Mythbusters does Knight Rider (Big Rig 06/06/07)

[doom1701]

I have to admit I fast forwarded through the build team myth; I'll probably watch the entire episode tonight. The main thing I was curious about was pulling a moving car into a moving semi--and I can't believe how incredibly well that worked. I figured they'd have some difficulty, but it looked like they just drove on in.

I probably should have realized that it would be simple when they went from a treadmill scale test to the real thing with real drivers--I'm guessing that this is something well documented already, and they were just having fun. It makes me want to find a semi that I can drive into...

I didn't catch all of the exploding tire myth, but seeing the result makes me very glad that, last month when I was behind a truck that had a tire ready to fall off it's rim, I gunned it and left him behind me. It looked like a dangerous situation, and it turns out it was.

[LoadStar]

I loved the fact that Jamie did the whole pulling out then pulling a 180 degree spinout to go in the opposite direction, just like they depict on the TV show. The question I have is - was the ramp that they built functional; as in, could they hinge it up and have it not stick up beyond the height of the trailer?

Of course, they skipped over the part of the myth where Michael Knight opens his car door full width while still inside this regulation size semi trailer. ;)

[snowjay]

I thought that was the best myth of the night! Although if you look close you can see Adam clipped the passenger side mirror when pulling in at 55mph.

[pcguru83]

This was one of the most enjoyable Mythbusters episodes for me in a while. The increase in gas mileage by drafting behind a tractor trailer was unreal. I had always heard you had to be REALLY close to get that effect, but turns out you get a significant increase in MPG (like 25% I think it was) even at 50ft!

[pjenkins]

50' is incredibly close (and very dangerous) to a tractor trailer at highway speeds...

i can't imagine doing that to save a few $s on fuel...

[doom1701]

I loved the fact that Jamie did the whole pulling out then pulling a 180 degree spinout to go in the opposite direction, just like they depict on the TV show. The question I have is - was the ramp that they built functional; as in, could they hinge it up and have it not stick up beyond the height of the trailer?

Of course, they skipped over the part of the myth where Michael Knight opens his car door full width while still inside this regulation size semi trailer. ;)

I never saw them pull the ramp up, but it appeared to be the proper size to pull up and not stick beyond the top of the trailer.

And yeah, there's just no getting around the fact that the Knight Rider trailer was actually a TARDIS. :)

[mtnagel]

I haven't watched yet, but they've drove cars up ramps onto trucks on Fear Factor several times before. Some fall off, but many make it. It's obviously possible.

If this makes no sense since I haven't seen it, then I apologize.

[LifeIsABeach]

I haven't watched yet, but they've drove cars up ramps onto trucks on Fear Factor several times before. Some fall off, but many make it. It's obviously possible.

If this makes no sense since I haven't seen it, then I apologize.

No, it makes perfect sense. Exactly what I came in to this thread to mention. Anyone who watched Fear Factor would know that this myth would be confirmed.

Pretty amazed by the gas savings. Not that I am a good enough driver to attempt it. Loved the part where they shot the rubber through the windshield.

[Jonathan_S]

Watching the Knight Rider part was cool. Although with the rain and the steel ramp, you could see that Adam fishtailed slightly in the 55 mph attempt.

I immediately thought, I'd love to do that in my car. Followed by; that probably a really, really bad idea. I imagine that an AWD car, like mine, would be very unhappy to have a 50 mph difference between the front and rear tires (when you are half on the ramp). Probably do horrible damage to something.

Even with 2wd I imagine it works better with an automatic that with a manual transmission.
With the automatic, the torque converter would be able to slip to absorb the 55 - 5 mph near instant decel of the driving wheels when they hit the ramp. But that would probably put a lot of strain on the transmission and clutch of a manual. Not to mention, if nothing slipped the car probably wouldn't go very well at ~5 mph in top gear :) It might stall before you managed to react. (Unless you shifted out of gear just before hitting the ramp and coasted onto it...)

Still, looks like a lot of fun :D

[MassD]

Pretty amazed by the gas savings. Not that I am a good enough driver to attempt it.

Well... you don't need to get THAT close. Back in my youth, I regularly made a 100 mile trek to visit my girlfriend. With most of that being on a single highway, I often searched for a semi to slide my GTI in behind.

