Got in my wife’s Saturn yesterday and noticed the tachometer dial was as big as the speedometer dial. Damn thing consumed a huge chuck the dashboard’s real estate. Yet, for the most part, I really don’t care what the engine RPM is.
I can understand the need for a tachometer when setting the engine’s idle RPM. Other than that, is it really needed by the average driver? Why is it there? For looks? To make it look like a high performance race car?
Many people want that information in order to judge wheter they drive efficiently, use the right gear (for manuals) and so on.
Also it helps you know if the car is idling higher than normal (a potential problem).
They make sense in a car with a manual transmission so you can pretend you are a hotshot race car driver and shift at exactly the correct rpm (as if you are too lame to do it by feel in ordinary driving).
As for why they put tachs in cars with automatic transmissions I have the same question as the OP. What can you possibly use them for in day to day driving? Yet, there they are!
It’s so manufacturer can use the same dash for manual and automatic, no sense in having to make two parts when one will work just fine. Oh, and it’s not always to be a hot-shot race car driver. If I’m coming off a stop and I’m next to a semi or a bus sometimes it’s hard to hear and feel the engine, this way I can just look at the tach and no when to shift.
Same thing (make sure your automatic isn’t shifting at the wrong rpm, potentially indicating a problem). Generally any halfway competent driver ought to know these things by sound and feel of response, but if you’re a little tone-deaf it helps to be able to put a number on it. Also it gives you an objective way to explain the problem to the mechanic (it was shifting at 2500, now it’s shifting at 3100).
I personally utilize the tachometer, even in an automatic, to check the engine speed. I try to keep it under 3,000 RPM except in the most extreme of circumstances. Any higher than that and I feel like I’m driving too aggressively. You could argue that I should be able to tell whether or not I’m driving too aggressively based on “feel”, i.e. the jerk of the car and the noise of the engine, when accelerating, but I appreciate having the objective numbers in front of me.
I’ve driven cars which are so quiet I must look at the tach to determine if the engine is running or not. Trying to start an engine which is already running is not good.
Folks who have an interest in mechanics use the tach for all of the previous reasons. Folks who have no interest in mechanics ignore them. Just my opinion.
I often pull a travel trailer with my truck, which has an automatic transmission. I heavily rely on the tach to determine my gear selection. Modern automatics perform almost like yesterday’s standards.
If you have an SUV or truck that is actually meant for real off-road duty or actual work, they can be helpful. Even in an automatic, you can switch down to Drive 1 for instance with the potential to red-line the engine while stuck in mud. A tachometer is useful under those circumstances.
Yea, I can understand its usefulness w/ manual transmissions and in special circumstances. But most cars nowadays have automatic transmissions, and most cars are used for run-of-the-mill transportation tasks.
I’m not saying a tachometer has no purpose in your average car, just that the size and prominence of the tachometer dial seems rather disproportionate when compared to its actual usefulness.
I think they’re mostly there because they’ve always been there. Inertia is a big factor in automotive design. But that’s not to say that plenty of people don’t find them useful. So it’s probably still the right choice to include them. Giving a few people too much information is better than giving the rest not enough.
They reason they’re usually large is for precision. It would be too hard to tell the difference between 3100 rpm and 3200 rpm on a gauge the size of the usual fuel gauge. You may question the usefulness of having that level of precision, but it’s obviously a feature that people want.
Having a tach is important enough to me that I simply wouldn’t buy a car that didn’t have one. Then again, I stubbornly refuse to drive anything but a manual transmission, so that may be part of it. But even in an automatic, I find it useful information to understand how the car is behaving. So if I buy an automatic in the future, I’ll still expect to have that instrument. I’d feel quite disconnected from the mechanics of the car without it.
So maybe the biggest reason that cars have tachometers is consumer demand. No one that doesn’t want them bothers to complain about their inclusion. But people who do want them would complain about their omission.
