Focus Paralane: Switching to 105 R7000 Power Meter

It was not long ago when I completed upgrading the Focus Paralane to a full Dura-Ace Di2 groupset. However, on that groupset, there was one component which is not from the latest R9200 groupset, and that is the left crank arm.

I was still using the older R9100 left crank arm with 4iiii power meter, as it is useful to have power readings even though I am not training with the help of a power meter.

When I was using the Dura-Ace R9100 2x11 speed crankset, the right and left crank arms were matched as a set. Then, when I changed to 12 speeds, I only swapped the right crank to R9200, leaving the left crank arm still as R9100 with power meter.

Now, I plan to install the unused R9100 crankset on another bike, and I would like to move the R9100 left crank arm with power meter over as well. Therefore, I need a left crank arm for the Focus Paralane.

I actually have many spare left crank arms, as I have two different left crank arm power meters, the R9100 and also a cheaper 105 R7000 version. In fact, the R7000 power meter was on the Focus Paralane previously, when it was a 1x11 speed setup.

The 105 R7000 left crank arm with power meter is currently on the Cervelo Aspero, but I think it would be more useful on the Focus Paralane, given that I ride it more often and on the road, where power readings are more useful than when riding on gravel.

This gives me a rare chance to have both the Dura-Ace R9100 and 105 R7000 power meter left crank arms off the bikes, for a side by side comparison.

105 R7000 crank arm on top, Dura-Ace R9100 crank arm below. 

They are both of 165 mm crank arm length.

Different surface treatment, and the R9100 crank arm looks more well used given that it has been in use since it was first installed on the Canyon Endurace.

United Trifold: 11 Speed Drivetrain Completed

Final post on the United Trifold derailleur drivetrain modification! It has been really challenging to do this modification, due to a lot of incompatibility and interference issues.

Finally, I have managed to make it work, albeit with some limitations. Let's take a look at the final setup.

At the second lowest gear of 27T sprocket. Chain is stretched to the maximum here.

There is still some chain tension halfway though the fold, which is good.

When fully folded, the chain will still hang loose. But the additional chain tensioner keeps it in place on the rear derailleur and cassette.

It is recommended to fold this trifold bike with the chain in the larger sprockets, because this is where the chain will have the least slack.

As shown above, due to the small chain tensioner on the rear derailleur cage, it is not sufficient to take up all the chain slack when folded. The chain still hangs slack, but it does not go all the way to the ground, unlike when I used the super short cage Saint rear derailleur.

I think this condition is still acceptable, as it only occurs when folded. The chain does not drop off even when the bike is pushed around in this condition. Also, when the bike is unfolded, the chain still stays on the cassette.

Chain tensioner goes close to the rear tire when folded, but I think it is still OK since the rear wheel does not roll when the bike is folded.

The chain sometimes rests on the rear derailleur body itself, since it becomes slack. Main thing is, it does not derail from the rear derailleur pulleys.

However, there are still other issues, such as chain interference with the frame. This one is also tricky as there is not much I can do.

Cannot use top gear of 11T, as the chain rubs the frame as shown by the marks here.

Also cannot use lowest gear of 30T, as the chain will rub the frame (semi-circle loop for routing the rear brake cable).

If you really want to avoid the chain rubbing, the rear brake cable guide can be sawed off the frame, since it is not required any more.

I had an idea to shift the entire cassette towards the non-drive side, by moving the hub adapter that is currently on the non-drive side of the rear hub. From the start of the single speed conversion, the hub adapter has been installed on the non-drive side of the rear hub, to boost the wheelset OLD from 130 mm to 135 mm in order to match the frame. It was natural to place the adapter on the non-drive side, so as not to affect the freehub body side.

However, I realized that if this hub adapter can be moved to the drive side instead, it will solve a few problems at one go.

By placing the hub adapter on the drive side, instead of the non-drive side, the cassette position is pushed inwards by 5 mm.

With the cassette pushed towards the non-drive side, the chain does not touch the frame in the 11T sprocket nor the 30T sprocket.

This means that the 11T top gear can now be used, giving a good top gear of front 52T and rear 11T on the 16 inch 349 wheelset.

