# Why have my cars had a tachometer?
**URL:** https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155
**Category:** Factual Questions
**Created:** [June 4, 2013, 9:46pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155 "2013-06-04T21:46:18Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)
#### Post date: [June 4, 2013, 9:46pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/1 "2013-06-04T21:46:18Z")
Why is precious dashboard space so often reserved for a tachometer? Knowing when to shift a manual? What casual driver uses the tachometer and not the engine’s sound? Avoiding red-lining a car? Again, sound communicates most of what you need to know, and beyond that cars’ electronics take care of limiting overall RPMs. And what possible reason do they have in an automatic?
I want, I don’t know, some useful information or maybe a nice pneumatic tube so I can launch goats. But no. I have a tachometer. What gives?
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### Author:  [@Telemark](https://boards.straightdope.com/u/Telemark)
#### Post date: [June 4, 2013, 9:51pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/2 "2013-06-04T21:51:49Z")
I’ve pretty much always driven standards, and I can’t imagine doing so without a tach. Sure, I could figure things out by sound or speed but why? I don’t use it every time but it’s good feedback. It’s also great for figuring out if your clutch is slipping, and if your idle is set wrong.
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### Author:  [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)
#### Post date: [June 4, 2013, 9:56pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/3 "2013-06-04T21:56:03Z")
They persist in cars that don’t really need them because they are cheap to implement, fill dash space, help inspire a sporty/techno/upscale look and actually do something while you drive.
In serious performance cars, especially those of the pre-electronic era, the tach is the most prominent gauge on the dash and the speedo is over where the fuel gauge sits.
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### Author:  [@bob\_2](https://boards.straightdope.com/u/bob_2)
#### Post date: [June 4, 2013, 10:05pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/4 "2013-06-04T22:05:10Z")
Because Americans love dials and gauges. Look at any picture of an American truck dashboard and compare that with a minimalist European one and you would see what I mean.
[http://americantruckgroup.com/wp-content/uploads/2011/06/660-1589-w900l-black-inside-dash-.jpg](http://americantruckgroup.com/wp-content/uploads/2011/06/660-1589-w900l-black-inside-dash-.jpg)
[http://www2.mercedes-benz.co.uk/content/media\_library/unitedkingdom/mpc\_unitedkingdom/trucks\_refresh\_2011/trucks/atego/overview\_\_\_applications/features/instruments\_715x230.object-Single-MEDIA.tmp/7202\_10\_VV\_AT\_009\_UK\_mod-715x230.jpg](http://www2.mercedes-benz.co.uk/content/media_library/unitedkingdom/mpc_unitedkingdom/trucks_refresh_2011/trucks/atego/overview___applications/features/instruments_715x230.object-Single-MEDIA.tmp/7202_10_VV_AT_009_UK_mod-715x230.jpg)
The tachometer on a truck is an aid to economical driving.
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### Author:  [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)
#### Post date: [June 4, 2013, 10:07pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/5 "2013-06-04T22:07:19Z")
It’s unnecessary but a cool thing to have for most cars. It makes things like minivans derivable for car loving guys. Probably 80% of the cars on the road have no need for a tachometer, and probably a half of those drivers really don’t understand, or care for that mater, what it is registering. However, if you have things like paddle shifters and manual mode on your 5, 6 or 7 speed automatic, you kind of like having a tachometer. Each engine will have a sweet spot in the rpm range and the tack will help you stay in it, or not. Short answer, it’s like wings on the back of a typical new car. It’s just for looks.
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### Author:  [@Twoflower](https://boards.straightdope.com/u/Twoflower)
#### Post date: [June 4, 2013, 10:07pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/6 "2013-06-04T22:07:43Z")
Used to be that a clock occupied the space next to the speedometer. When the clock became digital and moved over to the radio, they had to stick something there in its place.
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### Author:  [@GreedySmurf](https://boards.straightdope.com/u/GreedySmurf)
#### Post date: [June 5, 2013, 12:07am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/7 "2013-06-05T00:07:59Z")
> [@Telemark](#):
>
> I’ve pretty much always driven standards, and I can’t imagine doing so without a tach. Sure, I could figure things out by sound or speed but why? I don’t use it every time but it’s good feedback. It’s also great for figuring out if your clutch is slipping, and if your idle is set wrong.
I’m the opposite. I’d much rather change gears by ‘feel’. Why would I bother taking my eyes of the surroundings to look down at a gauge that tells me something I can intuitively tell by feel and sound?
In Australia (where there are still plenty of manuals sold), a lot of cars have dispensed with the tacho. Having one on the dash sort of tells you that the carmaker has decided “This car is a ‘sports’ model, and/or pitched at males” 😃
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### Author:  [@MLS](https://boards.straightdope.com/u/MLS)
#### Post date: [June 5, 2013, 12:23am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/8 "2013-06-05T00:23:40Z")
My current car has automatic transmission and has a tachometer. I use it to help improve gas milage.
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### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [June 5, 2013, 2:17am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/9 "2013-06-05T02:17:03Z")
None of my manual cars ever had a tach. All of my automatic cars have.
Replace it with a cupholder.
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### Author:  [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)
#### Post date: [June 5, 2013, 2:23am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/10 "2013-06-05T02:23:22Z")
I’m still incredibly angry they took away voltmeters and oil gauges… SUVs used to have them standard but new ones tend not to.