Pointless but somewhat appropriate anecdote: In college my girlfriend (now wife) had a Chevy Beretta with a manual transmission. It had no tachometer. Her friend had a Chevy Cavalier built in the same year, with an automatic. And it did have a tach. So two cars built at the same time from the same maker had it completely ass-backwards. Didn’t make sense…but this was in the era when GM still used different keys for a car’s ignition and doors, so the lack of common sense in Detroit shouldn’t be too shocking.
Is your Saturn perhaps derived from an Opel? In Opel-land manual transmissions are still the norm. Sure, even then you can do without a tachometer but they are kind of expected and their absence is considered a bit substandard.
It’s also a matter of expectations. Yes, you could say that it’s an affectation of trying to feel like a race car driver to sit in the “cockpit” and see an array of dials. But if you’ve grown up with that image of a dashboard in mind as an aesthetic ideal, looking at a dash that has just one big speedometer, or even worse, one with a digital dashboard that just has a big readout of your current MPH in the middle, can be at first disorienting (“what the --?”), then cheap (“what, all this metal and they save $20 on a stupid dashboard dial?”) and finally even a little insulting (“what, they don’t think I know the difference between the tach and speedo, like I might think I was doing 75 MPH when revving the engine to 7500 RPM?”).
To echo what Shagnasty said about trucks stuck in the mud, a tach would be useful in a car in snow and ice. It would also be useful for people who use the engine to brake while going down a big hill.
This is not quite true. Back in the 1950 or early 1960s only sports cars had tachometers. Everyday cars did not. It got to the point that there were some cars built with only a speedo and a fuel gauge. Everything else was an idiot light.
Then Detroit started to build muscle cars and noticed that one of the first things a muscle car owner did was add a tach. Not being complete boobs they thought, why let Stewart Warner make the profit on the tach, we can offer them as an option and make more money. This also make their cars more “sporty”, and “European”.* So full gauge packages became an option of muscle cars. Then in an effort to make their regular offers more “sporty” they started to offer tachometers on their less sporty (read mundane) models. Bit by bit a tachometer became the norm, not the exception.
Here are some pics that show the progression of gauges in a Mustang
1964 (4th picture down) Note the tach shown is an aftermarket unit.
1965-66 Pony interior No tach standard, but has an oil pressure gauge
1967 Mustang (bottom right picture) note the large tach. Another 67 Mustang This one has an aftermarket tach in the factory tach location.
Now a tachometer is a customer expectation in pretty much all cars. (Yeah, maybe you don’t want it, but survey 1000 customers and more will expect it than not)
You will also get trashed in the automotive reviews in the car magazines if you don’t have a tach.
Implemented across an entire product line, I doubt that the tach costs much.
*Sometimes known as adding showpower.
Tachometers are useful in automatic-transmission cars where the speedometer only goes up to 120 MPH (or even lower). Gives you some highly useful feedback about how far you’ve gone beyond that.
Yep. I distinctly remember advertising in the 70s pointing out the fact that the car had a tach, and implying it was a “serious” performance machine, the feature eventually finding its way down to the cheapest econobox. Now we’ve apparently come full circle, and a lot of people like the OP are asking “WTF do I want a ginormous tach for?”.
Related question - what is the idea of the speedometer on some Mini Coopers, and similar vehicles? What I refer to is a freaking HUGE speedometer placed in the middle of dash:
Bloody thing can be read not only by everyone in the vehicle, but from other cars pulling up alongside it. Surely, the only person who needs to read the speedo easily is the driver.
…and weren’t necessary, because of louder engines and less sound insulation. So they can have a function for an everyday driver nowadays, as already outlined, who might not have needed it back then.
A further thought: if you left it out, you’d still presumably sell it as an optional extra, and would need somewhere to put it. If you’re not going to have a big blank space, you’ll need two completely different dashboard layouts…
The size has a lot to do with show.
With an auto I use the tack. going up hill and down hill to see if I want to downshift or not.
I believe when getting on the freeway if you can by the end of the on ramp you should be traviling 65 or what ever the freeway is traveling not 45. but I do not like over reving the engine to get there so the tack will let me know if I need to let up or not.
