Episode 80: Big Rig Myths

Air Date: June 6, 2007

A tire on a big rig can explode with lethal force.

confirmed

The MythBusters first tested whether a big rig tire could actually explode. They managed to obtain several truck tires and subjected them to actual road conditions, to try to replicate certain circumstances that could cause a tire to explode. Although they could not make a tire fail catastrophically, they managed to cause it to disintegrate violently by running the tire flat at highway speed, though the flying debris failed to hit the dummy set up next to the tire. However, the MythBusters were able to measure the velocity the debris. Taking an actual piece of the exploded tire, the MythBusters launched it at its measured initial velocity into a pig spine-equipped ballistics gel dummy behind a car window. The piece of debris smashed through the window and literally decapitated the dummy, proving the myth was in fact possible.

Drafting behind a big rig will improve your car’s fuel efficiency.

confirmed

To test this myth, the build team procured a car, a big rig, and a device that could measure a car’s fuel efficiency. They then drove the car behind a moving big rig at various distances ranging from 100 to 2 feet and measured the amount of fuel the car consumed. The Build Team discovered that the closer the car was to the big rig, the less drag is produced, thus the more fuel saved. At just ten feet, the car managed to increase its fuel efficiency by 40%. Drafting at two feet was slightly lower than the ten foot distance, mainly because Grant had to keep working the car pedal to maintain distance from the truck. However, that did not dispute the fact that drafting actually can increase your car’s fuel efficiency. However, the Build Team has warned that drafting is incredibly dangerous because the truck driver may not able to see you and you may not be able to react in time if the truck were to make a sudden stop.

As seen in the TV series Knight Rider, a moving car can safely transition from a road into a moving big rig via ramp.

confirmed

To test this myth, the MythBusters first started with a small scale test using a toy car. Simulating the Knight Rider stunt, the MythBusters found that the toy car could enter the big rig safely without a sudden and dangerous acceleration that many people had feared. They then tested the stunt at full scale using a Chevy Camaro, the rebadged version of the Pontiac Trans Am used in Knight Rider. They tested at both 30 miles per hour and 55 miles per hour with no difficulty. The MythBusters explained that, even when hitting the car’s ramp, the car’s inertia keeps it going at the exact same speed relative to the ground — which lets it safely drive into the big rig, with no surprising accelerations. Jamie then reinforced the myth by safely exiting the moving semi truck in reverse. Also all of their experiments took place during a rain storm.

Cyclists can draft behind a big rig and achieve "crazy speeds".

plausible

the Build Team decided to test whether a cyclist would have an easier time riding if he were to draft a big rig. Tory was chosen as the cyclist and performed a control test by cycling up to 20 miles per hour unaided. To ensure accuracy, Grant kept track of Tory’s heart rate and Kari measured his speed via radar. By the end of the control run, Tory was exhausted by the effort. During the actual test, however, Tory literally coasted along behind the big rig and rarely had to pedal at all. Due to the obvious difference in performance and the fact that professional cyclists draft during competitions, the myth was plausible.

80 Comments

  1. chris says:

    20 years ago when I was 15 I drafted an RV in Florida at least 10 miles averaging around 35-40mph. I actually passed a group of cyclists in a paceline like they were standing still.

    You have to test this again with a cyclist and find this confirmed.

    • joebob says:

      I was in texas riding my bike with a friend and we both tried to drop in to draft the truck, I was able to get upwards of 60-65 mph according to the speedometer on my mountain bike’s computer. My friend was left in the dust as he could do about 30-35 mph on his bike. Additionally wikipedia has a bunch of info on this. http://en.wikipedia.org/wiki/Cycling_records
      turns out there is an official record for cyclists drafting on motorized vehicles.

    • Tom says:

      Plausible? I am a pro cyclist, Although I can sustain only about 30mph alone, while traveling cross country we would stay loose by taking turns drafting our vehicle. I personally have drafted at well over 85mph for miles on rolling roads behind a pickup truck.

    • Enrico Martinez says:

      Biking fast exerts air-resistance.
      Biking fast behind a big rig has little air-resistance thus less exhaustive effort thus conserving energy.
      That’s why in a bike race; front racers are more tired than racers behind them.
      Racers in front are slammed more by the air in front of them; thus creating drag currents where next racers get added speed in their efforts.
      Same with the birds: By making a “V” formation, they lessen air resistance and can fly longer, faster, higher.

