That Motor Trend 1 foot rollout

[D.E.]

Roll-out dates from a time before GPS timing equipment when a wheel-based timer was used and it couldn't measure accurately without roll-out. We (people who test cars professionally, which I did for over a decade) still use roll-out for continuity. And yes, it's around .2 to .3 seconds for the first foot for most quick cars. When I used a VBox to time our P85DL, 0-60 was 2.9 seconds with roll-out, 3.1 without. I suspect Tesla, like GM, uses roll-out for all stated times.

You were a professional car tester and couldn't figure out a way to measure 0 to 60 times without introducing a 0.2-0.3 second error? If that wheel timer won't do it, use something else. I'm about as far from a professional car tester as you can get but I can do a better job of it than that. Let me help you out.

Set up a movie camera on the vehicle bumper aimed at a tape on the ground. Set the frame speed to slow motion at 4:1. That will give you a frame rate of 120 frames per second. Put your driver in the driver's seat, start the movie camera, and get him to maximally accelerate.

You'll have a record of time and distance traveled. Find the first frame with movement and use the preceeding frame as the 0 start. Each frame represents 8.33 milliseconds. 1 MPH is 17.6 inches per second. 60 MPH is 1056 inches per second. At a frame rate of 120/sec, the first frame that shows 8.8 inches travel from the previous frame is your 60 MPH point. Count the elapsed frames and that will give you your elapsed time.

This should get you within 17 milliseconds. Do 10 runs. Toss out the high and the low values and take the RMS of the remaining 8 values.

 

[mike-415]

You were a professional car tester and couldn't figure out a way to measure 0 to 60 times without introducing a 0.2-0.3 second error? If that wheel timer won't do it, use something else. I'm about as far from a professional car tester as you can get but I can do a better job of it than that. Let me help you out.

Set up a movie camera on the vehicle bumper aimed at a tape on the ground. Set the frame speed to slow motion at 4:1. That will give you a frame rate of 120 frames per second. Put your driver in the driver's seat, start the movie camera, and get him to maximally accelerate.

You'll have a record of time and distance traveled. Find the first frame with movement and use the preceeding frame as the 0 start. Each frame represents 8.33 milliseconds. 1 MPH is 17.6 inches per second. 60 MPH is 1056 inches per second. At a frame rate of 120/sec, the first frame that shows 8.8 inches travel from the previous frame is your 60 MPH point. Count the elapsed frames and that will give you your elapsed time.

This should get you within 17 milliseconds. Do 10 runs. Toss out the high and the low values and take the RMS of the remaining 8 values.

At Car and Driver, we tested hundreds of cars per year (they still do). Cars are tested all over the globe and often with a single staffer on premises. Your method, while theoretically possible, wasn't practical prior to today's super-precise GPS given the conditions and time with each vehicle.

 

[DarkMatter]

This should get you within 17 milliseconds. Do 10 runs. Toss out the high and the low values and take the RMS of the remaining 8 values.

And then you will have numbers which are very precise, and cannot be compared to any numbers provided by other manufacturers or auto journalists. Sometimes inertia wins. The professionals do it their way for a reason.

 

[Pezpunk]

they've been doing it that way forever. if they changed their methodology, you would no longer be able to compare their results to any of their previous results.

 

[D.E.]

they've been doing it that way forever. if they changed their methodology, you would no longer be able to compare their results to any of their previous results.

That's absurd.

0-60 is the time it takes to go from standstill to 60 MPH. That is why it is called 0-60.

If a company claims a 0-60 time, that car should be able to accelerate from a standstill to 60 MPH in that time. If it cannot, then the claim is false. It isn't true because everyone else does it.

If one company lies and another is truthful, it doesn't follow that the truthful company should lie as well.

 

[DarkMatter]

The only way that's happening is if everyone retests for new numbers. Not going to happen, if nothing else because the car manufacturers don't want their numbers to get suddenly worse. (on top of that the ICE numbers are usually for doing a torque start with the brakes, which is even more deceitful as it takes preparation to have happen in real driving)

 

[malcolm]

This situation has only arisen with the advent of the performance electric drivetrain.

High levels of torque from zero rpm simply haven't existed before.

So what if you have to add 0.2-0.3 onto Tesla's 5-60 times?

I suspect you would have to add even more onto the best times for Mercedes, BMW, Audi et al.

So there will never be official figures published to confirm this, but it doesn't matter.

There's the grin-ometer instead

 

[stopcrazypp]

You were a professional car tester and couldn't figure out a way to measure 0 to 60 times without introducing a 0.2-0.3 second error? If that wheel timer won't do it, use something else. I'm about as far from a professional car tester as you can get but I can do a better job of it than that. Let me help you out.

Set up a movie camera on the vehicle bumper aimed at a tape on the ground. Set the frame speed to slow motion at 4:1. That will give you a frame rate of 120 frames per second. Put your driver in the driver's seat, start the movie camera, and get him to maximally accelerate.