On the other hand, the lowest gear of 30T still cannot be used, despite no more chain interference with the frame. Due to the inward offset of the cassette, the cross chain effect from the chain ring to the 30T sprocket is just too much. During pedaling, it makes quite a bit of noise and also vibrates a lot.

In this case, I decided to use the low limit screw of the rear derailleur to lock out the lowest gear (30T sprocket), limiting the drivetrain to 10 speeds, which is equivalent to a 11-27T casssette.

Another downside of this modification is chain drop when backpedaling in the lowest few gears. Again, this is due to the skewed chain line and short chain stay. It is annoying when pushing the bike backwards, but it can be avoided.

Gear range of this 11 speed setup (limited to 10 speeds) is 30 to 75 gear inches. Quite a nice gear range for folding bikes used for casual riding.

11 speed road shifter for flat handlebars, SL-RS700, with BL-R780 brake levers.

Additional shifter to the handlebar, unlike the previous setup with only brake levers.

The modification is not done yet! During the experimentation, I found that the rear brake cable outer casing kept getting in the way of the chain. From the earlier pictures, you would have seen that I moved the brake outer casing to the outside of the frame. Now I will show the final brake cable routing that is needed for this derailleur drivetrain setup.

Instead of passing through the loop (that was interfering with the chain on the 30T sprocket), the cable needs to run outside the rear triangle.

Also, the outer casing needs to stay close to the chain stay, to avoid crank interference or tire interference.

Here is how the outer casing needs to be routed, to avoid all interference.

Final bike picture with the derailleur drivetrain setup!

When fully folded, the chain becomes slack but this condition is acceptable for me.

Even though the chain is slack, it remains on the crucial areas.

Final setup is 9.8 kg with pedals.

With this, the modification is complete! It is possible to modify the United Trifold to use a derailleur drivetrain, although the process is not straightforward at all.

The end result is not as ideal as I want it to be, due to the unresolved chain management issue. As of now, I don't have a good solution for it, so I will let it be.

As for the ride, the multi-speed drivetrain allows me to use the bike for a wider range of rides, even those with a bit of road riding and also slope climbing.

Finally, the weight of the full bike has increased to 9.8 kg with pedals, up from the 9.3 kg of the single speed setup. This is a weight increase of 500 grams, for the additional derailleur drivetrain. Not as lightweight, but still a good weight reduction of almost 3 kg from the stock setup.

By changing to this derailleur setup, the function and purpose overlaps more with the Fnhon DB12 that I have. In a way, the United Trifold is an inferior version of the Fnhon DB12, being heavier, slower, with smaller gear range, and poorer braking performance. Only advantage the United Trifold has is being slightly shorter when folded compared to the 20 inch Fnhon DB12.

United Trifold: R7000 Short Cage Rear Derailleur + Extra Chain Tensioner

After experimenting with a few different derailleur setups on the United Trifold earlier, I decided to switch back to an 11 speed road setup. This time, I will use a short cage (SS) 105 R7000 rear derailleur, instead of the mid cage version earlier. By doing so, this would solve the ground clearance issue.

Short cage 105 R7000 rear derailleur on the left, mid cage version on the right.

Looks similar from this viewing angle

There is some difference at this area, where the cage is attached to the body of the rear derailleur. This is due to the different large sprocket compatibility between the SS (max 30T) and GS (max 34T) version.

Comparing the mid and short cage derailleurs side by side.

Mid cage length is about 87 mm

Short cage length is about 72 mm

Mid cage weight is 226 grams

Short cage weight is a bit lighter at 220 grams.

Just changing to the short cage R7000 rear derailleur will not solve the slack chain issue, as previously experienced on the mid cage setup. Other chain guides that are used on Bromptons will not fit this United Trifold due to the frame or crankset interference.

Therefore, I got this chain tensioner that was commonly found on older Birdy bikes, before the bottom bracket-based chain guide was invented.

Small extension which will be attached to the rear derailleur cage, to manage the chain when the bike is folded.

This small chain tensioner weighs just 16 grams

At the top gear (smallest sprocket), adjust the chain tensioner so that it just clears the chain.

Adjust the chain tensioner angle so that it avoids the chain.

Plenty of ground clearance, with the cage at its lowest point.

As the chain is shifted inwards to the larger gears, the cage rotates upwards, together with the chain tensioner.

No issue with ground or tire clearance, with the short cage rear derailleur.

