I love top-shelf pedantry. Minor, nonsensical characteristics in a given car can make or break it for me. The minutia can heighten or diminish the experience of driving and operating a machine. I have a long list of features that I need to call out at some point,  but today I present the greatest debate of them all: What is the correct way to scale gauges? 

Chris Rosales

If you don’t understand what I mean, most gauge clusters in a car usually have three to four gauges indicating engine speed in revolutions per minute (RPM), vehicle speed in miles per hour (mph), fuel level, and often coolant temperature. Although the basics are understood by most, there are interesting variations between how each of them are scaled.

What I mean by scaling is how the numbers or symbols are presented for each bit of information. Gas gauges are the biggest examples, especially when comparing European cars versus Asian and American cars. For whatever reason, the latter two always go for a classic E for empty to F for full scale. Europeans, however, choose to do math instead and use fractions from 1 to ½ to 0. Rarely, in the United States at least, is there a gallon scale. A liter scale is fairly common overseas, however.

Then there is the issue of how rpm is expressed on a tachometer, and every automaker chooses this without any real patterns across regions. Toyota and Lexus use x1000 rpm. Modern Volkswagens and some Euros go for a cryptic 1/min x1000. Honda does a x1000r/min. And that is only for cars with a single digit on their tachs. Some go for a x100 scale that leads to a 10 versus a 1 on the gauge. The McLaren F1 sidesteps all of this nonsense and represents four digits on its tach with a x1 scale. Wildest of them all, the post-1985.5 Porsche 944 doesn’t even declare its RPM scaling. Perhaps it only revs to 650 rpm. Perhaps.

Coolant gauges are a little better, with some doing a C to H scale (for cold to hot) and other using a true temperature scale. The truth about coolant gauges is much more sinister: Most of them lie anyways. Coolant temperature gauges are usually programmed with a buffer that shows the gauge at its optimum temperature while it fluctuates wildly. This is to keep consumers unconcerned, but the coolant gauge argument is for another time.

Chris Rosales

So the question I pose is this: Which way is correct? I feel like x1000 rpm is too simple and I kind of like the math of 1/min x 1000 that adds a layer of complexity to the machine. I also enjoy the Euro fuel gauges because F to E also feels like it is designed for people who are about to start taking their pension. I find the fact that a full tank of gas is “1” to European engineers entertaining. 

My perfect gauge cluster uses the 1/min x 1000 for the tach, 1 to 0 for fuel, a temperature scale represented in degrees fahrenheit, and a speedometer with MPH and KPH. What’s your vibe?

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