You'll have a record of time and distance traveled. Find the first frame with movement and use the preceeding frame as the 0 start. Each frame represents 8.33 milliseconds. 1 MPH is 17.6 inches per second. 60 MPH is 1056 inches per second. At a frame rate of 120/sec, the first frame that shows 8.8 inches travel from the previous frame is your 60 MPH point. Count the elapsed frames and that will give you your elapsed time.

This should get you within 17 milliseconds. Do 10 runs. Toss out the high and the low values and take the RMS of the remaining 8 values.

How many cameras back in the day before GPS can shoot 120 fps (especially one that can be mounted on a bumper)? Even today this is a premium feature. Most shoot 60fps max (some 30fps).

Your suggestion is also hard to set up even if possible and you would need someone to review the footage to do the calculation, and having to that many runs simply isn't practical.

As long as the convention is known, I don't see any issue with it. It allows C&D to do issues like this one without having to do any conversions:
Car and Driver

Do note also that 0-60 with 1 foot rollout is not the same as a 5-60mph run. The numbers are completely different between a car at a 5mph roll doing a 60mph run, vs one that started at 0mph, but measured at ~5mph.

 

[AnxietyRanger]

or an 85kwH Tesla that gives you less than 80KwH energy for propulsion.

Thanks for reminding us, that was one are where as @sorka mentioned Tesla was trying to make the big battery price premium look justified. The 60 kWh and 75 kWh batteries actually were close to the real capacity or even rounded down, while 85/90 were unmathematically rounded up...

Once again Tesla creating an apples and oranges situation in their specs... to artificially promote the high-premium product...

@wk057 called them out on this and they cleaned their act since the 100 kWh.

Less BS is better.

 

[snd92]

Before P85D was released there were no mentioning about rollouts. Every TMS (60, 85, P85) performed better than stated by Tesla. Later we see that a pyro/Ludi fuse was needed to obtain 0-60 times as advertised for P85Ds.

This concludes that Tesla f'd up the claimed performance and fixed it with by adding RL. Also, they needed to continue with RL on P90D(L) and P100D(L) to show "improved" numbers. Clever

 

[AnxietyRanger]

So what if you have to add 0.2-0.3 onto Tesla's 5-60 times?

One issue for me is the loss of traction benefit in accelerating, especially meaningful in 0-60. Overall such a policy makes lighter RWD cars look better than their real-life performance. That's a general concern IMO for AWDs.

And of course in the case of Tesla is makes Teslas look better than their competition in Europe artificially.

Tesla did not have to use the 1 foot rollout originally in their Performace specs. AFAIK they only started (ironically) with the P85D...

IMO Teslas already have such great specs they do not need to artificially inflate them. It is IMO very unfortunate that they have in many spec areas (HP, kWh, 0-60...).

suspect you would have to add even more onto the best times for Mercedes, BMW, Audi et al.

As far as I know this 1 foot rollout is completely an American thing. So, no.

 

[AnxietyRanger]

Before P85D was released there were no mentioning about rollouts. Every TMS (60, 85, P85) performed better than stated by Tesla. Later we see that a pyro/Ludi fuse was needed to obtain 0-60 times as advertised for P85Ds.

This concludes that Tesla f'd up the claimed performance and fixed it with by adding RL. Also, they needed to continue with RL on P90D(L) and P100D(L) to show "improved" numbers. Clever

Yeah, the less BS of the pre-P85D days was simply better.

 

[snd92]

Yeah, the less BS of the pre-P85D days was simply better.

In Norway, at least for 120 owners, this BS was solved by a settlement agreement

 

[Pezpunk]

That's absurd.

0-60 is the time it takes to go from standstill to 60 MPH. That is why it is called 0-60.

If a company claims a 0-60 time, that car should be able to accelerate from a standstill to 60 MPH in that time. If it cannot, then the claim is false. It isn't true because everyone else does it.

If one company lies and another is truthful, it doesn't follow that the truthful company should lie as well.

apparently you completely missed my point. Either go back and read it again, or read this: Motor Trend has been doing it this way forever, and continually compares their results to previous tests. changing their methodology would render their new tests completely incomparable to their old ones.

there are not multiple companies involved here.

 

[AnxietyRanger]

apparently you completely missed my point. Either go back and read it again, or read this: Motor Trend has been doing it this way forever, and continually compares their results to previous tests. changing their methodology would render their new tests completely incomparable to their old ones.

there are not multiple companies involved here.

The weird thing is that a car company would use the method of some magazine... Tesla refers to Motor Trend specifically in their disclaimer.

Seems kind of obscure, really.

Had they stated something like "as per U.S. industry standard, first foot is deducted" would make more sense IMO...

 

[D.E.]

H

Do note also that 0-60 with 1 foot rollout is not the same as a 5-60mph run. The numbers are completely different between a car at a 5mph roll doing a 60mph run, vs one that started at 0mph, but measured at ~5mph.

If that car is doing 5 MPH at the start of timing what difference does it make? If you are suggesting the car will perform differently due to engine output, starting from a steady roll at 5 MPH vs maximally accelerating, I agree. There are a lot of other factors in the two scenarios. There is tire flexion, suspension loading, center of gravity differences, exhaust pressures, turbo lag, you name it. Those differences are irrelevant to this conversation in that any start that involves the car moving at the start of timing is not a 0-60 time, regardless of the techique used to achieve that nonresting start.

One of the problems is each car will have a different speed at the end of that untimed foot. So the rollout inclusion will start timing with some cars already moving at 2 MPH and others at 6-8 MPH.

I have no problem with ICE cars maximizing torque at the start, just that they should start from standstill. The fact that the cars are not usually driven this way is irrelevant. The car should be able to reach 60 MPH from a standstill in the claimed 0-60 time. I also submit that it should be at 70 degrees, dry flat road, sea level, car with factory equipment, and whatever tires are normally supplied with the vehicle. Any deviations or corrections if necessary, should be disclosed along with the claimed time.

So you are right, the steady 5 MPH start vs the maximal acceleration through the 5 MPH start will be different. Both are invalid for a 0-60 measurement.

 

[D.E.]

apparently you completely missed my point. Either go back and read it again, or read this: Motor Trend has been doing it this way forever, and continually compares their results to previous tests. changing their methodology would render their new tests completely incomparable to their old ones.

there are not multiple companies involved here.

They can do any sort of consistent rollout timing they want if they want to compare. They are not 0-60 times so they should not claim that they are.

As far as multiple companies go, we have Motor Trend involved and we have Tesla involved. That's two right off the bat.

I don't think I missed your point at all. You are suggesting this flawed measurement is somehow valid because "Motor Trend has been doing it this way forever, and continually compares their results to previous tests". Historical mismeasurement doesn't validate the claim the car can reach 60 from standstill when it won't. They can still do rollout testing and compare rollout results. They just should not claim these are 0-60 results because they are not. Tesla should not claim these as zero to sixty results. Their cars cannot go from zero to sixty in these times. To purport that their cars can is simply a lie.

 

[AnxietyRanger]

Hear hear, @D.E.

 

[stopcrazypp]

If that car is doing 5 MPH at the start of timing what difference does it make? If you are suggesting the car will perform differently due to engine output, starting from a steady roll at 5 MPH vs maximally accelerating, I agree. There are a lot of other factors in the two scenarios. There is tire flexion, suspension loading, center of gravity differences, exhaust pressures, turbo lag, you name it. Those differences are irrelevant to this conversation in that any start that involves the car moving at the start of timing is not a 0-60 time, regardless of the techique used to achieve that nonresting start.

One of the problems is each car will have a different speed at the end of that untimed foot. So the rollout inclusion will start timing with some cars already moving at 2 MPH and others at 6-8 MPH.

I have no problem with ICE cars maximizing torque at the start, just that they should start from standstill. The fact that the cars are not usually driven this way is irrelevant. The car should be able to reach 60 MPH from a standstill in the claimed 0-60 time. I also submit that it should be at 70 degrees, dry flat road, sea level, car with factory equipment, and whatever tires are normally supplied with the vehicle. Any deviations or corrections if necessary, should be disclosed along with the claimed time.

So you are right, the steady 5 MPH start vs the maximal acceleration through the 5 MPH start will be different. Both are invalid for a 0-60 measurement.

That 5mph point is just a side point. The more important point is the first half.

They can do any sort of consistent rollout timing they want if they want to compare. They are not 0-60 times so they should not claim that they are.

As far as multiple companies go, we have Motor Trend involved and we have Tesla involved. That's two right off the bat.

I don't think I missed your point at all. You are suggesting this flawed measurement is somehow valid because "Motor Trend has been doing it this way forever, and continually compares their results to previous tests". Historical mismeasurement doesn't validate the claim the car can reach 60 from standstill when it won't. They can still do rollout testing and compare rollout results. They just should not claim these are 0-60 results because they are not. Tesla should not claim these as zero to sixty results. Their cars cannot go from zero to sixty in these times. To purport that their cars can is simply a lie.

Maybe you can get a lot of Europeans to agree with you (as they never use rollout in their numbers), but most Americans, especially if they have any familiarity with American performance cars, will just go "meh", as this is the way it has been done since forever (not just by Motor Trend, but also by Car & Driver and Road & Track).

0-60 with 1-foot rollout is also known as "Initial Vehicle Movement" (IVM) to 60. GM uses this term as does some official research papers (here's one from ANL):
"Figure 1 shows the Initial Vehicle Movement (IVM) time (the time at which the vehicle moves one foot) to the time at which the vehicle reaches 60 mph as a function of the vehicle specific power"
http://www.autonomie.net/docs/6 - Papers/Light duty/fuel_econom_sensitivity.pdf

You can write a letter to the editor to all three publications and complain if it really offends you.

 

[AnxietyRanger]

I can just see Clarkson making a joke of this: "The only thing Americans race is a straight line and they can't even measure that properly!"

But in all seriousness, press aside (which IMO is rather pointless when discussing manufacturer specs), are the 0-60 times in American car's official specs always with the 1 foot roll-out? If so, why does Tesla refer to Motor Trend in its specs - seems odd referring to a magazine...