (31.5 cm) + compression bolt = 565 + 45 = 610 grams
New Fnhon 4 bolt type (31.5 cm) + longer compression bolt = 552 + 68 = 620 grams.

In this case, changing from the new Fnhon 4 bolt type to the shorter Elosix 2 bolt type gives a weight saving of about 57 grams, which is only about 0.6% of the whole bike's weight.

New Fnhon 4 bolt type handlepost. Wider clamp but also more weight.

From left to right: Elosix 29 cm 2 bolt, New Fnhon 31.5 cm 4 bolt, Traditional Fnhon 31.5 cm 2 bolt.

The height of the new Fnhon 4 bolt type and traditional Fnhon 2 bolt type is almost the same, since both are labeled as 31.5 cm height.

After installing the new Elosix handlepost, I found that the tilting is still present.

Front wheel is perfectly vertical, but there is some tilting of the handlepost towards the right.

Strangely, there is still some tilting of the handlepost and handlebar after swapping to the new Elosix handlepost. In this case, it is likely that the handlepost may not be the issue after all. Maybe the fork legs are bent, or the frame head tube is tilted, which can also cause the same effect. It is difficult to conclude definitively since the tilting is small, and I cannot measure the parts accurately.

Regardless, the handlebar height is now reduced, which I much prefer over the previous one. Maybe it is because I am used to riding drop bar bikes with a low handlebar, therefore I am not used to riding flat handlebar bikes with a higher handlebar.

With the handlebar transplanted onto the new Elosix handlepost.

As the handlepost is shorter, the handlebar is located differently when folded down. I will need a new protective sticker on the fork leg to prevent the handlebar from hitting the fork leg.

New protective sticker pasted on the fork, to prevent scratches between the handlebar and the fork leg during folding.

Picture with the shorter handlepost! Although it is only about 2.8 cm lower, it does make a difference both ergonomically and visually.

Updated bike component specifications, with shorter and lighter Elosix handlepost. Bike weight without pedals and kickstand is now 8.8 kg.

I am happy with this change of handlepost, as the lower handlebar enables a more sporty riding position which I prefer. Although the handlepost tilting issue is not 100% solved, it is less obvious and no longer annoys me so much. Not sure if my previous folding bikes had this problem, but I have not noticed it before.

Elosix Rear Caliper Brake Adaptor (For kickstand mounting plate)

Just a quick introduction to this Elosix rear caliper brake adaptor. This adaptor is used to mount caliper brakes behind the seat tube on 20" folding bikes, using the kickstand mounting plate. By mounting the brakes at this hidden location, it does give the bike a cleaner look and is perhaps more aerodynamic than mounting it on top of the seat stays.

Elosix adaptor, comes with an M8 bolt, a washer, a spring washer and a square nut.

Mounted on a Dahon Mu Uno, with 1.75" tires on 20" wheels.

Using the double nut method of securing the bolt to prevent self-loosening.

http://www.boltscience.com/pages/twonuts.htm

Stock kickstand can still be mounted. A longer M8 bolt is required to thread through the kickstand and the Elosix adaptor.

Sufficient clearance with the left side crankarm

This mod is necessary for this Dahon Mu Uno, as the frame does not have any V brake mounts. Caliper brakes also cannot be mounted on the bridge between the seat stays as the seatstays are very tall and blocks the caliper brake arms. In the end this is the only viable method of mounting a rear brake on the Mu Uno frame.

Using this adaptor for 451 wheels might be possible, if slim tires are used. The frame may also affect the fitting of this adaptor. I have heard that this adaptor does not work on Tern bikes with 451 wheels due to interference. However, it may still work for Dahon bikes with 451 wheels.

The adaptor is made of aluminium, but it does look a little weak. It has been tested by riding and it works nicely, but I am not sure of the strength. Perhaps it would be a better idea to make the adaptor out of thicker aluminium or steel. After all, this adaptor is critical for braking and it must not crack or deform under load.