TACHOMETER RED LINES MAY FLATLINE IN THE NEAR FUTURE
First, thanks for the many years of Car Talk. I head straight for your column every week.
Secondly, why do cars still have tachometers? I remember the days when we really did need them. My dad bought a red 1952 MG-TD in 1954. I was about 16 years old, and I thought this was the greatest car I had ever seen.
It was really fun to drive – top down and windscreen folded flat. It didn’t go very fast, but it felt like it did. The little engine really revved up, and my dad always reminded me to watch out for that red line on the tach.
You didn’t need to worry about carrying jumper cables, because a very handy crank was stowed behind the driver’s seat. I saw my dad several early mornings cranking that engine so he could leave for work. We lived in Southern California, and he could leave the top down almost all year.
Anyway, I’ve noticed that most cars still have tachometers. Why? Most of us rarely glance at the tach, or we forget it’s there, or some don’t know what it’s for!
My wife and I own four vehicles. None of them are Peterbilt’s! We don’t need the tachometers and could not red line any of them even if we tried!
I can only guess that some obscure highway safety regulation mandates that every vehicle have a tachometer. Do you know the answer to this riddle? – Ed
No, it’s not a regulation, Ed. I think it’s one part tradition (it’s always been there), one part theater (it looks cool and suggests performance), and one part needing to fill up space on the instrument cluster (what are we going to do with all this extra space on the dashboard? Make the oil light 30 times bigger?).
You’re right that the tachometer – or the “tach” for short – which measures the engine speed in revolutions per minute or RPM, is completely unnecessary for most cars.
It was originally there to prevent you from revving the engine too high (“red lining it,” or letting the needle pass the red line on the tachometer).
If you revved an engine too high, centrifugal force could cause its internal parts to fly apart. I’ve always found it very exciting when that happens.
But the computers in today’s cars prevent you from ever red-lining an engine. You can’t do it if you try. And that’s even true with stick shift cars now. The computer will cut back the fuel injectors as you hit the red line.
Some people who drive stick shifts still like to know their engine speed. But most people have less than zero interest in it. And I think we probably will see instrument panels without tachometers in the coming years. For several reasons.
One is we’re moving to electric cars. There will be no engine, so there’s no need to know how fast its internal parts are moving.
Second, instrumentation is changing. Head-up displays now allow you to see crucial information without ever taking your eyes off the road and looking at your instrument panel. A head-up display projects key information, like the vehicle speed, on the windshield, so it appears to be floating at the end of your hood as your drive. So the instrument panel itself will become less important.
And finally, we’re also seeing more digital instrument panels, which are essentially computer screens instead of analog gauges and dials. As you might imagine, those can be configured to include anything the car can display.
And when you can see stuff on your dashboard that’s as exciting as where the nearest Denny’s is or the name of the Taylor Swift song that’s playing, why would you choose to watch your engine speed?
Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.