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Why do speedometers go so high?
April 4, 2011 1:37 PM   Subscribe

Why do car speedometers go so high?

Taking a roadtrip last week, I noticed that my minivan's speedometer goes to 160 mph. That is nuts. I would estimate that for 99 miles out of 100, most drivers do not go over 85 mph, and for 99.9999 miles out of 100 they do not go over 100 mph. I would also estimate that I would need to attach a jet engine to my minivan to get it above 130 mph. That means that over a third of the speedometer is almost completely superfluous.

I can think of a couple of reasons why speedometers might go so high, and Google suggests both reasons the most often: (1) Car companies have figured out that people want to see high numbers on them because it suggests a powerful engine, so they exaggerate the figures a bit for marketing, or (2) seeing the needle at 70 mph right near the middle of the dial is better for attention to the road or psychological justification of cruising speed or something.

But does anyone know the answer, through either a design theory or marketing class, or history of the auto companies, or a consumer study or some other more definitive source?
posted by AgentRocket to Travel & Transportation (28 answers total) 2 users marked this as a favorite
 
Another option you may consider - it means that car manufacturers only need to make one speedo that will function on many different models. Your minivan may only hit 112mph but that same speedo fitted in the company sports model may hit 155mph occasionally.
posted by longbaugh at 1:44 PM on April 4, 2011 [1 favorite]


Even more than that - my Ford Ranger had an identical dashboard to my friend's Mazda B-series. So I'd guess it's definitely a one-size-fits-all thing.
posted by restless_nomad at 1:48 PM on April 4, 2011 [1 favorite]


My speedometer from my 1989 car only goes to 85. It drives me crazy. There are several interstates that go up to 75 and 80, and it's really easy to inch a little bit over and not know how fast I'm going, other than "above 85." I wish my car had been standardized along with everybody else's. (Yeah, I think it's a standardization feature, too, since I know old crappy Ford Rangers that have speedometers up to 120 or 160, and those things were lucky to hit 80. Ever.)
posted by wending my way at 1:51 PM on April 4, 2011


I'm sure it's 50% marketing related, and maybe the other 50% what longbaugh mentioned. I too doubt that most cars can actually reach the top speed on their speedometers. For the ones that can, it might be partly a marketing/pride thing that the manufacturers instill in their vehicles, much like the makers of the Renault Espace F1 with a zero to 60 in 2.8 seconds and a top speed of 194mph..yes...a F1 engine in a minivan...and with the addition of real spoilers, who's call who domesticated stay at home dad now?? eh?
posted by samsara at 1:51 PM on April 4, 2011


As another example - the Aston Martin DB7 has several bits and bobs off the Ford Mondeo including the indicator stalks and (iirc) the rear lights. Car manufacturers love to save money by using parts across different models and you'll oftentimes find certain manufacturers sharing even more (Ford/Mazda Fiesta/121, Chrysler/Mercedes Crossfire/SLK etc.) Most companies share bits from the part bin as a cost saving venture and that explains a lot of it.
posted by longbaugh at 1:58 PM on April 4, 2011


They're aspirational. Also, sometimes hills an get big.
posted by craven_morhead at 1:58 PM on April 4, 2011


My 84 Mercury only went to 85 as well. It was fun to pin it, well, when I was 17 at least.
posted by tremspeed at 2:05 PM on April 4, 2011 [1 favorite]


(2) seeing the needle at 70 mph right near the middle of the dial is better for attention to the road or psychological justification of cruising speed or something.

It is partially that. In my car the tach and speedometer point straight up at 75.

My last Audi's owner's guide said something like during break-in period, you should not exceed x% of the maximum speed listed on the speedo. I remember it working out to being over 100mph so I wasn't too worried. This car's speedo went to 160mph but had a governor that kept it from going over 135ish.

I remember as a kid after the 55mph speed limit was enacted, that newer cars my dad was driving didn't have speedos showing over 85 or something. He still could (and did) drive them faster.

...most American drivers, right?

Which would be the people with speedos that went to 160mph. I don't think the roads in Liberia and Myanmar support sustained speeds like that.

I had a rental car (an American nameplate) that instead of listing the km/h in tiny type under the imperial mph, had a button on the dash that would calibrate the needle. So you could be driving along at 75mph, push the button and the needle would shoot to 120.
posted by birdherder at 2:07 PM on April 4, 2011


I'm surprised nobody's mentioned the fact that some modern speedometers (mine included) can switch from MPH to KPH (instead of having two hashmarks). 55 MPH is a decent speed, but that's 88 KPH.