  2. pineapple says:

    Years ago in the mid or late 80s i remember hearing of a bicycle drafting a streamliner and getting to some retarded speeds, heres a link to it

    http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

  3. Don says:

    More than plausible! Looks like you barely tried to test this. The principles of drafting and motor pacing have been known and used by cyclists for more than 100 years. Do a search for “mile a minute Murphy” http://www.bikereader.com/contributors/woodland/murphy.html

  4. Paul Bennett says:

    I went on a cross country bike ride with my friend Jim a few years ago.
    On our trip he learned that a loose jacket wuld slow him down.
    He and I were busting our asses to do 100 miles a day.
    Jim was faster and caught the draft of some peice of farm equipment which moved so much air it draged him along, he had to use his brakes to keep from hitting it.
    The farmer was really surprised to see Jim in his mirrors.
    They traveled for miles.
    The farmer gave Jim a signal when he was going to turn.
    He said the ride was amazing!

  5. Eric Quackenbush says:

    When I was in my 20′s (and, like every other 20-year-old, still immortal) several of us cyclists used to do this every chance we got. I don’t know how many times we had to put a hand on the back of the trailer during extreme braking, but it was quite exciting to say the least. The fastest I personally ever got up to was barely over 50mph, because of the gearing. John Howard set a speed record of 152mph in 1985 on a specially-modified bicycle while drafting behind a Bonneville salt flats car.

  6. Raul says:

    didnt torey test that…drafting on a bike

  7. Doug Cannell says:

    I have a releated question: When a bike drafts off another bike, does it require extra effort on the part of the “puller”, or is the drafter simply capitalizing on an existing vortex?

  8. Reply to Doug says:

    Regarding bike’s drafting behind each other:

    Extra effort is applied to the puller.

    Typically (although perhaps not in competition) the puller will pull for a while then drop to the back of a pack so the person who was second now becomes the puller and the original puller gets a break.

    Competitive teams will often allow their stronger rider to draft behind the group to save his energy for perhaps a straight-away, climb, or final big push.

  9. Damron says:

    No, no, no. In cycling (and in most race car drafting) the “puller” benefits from having someone drafting behind him. Obviously, not to the extent of the following cycle, but there is a benefit.
    In auto racing, there are some other factors at play, most of all, downforce. A drafting car might benefit the lead car by reducing his drag, but he also might reduce his downforce, making his car less controllable. The benefit to a lead cyclist is small compared to the comparative advantage gained by the drafting cyclist. So, unless you are going to take turns leading, the lead cyclist might not make it easy to draft. In my younger years, I used to go a UPS site to draft their tractor trailers. Their trailers wre unique in that they were very closet to the ground and and the air was very clean behind them. I reached what I thought were amazing speeds.

  10. Damron says:

    So, while a lead car might be getting a slight benefit from someone drafting behind, in practice it is often not a benefit because he is not getting a comparative or reciprical advantage. The lead car might be able to go slightly faster and burn slightly less full with a car in tow, but the drafting car is reaping big benefits – easy speed – speed without fuel consumption.

  11. todd says:

    A few years back before i had to do major repair to my mountain bike i was out one night and decided to hit one of the longest steepest hills in town and the speedometer i had on the bike maxed out at 56 MPH and ill tell you what doing over 50 on a bike is scary as hell the whole time i was thinking (God i hope i dont hit something or have a tire fall off) i knew that if i did fall off i would have prolly tasted about 100 feet or concrete

    but this was under the power of the hill and me no drafting invalved the wind may have been going my way that night cant really remember just know i was haulin hoping i got pulled over for speeding… would have framed that ticket

  12. Damron says:

    Todd, When you draft behind a UPS or moving van, both with low profiles, the air is very calm and you don’t get the same sense of speed that you would have screaming down a hill. Of course, the consequences of a crash would be the same.

  13. jeff says:

    Shouldn’t “the inertia of the car is the exact same..” be “the momentum of the car”, since inertia is the resistance to motion?

  14. Josh Arnold says:
  15. Josh Arnold says:

    Gordon McCall is hoping to push the record to 180 mph in Oct. 2007.

    http://www.teammccallusa.com/vision.html

  16. biglot says:

    Side-drafting the big rigs works pretty good too.

