Hydraulic brakes on the Ninebot Max G3 and GT3 E: the complete guide

Our brake adapters, CNC-machined from 6061 aluminium and engraved SR. They let you fit a hydraulic caliper on a 140 mm disc.

The Ninebot Max G3 and GT3 E are great scooters, but their stock brakes quickly reach their limits at speed, in the rain or going downhill. Switching to hydraulic brakes transforms the scooter. Here is everything you need to know before you start.

Why switch to hydraulic brakes

A cable brake transmits the force of the lever through a cable that rubs inside its housing. Over time, the cable stretches, the housing gets dirty and you have to squeeze harder and harder for the same braking. A hydraulic brake transmits the force through fluid, with no friction.

• More power for the same effort on the lever: you brake with one or two fingers.
• Better modulation: you feel exactly where you are and avoid locking the wheel.
• Consistent braking over time, in the rain as well as downhill.
• Less adjustment: hydraulic calipers compensate for pad wear on their own.

On a heavy scooter ridden every day in the city, you feel the difference from the very first emergency stop.

What you need for the conversion

1. Brake adapters

Neither the Max G3 frame nor the GT3 E frame is designed to take a hydraulic caliper. The brake adapters bridge the gap: they bolt onto the original mounting points and position the caliper exactly where it needs to be in relation to the disc.

We designed and tested them in our Brussels workshop. They are CNC-machined from solid 6061 aluminium, then anodised: the colour is in the metal, it will not flake. You need one per wheel, so two to equip the front and rear.

• Ninebot Max G3 brake adapters (black, red or pink limited edition)
• Ninebot GT3 E brake adapters (black or red)

2. Two 140 mm discs

Our adapters are designed for 140 mm discs only, no bigger, no smaller. From the factory, the scooter has 120 mm discs, 1.9 mm thick. We replace them with 140 mm discs, 2.3 mm thick: larger and thicker, they handle heat better and deliver more braking power.

3. A hydraulic brake kit

The kit includes the levers, calipers and hoses for the front and rear. It comes already filled with oil: in most cases, no bleeding is needed (see the fitting guide below). Our adapters have been tested and approved with NUTT hydraulic calipers in both 2-piston and 4-piston versions, as well as with Xtech. The kit we offer is the NUTT 4-piston Y5 kit.

4. Two Hall sensors

This is the part many people only discover during fitting. When you brake, the scooter has to cut the motor. NUTT levers come with a 2-wire sensor, while the Ninebot electronics expect a 3-wire Hall signal. The result: without an adapter, the motor cut-off does not work, or the scooter shows an error.

Our Hall sensor fits onto the NUTT lever and sends the scooter the signal it expects.

We developed our own Hall sensor for NUTT levers, now in its V2 version. It fits neatly onto the lever and plugs straight in, with no cutting or soldering of the original wiring. With it, everything works as stock: motor cut-off when braking, brake light, and even boost mode. Every sensor is tested one by one before shipping.

If you buy the complete kit, the sensors are already fitted to the NUTT levers. All that is left is to plug them in and calibrate them, which takes a minute (see step 6 of the fitting guide).

The Max G3 and GT3 E do not use the same connector. The Max G3 version is available now; the GT3 E version, with its own plug, is coming very soon on the same product page.

The complete kit and its price

For the Max G3, we offer everything in a single order: 2 brake adapters, 2 Hall sensors, 2 discs of 140 mm and the NUTT 4-piston kit, for €290. Bought separately, the same parts come to €319.

Already have some of the parts? Everything is also sold individually: adapters only, sensors only, or adapters and sensors together. Some parts are sold on pre-order: the shipping time is shown on each product page.

Fitting, step by step

We filmed a complete conversion in our workshop, from disassembly to the test ride. The steps below cover the essentials: keep the video handy, it shows every move (in French).

Watch the fitting video on YouTube

1. Clean and prepare

Start by cleaning the scooter, especially around the wheels and brakes: it makes the work easier and keeps the new discs clean. Then lay the scooter on its side on a clean surface.