In other news, I always giggle when I'm driving in Canada.
posted by Heretical at 2:07 PM on April 4, 2011 [1 favorite]


Marketing, part reuse, rough concordance with driver expectations. There's also the question of calibration to ensure greatest accuracy in the middle of the speed range -- but that might be superseded by electronic speedos.
posted by holgate at 2:08 PM on April 4, 2011


Which would be the people with speedos that went to 160mph. I don't think the roads in Liberia and Myanmar support sustained speeds like that.

I presume he's referring to places like Germany. Lots of people drive faster than Americans and have perfectly fine roads.
posted by zachlipton at 2:20 PM on April 4, 2011


Right, and places like Germany presumably have speedometers that are primarily in kph (the US, Liberia, and Myanmar being the 3 countries in the world not on the metric system)

I presume he's referring to places like Germany. Lots of people drive faster than Americans and have perfectly fine roads.
posted by brainmouse at 2:23 PM on April 4, 2011


Also, sometimes hills an get big.

Anecdotal answer:

My first car was a '78 Honda Civic, 4-speed manual transmission. It was 14 years old by the time I got it, and even factory-new it would never be considered a fast car. The speedometer went to 110, though, and for a while I had fun seeing how close I could get to that theoretical limit.

So one day I decide to drive up the I-5 north of Los Angeles. I putter up the hills, crest...

And suddenly it became very, very important that the speedometer went as high as it did. Maybe there was a tailwind, maybe gravity was especially capricious that day, but I was white-knuckling the wheel and brake pedal as my Civic decided to hit 105 mph. If my speedometer had only gone to 85 mph then I never would have known how much danger I was in, how very close I was to being completely out of control.

So, yes, your minivan might only hit 85 on a flat, straight road, but there are driving conditions that you might not be expecting.
posted by lekvar at 2:23 PM on April 4, 2011


The 85 mph max on speedometers was legislated.

Speedo calibrations are now up to the manufacturer and very often serve multiple markets. UK cars have their speedometers graduated in mph AND kph.
posted by jet_silver at 2:39 PM on April 4, 2011


In the old Datsun 240/260/280 Z range the speedo went to 160 or something ridiculous, but 80 was at 12 o'clock. When the car did 80 in 4th gear the tach also pointed straight up as did the oil pressure gauge and the volt/amp meter. A tiny slice of automotive heaven.
posted by pandabearjohnson at 2:43 PM on April 4, 2011 [2 favorites]


I presume he's referring to places like Germany. Lots of people drive faster than Americans and have perfectly fine roads.

Right, and places like Germany presumably have speedometers that are primarily in kph (the US, Liberia, and Myanmar being the 3 countries in the world not on the metric system)


And the UK. Speeds are in mph here, and our highest speed limit is 70mph.
posted by talitha_kumi at 3:09 PM on April 4, 2011


Some good reasons in here. A few more:

A lot of people track their cars too. Not that you stare at your spedo when cruising through a bank at 125 =] but it looks good for the in car camera.

Plus, what if you put a turbo and nitrous system on your van? You could easily get it up to 160 - FORWARD THINKING!
posted by zephyr_words at 3:09 PM on April 4, 2011


My ancient VW Bug's speedo went up to 120..... like THAT was ever gonna happen! Ha!

I vote for 'aspirational'.
posted by easily confused at 3:32 PM on April 4, 2011


"seeing the needle at 70 mph right near the middle of the dial is better for attention to the road or psychological justification of cruising speed or something."

This is a significant advantage on cars with a long speedometre (as opposed to a dial). I buried the needle (120mph) on my '66 on several occasions and the speedo was pretty well useless above 100ish and equally below 15-20 mph.

restless_nomad writes "my Ford Ranger had an identical dashboard to my friend's Mazda B-series. So I'd guess it's definitely a one-size-fits-all thing."

It's not just the dashboard. The Ranger/B-series pickups are badge engineered siblings.
posted by Mitheral at 5:56 PM on April 4, 2011


@samsara I too doubt that most cars can actually reach the top speed on their speedometers
In fact all common cars cannot actually reach the top speed indicated on the speedometer. Modern electronic engine sensors and computer controllers monitor your cars speed. If you exceed a predetermined speed then fuel flow to the engine is shut down for a very brief period of time until the car resumes what is predetermined to be a safe speed. Safe for the passengers in terms of the cars handling limits and safe for the operating parameters of the engine to prevent it from blowing up.
posted by No Shmoobles at 7:18 PM on April 4, 2011


I would guess we have speedometers with large ranges for the same reason one can't go ten feet without crossing the path of a "family" style vehicle with more than 300 horsepower; Because America is a ridiculous country full of ridiculous people.

