The LMX64, a powerful freeride E-MTB from France

November 1, 2019
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A “freeride” bicycle is used to go up a steep hill, and the hill is so steep that when you start to go downhill, you pretty much don’t need to pedal at all.

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Adam Mercier lives in beautiful Lyon, in eastern France (near the mountainous Swiss border). LMX has grown, and now his business partner is Lucas Suteau.

You can use an LMX64 for many different things, but this is what a “freeride” is all about. This location is Lake Salagou, near Montpelier, on the Mediterranean coast.

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How They are Made

It would be easy to assume that any new ebike has its frame made in China to save on costs, but Adam has firmly decided that he must make the frames in France. Of course the forks, shock, wheels and other standard bicycle components are sourced from Taiwan, China, and other common suppliers, but the unique part is the frame, and Adam needed it to be strong and also very light.

Lucas is shown here welding the motor section of the LMX64 in an alignment jig

After welding the aluminum frames, they are heat-treated in a large oven. Then the frames go through T4 quenching, then a T6 phase. It would be a little cheaper to have the frames made in China, but since Adam insists on making them himself, he has complete management over quality-control. This also eliminates shipping delays, along with any supply glitches due to international trade disputes.

The Steer tube is aligned at a very slack 65-degrees, which allows this ebike to take hard bumps when riding downhill on a steep run. The LMX64 uses a ZS56/ZS44 headset, and this means the inside diameter of the top of the steer-tube is 44mm, and the larger bottom bearing fits a tube ID of a beefy 56mm
Adam and his business partner are scaling up production, but their main focus is on maintaining quality
Here is an LMX64 partially assembled, but with no paint yet. The small chainring and 65-degree headtube angle show that this is definitely designed for serious downhills. With the stock shock and settings, the rear axle has 180mm of travel (7-inches)

The downtube uses a cradle-interface for the common 52V shark battery packs. There is room to use a larger pack, but Adam feels its better to use several small batteries for a day of riding instead of a larger one, so the LMX64 can remain as light as possible on the high-speed downhills that he loves.

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The Drive System

When designing a mid-drive ebike, it can be helpful to give the motor the use of the gears in the rear wheel. Doing that would allow the motor to efficiently run at the highest possible RPMs by downshifting when you arrive at a steep uphill.

However, if you are running the motor-power through the bottom bracket, This can put a lot of strain and wear on the bicycle chain and sprockets, leading to a frequent replacement of those components. Adam felt that if he had enough power, the motor would not need any gears, even for very steep sections. The latest version is rated for 2000W of peak power.

The V2 in the pic below (from 2009) has a single-speed freewheel for the pedals, located at the rear wheel’s axle. The motor-drive uses a large sprocket that is firmly fixed to the rear wheel, so the motor does not put any strain on the pedaling drivetrain. A freewheel for the motor is located at the motor in this version, so the motor does not have to spin when he is rolling downhill.

I’m mentioning the V2 because it shows that he has been experimenting for many years, and Adam is not new to this.

The second version of Adams off-road ebike, from 2009

Adam refined his original prototypes, and once he was happy with the two parallel and separate drivetrains, he decided to move the motor-drive to the left side. In the pic below, the chain is managed by two red idler-wheels and chain-guides. The top idler is in a fixed position, and the bottom idler swings under spring-tension in order to keep the chain tight as the rear suspension cycles up and down.

The motor-drive on the LMX64

The motor is available with either a 12T or a 14T drive sprocket. The 14T would have a higher top-speed, but less wheel torque, and also…the 14T would run quieter. The chain is the #219 type, which is famous for being used on very high-powered racing Karts.

The #219 chains also have the feature of using smaller links than a standard bicycle chain, which allows the designer to package a very high reduction into a single stage from the motor to the rear wheel. When using the 100T sprocket on the rear and the smaller 12T on the motor, it has an impressive 8.3:1 reduction.

Here’s the front drive-sprocket cover, made from red-anodized aluminum. This owner has made a black plastic 3D-printed cover to enclose it even more. Notice how small the #219 chain links are. Pic courtesy of ES member “Cowardlyduck”

By moving the motor from the wheel to the frame, it improves the “unsprung weight”. This allows the rear wheel to be as light as possible, and that means it can respond to bumps and jumps much better than a heavy rear hubmotor.

