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2002 BMW M5 E39 Dinan
2,230 Posts
Discussion Starter #1
This is an unusual vehicle build that I am documenting here; a proof of concept of the world's safest motorcycle.
Being a spectator to the process, finding it exciting and unique, I took my time to document the build.

My friend Markus Scholten has for the last couple years been designing a new motorcycle concept.
As he, himself, says: "The concept is old, but our approach is new".

The machine is called the CiTi "Cutting Traffic" Commuter.

His idea was to create a fun motorcycle vehicle that is relatively safe in traffic, can split lanes (more narrow than a Police motorcycle), protects from the environment with a full body shell while providing cabin temperature control, get roughly 50 miles to the gallon and easy to drive. At end of the day it is still a motorcycle and behaves like a motorcycle, including leaning into turns, so it should not be mistaken for a car with 3 wheels.

How the build came to be: Markus is an mechanical engineer, who's previously worked for BMW, Range Rover, GM, Karman and a good list of other companies. When I first met him at my old work, where he joined a week before me, to design custom high end vehicles, he showed me the 3D renderings/models of the CiTi and I thought "Nice design, but how are you going to get it built?". Usually the mechanical engineers that I come across are paper pushers, un-skilled with hands-on applications, sheet metal bending, etc, but Markus is one of the few people that the longer I know, the more impressed I am with his skill set. He speaks softly and understates himself too often IMO. BMW fanatic and true car nut too- that's how we connected; first time I met him, first thing he said to me was "I have been looking for that car in good condition forever.", I was confused because if he was talking about my M5, when did he even get a chance to see I have it? I just walked in...

The intention for Markus is to make this a commercially viable production vehicle, but for investors, paper drawings & 3D models don't cut it; before investing, they want to see the product in real life, functional. Accepting this fact, Markus set out to build the proof-of-concept on his own.
(Proof-of-Concept -> Prototype -> Production Vehicle)

The 2nd day of the build:

Around beginning of 2014, while working at his regular day job, he connected with a former co-worker from another auto manufacturer, who was willing to help fund the proof-of-concept build. Rented an empty garage in Orange County, CA, and started working on the proof-of-concept, at night after work, every night after work till about 2am. I noticed he started showing up a little late for his regular work at that time, mainly due to exhaustion. Still surprised that all those long nights with the grinder (with shield off and couple hundred disks/plates wasted) and he didn't get a single cut on his hands.

The twisted metal bars that will become the CiTi Commuter.
The initial frame-work getting bent with metal bender, based on CAD drawings he created in Catia V5. In the backgroud you can see a disassembled Aprilia motorcycle, from which he will take the engine and various other mechanical parts required for the CiTi.

The Aprilia motorcycle getting disassembled in the foreground, and Markus preparing to bend metal in the background.

Couple days later, the CiTi frame started to appear. I was surprised by how fast he got it to the point.
While it looks like he's far on his way to completion, the devil is in the details. The frame is the easiest part.

Markus and Mandaar (the former co-worker & investor) testing out the seating position. Markus is 6'4" tall (195cm) and intention is to make sure he, himself and the other side of the the height spectrum, all can comfortably fit in the vehicle. Even with 3D computer models, many hours were spent on manual seating adjustment/testing.

Sat-Sundays 'funday' included customizing differential & engine mounts, and fabricating rear control arms.

Fabricating the engine mounts. The tools were not meant for Markus' level of required industrial application.
Many drill bits were destroyed/dulled.

Engine mounts in place, just finishing them off. Wheels and suspension components about to be fabricated & installed.

Wheels and suspension components fabricated and installed. Getting the rear suspension to balance properly was a real challenge, especially with a skeleton shop & tools setup; few tools available apart from MIG welder and grinder.

Here I'm test-sitting the CiTi with my 6'5". I am using a chair that has a thick padding and not intended for the bike, hence the head sticking out a little.

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Me, testing out the leaning suspension mechanism, before engine goes in and spring rate is set to strong stiffness to account for the extra weight.

Rear wheels installed, preparing to install motor, that's still on the ground. The motor has 180hp and comes from an Aprilia motorcycle; plenty to get in trouble with. Other engine options are considered for production.

Typical R&D obstacles: Refinement of brackets for proper fitment before engine goes in.

Suspension adjustment with grinder and MIG welder. 100's of grinder plates were used on the project.

Motor lifted into the CiTi. Once again testing out seating position, suspension operation and clearance between suspension and seat factoring extra weight of engine, including spring rate and leverage adjustment on rear control arms.

Close-up of engine in place and engine mounts. The differential had to be customized to reverse to function since engine also sits in reverse position.

Getting ready to do installment of wiring, brake lines, and the details (where the devil hides).

Another angle.

Undercarriage protection / floor visible to the right about to be installed. Contemplating between using pedals for Brake/Accelerator or regular motorcycle handle bars.

Engine wall and fuel tank installed. CAN-Bus wiring completed. Changed from pedals for brake/accelerator to motorcycle handle-bars for greater control and leverage, at least for purposes of proof-of-concept.

Exhaust and piping fabricated & installed. Bike is running at this point. The fine tunning and working out the kinks is what takes the effort and most of the time.

The Aprilia handle bars and instrument cluster visible in distance. The production model is intended to feature LCD-based instrument cluster running on Tegra 2 processor using Nvidia Composer (Same technology as Tesla Model S).

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Exhaust cans installed, but no headers. Spewing blue flames of beauty.

The "mandatory" standing back and evaluation with other local motorcycle builder(s) stopping by.

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One of first test drives with CiTi.

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Markus testing out the tilting/suspension mechanism.

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I ended up utilizing Markus' shop to do a long list of maintenance items on the M5 before I set out on a cross-continental trip with the M5. Figured I snap some photos of both next to each other, since CiTi's gonna be in the garage complimenting the M5 once the CiTi hits production.

The body enclosure will be built for the prototype, as this is only a proof-of-concept.
The CiTi is off the work bench, ready to be shown to potential investors and ready to hand out test-drives.

During the production, Markus wanted to do a photoshoot, so the pictures can be posted online and create attention with eye candy, hopefully attracting investors & financiers... which will be needed for production.

I initially did not want to jump on the photoshoot, but since Markus started running short on good options and I got worried he'll fork out over $1500+ and will not be satisfied with the photos, I told him I'll do it. Brought along my photographer friend Justin ( and DJ Ella to pose with the CiTi commuter, to give the photos an extra kick. Also big thanks to GMS Garage in Orange, CA for letting us use their garage on the weekend for the shoot.
GMS Garage has done an E39 540i Touring conversion to E39 M5 Touring.. so, if you need that, look them up.

Last, but not the least.. investors are welcome & will be entertained!


2,773 Posts
That is very cool indeed, but it has 3 wheels and is a trike, not a motorcycle :)

427 Posts
That is very cool indeed, but it has 3 wheels and is a trike, not a motorcycle :)
That was literally going to be my reply! Awesome concept and would love to see more!
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