Back to all

Tacky or Techie? The Tachometer.

June 9, 2019

There's a gauge that many vehicles have that says RPM on it.  And there are a lot of people who either don't pay any attention to it or don't even know what it is. Here's why it's a good gauge to know about.

It's called a tachometer, and that "RPM" label means it is measuring how many revolutions per minute (RPM) the engine is turning.  Automotive experts know that a vehicle's engine can be damaged if it turns too fast (revving too high) or too slowly ("lugging" the engine).

A tachometer (sometimes called a tach) is almost a "must-have" gauge for vehicles with a manual transmission; the driver has to manually change gears; the tach helps the driver know when revolutions are in the optimal range.

Some say you don't need a tachometer if you drive a vehicle with an automatic transmission. It's true that most drivers of automatics don't even look at it.  But there are times when paying attention to the tach can help you prevent an expensive repair.

Here's a good example.  Manufacturers now build many of their automatic transmission vehicles with shift paddles.  They let you shift gears without a clutch. That's manual shifting, and drivers need to know they're not revving the engine too high. That's where the tachometer comes in, since it shows you visually when you are in the red zone (RPM too high).

Here's another way the tach can help you: fuel economy. Generally speaking, the lower the RPM, the better the fuel economy. It's not good to go too low, of course, and the tachometer will help you find that spot of maximum efficiency.

You can also spot problems by paying attention to the tach.  When your vehicle stays in first gear longer than usual (higher reading on the tach), then the RPM dip lower than usual after shifting, it may be that your vehicle's transmission is skipping a gear.  Plus, if your vehicle's RPM go up but your speed doesn't, it could mean your transmission is slipping.  Either situation should be checked by a trained technician.

If your commute takes you down some long grades, you might like to put your vehicle in a lower gear to help slow down the car (and not burn up the brakes). Having a tachometer keeps tabs on when your engine is revving too high.

So, consider the tachometer a "bonus" gauge.  It's one more helpful assistant that can help you spot and prevent problems in your vehicle.

South Side Garage
2220 Pole Rd
Moore, OK 73160
405-308-1514

More articles from Southside Garage

Objects in the Mirror (Rearview Mirror Safety and Maintenance)

June 9, 2025

You may remember a song that went, "Objects in the rearview mirror may appear closer than they are." While that was a song about life's lessons, there are a few things we should all know about how important rearview mirrors are to safe driving. While new electronic devices are helping drivers be ... More

Straight to the Point (Alignment Signs of Problems)

June 2, 2025

Its just common sense that your vehicle will drive better if all the wheels are lined up with each other and the road the way the engineers intended. When theyre not, that is called being out of alignment. Here are some signs that your alignment has problems. Your steering wheel isnt straight... More

A Clean Connection (Battery Cleaning)

May 26, 2025

A clean connection is a wonderful thing. Think of a good cell phone signal or an airline connection with ample time and short distance to the next gate. Good connections are also important for your vehicles battery, and one secret to that is to make sure its periodically cleaned. If its been a w... More