By mounting the motor in the frame, we also have the option of spinning the motor much faster than the rear wheel, by adding some type of RPM-reduction. This means that we can use a smaller and lighter motor to achieve the same power, and then simply spin it much faster than the wheel to get the same wheel-torque. Doing that also has the practical effect of lowering the amp-draw of the battery pack, while still providing the same wheel-torque as a large and heavy hubmotor.

The debate between hubmotors and mid-mounted motors will likely continue for the rest of my life, but for trails that have serious jumps and technical sections that require an experienced and subtle hand to navigate, a lighter ebike will often be much more satisfying.

The rear brake disc is 203mm, and the large diameter #219 sprocket has 100 teeth. The drop-outs are custom-CNC’d and welded into the frames. The custom swingarm and drop-outs allow the LMX64 to have this unique assembly of components.
The right side of an LMX64, with an 11-speed freehub.

The pic above shows the right side of an LMX64, and it highlights a well-regarded close-ratio 11-speed derailleur. This allows the rider to find the “perfect gear” when pedaling up a hill with a constantly changing grade. The small chainring means that the stock gear ratios will not be useful at higher speeds, however, they are designed to give the rider the greatest number of options for the uphill climb.

This picture above, also shows the optional license-plate holder. I made sure to add a picture with this feature, because LMX will soon pass its homologation testing to become a street-legal moped/enduro in France (ebikes in the EU with no moped license have a 250W-500W power limit, depending on the country, and the LMX64 uses 2000W). Of course that “street” version would have street/dirt “dual-purpose” tires and a headlight, among other details.

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The LMX64 on a country road

Many young Americans love motocross, but the Europeans have been in love with motocross long before the US, because they invented it. The word stands for MOTOrcycle CROSS-country, and the MX in their name stands for motocoss.

I think this is because in the early days of motorcycles, it was easier for Americans to hot-rod on public roads, but the European cities had more restrictions. This meant that if a young man from France wanted to ride a powerful motorcycle as fast as he could, his best option was to go off-road.

Below is a short youtube of a mountain bike competition in Kluisbergen, Belgium. The LMX won first place against several more powerful ebikes, and Adam credits this “win” due to how light and nimble the LMX64 is.

An LMX64 on the mountains above Lake Salagou in the south of France

Here is a map of central Europe, showing where Lyon is located. European customers may have to pay a Value-Added-Tax (VAT), which is a sales tax to support the social programs in Europe. USA customers do not have to pay the VAT, but…they do have to pay a very high shipping cost if you want to own an LMX64…

France and Germany are not only centrally-located in Europe, they are the financial core of the EU. The weather at the south of France is considered to be the “southern California” of the Mediterranean…

Here is a recent 2019 LMX64 video.

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Written by Ron/spinningmagnets, November 2019

Grew up in Los Angeles California, US Navy submarine mechanic from 1977-81/SanDiego. Hydraulic mechanic in the 1980's/Los Angeles. Heavy equipment operator in the 1990's/traveled to various locations. Dump truck driver in the 2000's/SW Utah. Currently a water plant operator since 2010/NW Kansas


3 Comments

  1. I think the isolation of the motor and drive onto the non-drive side of the bike is the way to go with a mid drive ebike.

    It’s simple and you only need 1 freewheel and the motor is completely isolated from the gearing of the bike. You can have a X12 and a triple ring on the crank and have a 2 mph hill crawler and a 40 mph bike and pedal along with both speeds with decent cadence. As the power of the ebikes gets more insane, I think all high end ebikes will start separating the drive trains completely.

    • I agree. the big rear hubmotor ebikes are pulling 3,000W-6,000W, and theres no way you can get that kind of power running through the bottom bracket. The Euro 250W-500W Bosch-drives desperately need all the help they can get, when it comes to gearing and transmissions. However…for 2,000W or more, there is a real argument for a mid-mount motor that has its own drivetrain, just like the Sur-Ron and the Zero motorcycles

  2. Separate drivetrain on the left side is the way to go above 2000w, no doubt. I’m not sure weather it’s the separate drivetrain or just higher power in general that makes the harmonization between motor and human harder. In fact i own the bike above (in front of the LMX cardboard box), and i feel the PAS tuning/programming is key. A proper torque sensor and finely tuned programming will make high powered ebikes as harmonized as they can be.

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