Mind you, we aren't talking NASCAR stuff... just close enough to feel the difference in the drag. Like the saw on the show, you really don't have to be all that close. You start to feel your car bounce a bit side to side and the wind noise drops quite noticeably. The difference in gas consumption was oftentimes huge.

And, to be honest, a 150' distance is somewhat excessive. It's a semi... if all hell breaks loose in front of that thing and it has to make an emergency stop... well a Kenworth ain't a Porsche, that's for sure.

[Einselen]

I agree with the previous posters which stated the whole Knightrider thing has been done before on Fear Factor. That was actually one of the few episodes of FF I have seen. I think it had to do with movie stunts, like driving through the side of the barn, driving into a moving semi, etc. I think Mythbuster did it just so Adam could complete the dream of actually doing it and not to disprove it.

As far as the drafting goes, I will admit there are times I am close to a semi, but for the most part that is only when the semi gets into the fast lane to pass the slower traffic in the slow lane, which it is required by law to be in for most of its trip. I drive close enough where the driver can still see me sitting there and I can stop in time, but not to far out where I am getting the turbulence from the air coming off the truck. It makes for a smoother ride. Also like I said usually speeds on the highway around here are 70-75 and many trucks are going 60-65 over in the slow lane. I would rather go a bit faster and hit the speed limit and get there a little earlier rather then driving behind a semi for the entire trip to save some gas milage.

[heySkippy]

Seems to me if you're close enough behind the truck to draft, you're also going to be peppered with gravel, rocks, etc kicked up from the tires. It would be a foolish economy to save a bit on gas but ruin your paint in the process.

[LoadStar]

My dad's old pickup, an early 80's GMC pickup, would draft so well that he could get into a zone behind the truck and almost completely let off the gas and just allow himself to be pulled along.

[classicX]

I would rather go a bit faster and hit the speed limit and get there a little earlier rather then driving behind a semi for the entire trip to save some gas milage.

Let's see how you feel about that in two years. ;)

[Einselen]

Let's see how you feel about that in two years. ;)

Not to mention the safety issue with following to close behind a truck, but currently I am enjoying gas prices. Diesel is not changing much and still under $3/gallon here and not to mention there is BioDiesel as well :)

To talk about this episode though I thought it was a good one, entertaining at least especially with the Knight Rider myths. The past few episodes have been ho hum in my book, but this one made me relove the show, ok I never stopped.

[5thcrewman]

:mad: Why wasn't I notified that Kari was in the Portland area!!! :mad:

[MarkofT]

Seems to me if you're close enough behind the truck to draft, you're also going to be peppered with gravel, rocks, etc kicked up from the tires. It would be a foolish economy to save a bit on gas but ruin your paint in the process.You are not going to do this on unimproved or just plain poor roads. Most of the open freeways in the US are well used and kept clean of anything that could be kicked up. Not to mention that you have the mud flaps, the "bumper" and usually 15 feet of trailer behind the wheels.

I used to draft frequently but haven't done much recently since moving from the countryside to the urban concrete jungle. No use drafting in 30 MPH stop and go traffic.

[vman41]

I think the exploding tire is somewhat less hazardous to the moving traffic than to people and object that are stationary by the road. Even worse would be when the chunks are thrown at oncoming traffic.

[Unbeliever]

You are not going to do this on unimproved or just plain poor roads. Most of the open freeways in the US are well used and kept clean of anything that could be kicked up.

As a motorcycle rider, let me say that you'd be surprised at the amount and what does get kicked up on the freeway.

--Carlos V.

[JYoung]

The "Driving the car into the moving semi" stunt actually goes back to 1976 with The Gumball Rally (http://us.imdb.com/title/tt0074597/).
(They drove a Ferrari at speed into a semi-trailer.)

The other issue with the Knight Rider stunt was that Michael always stopped just inside the trailer door.
I was a little disappointed that Jaime and Adam didn't show how much stopping distance would have been required inside the trailler.
I've always suspected that most of it was required.

Of course the only reaction seeing that tire chunk hit the ballistics gel dummy,
Woooooooooooooooooooooaaaaaaaaaaaahhhhhhhhhhhh!

