Back to all

Tacky or Techie? The Tachometer.

October 9, 2022

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.

Blair's Ferry Automotive
1565 Blairs Ferry Rd.
Marion, Iowa 52302
319-447-6310

Need Service?

Request a Quote

More articles from Blairs Ferry Automotive

Let's Clear Some Things Up (Headlight Restoration)

August 25, 2025

You know how exposing your skin to sunlight can cause sunburn and other unhealthy things. Sunlight can also create major problems for your headlights. After they've been exposed to ultraviolet light, acrylic headlights can yellow and fog due to oxidation. And when that happens, less light can ... More

Objects in the Mirror (Rearview Mirror Safety and Maintenance)

August 18, 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

Mercury Rising (Hot Weather Vehicle Concerns)

August 11, 2025

The heat is on, and your vehicle takes a beating when it is. Several of your vehicle's systems are under extra stress in hot weather, so here are a few to make sure are getting the care and maintenance they need. It makes sense that the cooling system is one to make sure is in top shape. Vehicl... More