Classic Speed®

Drive your mechanical speedometer accurately via GPS

JANUARY 2020 - A note to our customers:

Thank you for your patience as we (and many other small businesses) dealt with the fallout of the recent tariffs with China. We are now seeing some light at the end of the tunnel. We have a waiting list of people from all over the world who have reached out to us looking for a solution to their speedometer drive issue. During this period, CAI focused on new ideas – as you will recall, as auto enthusiasts/investors ourselves, our goal is to make classics more safe, driveable and reliable.


We have now thoroughly developed, proven out, and streamlined the manufacturing, delivery, sales and marketing processes for Classic Speed. It’s a ready-to-run business in itself with 100’s of users in over a 100 different vehicle models. As such, we have decided to sell the Classic Speed part of CAI (including the IP) and are in discussions with several interested parties who we feel have the capability to bring Classic Speed to the next level. 


If you, or someone you know, are interested in learning more about this opportunity, please reach out to us for additional information.


Watch here for further updates!


Classic Speed® takes the place of the transmission, wheel, or any other method, to drive your mechanical speedometer accurately.


Simply unscrew the speedometer cable from the original source and screw it onto the end of the Classic Speed unit. CAI can also provide a new custom cable. And since your speedometer is now connected directly to Classic Speed, your speed reading becomes ‘car independent’ – meaning your speed will always be accurate regardless of any modifications you make to the car. A quick 1 minute setup, while parked in your driveway or garage, matches a user’s own speedometer to Classic Speed. And since each speedometer is different and can change over time due to wear or a desire to move Classic Speed to another vehicle, this matching can be done as needed over the years. If your vehicle is 12v, negative ground, Classic Speed (U.S. Patent No. 9,802,487) will work in your classic or hot rod!

$275.00 USD plus shipping​

U.S. Patent No. 9,802,487

Currently out of stock

Classic Speed

Spec Sheet:

(click on pdf)

Classic Speed

Installation Guide:

For both MPH and KPH units

(click on pdf) 

Installation Photo Gallery

Click here to check out some of our

 Classic Speed installations!



Read the

press release here

For the engineers among us... more details...


Classic Speed® is an electro-mechanical device that drives a classic car's mechanical speedometer to ensure accurate speed. It is quick and easy to implement, non-vehicle dependent, and less disruptive than any other solution out there. Everyday use of Classic Speed is transparent and seamless to the original driving experience.


Problem statement:

The speedometers of pre-1985 automobiles are driven mechanically by a cable connected to the vehicles’ transmission. Elements such as varying tire diameter, drive system gear ratios, and aging mechanical systems can severely alter the accuracy of both the speedometer and odometer. This can result in expensive and unnecessary speeding violations, along with a reduced vehicle value due to a higher than actual odometer reading. 



Classic Speed replaces the original method of driving the speedometer by utilizing GPS for deriving ground speed, translating, and delivering the information via the speedometer cable to the speedometer. 

Tracking up to 22 satellites on 66 channels, there's a small, active antenna that sits anywhere there is line of sight to the sky. It uses that signal to calculate ground speed, and then uses the internal software of the program to change that ground speed into a signal to drive an electric motor in the Classic Speed unit. Classic Speed takes the place of the transmission to drive your speedometer. You simply unscrew your speedometer cable from the transmission and screw it onto the front of the Classic Speed unit. Do a quick, simple calibration with the provided dongle to set up your own speedometer, and you’re off! And since the mechanical speedometer is connected directly to Classic Speed, your speed reading becomes ‘car independent’ - your speed will always be accurate, regardless of any modifications you make to the car.  


As for places where you can’t locate a satellite, e.g. tunnels, there’s no need to worry. Classic Speed works to accommodate! If satellite triangulation is lost, we have an algorithm to continue to drive the speedometer based on an average speed of the last few minutes. This is more to keep the inertia of the system going than to let you know how fast you're going. Exit the tunnel, automatically re-acquire sats, and you are back in business!

Features and benefits:

  • Classic Speed is a stand-alone solution that drives the speedometer with accuracy regardless of any changes in tires and/or gear ratios. Installation requires only basic knowledge and tools. Other solutions such as recalibrating the speedometer or adjusting gear ratios are vehicle dependent. They often require the services of a professional, may disrupt other systems, and even then the speedometer will always be subject to inaccuracy. Also, these other solutions can become obsolete as soon as the next relevant change is made. Furthermore, adjusting gear ratios is not an exact science, resulting in only a close correction of the speedometer reading. That said, we do require a good working speedometer and cable!

  • Additionally, recalibration requires that the speedometer be removed from the vehicle, generally by a professional. This can involve labor, time, and money. The space the speedometer occupies behind the dashboard is often cramped and crowded with other electrical and mechanical systems that are easily damaged. But to repeat once again, we do require a good working speedometer and cable!

  • Classic Speed is truly 'car independent'. Have a TD with a Pinto engine? This is exactly the type of situation it's perfect for! And if you were to change out that Pinto engine for a Datsun or back to MG, Classic Speed is "future proof" - so it will work with that too. It does not matter what is powering your classic car or hot rod. 

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