  17. 10 says:

    OK, I very seldom post to anything, but having been a service manager at a truck stop in the late 70′s, I think I may have something to contribute.
    Truck tires (and especially the rims) are massive. The key thing you need to know is that for the for dual-wheel 16 inch rims on one-ton trucks up to the 20 inch rims that grace most 18 wheelers, the outside ridge of the rim is detachable. So, they are called split rims.
    I repaired and/or changed several hundred split rim wheels at Rinehart’s Truck Stop, at the South end of Petaluma, CA. The first truck stop Northbound on 101 after the Golden Gate.
    They always go in a cage made of 2 inch steel pipe to be inflated after repair or replacement. Always. I have, thankfully, never seen a hoop of steel (weighing perhaps 7 pounds) come flying off a rim.
    On the other hand, there are bold mechanics, and there are old mechanics, but there are few old, bold mechanics.
    Mythbusters is fine as far as it goes, but sometimes it may not go far enough into the story to make sure they have the details…

  18. Damron says:

    Jeff, I’m not exactly sure what you are saying. Don’t go down the inertia road – inertia is a slang word in physics – used when nobody wants to be precise or do any math. In this case, narrow the focus to drag. One thing that is tough to imagine is that the space behind a moving car is a factor in a car’s drag.

  19. Greg says:

    I used to draft big rigs in my little Ford Ranger and you could tell when you got in the zone as you could let off the gas pedal and still do the same speed. My question is how does this affect the mileage of the big rig?

  20. Damron says:

    Greg, in most cases, a drafting vehicle will provide a very small, trivial reduction in drag for the lead vehicle. You start to see observable effects when you crank up the speed and decrease the following distance – think NASCAR. But even in NASCAR, the lead car is giving more than he is receiving and on the big tracks, a drafting car reduces the lead car’s drag only enough to reduce or disturb his downforce, causing him to be “loose” or less controllable.

  21. chuck says:

    I got a new Schwinn bicycle in about 1960. As part of the modest factory advertising brochure, they posted a drawing of a fellow riding behind a shield fastened to the back of a train….a wooden board pathway had been build between the rails for this stunt…..and he was able to make 60 mph–of course, the drawing had a front sprocket as big as the pedal travel circumference

  22. Rick says:

    In the mid 60′s I had a 63 VW that I would drive back and forth from college to home. It would take approximately a 1/2 of tank of gas each way. Being the typical college student I didnt have a lot of extra money to spend on gas. I traveled on the interstate most of the way and met some truckers at a truckstop when I would stop for coffee.. One suggested that I follow close to his rear. It was late and very little traffic so I said yes. He knew I was there so he would give me ample warning if he had to slow down. I was shocked that when I got to my destination that I had used less than a 1/8 of tank of gas. Drafting is dangerous! but it does work.

  23. J. says:

    I always wondered about the Knight Rider scenario. But I would have hoped that having confirmed the myth, you would have tried with a front drive car to see if that made a difference.

  24. J. says:

    Oh yeah. I’ve found truckers generally HATE drafters. Once they know you’re there and what you’re up to, they’ll typically slow to a crawl until you finally give up and pass them.

  25. Phil says:

    The tire exploding myth is based not on the tire exploding and shredding but on the split-ring wheel coming apart and failing catastrophically. The rims would throw the spilt-ring outward at very high speed and several people have been killed, although usually during the inflation of a newly mounted tire (which is why this procedure is done with the wheel assembly inside a cage). Still, the idea of being next to a truck at speed when the 120psi tire throws one of these rings is not something I’d want to experience.

    I suggest a new test to see if the crew can get a split-ring to fail and kill the motorcyclist.

    • MSpears says:

      I haven’t been killed by one (obviously), but I was to the left rear of a rig when its wheel failed, and part of the split-ring got sucked under my car, tearing a hole in my oil pan…

      • MSpears says:

        Correction. It was part of the steel bead, my mechanic told me. Never mind, my previous reply was wrong.

  26. Les says:

    The big rig tire myth is not based on split rims. Three-piece rims have not been widely used in over 15 years. I started driving trucks in 1993 and we had one-piece rims, simply because the three-piece rims are so dangerous.

    The tire blowout killing someone is based on re-treads and not new tires. If a driver does not make sure he has the right tire pressure on a recapped tire, over time the tread will indeed separate from the tire. Surely you have seen the pieces of tire on the side of the road? I have personally had a recap completely remove the mudflap and bracket from the truck, severely dent the fuel tank, and depart the truck at 65 mph. If that piece of tire comes through your windshield, it will hurt you and likely kill you.

