Why are tachometers next to speedometers?


Why do they install tachometers next to the speedometer. I never use it. It seems like a waste of money. the cars from the 60’s and 70’s never had them.


Why in the world is that a problem for you ? Some people like them and you are free to ignore it.


What you described is pretty much standard practice, industry-wide

Most people don’t have a problem with it

Personally, I would rather have a tachometer, versus not

Your Corolla is much better equipped, versus one from the 1970s

Is there some gauge you’d rather have, in place of the tachometer?


My 2012 Camry LE has a tachometer, a dash gauge that tells me my average fuel mileage, an odometer readout the tells me gas mileage and a touch screen that tell me mileage.

What it doesn’t have is oil pressure, temperature, volt or amp gauges.


My car doesn’t have a tachometer and I don’t miss it. A manifold vacuum gauge would actually be more useful as far as I’m concerned. If the vacuum is too high, you need to upshift regardless of the tach reading.


In case the OP is not aware of it, that tachometer can come in very handy to help diagnose certain mechanical problems. If his car has an automatic transmission, the tachometer can help him to realize when his transmission is slipping, and if it has a manual shift, the tach can make it fairly clear when the clutch is in need of replacement.


Not to mention it makes figuring out shift points easier, especially if you’re driving a car that’s unfamiliar to you. Doing it by sound is an inexact science, especially when you go from one car that redlines at 5500 to one that doesn’t hit VTEC until 5500.


Needed for a car with a manual trans, sure, but most folks (with AT) wouldn’t miss it. The frequent posters here aren’t ‘most folks’, of course!


Back in the '60s, I knew a guy whose father had just bought a Datsun sedan, with manual trans.
His father gave him a 20 minute lesson in how to drive a stick shift and decided that his son was good to go.

I’m not sure if that little car had a tach or not, but the one thing that this guy didn’t seem to understand was that when you reached the obvious redline point in one gear, you were supposed to shift to the next gear immediately. Instead, he would accelerate the car to the point where it was screaming in first gear, and continue to drive at essentially the same speed for another 30 seconds or so, before shifting to second gear. Then, when the engine got to the point of screaming at its limit in second gear, he would continue to drive for… too long… in second gear, before upshifting again. Lather, rinse, repeat, ad infinitum.

I don’t recall if that car had a tach, but somehow I don’t think that it would have helped him.


I imagine it didn’t have much of an engine either, before too long. :wink:


Actually, the transmission was the first to go, with the engine bringing up the rear about a year later. This was the car that he took to college, and the car got no servicing whatsoever for at least one year while he was away. Even though those early Datsuns were essentially pieces of crap, his driving style and his lack of attention to maintenance certainly didn’t help.


The ONLY people who NEED a tach to shift are race drivers…The average driver who needs a tach to shift doesn’t know how to driver a manual. I’ve NEVER looked at the tach to shift…never needed to, and never had a problem. Yes an unfamiliar vehicle may take me 5-10 minutes to figure out it’s range…but after that I’m good.


A tachometer on a car that has an automatic transmission might help you notice or diagnose a problem if there is a major change in shift patterns not related to throttle position.

A tachometer on a car that has a manual transmission helps prevent you from accidentally red-lining it, or can help you identify the best shift points to maximize either fuel efficiency or power.

On a tow vehicle, a tachometer provides a visual queue that you might have forgotten to engage or disengage the overdrive.

In all three cases, I’d hardly call the tachometer “useless” or a waste of money. It’s only a waste if the driver doesn’t know how to use it, or doesn’t value the information it might provide.

As to why they’re usually installed beside the speedometer, it’s so you don’t have to move your eyes around and take them off the road for very long in order to take in information. This is why some companies put the radio high on the dashboard, so your eyes can move quickly back and forth between it and the road, without having to look down at the radio controls.

Personally, I can live with it or without it. My manual transmission '98 Civic doesn’t have a tachometer, yet many automatics I’ve driven have them. Only one of the three motorcycles I’ve owned had one, and I rarely looked at it.

To some degree, a rev limiter makes a tachometer redundant, at least in terms of accidentally redlining an engine, but that’s only a small piece of what it can be used for.


I had a 1997 GMC 1500 pickup with kind of a flaky transmission.

One day I was driving it on the highway with cruise on. I glanced down at the gauges, which included a tachometer. I noticed the tach was running way higher than it normally did at highway speeds, which clued me in that there was a problem. Turns out I had to have it towed and ended up getting a new transmission.

For that reason, I always keep an eye on the tachometer on both of my vehicles. It provides valuable info to me.


May not useless…but hardly ever needed. But let’s not look at this as a Tach or No-Tach. The dash is a very defined space. I’d rather see more informative gauges. Oil temp/pressure, battery voltage just to name a couple. Both those gauges are far more useful then a tach.


The battery voltage gauge in my MR2 is pretty useless. In fact it’s so useless that on the turbo models they replaced it with a boost gauge. It’s literally a “we need to fill this hole” gauge for the NA cars.

Any time I’ve had battery voltage issues in that car, I’ve known about them without looking at the gauge because the car was slow to crank or didn’t start at all. Pretty good clue. :wink:


When I use my paddle shifters because I need to accelerate in a hurry, I like to check the tachometer to make sure I’m not getting too close to the redline, as I’d rather not rev that high on a regular basis.


Perhaps the OP would prefer this layout. Driver did the shifting, copilot watched the speed and mileage to determine next turn in a rally.


Q-Why is there a tach?

A- To make the dash look more full to the novice driver- who are the majority of customers.Too much empty space gives the impression that there isn’t much going on. Add a tach- simple and cheap since the ECM is already monitoring RPM’s, and PRESTO! I have a fuller dash that looks more impressive.


Porsche takes it to the extreme, with the tach front and center: