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Why anyone needs a car that does 155 mph or a roof rack good for 140 mph

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Actually the car is limited to 155mph
They Who Know figured this was the sensible speed to limit it at.
But who actually wants to drive at 155? Maybe those who want to drive fast would drive faster if it wasn't limited to 155. And those who want to drive slower...nearly 100 % of the population..want to drive slower. Maybe a top speed of half that would suit 99%. Or 2 std deviations.

I rarely go over 125 mph. And only when I am being an idiot.
I understand Elon said the roof rack on MX is good for, no, guaranteed for 140 mph.
Why would you drive with a roof rack at 140? I suppose I might have done when I was a bigger idiot than I am now.
Would you carry kayaks up there? 2x4s? 4x8 ft. plywood? Mother-in-law?


Perhaps it is just to compete with others in the market, but the same question applies. Why?

Perhaps it is because they can. (build a car that does 155).
But since they can possibly get much greater speed from S and X, why limit it so it looks like you can 'only' do 155?

I think there is one basic area you can legally do those speeds in Australia. (Northern Territory). And Germany. Where else? Antarctica?
Perhaps the cars are designed to be sold to idiots.

BTW, in 6 months on the 'other' forum, I never copped a McLary bashing. Idiot, lol. What he missed.
 
At car shows I do get questions about what the top speed it. It's apparently important to those folks who equate top speed with being better. I don't really get this myself, but I fully get that if the top speed isn't very high, sales will suffer if the car is a high end car.
 
Tesla needs a car that can go 155 because they are trying to draw buyers from Mercedes AMG and BMW M cars who will look at that specification carefully, even if they never actually drive that fast. 155 is the limit for most sports cars because of tires - only a very few highly specialized tires can handle the heating above this speed for any length of time.
Walter
 
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It's a fair set of questions to ask, but I would suggest the answer lies in the same field where you'll find the answer to "Why would anyone want a car that is strong enough to stack five of them atop one another?".

If I have a roof rack that's good to 140mph, that means that I needn't worry about it....consider it...even think about it at 80.

And so on.
 
Tesla needs a car that can go 155 because they are trying to draw buyers from Mercedes AMG and BMW M cars who will look at that specification carefully, even if they never actually drive that fast. 155 is the limit for most sports cars because of tires - only a very few highly specialized tires can handle the heating above this speed for any length of time.
Walter

While that used to true, things have changed. Cars that go over 150mph became common starting in the 1990's, even downright cheap.
It used to be that a ZR designation was the catchall for high speed tires (up to 150), but now there wide selection of tires for today's faster cars.
W - rated are <168mph, Y - <186, and (Y) past 186. Now that dozens of affordable cars can exceed 186, you should always replace your OEM tires with the same OEM tire if you intend on going over 186, and especially if you are going past 200mph.

If there are cars that go over 200, then why did they stop the scale at Y? They had already used Z a long time ago. The parentheses thing for Y rating is a catchall. It is what you see on Bugatti Veyron.

Why so many crazy fast cars today? Since CAFE standards made cars more aerodynamic, and ICE engines get good MPG at low RPM, unless they put an electronic limiter on a car, they go pretty fast up top. You can't go 0-60mph quickly, have tall mileage gearing, and good aero, without the ability to go really fast up top.

The 155mph is a "magic number" and is where a lot of cars are capped at due to european influence (250 kmh), and so is 186mph (300kmh). Tire numbers are 149, 168, 186mph.
 
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(Original OP)
Lots of good answers, but no answer yet?
Is there anyone here who has driven MS or MX at 155 (250 kph) or the MX with a roof rack at 140?

I have. I am located in Europe. I have taken my P85D to the track and I have been at the German Autobahn several times where it is legally possible to max the car out at certain locations. The max speed of my P85D is 249 kph. Above 235 kph the rear motor is put in torque sleep because it can not go beyond 16000 rpm. The front motor can run up to 18000 rpm but at 249 kph / 250 kph it is over. I would even say that above 200 kph the car is accelerating so slow that one has to be aware that other cars with more than 350 to 400 hp can overtake you quite easily.

Having 21" wheels and the sport suspension my car is quite stable at high speeds. I don't have a problem pushing it to the max providing traffic permits.
 
(Original OP)
Lots of good answers, but no answer yet?
Is there anyone here who has driven MS or MX at 155 (250 kph) or the MX with a roof rack at 140?

I can tell you a production GMC truck will actually peel off the trim at speeds over 175mph. We had to tear them all off to hit 200 mph. About 936rwhp was necessary.

If you could alter the gearing on a Model S, it would exceed 200mph, but very briefly. The power required would empty the battery in just a few minutes. Depending on the cooling system, it could be very brief.
 
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He was indeed talking about the Model X; with these vacuum mounts (not suction cups....) a rack (Whisper, I'm sure) are supposed to be good to 140mph. Me, I'd not go a whisker over 135 with 'em.

Picture here:

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