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Tesla to Use Interim Transmission to Get Production Roadster Out the Door

Faced with ongoing problems in developing a transmission that will deliver on the electric Roadster’s initial specification for acceleration (0-60 in 4 seconds), Tesla Motors will begin production in 2008 with an interim transmission design, according to CEO Ze’ev Drori.

The interim transmission will support acceleration from 0-60 in 5.7 seconds. When the final transmission is ready, Tesla will retrofit all cars, at Tesla’s expense, to meet the promised performance specifications.

It should be noted that the interim design is one we have a lot of experience with, having accumulated more than 100,000 miles of usage in our fleet. We have found these transmissions to be highly reliable and durable. It should also be noted that this was the transmission fitted to VP10 for the test drives we did with all of the top US car magazines in early December. I think you will enjoy the driving experience as much as they did, even with this interim solution.

—Ze’ev Drori

Drori said that the goal is to start full production of Tesla Roadsters in spring 2008. Due to some uncertainty over production ramp rates, Tesla is still not clear how many cars will be completed in calendar year 2008.

We plan to accelerate production until all 2008 orders are filled, although we expect some number of cars to be delivered in early 2009.

—Ze’ev Drori

In his update, Drori also noted that an error in the calibration of test equipment resulted in an overstatement of the EPA range testing for the car. A recent re-test resulted in an EPA combined range of 221 miles, which the company believes to be accurate. The original target for the Roadster was 250 miles.

We will need to re-test the car prior to full production, so the current test should be considered an estimate. The transmission is an important factor in determining drivetrain efficiency, so the final design may impact the result in either direction slightly.

—Ze’ev Drori


richard schumacher

Why did they reject a two-motor power split transmission?



This is perhaps the best compromise that they could come up with.

People still get the keys in their hands, and to absorb the hype, and drive a car thats still quite reasonably fast.

And they know that eventually they are still going to get everything they were promised. (At zero additional cost)


Good now. Great later.


Hmmm. Range less than promised, performance less than promised, with more promises to fix things in the future. Over promising and under-delivering is not a good way to establish a reputation. They would have been better off making more modest claims from the get-go and delivering something that outperformed expectations. I hope they learn from this, wish them luck and hope they succeed.


A two-motor PSD is overkill. All they need is a dead-simple two-speed transmission. It's quite incredible their supplier can't deliver.


A classic example as to how silicon valley does not 'get it' as to how to do cars.

This is exactly how the software industry is used to releasing software that is buggy (with 'known bugs'), and which can be fixed at extra or no cost down the road!!!

Getting a car out on the road, in the customers' hands, *knowing* the transmission is going to fail in a few thousand miles? Come on!

How many among us believe that transmission is the only 'known' problem? Tesla have the wrong transmission supplier working for them.

If anyone wants the answer to 'why the auto industry take so long to evolve and change', here it is..

Putting cars, which have a huge amount of safety-critical, real-time, embedded control systems on-board, and can do serious harm to occupants and other vehicles, in the hands of people who have absolutely no knowledge of how these systems work, and make the cars last a good 12-15 years with only gradual decay in their performance, is, to put it mildly, 'non-trivial'.

Enormous amount of design, engineering, prototype testing, verification and validation as well as durability testing goes into making each new vehicle as foolproof and long-lasting as possible.

Any professional working within 'mainstream' auto industry can attest to this. Silicon valley types tend have absolutely no comprehension as to the discipline that automotive engineering is.

Hey, if it were that easy, there'd be a car company down every strip mall!!


I think a 2 speed makes sense. Low for around town and high for highways. This is pretty much what I figured would be necessary for EV conversion cars. Electric motors are great, but they have their limits.

I think 5 seconds to 60 mph is fast and 120 mph top speed is fast and over 200 mile range is good. I do not think that they will have lots of order cancellations due to this. But if they can not deliver or the quality is poor, then that is another thing.


Carnut, the transmissions won't "fail in a few thousand miles". Tesla will ship a reliable transmission that doesn't meet the 0-60 performance spec and later replace it with a reliable transmission which does.

The car company which knowingly ships unreliable tranmissions is named Chrysler.


What Tesla Motors needs is to be more realistic. As an electrical engineer I can say that I am impressed (if not skeptical) that they managed to build a 248 hp electric motor that weighs only 70 lbs. Tesla does not need a transmition at all! What they need is the same motor for the front wheels. Have 100 Kg of A123 Systems Lithium batteries for the rear wheels for brutal acceleration, and have 300 Kg of Electrovaya high energy density for long range. Problem solved. This is my prediction: Tesla downfall will be their battery pack -it solves a problem that no longer exists-
Tesla invested such a vast amount of money in their battery design that they refuse to face reality, thermal management is irrelevant if battery internal resistance keeps plumetting at the current rate.


