Roadster Paddle Shift

Activating The Paddleshift

On the Roadster, there is only 1 good way to do this. TAN Coding.

This really is the only option you should consider when adding paddleshift to a Roadster. You (or a smart specialist) fits the paddleshift steering wheel and then uses MB Star (and probably a dodgy TAN code calculator) to create the correct TAN code to activate the paddles.

This TAN code would cost around £100+ from smart. It’ll be much much cheaper from a specialist. When the paddle steering wheel is fitted, a connection must be swapped over in the drivers side footwell. Non paddle wheels use white/white, paddle wheels swap to the black plug.

Andy S managed to get these 2 great photos to show where the connections are. They are usually taped up to the brown earth wires above the relay holders behind the SAM unit.

Above you have see the connection (already swapped to black/white for paddles). The black plastic part below the connection is the relay holders that hold the heated seat and wiper relays.

You’ll have to lower the SAM unit out of the way and post yourself into the footwell to find these.

White = no paddle steering wheel.
Black = paddle steering wheel.

Horn Doesn’t Work

If you swap the connector over before coding the paddles, the paddles won’t work (obviously) but also, the horn won’t work either. It’s because, before the connector swap, the horn ran straight through the SAM unit. However, when the connector is swapped, both the horn and the paddles are run through the speedo. The speedo is coded to understand the difference between a paddle and the horn switches.

The speedo then sends the paddles to the ECU and the horn to the SAM unit.

So, don’t swap the connector over until you have coded the paddles.

Paddles And Buttons

The official paddle wheel comes in a bunch of different types.

2 spoke Brabus (600cc only)
2 spoke (700cc only)
3 spoke found in the fortwo pulse and Roadster (700cc only)
V6 Roadster Brabuswheel (700cc only)
3 spoke wheel (999cc only)

There was never an official button change steering wheel but there have been many 3rd party and home made button shift wheels as it is a lot easier to make than paddles. There are also 3rd party paddle kits that fit to the standard steering wheels.

Differences Between Steering Wheels

The difference is very easy to see although both types of wheel look the same. Look at the black cartridge on the back of the wheel, you will notice either one or two electrical connections. If it has one connector, it is for a 600cc smart or early diesel. Two connectors signify it is designed for a 700cc and newer diesels.

The wheels with two connections can be used on 600cc cars simply by not using the extra wiring connection. The one connector version cannot be used on a 700cc smart.

Disassembling The Steering Wheel

Disassembly of standard and both types of paddle wheel can be found here.

Recognising New And Old Style Paddle Wheels

Take a look at the pastic cowel at the back of the wheel, where the paddles exit:

Squared off – meaning it is an old style paddle wheel with bolted in paddles.

Rounded off – meaning it is a new style paddle wheel with clipped in paddles.

Paddle Resistances

This is not public knowledge, the people who know like to keep it to themselves. It’s part of their evil scheme to take over the world, probably. In the years I have owned a smart, I have read many supposed truths about the values of these resistors. The problem is that all of the 3rd party gear change boards use different values, somewhere along the line the truth was lost in the confusion.

Smart Standard Paddle Wheel (suitable for a Roadster)

Horn – 4K Ohm
Up paddle – 2K Ohm
Down Paddle – 1K Ohm
Nothing pressed – 8K Ohm

There is a big difference between the way the 2 are wired. The old style wheel used serial wiring and therefore only used 1 resistor at a time.The new style wheel used parallel wiring. This means that the 8K resistor is used as well as the horn, up or down resistor. This would give a totally different resistance.

Horn = 8K + 4K = 2.66K combined
Up Paddle = 8K + 2K = 1.6K combined
Down Paddle = 8K + 1K = 0.89K combined

What Paddle Wheel Do I Need?

You MUST get a paddle wheel that has 2 electrical connections on the back. These are for 700cc smarts. This will fit a Roadster and a 700cc fortwo. You CANNOT use a paddle wheel with only 1 connection.

Chances are, a suitable steering wheel will have the rounded apertures for the paddles. However, it is vital that you check that there is 2 electrical connections on the back. Also make sure that this steering wheel isn’t for the 2nd generation fortwo.