Why Do Some Truck Tires Don't Touch The Ground?

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  • Опубліковано 22 гру 2024

КОМЕНТАРІ • 1,3 тис.

  • @TruckTropia
    @TruckTropia  Рік тому +182

    Want to see Decoding Truck Axle Configurations: 4x2, 6x4, 8x4 and More ? then click here to get a better understanding of truck configurations ua-cam.com/video/BjHXyLHiEoo/v-deo.html

    • @EarendilStar
      @EarendilStar Рік тому +4

      I’ll be honest, it was hard to listen past 34s where you said the axles support the weight of the vehicle. Was this an uncommon mistake by this channel?

    • @smcdonald9991
      @smcdonald9991 Рік тому +1

      Excellent video, knowledge dense!

    • @aaronsanborn4291
      @aaronsanborn4291 Рік тому

      😂 you're explanation is mostly incorrect but hey I only drive a tri-ax

    • @cappa351
      @cappa351 11 місяців тому

      Went straight to conclusion.

    • @TheAlison1456
      @TheAlison1456 11 місяців тому

      Decode the cartesian plane.
      Oh, it's not a cryptographic code, but a tool and concept? So it can only be explained?
      Learn something everyday.

  • @kevind4323
    @kevind4323 Рік тому +4718

    TLDR: The axel can be raised or lowered to distribute the weight of the truck for various reasons including traction, fuel efficiency, reduced costs and maintenance.

    • @moparjr89
      @moparjr89 Рік тому +93

      Main reason weight distribution to stay legal on axle weights. Per dot regulation you can only have so much weight on an axle. Having a lift axle allows more weight to be carried legally

    • @Psyopcyclops
      @Psyopcyclops Рік тому +251

      Thanks for that. No need to watch the video now. I’m out! ✌️

    • @jc_yadigg
      @jc_yadigg Рік тому +189

      bro really tried to spend 6 minutes to explain 1 sentence

    • @maxx-er3fj
      @maxx-er3fj Рік тому +57

      ​@@jc_yadiggand he repeated ut 25 times💀

    • @notitots20
      @notitots20 Рік тому +3

      also road wear which is also related to legal restrictions on road use.

  • @problemimentali
    @problemimentali Рік тому +646

    I once got a ride from a truck driver and I asked him this exact question and he gave me this same explanation in details. He also explained me how the gear box of a truck works, which is quite different from a car. That was a very informative trip.

    • @JonSanders
      @JonSanders Рік тому +42

      Did you have to "pay him back" for the ride? 😮

    • @JonSanders
      @JonSanders Рік тому +19

      @@poopyanalbumhole good thing it was a joke!

    • @Dargonhuman
      @Dargonhuman Рік тому +9

      @@JonSanders Oh no, that was free. I may be broke but I'm no prostitute.

    • @JonSanders
      @JonSanders Рік тому +8

      @@Dargonhuman I've just seen movies and have heard crazy enough stories to never try such a thing. I'm glad you're trusting and nothing happened, though ❤️

    • @Dargonhuman
      @Dargonhuman Рік тому +11

      @@JonSanders lots of stuff happened. It was all consensual though.

  • @WhiteTiger333
    @WhiteTiger333 Рік тому +506

    Oh! I knew it had something to do with how much weight the truck was hauling. But I just learned that the raised wheels don't just plunk themselves down on the road when the weight is "enough". I appreciate learning things like this. I was also not aware of the other reasons it can be advantageous to raise or lower the 'extra' axles.

    • @Big_Theft_Auto
      @Big_Theft_Auto Рік тому +1

      Same!😅

    • @richardpowell1425
      @richardpowell1425 Рік тому +20

      If you put enough weight on the truck all the axles will touch the road 😅

    • @saurabhsonic
      @saurabhsonic Рік тому +3

      gotta love UA-cam!

    • @anderstermansen130
      @anderstermansen130 Рік тому

      wtf no? It have nothing to do with weight, the LORRY is hauling. Its the spare tire.

    • @Win7ermu7e
      @Win7ermu7e Рік тому

      I always thought the ones up on the frame like that were spares. . .