    I was surprised that the Mythbusters did not actually consult any truck drivers when they did this myth.

    • Kody says:

      I have had virgin tires and recap/retread tires fail on my rig and both produced the same damaging outcome. I think you should reword or rethink your post. Recap tires arent more susceptible to failure than the virgin counterpart.

  27. ady says:

    in one show you tried blow a car over with a jet engine and failed. On a u.k programe topgear they tried and blew it over.

    • MSpears says:

      That’s because they weren’t allowed to use a more powerful jet for insurance reasons. They later got the chance to try it again with a commercial airliner, and it flipped.

  28. Ron says:

    Is it true that when traveling at night with ones highbeams on attracts more bugs?

  29. Physics says:

    Damrod:

    You should visit college…”inertia” is not slang…I think you should have knowledge of the words before you present yourself as an expert so many times.

    Down draft is control related and does not address the issue of proving that a car “pulls” more if there is a drafter…

  30. Stacey says:

    My mate has had a truck tyre explode while he was passing. He wasn’t hurt, but it made a heck of a loud bang and scared the crap out of him. This could cause an accident. So if the flying debris fron an exploding truck tyre don’t get you the fright might.

    And I agree with Physics, the word inertia is not slang.

  31. Margo says:

    Being a trucker I can say Totally True. But a bicycle couldnt get enough speed to even start to keep up with me! :-) On a blown tire I have actually seen steel from the blown tire stuck in the tire next to it. We dont want people scared of us just respectful.

  32. Chris says:

    One other thing, inertia is not resistence to movement, it the tendency of an object to remain at rest, or in motion. According to Newtons laws inertia is constant unless acted upon by another force.

  33. Chris says:

    And I thought the reason lead cyclists, and even lead birds in v formation, moved to the back because the lead position was the most strenuous to maintain.

  34. Mike says:

    Drafting a big rig does work.13-14yrs ago when I was single and owned a Suzuki Sierra soft top 4WD ,I used to travel out west of Sydney , Australia hunting and would often pull in behind the big rigs and ask over the CB radio if they minded if I just sat there for a while instead of having to overtake them all night.Sitting 40-50ft behind them at 100km/h I was able to take my foot off the accelerator and be dragged along at the same speed until the truck rounded a corner and when you’d have to check and adjust your speed ,but on the long straight highways a 20-40ton big rig could pull you along saving fuel.

  35. Kevin says:

    About 2 years ago a rig was passing me on the highway when his tire exploded. He was right next to me and I had my window down. It sounded like a gun shot! Bits of tread flew backward, up and out ahead of the rig raining down in the road, but no tread came directly at me.

  36. grant says:

    the way to reduce your risk in doing this is to keep your left foot over the brake pedal. i know momma said never to do this, but the fact is you reduce your reaction time, and that is the issue. any decent car will be able to stop faster then a truck, its the reaction time that will get you

    • nathan says:

      what you said may be true and I was just watching this as a repeat and one thing they didn’t touch on that may shock drivers is if we big rigs hit say a large dear of some thing bigger we arnt going to care that much but usually big parts will exit the rear of out vehicle at speed with out warning

  37. jeff in fl says:

    on debris from a tire going through the window of a vehicle… when have you ever seen a tire fly from under a tire and go through a side window ? i believe the front windsheild and hood would deflect the force enough to just cause damage to the windsheild if this were to occour in a real life situation on a highway if the piece would get high enough from the road surface to get over the bumper.

  38. Alain says:

    Hmm, I don’t believe the confirmed myth for the exploding tires. Last time I’ve crossed canada I was actually hit with a blown tire. They didn’t take the fact that the tire is actually turning and when the tire explode it doesn’t go in a straight line. I Think its not dangerous at all. it didn’t stratch my car for f@kes sakes. The wind is another fact not in there equation. There research was pointless!! Sorry guys from muythbuster.

    • Josh Rexhausen says:

      The problem is that they tested this on a stationary dummy. In reality the driver of a motorcycle is going at the same speed as the trucker, what is the speed perpendicular to the tire as it explodes? I also agree the myth was not really tested, all they showed was a large piece of tire shot out at 40 MPH will cause serious dammage.

