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Speedometer Inflation

bumpybumpy Posts: 4,435
Is there any good reason for cars to have such ridiculously high numbers on the speedo?


The only way a Mini Cooper could ever see 150 mph is going downhill with a tailwind while being bump-drafted by a C63 AMG.


  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,587
    Well it's limited to 139 mph but with speed errors + or 1 say 5%, it might not be THAT far off from reality. I think it would take a while to get there however, which is true for most cars as they approach theoretical top speed. Once aerodynamics kicks in, every new inch of speed requires a more HP than the last inch of speed.

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  • andre1969andre1969 Posts: 23,040
    I guess if nothing else, it beats the heck out of the old days when speedometers were limited to 85 mph. Although back then, I guess there were plenty of cars that would have had trouble doing even that.
  • andys120andys120 Loudon NHPosts: 18,650
    My '86 Mustang 5 Liter had no trouble pinning the needle against the 85mph stop. :blush:

    2000 BMW 528i, 2001 BMW 330CiC

  • bumpybumpy Posts: 4,435
    There was one time I did manage to get the needle on the Citation to slide past the "85" on the strip speedo before I ran out of straight road, though I wouldn't presume that the car was actually going faster than 85 mph.
  • 210delray210delray Posts: 4,722
    That Mini photo illustrates the many problems with today's speedometers. Though huge in diameter, only slightly more than half of the space is occupied by legal speeds (up to 80 mph). Then, there's not enough room to label every 10 mph increment, as was always done in the old days when speedos seldom maxxed out beyond 120 mph. Last, there aren't even hash marks for 5 mph intervals, so it makes it hard to go 25, 35, 45 mph without looking too long at the dial.

    If I ran the world, I'd have speedometers top out at about 100 mph, with each 10 mph increment marked and hash marks at every 5 mph increment (but no more).
  • oldharryoldharry Posts: 413
    GPS units tell us the truth about real speed, and distance traveled.

    One frequently praised car company had to extend warranties as a result. :D
  • habitat1habitat1 Posts: 4,282
    If I ran the world, I'd have speedometers top out at about 100 mph, with each 10 mph increment marked and hash marks at every 5 mph increment (but no more).

    If I ran the world, everybody would use the guage cluster / instrumentation in my 911S (997 model). Large 8,000 rpm tach right in the middle with a digital speedometer readout inside the dial, The smaller 200 mph analog speedometer dial is to the left. I rarely look at it. I think it's almost unnecessary - perhaps only there as a backup or from "tradition". The other guages - oil temp, water temp, oil pressure, fuel level - are perfectly positioned.

    Even my former Honda S2000, with its large horizontal digital LED tachomter and digital speedometer readout was better than any analog dial, no matter how limited it is and how many hashmarks it has. Plus, the Honda was deadly accurate. I'd match it abainst a GPS on a laptop computer and on a highway cruise, its speedometer would change form 64 to 65 at exactly the point the GPS readout on the laptop went from 64.9 to 65.0.

    P.S. Where the heck is the tachometer in the Mini? Not having that dead center would be my biggest complaint. I guess you can tell I only drive manual transmissions.
  • bumpybumpy Posts: 4,435
    Where the heck is the tachometer in the Mini?

    Centered behind the steering wheel.
  • fintailfintail Posts: 41,905
    Here's a funny tangent..exhaust pipe inflation. I notice dual exhausts (or at least tips) trickling down to many cars that are anything but performance models. Is it really necessary?
  • bumpybumpy Posts: 4,435
    That's an NVH thing. They're really just a single exhaust with two mufflers and two outlets, split right around the back wheel.
  • fintailfintail Posts: 41,905
    I have to think there's somewhat of an image issue as well. Even non-car people recognize that dual exhaust usually means more power. Funny thing, my E55 has outlets only on one side...but I am pretty sure it is faster than the rental-spec looking Sonata I saw with duals.
  • bumpybumpy Posts: 4,435
    Large single outlets flow better at the cost of more noise. The V6 Sonata isn't exactly a slouch, if you believe that story about the guy in Arizona.
  • habitat1habitat1 Posts: 4,282
    That is either the worlds best or worlds luckiest driver. Topping out at 147 in a Sonata must have meant he had his pedal to the metal for at least a ful 40-60 seconds. And maintaining control of a front wheel drive car at that speed must have meant he had picked an extremely straight 4-5 mile stretch of pavement, or he is a candidate to run the land speed record in Steve Fossett's rocket car. The slightest twitch of the steering wheel at that speed could have produced a crash in which they could have used Glad Sandwich Bags to pick up the body parts.
  • ny540i6ny540i6 Posts: 518
    I've got a couple thoughts/opinions/theories about speedos and what they say/look like:

    first: Analog/digital - I prefer Analog, probably for tradition, even though digital is simpler, easier to read etc, etc. Same reason I prefer analog watches (until I try a quick glance at either my watch, or my cell phone).