2. Strip down the rear

• Remove the plastic cover and the bottom deck plate.
• Cut the two cable ties holding the motor cable.
• Remove the torque stops from the axle.
• Release the brake cable tension (10 mm nut), then remove the original caliper with the 4 mm Allen key. Keep the screws and the housing protector, you will reuse them.

3. Swap the disc

Remove the original disc (120 mm) and fit the 140 mm disc using the original screws. The triangle engraved on the disc must point in the wheel's direction of rotation. Tighten firmly, by feel, without overdoing it.

Then refit the plastic and the grommets, and put two cable ties back on the motor cable: it must never be able to touch the tyre.

4. Same job at the front

The process is the same. Be careful to keep the wheel spacers and put them back in the same place. If the bearings are worn, now is the time to replace them (6001 RS bearings). Refit the rubber and the cable tie that hold the housing.

5. Fit the adapters, calipers and hoses

• The adapters are identical front and rear. Fit them logo facing outwards.
• Remove the pads from the caliper before bolting it to the adapter: never force a caliper onto the disc. The hose points upwards.
• To route the hoses through the frame, use the old brake cable as a pull-through: tape the hose to its strands and pull.
• Mind the crossover: the left-hand hose goes to the right-hand brake, and vice versa.
• Refit the grommets starting from the bottom, then the internal cable tie.

6. Swap the levers and calibrate the sensors

At the handlebar, unscrew the display (PH2) and disconnect the connectors, which are protected with silicone. Remove the bar ends (3 mm Allen key), the switch unit, the throttle and the indicator, then replace the original levers with the NUTT levers.

Plug the Hall sensors into the display, the right way round. Route the wires through the central channel of the stem without pinching them. Switch the scooter on: if it shows a brake error, loosen the two screws at the back of the lever and slide the sensor until the error disappears, then tighten again.

7. Cut the hoses to length

This is the step that needs the most care.

1. Slowly unscrew the hose fitting at the lever with the 6 mm spanner.
2. Cut the hose to the right length, cleanly and squarely.
3. Recover the original olive and slide it onto the hose together with the nut.
4. Press the insert into the hose with the press.
5. Push the hose into the lever, start the thread by hand, then tighten until the olive is properly compressed.

If you work cleanly, you only lose a few drops of oil and no bleeding is needed. If the lever feels spongy or pulls all the way to the bar, the system needs bleeding. Then clean off any trace of oil with brake cleaner, especially near the discs.

8. Fit the pads and align the calipers

• Push the pistons all the way back, slide in the pads with the caliper in place on the disc, and fold over the safety pin.
• To align, pump the lever then hold it squeezed. Lightly snug the bottom screw, then the top one.
• Check by eye that the disc is well centred, then tighten fully. No washers needed.

9. Check before riding

• Set the lever angle so that the levers fall naturally under your fingers.
• Switch on: no error should be displayed.
• Brake at the front, then at the rear: the brake light must come on each time.
• Check that boost mode works.
• Do a test ride at low speed, then a few progressive stops to bed in the pads.

A winter tip: in cold weather, cable housings stiffen. Wait until the scooter has warmed up before folding it, or they may crack.

Frequently asked questions

Is it compatible with the GT3 Pro?
No. Our GT3 adapters are designed for the GT3 E only.

Can I keep larger or smaller discs?
No, the adapters are designed for 140 mm discs. With another diameter, the caliper no longer sits in the right place.

My caliper is neither NUTT nor Xtech, will it fit?
Possibly, but we have not validated it. Contact us before ordering with your caliper's reference: we will check together.

Do I need to bleed the brakes?
Usually not. The kit arrives filled with oil, and if you shorten the hoses cleanly, very little is lost. You only need to bleed if the lever feels soft after fitting.

Can I do it myself?
Yes, if you have the tools and are used to working on your brakes. Cutting the hoses to length is the trickiest step. If you prefer, we can fit it at the workshop.

How much does workshop fitting cost?
€60 per brake, so €120 for front and rear, parts not included.