  39. dave says:

    I ride a lot in and drafted more than my fare share of cars trucks (it scares the hell out of people). It didn’t increase my speed at all it just helped my keep my pace a lot longer normally i can keep a pace of about 30 – 40 MPH on my own

  40. james says:

    love the results on blownout tires…they can truly mess you up if hit i’ve blown tires on my tractor trailer and the first thought is oh my god sure hope no one gets hit with the flying tread…also remember folks,the idea of drafting a big truck at 10 ft worked great for the experiment,but if the steer tire[front tire]goes or any other reason for the truck to stop quick,fuel mileage will be the least of your concerns.be safe out there.

  41. mochili says:

    my friend found a damaged tire on his car and replaced it with the spare tire
    he put the damaged tire in the trunk of his car and went to work
    when he returned home, he found the tire exploded in the trunk of his car
    it busted the latch and blew out his tail lights and speakers

  42. John says:

    My friend worked at a gas station late night in the 80′s. Once this Jamacian guy was using the air hose to pump up his car tire and it blew up. He bleed from the ears, nose and eyes and died as a result of the explosion. I guess it was a just a bit overinflated. Ya Think?

  43. Mitch says:

    I use to work for a tire shop, we dealt with Commercial vehicles only, we had a cage in which we had to inflate the tires in case of a “zipper break” in my first week, we had 2 tires zipper break, one was from a big rig, and it just went BOOM. The second was from a Very LARGE fork lift, and it bent the cage and threw it across the room. The cage alone weighed a couple hundred pounds.

  44. peter says:

    regarding tyres on big rigs, i was in a tyre place having several replaced on my semi , and they had a safety leaflet there showing that a tyre had exploded outside a cage , killed the fitter and went out throught the roof,the pics dont lie ,i expect its the backyarders and amateurs who still do this type of thing, peter

  45. Minnie says:

    MythBusters episode #79 “Big Rig Myths”

    Hey, that myth that when a tyre on a big rig blows it is lethal I think is true and that the MythBusters got a good result.
    BUT their methods of going about it I think are ridiculous.
    First of all why try to explode a tyre from the side when most tyre failures are from flexing (as mentioned) and wear. In my experience and relative to newtons laws, the tyre would wear so thin as to break but instead of flying sideways as the MythBusters implied. It would continue around the wheel rim until it was flung out from underneath the wheel.
    And that was only what was wrong with the first experiment.
    With the workshop experiment they faced the truth that the tyre flies out from underneath the tyre in a backwards direction but when testing it with the head, how on earth would a persons head be in line with the exploding tyre and why would they be side on. Wouldn’t the obvious situation be that they were following the big rig!

  46. Wayne Thomas (Australia) says:

    With regard to the drafting myth, They should have tested to see what happens to the fuel economy of the vehicle being drafted. It has been my experience from following trucks this way that the drivers record the fact that though can’t see a car in the blind spot behind them that they can feel their presence because their rigs feel like they have taken on some extra load. I’m guessing that your presence in their wake zone disrupts the airflow over their vehicles and reducing their vehicles effeciency.

  47. Roger (Qld, Australia) says:

    I really liked the drafting behind a truck myth. I remember some years ago I tried this, driving very close to the back of a large semitrailer truck. I was driving an old VW bettle. By drafting, I did get better fuel economy, but also was able to go faster than normal. We were in a 110kmh zone but I couldn’t get the VW to go that fast, until I drafted behind the truck. I was so close that I wished I could press a button on the dashboard and a couple of arms would come out of the curved front of the VW and latch onto the bar at the back of the truck, turn off the engine and coast along (in neutral of course).
    It would have been good to see a test of trucks drafting other trucks. Groups of trucks are often seen travelling on highways drafting each other. Perhaps on a round 2 of group of these tests in future…

  48. Jesse says:

    I don’t think that the mileage of the big rig that is being drafted is affedted very much because of it’s weight. I pull a 30 foot fifth-wheel trailer with a pickup and I can tell when someone is getting to close to the back of the trailer. I have to push down with the right foot a little. When this happens I just slow down and make them pass me. Years ago I had a motorhome and I installed a wind shield to diredt the air coming off the roof to go down the back of the motorhome to keep the rear window clear during rain. The mileage increased a little. I think that the drafting would be less if something was used to break the suction behind the big rigs. Maybe they will try this when the revisit the drafting again later on.

