Lotus Position

By Martin Eberhard, Co-founder of Tesla Motors

July 25, 2006

Holy smokes! There is no way I can respond to all your comments, but thank you everyone for writing. This time I will discuss one common thread that many of you raised: what exactly is Tesla’s relationship with Lotus? Along the way, I will address a few other threads from your feedback. Once again, I am writing without Marketing’s filters, so I apologize in advance for any “pc” slips.

Much as I love cars, I am the first to admit that neither I, my co-founder, Marc Tarpenning, nor our original investor (and chairman of our board), Elon Musk, is an automotive engineer. We have quite a few excellent automotive engineers at Tesla now, but three years ago, we did not. (Several have worked for Lotus in the past, but that’s another story.) We wanted the first Tesla car to handle like a proper sportscar, so we approached Lotus Cars, known to make the finest-handling sportscar on the road. (Marc and I cornered Roger Becker at the 2004 LA Auto Show and convinced him that Tesla was worthy of consideration.)

Since our first meeting with Roger Becker, Tesla has built a strong, friendly relationship with the team at Lotus, focused primarily on bringing a great new sportscar to the market quickly and efficiently. Our relationship has several aspects, which I will begin to explore in this article:

Tesla has licensed key technology from Lotus, principally related to structure and safety
Tesla has contracted Lotus Engineering for various engineering and styling jobs
Lotus Cars is the contract manufacturer for the Tesla Roadster, with Tesla as a key supplier to the factory in Hethel

Technology

For those of you who don’t know, the Lotus Elise’s chassis is a work of genius. Richard Rackham’s insight was to construct the entire chassis out of a collection of custom aluminum (aluminium, as he calls it) extrusions that are bonded (glued) together. Extrusions are strong and easily manufactured with complex cross-sections. Bonding allows for thinner aluminum than welding as it has a larger material area to transfer loads between members and avoids material degradation due to the heat of welding. You Lotus fans will attest: the Elise is a proper Lotus, and Colin Chapman would be proud. It is light, stiff, nimble, and quick. It is also small, spartan, quirky, and not for everybody.

Some have suggested that the Tesla Roadster is built on a Lotus chassis. This is not true. Tesla licensed the Elise chassis technology, but Tesla’s UK-based chassis engineering team designed the Roadster’s chassis using that technology. The suspension and occupant protection systems are very similar. But here are a few key differences:

Tesla re-engineered the main chassis rail extrusions, making them stronger and thereby allowing us to lower the doorsill height by 2 inches, drastically improving ingress/egress. (Elon and I are both more than 6’ tall, so improving ingress was a requirement!)
At the same time we changed the way the chassis rails bend just behind the seats. Lotus simply bends the rails. Tesla instead miter-cuts the rail, then bonds them together at the exact correct angle with a custom bracket. This solution works with the new extrusions to lower the sills, and reduces manufacturing complexity.
We eliminated the box section that surrounds the gas tank on the Elise. The Tesla Roadster achieves equivalent (actually slightly higher) stiffness with the structural box that encloses the battery pack
We designed a unique rear sub-frame, to accommodate a battery pack and electric drivetrain rather than a gas tank, engine, and exhaust system
We lengthened the Tesla Roadster’s wheelbase by 2 inches – rearward of the seats, giving us a tad more room for the battery pack, shifting the weight forward to keep the distribution reasonable, reducing ride choppiness, and giving the car a little more sophisticated look
We beefed up the composite crash structure at the front (one of Lotus’s clever innovations) to accommodate the higher weight of the Tesla Roadster
The suspension geometry is identical to that of the Lotus, though we strengthened many components, again to accommodate the increased weight
We use larger brakes – both front and rear

And of course, our engineers extensively modeled the new Tesla chassis starting with the computer models so carefully built by Lotus. We are right now proving what the computer models told us through harsh durability and safety testing on real cars. So far, things look good. (Though very painful to slam brand new cars into a concrete barrier!)

Tesla also licensed key safety systems from Lotus. Obviously, we did this to save time and money. But it goes deeper than that. Many suppliers of critical safety systems (principally airbags and ABS brake systems) are geared up to work with very large OEM manufacturers. Over the years, Lotus has carefully cultivated relationships with suppliers for these systems, and the result is a “federalized” Elise with all the right systems. By using these systems unchanged – and with Lotus as a supply chain partner for them – we have access to components that we might otherwise not be able to acquire at all.

By using Lotus’s airbag system and surrounding dashboard hardware, we achieved interior safety compliance. Some components consequentially look like an Elise: the steering wheel and its column; the upper dashboard molding including the passenger airbag hatch, etc.

But we felt that much of the Lotus interior was too spartan (and too uncomfortable) for the Tesla Roadster. So we redesigned most of the interior:

We completely redesigned the seats, widening them by several inches, replacing Lotus’s fiberglass with carbon fiber, upgrading the padding material to the finest space-age foam available, and re-styling the looks
We designed our own beautiful, exposed carbon-fiber console that (can you believe it?) includes a cup holder
We included a custom, color LCD display for all kinds of interesting information about the power train, the battery system, etc.
We included a superior Blaupunkt radio with iPod connector and with optional satellite radio and satellite navigation system
We carpeted the floor to reduce noise and heat transfer from the road (floor mats are also available)
We designed our own doors with electrically-activated latch (giving it that “shaved” look – no visible door latch), leather-trimmed door panels, controls for the power windows, central locking, and electric trunk release
As mentioned above, we lowered the doorsill by 2 inches to accommodate both taller and shorter people (and people wearing skirts and heels :-))

Engineering and Styling

Lotus Engineering principally does engineering and design work for other car companies. I dare say that few major car companies have not hired Lotus Engineering for some work or other over the years. Tesla hired Lotus Engineering for various bits of analysis, engineering, supply chain help, and of course, body styling. This time, I will focus on styling.

