Pet Peeve: Tachometers

[Quattro Pete]

Originally Posted By: spackard
Well, how's about the European fuel gauge -
0/1 (= empty)
1/2 (= half full)
1/1 (= full)

Mine just says 0 instead of 0/1.

And the C300 says:
1
1/2
0

Quote:

Would it really make sense to put:
0.0
0.5
1.0

I'd prefer 0, 50%, 100%.

 

[friendly_jacek]

I actually remember seeing gas gauges that showed liters. They are rare though.

 

[ksp7498]

I think my biggest complaint with gauges these days is how they go far higher than they need to. The speedometer in our 2008 jetta went to 160. Seriously, 160 for a 170hp sedan? It's especially baffling because the official top speed is only like 130. Similarly, our Fit's speedometer goes to 140 and there is no way in heck it could go that fast. Maybe 100 with a tailwind. I assume they do this so the car "looks" faster, but the end result is that a large portion of the speedometer is completely useless. I guess people have negative associations with the old 85mph speedometers from the 80's so now it's gone too far the other way.

 

[Quattro Pete]

Originally Posted By: ksp7498
I assume they do this so the car "looks" faster,

I think it has to do with the fact that most analog gauges are the most accurate in the center portion of the scale. So they want to make sure the usable speeds are placed there.

Not sure if this is still true today since all those nice analog looking displays are fed signal from a computer anyway, so the computer could easily correct the issue.

 

[OVERKILL]

Originally Posted By: Quattro Pete
My big pet peeve is coolant temp gauges with massive dead ranges in the middle. For example, this one won't budge from 12 o'clock even if the temp fluctuates from 75C to 115C (167F to 239F).

That's interesting, because the one on my M5 is very relative to temperature and moves all over the place.... Mind you, I also have an oil temperature gauge, so it appears that BMW dampens the non-M car gauges eh? I didn't know that

 

[OVERKILL]

Originally Posted By: spackard
Well, how's about the European fuel gauge -
0/1 (= empty)
1/2 (= half full)
1/1 (= full)

It should be:
0/2
1/2
1/2
So I can see I either have zero of something, one of something, or two of something. Quit switching the denominator.


Nope, if you remember fractions from grade school you should recall that you always reduce the fraction. So 2/2 reduces to 1/1 (or becomes 1) which is why it is displayed that way.

And this second part is also why Quattro's point is relevant, as not all Euro marques do it the same. Mine is 0, 1/2 and then 1/1. And my tach, like his, is 1/Min x1000.

 

[Tegger]

Originally Posted By: Hokiefyd
Why, then, are most tachometers labeled RPM x 1000?... Does anyone here own a tachometer that is labeled correctly?

My Honda's tach is labeled x1000r/min, which is correct.
The Toyota tachs I've seen all say x1000RPM, which is correct.
My old Mazda's tach said x1000rpm, which is correct.

 

[Hokiefyd]

Originally Posted By: Tegger
Originally Posted By: Hokiefyd
Why, then, are most tachometers labeled RPM x 1000?... Does anyone here own a tachometer that is labeled correctly?

My Honda's tach is labeled x1000r/min, which is correct.
The Toyota tachs I've seen all say x1000RPM, which is correct.
My old Mazda's tach said x1000rpm, which is correct.


None of those is correct. Your tachometer labels tell you that the indicated numbers are x1000 the actual engine speed. If your tach shows 2, then what the gauge is saying is 2 is x1000 the actual RPM. It's telling you that the RPM is 0.002 revolutions per minute, which is not correct.

Another member is correct: the tachometer label most commonly seen today gives you the formula to calculate the engine speed based on the gauge reading, rather than giving you the corrected engine speed (which is divided by 1000 to show on a tachometer with single digits). This is not consistent with other gauges; every other gauge (such as speedometer) correctly gives the units displayed.

If they want to give a formula to calculate RPM, an equation, then they should label it such, like:

x1000 = r/min (or RPM)

That would be correct. You take the gauge reading, multiply it by 1000, and that equals the RPM. Most tachometer labels are missing a critical equals sign (if they want to label it that way).

I find it interesting how at least one tachometer was labeled correctly in the past (the photo of the Chevelle I posted earlier), but I haven't seen one since that is technically correct.

 

[Hokiefyd]

To put it another way, common convention for gauge labeling is:

[gauge reading equals] "label"

So, [speedometer gauge reading equals] MPH. Nobody puts "= MPH" on a speedometer; the leading "=" is implied.