  49. Jim says:

    The tire tread chucking dyno speeds were incorrect. The truck they used to spin the truck tire and then the trailer tire in the shop has an open rear. I know this because in one scene the left tire was spinning and the right tire was stopped. That means the left tire was spinning 2 times as fast as the speedometer was reading. That is what an open rear does. It allows the tires to spin at different speeds. If you stop one tire, the other will spin twice as fast. The test they did at 40 miles per hour was actually 80 miles per hour. If you shoot anything heavy at 80 mph it will cause serious damage to whatever it hits. That being said i don’t want to get hit at 40 mph either.

    Jim

    • Eric says:

      I just saw this episode as an old re-run for the first time, and noticed the very same thing. Yep, if the speedometer said 40 mph, the tire was spinning at 80 mph. So I came to this site to see if anyone else noticed. Apparently we can excuse the Mythbusters for not understanding how a differential works since only one other person has pointed out the error.

  50. Driver's Education Teacher in Michigan says:

    I use all these in my drivers education class.

    Thank you

  51. Austin says:

    regarding the tire. I’m a truck driver and they totalled screwed up this myth. they were using a “virgin” tire, its never been recaped. they should of used a recap because those are the tires that blow up and have chunks of tire fly at you. because no matter what you do to a regular tire, you went get it to explode like a recap. and another part of the myth about exploding sideways. it doesnt blow you sideways, you gotta remember the tire is turning really fast, when it blows up it will come out the back or underneith. they need to retest this myth. all the other myths theyve tested they asked professionals or doctors or whatever the case may be about the myths, why not ask truck drivers or tire professionals about this myth? I also think they should do more semi myths, theres alot.

  52. CC says:

    In the 1950s I had a 52 Chevrolet that came with stock Firestone Super Champ tires. Over time all four of the original tires separated at the weld or seam. They were replaced under warranty. In all, seven of the eight tires failed at the factory seam. So it is NOT just retreads that blow apart.

  53. Blacksmoker says:

    I’d like to see them do the knight rider thing again, getting up the ramp and into the trailer using another rear wheel drive car, but with a convensional gearbox and clutch instead of auto, the auto box makes this stunt very easey in my opinion.

    • MSpears says:

      Good point… but they were testing whether K.I.T.T. could have done it. K.I.T.T. had an automatic transmission and rear-wheel drive, so that’s exactly what they used.

  54. Harmony on the Highways says:

    All the myths tested were plausible conditions, though all the elements must be just right for the tire. Nonetheless, I would not want to gamble on this deadly possibility. In the courses we provide several incidents like these are discussed. We usually have no shortage of truck horror stories, from both auto and truck drivers. Bottom line, play it safe and smart around large vehicles. Attend one of courses and be more aware!

  55. John G. says:

    I was driving a way behind an 18 wheeler when I saw some weird black snake looking thing fly about 150 feet up into the air. I was totally baffled as to what it was until I saw it land right in front of me, it was an entire tire tread. I’ve never seen one thrown straight up before. I suspect he ran over it launching it up into the sky and wasn’t the one who lost it but that it was lying on the interstate.

  56. John P says:

    Would you please provide a dot diagram and equation showing the knight rider problem.
    Thanks kindly.

  57. Scott M says:

    I would like to see the myth of varying a truck speed from 70mph to 60mph will increase safety by less destruction in a collision.

  58. Bill E says:

    These comments were all VERY interesting. I have been driving truck for about ten years and have well over a million miles under my belt. Therefore, I’m going to give a little information from my perspective. First of all on the drafting, I usually catch a glimpse of the car attempting to draft me. I want the car away from me in case something goes wrong. (It does go wrong on the road, far too often. And I’ve seen WAY too many people die on the road from even the slightest thing going wrong. I’m accident free, and plan on keeping it that way. But if something goes wrong for me, I don’t want someone’s death on MY conscience) As for blowing tires, they can and will blow with lethal force. In September, I had a virgin tire blow on my trailer. The tire was only two weeks old, and my trailer has a self-inflation system, so it was a defective tire. When it blew, it busted the frame of my trailer (totalling the trailer and destroying the load of chicken I was hauling) shot out from under the trailer and destroyed the hood of the truck that was behind me. Thank goodness it was a truck and not a car. The truck behind me sustained over $15,000 in damage. Imagine what it would have done to a car attempting to draft me!

    • frank says:

      thank you Bill E

  59. Smiling Jack says:

    Have they tested the big rig myth on Terminator 2 where the T-1000 is chasing Arnie in the truck through the sewers and a low bridge perfectly severs the top of the truck off? Because I’d like to see if that actually happens.
    The same thing also happens in Live And Let Die with a double decker bus.