    second: in my opinion, analog gives a greater sensation of speed - the needle is positioned someplace on an absolute sweep - if it is "over there" I must be going fast. This of course, leads to a problem with many speedos that top out at 150+ mph... the "sweet spot" on the speedo is around 80. As an example, in my car the speedo goes to 155, and the car will do 155+. However, if I glance at the speedo, 80mph is just around straight up. Mentally (for me) 60 looks like where 40 should be, etc.

    third: I think that for many manufacturers there is still a catering to the adolescent in many buyers - I remember as a kid bragging to friends about our Olds Cutlass with the 120 mph speedo - after all, if GM said it could go 120.....

    fourth: Mass production - some cars are sold internationally, so if the car is capable of speeds that are legal elsewhere, too expensive and complicated to produce speedos for different markets

    fifth: Legal - If the speedo tops out at 100, but the car can do 110, who gets to answer the product liability questions if I hit something. And of course - who gets to retrain all the highway police whose first question is "Do you know how fast you were going?" ;)
  • nippononlynippononly SF Bay AreaPosts: 12,726
    Naw, the follow-up to that story is that the guy went to court with testimony from Hyundai itself that the car was incapable of doing that speed, and the ticket was thrown out.

    And I have taken my FWD RSX up to 130 (indicated) at which speed it was remarkably stable-feeling. But then, I am not in the habit of twitching a lot. And in reality that was probably actually 125 mph, as the speedo in that one also over-read by 3% or so.

    2014 Mini Cooper (stick shift of course), 2016 Camry hybrid, 2009 Outback Sport 5-spd (keeping the stick alive)

  • starrow68starrow68 Posts: 1,142
    Here, everyone presumes that driving on public roads with published speed limits
    is the only possiblity. I spend many weekends and some week days running
    around road courses like Laguna Seca, Sears Point (Infineon), Thunderhill, Button-
    willow and Reno-Fernley Raceway. Even get to Spring Mountain MSP in Pahrump,
    NV on occasion. There are a hundred or so other folks with mostly street cars that
    they drove to the event and most drive home at the end of the day. BTW, a well set
    up MiniS on DOT-R tires can be as fast as a C5 Corvette on street tires. Even the
    non-race cars will get up to 150mph at some points on various tracks, while my
    C5 Coupe has never gone beyond 135 and usually tops out between 105 and 120.
    Learning to control what is capable of doing the numbers in front of you isn't a bad
    idea for anyone.

    BTW, my GPS is within a couple tenths of matching my Heads Up Display speed.
  • caazcaaz Posts: 209
    Hey.... Quit making fun of my dual exhaust on my metro....I swear it makes it go faster.

    P.S. i'm in Ca. & AZ. every week... Az has the nicest smoothest roads and freeways ever....I can see the Sonata man achieving 147 no problem... I did 139 in my 740i between Lake Forest Drive & El Toro Road, which is only 3/4 mile apart... so im sure 3 or 4 miles would work in Az. BTW.. Az's Freeways are much better than Ca. roads

  • habitat1habitat1 Posts: 4,282
    You make some good points. I also generally prefer analog to digital. But I have also noticed that 95% of the time I am driving "enthusiastically", I am glancing down at the tachometer, not the speedometer. For the reasons you stated, I would NEVER want a tachometer that was merely a digital readout of the RPM's. It is much easier to anticipate and shift before redline when you have a the visual aid of a needle sweeping around towards it. In the case of my former S2000, the extended LED readout accomplished the same thing.

    But checking out the analog speedometer on my 911, which tops out at 200, you need a magnifying glass to see the difference between 65 and 70. So if I'm trying to shave it close to the "ticket limit" in cruise control on the highway, I'm using the digital mph readout in the center of the tach, not the analog speedometer. Yet I would be the first to complain if Porsche took the analog speedometer completely away, as, from an aesthetic standpoint, the 911 has the most attractive guage cluster I've seen. Just like I don't think Rolex will be dropping analog in favor of a digital face. It's not about function as much as looks.
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,425
    0 to 25 = Green

    25 to 50 = Amber

    50 to 110 = Red

    All the above in the '46 Chrysler Windsor.

    (Some claimed that above 110 the radio played, "Nearer My God To Thee" ;)
  • fintailfintail Posts: 41,905
    Sounds like the speedometer on my fintail, which as with all of them is a veritcal stripe like a thermometer rather than a round or horizontal needle.

    At low speeds ca. <25mph, it is yellow. From about 25-40 it is yellow-red striped, and from 40+ it is red. It reads to 120, but I think the car is only good for about 110.
This discussion has been closed.