[stevis]

thanks....

[fireman9302]

thanks....

And the spam begins............

[lordargent]

Fear Factor several times before. Some fall off, but many make it. It's obviously possible.

If this makes no sense since I haven't seen it, then I apologize.

To be fair, fear factor does a few things to ramp up the difficulty (for example, having the semi drift from side to side, or using skids instead of a ramp)


You are not going to do this on unimproved or just plain poor roads. Most of the open freeways in the US are well used and kept clean of anything that could be kicked up.

ROFL, that's a pipe dream. Trucks drive onto an area full of gravel, gravel gets wedged into the wheels, then pops out somewhere on the freeway.

Not to mention that there is plenty of crap on the roads.

/counted ~80 hubcaps over on the side of the road on a trip from San Diego to LA

[ping]

The other issue with the Knight Rider stunt was that Michael always stopped just inside the trailer door.
I was a little disappointed that Jaime and Adam didn't show how much stopping distance would have been required inside the trailler.
I've always suspected that most of it was required.

No stopping distance was needed. He could have stopped on the ramp if he wanted to (in fact, I just watched it again on Youtube and he almost did stop on the ramp. Once he's fully on the ramp you can see he needed to accellerate just to get all the way up).

[trausch]

Well... you don't need to get THAT close. Back in my youth, I regularly made a 100 mile trek to visit my girlfriend. With most of that being on a single highway, I often searched for a semi to slide my GTI in behind.

Mind you, we aren't talking NASCAR stuff... just close enough to feel the difference in the drag. Like the saw on the show, you really don't have to be all that close. You start to feel your car bounce a bit side to side and the wind noise drops quite noticeably. The difference in gas consumption was oftentimes huge.

And, to be honest, a 150' distance is somewhat excessive. It's a semi... if all hell breaks loose in front of that thing and it has to make an emergency stop... well a Kenworth ain't a Porsche, that's for sure.

I agree. If there is a problem a Semi can't stop very fast. Plus if there is a problem why not let the Semi "Blow the Road" for you?

[gschrock]

As a motorcycle rider, let me say that you'd be surprised at the amount and what does get kicked up on the freeway.


As someone that's had far too many dings in the windshield repaired over the years, I agree with you. Course, in Michigan it probably doesn't help that the roads always seem to be under construction.

[Church AV Guy]

As a followup test, I would like to know if the semi uses more fuel when you are drafting behind it. I suspect so, or else you are getting something for nothing, and never happens in the real world. I would also like to see the effect of one car drafting the semi, and a second car drafting that car (the effect on the milage of the second car). Driving two feet behind that semi, even under controlled conditions looked insanely dangerous.

[Sherminator]

The Semi should not be affected by something riding in the wake that it creates.

If NASCAR teaches us anything, the semi might benefit slightly from anything behind it sitting in the low pressure wake, reducing some of the low pressure drag.

Source: [livescience.com] (http://www.livescience.com/technology/070215_nascar_aero.html)

[mattack]

I have to admit I fast forwarded through the build team myth; I'll probably watch the entire episode tonight. The main thing I was curious about was pulling a moving car into a moving semi--and I can't believe how incredibly well that worked.

HAVE THESE PEOPLE NOT WATCHED FEAR FACTOR?

Sheesh, they did that SEVERAL times.

Edit: and I prove that I didn't read this whole thread before replying. (I didn't search for fear factor, but I skimmed, not successfully.)

[mattack]

As a followup test, I would like to know if the semi uses more fuel when you are drafting behind it.

I thought it would too.. but I had this discussion with others, and they said it wouldn't, that the semi would get better mileage too..

so then my reaction was along the lines "then the extrapolation of that is that if you get something infinitely long, it gets infinite MPG"...

their answer: They have that, it's called a train.

Not really infinite, but you get the idea.. (Also, Mythbusters debunked the 'blown over by a train' thing too.)

[walkerjs]

When you're in a Jeep Wrangler drafting something on the order of 50ft behind a semi you can really feel it considering that a Jeep has the aerodynamics of a tool shed.