# doggydogworld,

I've been keeping track of Tesla's progress and 'overpromising and not delivering yet'. Here's a quote from Elon Musk-

"Q. What is limited vs. full production?

Elon: It is a little too early to say, but it will not be a large number. Those cars will have a transmission which is not the final transmission. It will have an interim transmission. It will still be safe, but it won’t have the performance characteristics that we promised. And there may be some durability issues, not something that is made to last 10 years, but it should be fine for several months.

We’ll have to swap that out, and we don’t want to make a whole bunch of cars with that transmission. But it will give us some good feedback for real-world driving conditions. All the crash tests and safety tests are done. One might think of this as a public beta, if it were software."

The transmissions being installed have, in my opinion, 2 problems- 1-2 shift under full torque to get the spec acceleration of under 4 seconds (actually, the thing is supposed to shift exactly at around 60 mph), and second is that the design failed durability (if not, why would they go to so much trouble finding other suppliers to redo the trans?)

Here's the URL -

I would *like* to think they dig doing cars, but they are far behind the learning curve. So, the latest thing I've heard is that the future vehicles will now have range extenders (read: engine), a-la Volt. If one is having so much trouble controlling an e-motor coupled to a trans, I don't know how they are going to integrate engine thermal, electrical, electronic/software, emissions/control/aftertreatment and thermal systems control!!

At this point, I'd be thinking of simplifying, and not complicating things with Tesla design!!

As to Chrysler, yes, all OEMs have had recalls from time to time, and Chrysler have had may be more than their fair share too. Sure, when millions of vehicles are manufactured, occassionally there are slip-ups. However, to my knowledge, no OEM worth their salt have knowingly shipped transmissions that will fail 'after a few months' when they are expected to last at least 15 years!! I think that for any mainline OEM, the car program would be at a halt / delayed until transmissions with tested durability are available in a similar situation.

Another interesting thing to note is the 100,000 mile number being quoted for the transmission being shipped. Typical durability schedules for vehicles / powertrains run into hundreds of thousands, if not a million or more miles being put on the engine / trans until they are totally worn out.

I wish Tesla success but they need serious help from the same industry they are trying to reinvent.

Remember - the only thing that is new in that vehicle is the battery system. Everything else is at least forty (IGBTs) to over a hundred year old technology (e-machine and mechanicals). So, it's really silly to have your transmissions fail on you given that each of the 220 Million or so cars in this country today has a transmission that works (or else, it would not be a functional car!!)


Why do we call it a "start-up company?"

Fascinating that this is the vehicle type people here so adamantly want - yet they cut no slack to the people putting up their money, time and effort to make it happen. Without Tesla, A123, Altairnano and a few of the super-cap makers - big auto industry would still be claiming the "EV battery technology is ten years away."

Yes, they are releasing their vehicle with an incremental transmission that accelerates a little slower than the spec. The point is someone is building an EV and has pre-sold enough to start the ball rolling for everyone else.

FYI it was independent people from the software industry that blew NASA, ESA, China and other engineers out of the water with the X Prize winning Spaceship One. But hey, it's a whole lot easier to whine about experience and over promising than to get behind those who are taking the risks to deliver what you want.


I think this is a crippling credibility issue. It's about as bad as saying the windscreen will break after a few thousand or the brakes will only last a few thousand or the seats will only last a few thousand. What is this? Car transmissions have been basically maintenance free and durable to over 150,000 miles for decades, before you might have to start thinking of replacing the gearbox. It's basic. Basic. It is in fact risible that they can't get a transmission. Laughable - or cripplingly serious. Many Amateur EV converters simply lock the IC manual transmission into second gear - even Zytek are just doing that with their Smart conversion. All "Tesla" had to do was take an ordinary manual transmission and take out gears 1, 3 and 5. I thought Lotus were supposed to be building this thing, with "Tesla" supplying the electric components - the battery being the only new thing basically, motor controller and motor off the shelf. So what was so difficult about taking a stock Lotus design and doing an EV conversion? If a company like Lotus can't get the transmission right, what is going on??? Or is the partnership with Lotus just window dressing to get punters to sign up?

I suppose they just think the average "consumer" these days is so brain dead they can tell them any old story. Frighteningly, they are probably right.


Golly, Mr. Wizard, my Tesla only does 0-60 in 5.7 seconds! That's a whole 1.7 seconds longer than I expected! EVs are dead.

Robert Marston

I think it's amazing that some company that never produced a car before comes out with both the longest range electric vehicle ever produced and the fastest electric vehicle ever produced.

These problems are minor bumps in the road given the revolutionary nature of the technology involved. If Tesla can keep the new transmission close to a 250 mile range and a 4 second acceleration to 60 it will be a win in my book.

And what's the matter with upgrading a car after it's produced? It's a bit better than dumping something substandard on the market and then making excuses. It's quite a bit better than promising to produce something amazing and then failing altogether (hahem GM...).

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