[gauge reading equals] x1000 r/min is not correct. It's telling you that the gauge is reading equals 1000 times the r/min which is not accurate. That's why it annoys me; it's inconsistent with other gauges.

 

[Quattro Pete]

Yeah, it seems the concept has been lost by everyone these days, even Ferrari:

And then there is Porsche - they've decided not to include a label on the tacho altogether.

 

[Hokiefyd]

Exactly; that Ferrari's tach does NOT display RPM x 1000; it displays RPM / 1000! I also see that Porsche hasn't reduced its fraction properly (fuel gauge).

Some are on the "save the manuals" campaign. I need to start a "save the correct gauge labeling" campaign!

A little light humor for a Monday afternoon.

 

[Quattro Pete]

Originally Posted By: Hokiefyd
I also see that Porsche hasn't reduced its fraction properly (fuel gauge).

Ha! I'm surprised they haven't labeled it as 16/32 and 32/32 for the US market.

 

[Nick R]

I always thought this was simple. It says 1,2,3,4,5 and RPM x1000.
It's saying Revolutions Per Minute, and to multiply by 1000 to get the actual rpm.
Makes perfect sense to me. People are stupid. They aren't going to understand it the other way.

1x1000 = 1000
2x1000=2000
3x1000=3000
and so on.

 

[Quattro Pete]

Originally Posted By: Nick R
People are stupid. They aren't going to understand it the other way.

I would venture a guess that most people don't even look at the label. They wouldn't have noticed even if it said "Peanut butter jelly time".

 

[davebarnum]

'x1000 = r/min (or RPM)' //INCORRECT. Remember algebra? Multiply both sides by 'min.'

minute x 1000 = revolutions //also INCORRECT. Because...

This is NOT an equality. This is an indicator of engine speed. Honda, Toyota and Mazda tachometers are labeled correctly.

 

[supton]

Originally Posted By: Quattro Pete
My big pet peeve is coolant temp gauges with massive dead ranges in the middle. For example, this one won't budge from 12 o'clock even if the temp fluctuates from 75C to 115C (167F to 239F).

I like to call those "idiot gauges". No better than an idiot light, really.

 

[Quattro Pete]

Originally Posted By: supton
I like to call those "idiot gauges". No better than an idiot light, really.

Correct.

 

[javacontour]

Actually, isn't the one in the picture INCORRECT.


It says RPM/10. Don't gauges list the unit of measurement?

So if the needle reads 10 then according to the units listed on the gauge, is it turning 1 RPM?

I think we know what they meant to say. But that's because we are car enthusiasts. Grandma may get confused and take that 30 as speed as we've seen described here.

Originally Posted By: Hokiefyd

 

[davebarnum]

Originally Posted By: Hokiefyd
Originally Posted By: Tegger
Originally Posted By: Hokiefyd
Why, then, are most tachometers labeled RPM x 1000?... Does anyone here own a tachometer that is labeled correctly?

My Honda's tach is labeled x1000r/min, which is correct.
The Toyota tachs I've seen all say x1000RPM, which is correct.
My old Mazda's tach said x1000rpm, which is correct.


None of those is correct. Your tachometer labels tell you that the indicated numbers are x1000 the actual engine speed. If your tach shows 2, then what the gauge is saying is 2 is x1000 the actual RPM. It's telling you that the RPM is 0.002 revolutions per minute, which is not correct.

Another member is correct: the tachometer label most commonly seen today gives you the formula to calculate the engine speed based on the gauge reading, rather than giving you the corrected engine speed (which is divided by 1000 to show on a tachometer with single digits). This is not consistent with other gauges; every other gauge (such as speedometer) correctly gives the units displayed.

If they want to give a formula to calculate RPM, an equation, then they should label it such, like:

x1000 = r/min (or RPM)

That would be correct. You take the gauge reading, multiply it by 1000, and that equals the RPM. Most tachometer labels are missing a critical equals sign (if they want to label it that way).

I find it interesting how at least one tachometer was labeled correctly in the past (the photo of the Chevelle I posted earlier), but I haven't seen one since that is technically correct.


'x1000 = r/min (or RPM)' //INCORRECT. Remember algebra? Multiply both sides by 'min.'

minute x 1000 = revolutions //also INCORRECT. Because...

This is NOT an equality. This is an indicator of engine speed. Honda, Toyota and Mazda tachometers are labeled correctly.

 

[oldhp]

Bah........if it ain't whinin'......it ain't time to shift!!!!!!