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.