I do know that the 85 mph speedometer was a product of the 55 mph national speed limit after the oil shortages of the 70's. I guess the manufacturers figured one wouldn't attempt to exceed 85 mph, thinking that is all the vehicle was capable of. I know that I've met more than my fair share of people who drive vehicles a step above a 1906 Get Out And Push yet swear that since the speedometer says "X" the car will do every bit of it, even if the number is ridiculous. So, if it works one way, who's to say it won't work the other as well?

I have to say that given how fast people drive in New Jersey (speeds on major highways are typically between 75-90 mph, and that's just to keep from being run over in some instances) I think that having a speedometer read at least 120 is a good idea, just to give the right side of the speedometer a break from getting beaten up by the needle all of the time.
posted by chosemerveilleux at 7:22 PM on April 4, 2011 [1 favorite]


chosemerveilleux writes "I guess the manufacturers figured one wouldn't attempt to exceed 85 mph"

The 85 mph speedometer was the result of government mandate (along with the shift light and seatbelt interlock that wouldn't let you start the car unless your belt was done up).
posted by Mitheral at 8:13 PM on April 4, 2011


Lots of good answers here, and I'm sure it has to do with a lot of factors. A few other items worth knowing just based on my own use in an A4...

The latest Audi A4 has a speedo that goes to around 160 (and this is a 2011 model). That means that 80mph is right in the middle, which has certainly been helpful when driving as you always know not to cross the midpoint. Additionally, I've gotten my old A4 up to 130mph easy, at that point it was limited. I don't know about the new ones, but they are either limited at 130 or 155. I'm pretty sure that with a long enough straight, you could probably get up to 140 if not 155. The dash from an American A4 is certainly being used in the German A4s which could be used on the Autobahn where hitting 120 is a daily reality...

... LASTLY... you can tune a car (no one has said this!). So while that A4 goes 120 today, I could very easily make it go 160 tomorrow. If your car has a max of around 100, it would be foolish to make this the max because if you were going 100 and then went down a hill, you would easily go beyond that. I doubt there is one reason, but a multitude of reasons that vary on the manufacturers.

Complete aside... Veyron Speedo
posted by darkgroove at 9:19 PM on April 4, 2011


Interestingly, my 2011 Audi S5's speedometer goes up to 200. 60mph is only at 9 o'clock. This is actually pretty annoying to me -- the speeds I actually drive are all compressed down at the beginning of the speedometer. I find myself relying a lot more on the digital speedometer readout than I have in any other car. I wish they'd have just used the same 160 limit the A4 (and I think our A6, though I'm not positive and I'm too lazy to go check) has.
posted by sharding at 9:41 PM on April 4, 2011


In Britain you learn metres and kilometres and kilos at school and use yards and miles and pounds and stone in real life. The government has now given up on the last forty years of half hearted attempts to impose the metric system, beyond paying lip service to E.U. edicts, because people never accepted it and their kids didn't either. Other people's experience will doubtless vary but I have never, ever heard anyone ask how many kilometres away something was or to move the piano seven centimetres to the left.

The British don't hate the French either, we don't even hate Australians now we regularly thrash them in the Ashes. Sorry, but this is my first post on Metafilter so I don't know where to put the obligatory 'fucking' in an otherwise utterly mundane statement. I'll get the hang of it soon, I'm sure.
posted by joannemullen at 1:03 AM on April 5, 2011


Once upon a time, in HotRod magazine of all places, I read a very thoughtful article which discussed the "content and transfer" of information displays (like dashboards). His two examples were telling time by looking at the sky (good to within about 4 hours, so crappy content, but very efficient transfer) to the very first LED digital watches which were super accurate but you had to press a button and be in a cave to see the time (high content, terrible transfer).

I think that's what drives this decision. For most gauges, at least back in the day (and old engineering best practices die hard), the middle portion of the gauge was the most accurate and that the needle is visually close to straight up at around the maximum US speed limit, where it's arguably most visible.
posted by Kid Charlemagne at 4:48 AM on April 5, 2011 [1 favorite]


[few comments removed - folks, this isn't the "let's talk about speeding" thread or about needling people from other countries, thanks.]
posted by jessamyn at 7:39 AM on April 5, 2011


The 85 mph speedometer was the result of government mandate (along with the shift light and seatbelt interlock that wouldn't let you start the car unless your belt was done up).

You are right indeed, and I completely forgot about the shift light. But how can one forget about the early '90s seatbelt on a track? I think the proper term was automatic seatbelt; Mrs. Chosemerveilleux calls them "fucking annoying."
posted by chosemerveilleux at 3:58 PM on April 5, 2011


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