In the beginning, I thought that we would carry over some of the Elise body panels – just because the cost of tooling so many parts seemed daunting when Tesla had practically no money.

But Elon Musk (who, as a McLaren F1 owner, has pretty high expectations for a car’s looks) pushed me not to be such a wimp. Supercars are not made of fiberglass, and our market will demand a more sophisticated look than that of the Elise. Once I was convinced that carbon fiber was the way to go, everything Elise went out the window except (if you will forgive me) the front and side windows.

Though expensive and time consuming, this decision gave us the opportunity to fix a few things: unlike the Elise, the Tesla Roadster includes federally-compliant 2.5 mph bumpers, federally compliant HID headlights, and all LED rear lights.

A car’s windshield is an expensive and tricky bit, entangled with safety, rollover protection (when you consider the windshield surround), legal visibility requirements, waterproofing, interaction with the wiper, etc. It made a whole lot of sense to use the Elise “glass house” and rubber seal system. However, even there, we improved: the Tesla Roadster’s glass has an expensive but effective UV- and IR-reflecting layer embedded in it to keep the cabin cooler on hot days.

With the basic vehicle dimensions, the glass house, and the drivetrain requirements settled, we hired several well-known sportscar stylists to submit proposals for the Roadster styling.

I knew exactly what I wanted the car to look like – at least in my own mind. But I am one of those engineers who can’t even draw a circle. My six-year old boy draws better cars than I do. :-( I spent time with a couple of these stylists, describing what I wanted. The proposals came back all wrong. They looked like cartoon electric cars – all kinds of doodads, fake solar panels, bogus cooling thingies, etc. Not even close to what I wanted!

I have a good friend, Bill Moggridge, who is one of the founders of IDEO, - a major design studio that designs practically everything except cars. Bill is a designer’s designer with cutting edge taste and impeccable style. He also knows me well enough to listen patiently to my ramblings and sort out what I want. Bill wrote a Keynote presentation for me in which he invented a 5-axis space that describes the looks of a car. For each axis (e.g. macho at one end, curvaceous at the other or throwback at one end and futuristic at the other), Bill provided example cars that typified the extremes. Then we negotiated where, exactly, on each axis I imagined the Roadster.

We gave this presentation as a brief to all the stylists working on Tesla proposals. What a difference! Suddenly we were getting proposals that looked like what I had in my head.

When the proposals came in, I emptied a room at my house down to blank white walls, and hung the dozens of sketches from each designer on the walls. We invited everyone we could rope into the task to vote on the proposals. I was in favor of a lengthy questionnaire, asking the viewers what they liked and did not like about each design.

Bill had a better idea: give each viewer 3 red sticky-notes and 3 green sticky-notes. Red = bad, green = good. Put ‘em wherever you want. It was amazing. After the first 50 or so people voted with their sticky notes we saw the following: several stylists had a smattering of red and green notes on various features – a bunch of red notes on an ugly grille, a few green notes on an interesting taillight, etc. One stylist was so disliked that his name was covered with red (Okay, his last success was an SUV, so what should I expect?) But Barney Hatt – one of Russell Carr’s guys in the Lotus Design Studio – collected a wall of green. No doubt about it. Barney had a few red notes to be sure, but he was hands-down the winner. I never expected it, because his first proposals (before Bill’s brief) were awful.

Lone Ranger

The beak

Elon and the Tesla team spent a lot of time – and several trips to England – working with Barney to perfect the styling.

We changed a lot from his original proposal, and we worked with him to get what we wanted from the several clay models. I won’t bore you with the details, but here’s a few anecdotes: Barney originally designed the Roadster with a ridge down the hood that ended in a peaked front. This made Elon and me cringe, but I couldn’t sway Barney. What was it about the “beak” that looked so bad to us but not to Barney? Then it hit me. I was driving down the street and passed one of those iconic Pontiac Firebirds from the ‘70’s. Remember the ones with the chicken barfing on the hood? That Firebird had the exact same beaked look. To an American eye, the beak screamed “redneck.” But the British had the taste never to import that car… I sent him a few choice photos of the Firebird, and he got it.Also, Barney’s original sketches included a black front that was an attempt to integrate off-the-shelf headlights. This looked terrible on the ¼ scale clay model – someone dubbed it “the Lone Ranger” look.

No matter how we tweaked it, the front looked bad. Again, Elon pushed us to spend the considerable money necessary to develop custom (and DOT-compliant) headlights to make the front look great.Just about three years from the day Marc and I started Tesla, we saw our first real Roadster from the assembly line. What a car! Bye-bye golf carts: this is what an electric car should look like.

Manufacturing

Lotus Cars is one of the very few companies in the world that has manufactured cars for competitors: the Vauxhall VX-220 and its cousin, the Opel Speedster, were manufactured on the same line that builds the Elise and the Exige. Their assembly line is designed such that they can intersperse different models on the same line – no easy feat. This made them a natural partner for manufacturing.

Lotus certainly is not the least expensive car factory in the world, and the exchange rate to the Pound Sterling keeps getting worse, so for us, the Hethel factory is limited as a contract manufacturer only for high-end cars. But they are great partners for the Roadster.

Tesla Position

The Tesla Roadster does indeed carry some Elise DNA. But it is a very different car, designed to meet different goals and deliver a different experience. We at Tesla are quite pleased with our friends at Lotus, but our destiny is to become a full-blown car manufacturer, with our own factory and a broad product line. I expect that Lotus Engineering will continue to do work for Tesla for a long time – for example, who knows ride and handling like they do? But they are only one resource for us as we grow.