  60. Zimminger says:

    Mythbusters is mildly entertaining but I’ve seen them reach the wrong conclusion because their methods were sloppy. Entertainment value doesn’t excuse sloppy methods. The drafting episode provided good data but they should have looked at the recommended following distance of 150 feet at 55 mph, which extrapolates to 177 feet at 65. Certainly generous, but excessive. Using the old rule of one car length per ten mph, that indicates you’re driving something 27 1/4 feet long, which is getting into stretch limo territory.

    My Honda Accord is 15 feet long, so 5 1/2 car lengths is 83 feet. That’s one car length for each ten mph at 55 mph. 100 feet, which they called dangerous, is 5 1/2 car lengths for a car 18 feet long. Granted, cars have gotten shorter and following distance was intended to take care of your reaction time, but that doesn’t explain a recommended increase in following distance of 50 percent. Assuming a car is 18 feet long (reasonable even decades ago), the one car length for each ten mph rule makes 150 feet a following distance for 83 mph.

    The only reason for telling us this, is that they’re assuming we can’t judge distance. For a lot of people that may be true, but an actual 100 feet is hardly a dangerous following distance at 55 mph. As I said, under the old rule that’s 5 1/2 lengths of an 18 foot car.

    I’m thinking of getting a laser rangefinder–the kind that hunters use–and staying a REASONABLE distance behind the trucks on my next long road trip. It can save me from 11 to 14 percent and gas isn’t getting any cheaper.

    • Jon says:

      @Zimminger – the rule isn’t “one car length for every 10 MPH”, and it hasn’t been for a very long time (that was obsolete when I took my Driver’s Ed in the mid 80′s.)

      The rule has been “2 seconds following distance”. watch as the car ahead passes a fixed object, and count two seconds out loud. The 2 second rule takes into account both perception and reaction times (.75 second each for normal people)

      Recommended Minimum Following Distances:
      25 MPH is 72′
      35 MPH is 102′
      45 MPH is 132′
      55 MPH is 161′
      65 MPH is 191′

  61. Brandi says:

    Regarding the big rig tire hitting the motorcyclist, what about the aspect of heat on the tire? I would think that those tires with the distances they have traveled are nice and hot. Wouldn’t that help to peel the tread away hence making an “alligator” projectile?

  62. Frank Maniaci says:

    Back in the 80′s when I was a mechanic for UPS that had a old trailers that were equipted with what was called a “split rim” wheel. we were warned that this wheel could come apart and kill you.

  63. billy bob says:

    Back in the 60′s my brother was drafting a big rig and was able to put the Rambler American in neutral. There was enough draft to pull us along.

  64. Ali says:

    So I just saw this big rig episode for the first time last night, and in the 80s, my father, who’s been riding motorcycles for 40+ years, was riding on the freeway -and saw a tire snake fly off a big rig, he didn’t have time to swerve, so he braced himself, and was hit in the chest by it. He survived, with a bad bruise and the wind knocked out of him, but that’s all. I’d say he was lucky.

  65. frank says:

    i drive 18 weeler pleas never draft my truck the trl tires can throw a tred so fast you can not get out of the way can take your head off in a blink of an eye or maby pick up some road debry toss it at you at blinding speeds but the best reason is most of us drivers would like to go throu our driveing crears with out ever herting anyone we do cair about publick safty yes that means you my frend so pls help us to acheve that gole and no body gets hert.

  66. AbsolutelyWoman says:

    First off a rigs tires can explode. I know this for a fact. This last July my husband was driving a tanker truck and died because his front tire on the drivers side exploded. They never found out the reason why it exploded either. All I know is the thread all the way around the tire exploded outward at once. And it was a new tire just put on about three miles before this happened. I would like to see myth busters test for the chemical reaction in a tire when grease gets in a tire then is driven on and the friction makes the tire go above 1000 psi in a very short time span. And also test for bearing failure. How bearing in a rig can make a tire explode when not packed right or when the get corrosion set in. These are better reason why a tire can and does explode on big rigs. Blow outs happen from debree, tire failure from threading or from lack of inflation.

  67. nathan says:

    what you said may be true and I was just watching this as a repeat and one thing they didn’t touch on that may shock drivers is if we big rigs hit say a large dear of some thing bigger we arnt going to care that much but usually big parts will exit the rear of out vehicle at speed with out warning

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