Whenever I'd get behind a semi and I could feel a little side buffet I'd know that I was "in the zone" and was probably increasing my gas mileage to something on the order of 25mpg (which for a vehicle that gets 18mpg unassisted with a four-cylinder is pretty good.) The distance was not scary close, and I know that tractor trailers don't put on the brakes unless they really have to. Even if they do, you can outbrake a semi in nearly all conditions. Well, ice/snow/really wet and all bets are off.

Also Jeeps are high enough that at that distance any stuff that gets kicked up isn't going through the windshield.

Same thing back when I rode a motorcycle, but there the "stuff getting kicked up by the tires" factor is more prevalent and bikes get good enough gas mileage as it is so I didn't really do it all that often.

[ping]

I really don't get the "wow that's so dangerous" stuff. As long as you're paying attention and watching the brake lights (and don't have someone behind you doing what you are without paying attention), no matter how hard the semi brakes, you'll be able to decelerate more than him. Simple physics. Reverse the order of the vehicles, though, and you're in big trouble if you should need to brake.

[TiVo'Brien]

......... Loved the part where they shot the rubber through the windshield.Was it a windshield? It looked to me like a side window. I was kind of disappointed they didn't use a windshield since for a tire strip to go through a side window the car and truck would have to be at 90 degrees to each other, which wouldn't happen on a highway.

[doom1701]

HAVE THESE PEOPLE NOT WATCHED FEAR FACTOR?

Sheesh, they did that SEVERAL times.

Edit: and I prove that I didn't read this whole thread before replying. (I didn't search for fear factor, but I skimmed, not successfully.)

I think the more important question is "Have Mythbusters Viewers ever watched Fear Factor?" I know I could never stomach that show.

[Ntombi]

I agree; I stopped watching Fear Factor during the first season. I never knew the Knight Rider stunt was possible.

As for drafting, I've drafted 18-wheelers plenty. I don't get crazy close: I make sure I can still see their side view mirrors so I know they can see me, but I've definitely taken advantage of a little draft even from that far away.

Yes, it does lead to some random gravel or whatever being launched at your car.

And I was amazed looking at when Grant was 2 feet behind. That looked stunning, and would have freaked me out, though I'd love to try it in controlled circumstances!

[f0gax]

If Knight Rider had been shot in 2007, I'd have been skeptical about if the truck stunt was possible. They could have easily digitally edited out the giant "rig" that pushed the car into the truck.

But it was made in 1982 or something, and nearly every week the car drove up the ramp. And it sure as heck didn't look like chroma-key or anything like that. So throughout the entire Mythbusters I was saying to myself "Of course it'll work".

For as cool as the gags were in this episode, they all were pretty much straight-forward. A hunk of truck tire rubber will seriously f you up if it hits you. Yes, you can drive up a truck ramp at highway speed. The only thing surprising was how dramatic the MPG gains were in the drafting gag. Other than that, meh.

[doom1701]

If Knight Rider had been shot in 2007, I'd have been skeptical about if the truck stunt was possible. They could have easily digitally edited out the giant "rig" that pushed the car into the truck.

But it was made in 1982 or something, and nearly every week the car drove up the ramp. And it sure as heck didn't look like chroma-key or anything like that. So throughout the entire Mythbusters I was saying to myself "Of course it'll work".


Well, you've got to remember that A) these are ordinary guys who had just a bit of stunt driver training, and B) the "pull into the truck" shot in Knight Rider was more or less stock footage for them. It wasn't like they filmed it for every episode.

[f0gax]

Well, you've got to remember that A) these are ordinary guys who had just a bit of stunt driver training, and B) the "pull into the truck" shot in Knight Rider was more or less stock footage for them. It wasn't like they filmed it for every episode.

The point being though, the KR folks did it as a "practical" gag rather than something with effects. They drove the car up the ramp, while both the car and the truck were moving. So, therefore, it could be done.

And if I remember correctly, the shot from inside the truck always looked the same. But when they showed it from the side it would vary depending on what was going on. I don't doubt that they had maybe 5 stock shots that would fit almost every situation. But it appears to me that they did it several times on camera. Again, using practical methods rather than SFX.

Point being (again) it was done on KR. So of course it would work. And again (as posted above) on Fear Factor.