Chain at the lowest gear (largest sprocket). Chain length is barely enough, as shown by the super-stretched cage position.

Barely any chain engagement with the top guide pulley. Still able to shift though.

With this additional chain tensioner on the short cage R7000 rear derailleur, I am able to find a balance between good ground/tire clearance, and also sufficient chain management.

In the next post, I will summarize this derailleur drivetrain modification of the United Trifold.

United Trifold: Saint Rear Derailleur and 10 Speed Cassette

Since the mid cage 105 R7000 rear derailleur is not suitable for the United Trifold, I had to find another set of components which will better suit the small wheeled bike.

The problem I faced previously was insufficient ground clearance, as the mid cage rear derailleur had a rather long cage. Therefore, I decided to get a rear derailleur with a really short cage, to solve this problem completely.

What I know is that the Saint or Zee rear derailleurs from the downhill groupsets have the shortest cage, which is why I decided to try the Saint rear derailleur on the United Trifold.

However, as the Saint rear derailleur is a 10 speed component, this means that I need to change the cassette and shifter to a compatible 10 speed type. For convenience's sake, I will continue to use the 11 speed chain first. The chain ring and crankset does not affect compatibility.

Saint RD-M820 rear derailleur

Super low profile! Barely sticks out from the side.

Really long inner link arm, as the cable pitch for MTB is longer than road. The high and low limit screws are located far apart from each other.

Super short cage! I forgot to measure the length, but it is really short. Definitely no problem with ground clearance.

As a MTB downhill component, it comes equipped with a clutch. Nice to have but not necessary.

Weighs a pretty chunky 271 grams, due to the extra robust construction for downhill riding.

Side by side comparison with the previous R7000 mid cage rear derailleur.

Big difference in cage set length and also inner link length.

Here is a 11-28T 10 speed cassette, similar to what I used many years ago on the Dahon Vitesse 2x10 speed setup.

105 5700 11-28T 10 speed cassette weighs 249 grams

Installed onto the wheelset with no issues. A 1.85 mm + 1 mm spacer is needed at the back of the cassette.

Looks good on the wheelset!

Next, I need a 10 speed MTB shifter, as it needs to be compatible to the 10 speed MTB Saint rear derailleur. A Tiagra 4600 road flat handlebar shifter is not compatible due to the different cable pitch.

Deore XT Trekking SL-T780 10 speed shifter, which I used many years ago on the Polygon Cozmic MTB.

Upon installation of the rear derailleur to the bike, I found that there was quite a bit of friction from the clutch unit, even though the clutch was turned off. Therefore, I opened up the clutch to take a look. Here is how you can service your clutch too!

How it looks with the internal clutch unit removed from the rear derailleur.

Here is the clutch unit. It can be serviced or replaced if it is faulty.

Then, I realized that the rear derailleur will function perfectly fine without the clutch unit. As I don't need the clutch function, I decided to just remove the clutch unit, allowing the rear derailleur cage to swing smoothly, and also reducing the shifting force.

Once the 10 speed shifter has been installed onto the bike, along with the other 10 speed components, I took the bike for a test ride!

A derailleur drivetrain looks good on the bike!

Lots of ground and tire clearance, due to the super short cage Saint rear derailleur.

The whole bike looks good in the sun. Purple and yellow colour combination is weird but really outstanding.

Went to the same step that caught the R7000 rear derailleur previously. No issue this time!

Good clearance for the rear derailleur cage.

The optical gear display on the shifter is good as well, due to the clearly defined gear indication.

Can clearly see which gear I am currently in, and how many more available on either end.

Based on the test ride, this 10 speed setup has passed with flying colours! However, I also need to check how well it works when it is folded. Due to the short cage, it is expected that the chain would become even more slack when the rear triangle is folded down.

When folded, the short cage barely takes up any slack chain.

Due to this, the chain becomes way too slack, as the chain is long enough to touch the ground already.

As the chain is way too slack when folded, it will touch the ground, which is not acceptable for me. Also, due to the short engagement between the chain and cassette when folded, the chain is likely to drop off the cassette when the bike is unfolded again.

Therefore, even though this 10 speed drivetrain rides really well, it is not good enough due to the poor chain management. I need to keep trying alternative ideas that will work better.