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### Author:  [@septimus](https://boards.straightdope.com/u/septimus)
#### Post date: [June 5, 2013, 2:57am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/11 "2013-06-05T02:57:25Z")
> [@Telemark](#):
>
> … I don’t use it every time but it’s good feedback.
Yes. Redundancy is under-appreciated.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [June 5, 2013, 4:01am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/12 "2013-06-05T04:01:45Z")
I don’t understand why anyone wouldn’t want to know how fast an expensive to own and operate engine is running.
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### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [June 5, 2013, 11:29am UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/13 "2013-06-05T11:29:54Z")
> [@TriPolar](#):
>
> I don’t understand why anyone wouldn’t want to know how fast an expensive to own and operate engine is running.
This. Unless a person has [perfect pitch](http://en.wikipedia.org/wiki/Perfect_pitch) (and can do some math based on how many cylinders your engine has) it will be difficult to know what RPM the engine is operating at without a tach. This is less critical on automatics, but for manual transmissions, it’s nice to know where the redline is so you can shift before you encounter the stumble-generating rev limiter at the redline.
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### Author:  [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)
#### Post date: [June 5, 2013, 12:15pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/14 "2013-06-05T12:15:05Z")
A lot of luxury cars are so quiet you need the tach to tell how hard the engine is working or if it’s running at all. Of course, if there’s a feature on luxury cars that’s cheap to put on other cars, you can bet they will.
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### Author:  [@Sparky812](https://boards.straightdope.com/u/Sparky812)
#### Post date: [June 5, 2013, 12:35pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/15 "2013-06-05T12:35:40Z")
You’ve answered almost all of your own questions in your OP.
The tach is useful information especially to a manual transmission driver.
Secondly, usually car manufacturers will use one dash cluster for multiple models including both transmission options.
> [@TriPolar](#):
>
> I don’t understand why anyone wouldn’t want to know how fast an expensive to own and operate engine is running.
Ditto!
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### Author:  [@simple\_homer](https://boards.straightdope.com/u/simple_homer)
#### Post date: [June 5, 2013, 1:01pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/16 "2013-06-05T13:01:15Z")
> [@bob\_2](#):
>
> Because Americans love dials and gauges. Look at any picture of an American truck dashboard and compare that with a minimalist European one and you would see what I mean.
>
> The tachometer on a truck is an aid to economical driving.
Your link shows the dashboard of an American tractor-trailer (articulated lorry) .
How does that represent what most Americans drive ?
Most American cars and trucks have dashboards similar to the European example that you linked.
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### Author:  [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)
#### Post date: [June 5, 2013, 1:19pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/17 "2013-06-05T13:19:48Z")
I have one on the minivan which makes me giggle because it’s an automatic, but I don’t mock it too much it because it’s a 6-speed with the option to shift manually (without a clutch, of course). And because it’s such a quiet ride, it would be difficult to drive it by ear as a pretend manual.
My MR2 and my Golf both have tachs, are both manuals, and are both old enough to drink. I look a the tach about as frequently as I do the speed because their peak power band is in the high rev area–the MR2 really kicks it between 4000-6500 rpm and the Golf likes to be around 3000-5000 (I don’t know about the SRT4–I hate driving that thing). If you drive below those levels, the cars are sluggish and I question if the fuel economy is any better. Get above that zone and the engine’s just spinning fast without giving significantly more power. Now, I _could_ listen carefully to the pitch of the screaming engine to figure out when to shift, but there’s other things I need to focus on when I’m driving. I only have to glance half an eye at the tach to keep me in the sweet spot. Plus it’s a great aid for adjusting the idle or getting a clue about upcoming engine trouble asociated with a bouncing idle.
I guess some people care about being interactive with their cars, and other peole just want to get from here to there without thinking about the machinery. There’s lots of things like that in life.
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### Author:  [@Bert\_Nobbins](https://boards.straightdope.com/u/Bert_Nobbins)
#### Post date: [June 5, 2013, 3:40pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/18 "2013-06-05T15:40:27Z")
> [@GreasyJack](#):
>
> A lot of luxury cars are so quiet you need the tach to tell how hard the engine is working or if it’s running at all. Of course, if there’s a feature on luxury cars that’s cheap to put on other cars, you can bet they will.
I don’t know if my car [http://www.topgear.com/uk/skoda/octavia-vrs](http://www.topgear.com/uk/skoda/octavia-vrs) counts as luxury, but the engine is so quiet that the tachometer is something of a necessity. I find myself looking at it more than the speedometer, even though the torque/rpm curve is impressively flat. And there are also 6 gears to sort out, of course.
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### Author:  [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)
#### Post date: [June 5, 2013, 4:32pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/19 "2013-06-05T16:32:03Z")
I interpret the OP’'s question as: _Why do some people obtain information visually, when they can obtain it aurally?_
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### Author:  [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)
#### Post date: [June 5, 2013, 4:58pm UTC](https://boards.straightdope.com/t/why-have-my-cars-had-a-tachometer/660155/20 "2013-06-05T16:58:43Z")
> [@Sparky812](#):
>
> …usually car manufacturers will use one dash cluster for multiple models including both transmission options.
Can’t believe it took 15 posts to get to the correct answer.
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