  • @Skelterbane69
    @Skelterbane69 Рік тому +196

    Being able to lift the boggie axle and apply as much pressure on the powered axle is definitely a must, up here in Sweden, during the winter.
    However, once you get on the motorway, you usually have it lowered, so that the truck isn't so wobbly to keep going straight.

    • @saab93secv
      @saab93secv Рік тому +21

      Glad you say this because the video did not make it clear that the way to increase traction is to RAISE the axle.

    • @leifgunnartoth8070
      @leifgunnartoth8070 Рік тому +7

      Same in Norway. Usually the lorries can't lift the boggie if the weight is too high, but up here in the north, we can. Lifting a boggie axle when fully loaded, can give you 20+ tons pressure on the driveaxle, and therefore gives you ALOT more grip on slippery surface.
      Like Skelterbane69 says, once we're on the bare road, the axles goes back down to keep the lorry more stable :)

    • @knightwing4
      @knightwing4 Рік тому

      In America most of the time those are automatic. Thats why i dont like them. 2 drive axels are much better the a drive and a lift axel.

    • @Skelterbane69
      @Skelterbane69 Рік тому

      @@knightwing4 Our backup truck is a DAF and it's automatic like that too and I hate it. Absolutely worthless in the winter. Wish we had a truck with tandem axles, but it's unnecessary for what we deliver anyway.

    • @leifgunnartoth8070
      @leifgunnartoth8070 Рік тому

      @@knightwing4 In what way is fixed tandem drive better than a lift axle? On a tipperlorry, it's understandable. But for 99% of the lorries out on european roads, a boggie lift axle is the way to go. Less wear on the tires, easier to menouver around narrow streets.

  • @Ronald.Golleher
    @Ronald.Golleher Рік тому +773

    The largest reason in the US, mentioned in the video, is for weight distribution on construction vehicles, like cement trucks or dump trucks, or heavy haul trucks.
    Another thing not mentioned in the video is that lift axles are rarely, if ever, powered and are only there to provide extra load-bearing capacity.

    • @coolsnake1134
      @coolsnake1134 Рік тому +3

      So how do they lower when needed and raise when you don't need them? Does the vehicles frame rails actually flex a bit under the load and the flexing and sagging of the frame is enough to bring the wheels to the point where they touch the road?

    • @Ronald.Golleher
      @Ronald.Golleher Рік тому +37

      At 4:52 you can see two sets of air bags. The smaller ones lower and on their side will inflate and push the axle upward, the larger ones deflating at the same time. The large ones are the main suspension bags, and will inflate to push the axle down to the road and bear weight while the smaller ones deflate.

    • @gumballer133
      @gumballer133 Рік тому +10

      ​@coolsnake1134 They are on air bags, air up and air down. You just flip a switch in the cab. It's pretty easy. Most of my dump trucks have 4 lift axles, leave them up empty or put one or all down when loaded. Because the lovely state of Ohio will bust you if not.

    • @johnarnold893
      @johnarnold893 Рік тому +2

      @@gumballer133 Did you know that it is illegal to use them in Canada?

    • @gumballer133
      @gumballer133 Рік тому

      @johnarnold893 Really? They have to be down permanently?

  • @kendramiller1830
    @kendramiller1830 Рік тому +138

    I always thought they were required by law to carry a certain number of spare tires. This makes so much more sense. Thanks

    • @SuperBobblehead77
      @SuperBobblehead77 Рік тому +21

      Yes they are not spares they do have a purpose. As a trucker I giggled at this comment no hate to you but I wanted to comment for fun 😂

    • @DutchVanDerLindo
      @DutchVanDerLindo Рік тому +4

      @@SuperBobblehead77 truckers being assholes as always...

    • @TacticalRuse
      @TacticalRuse 11 місяців тому +1

      @@DutchVanDerLindo Spare Tires he said 🤣🤣

    • @Christophertruck
      @Christophertruck 11 місяців тому +6

      ​@@SuperBobblehead77 it was a joke stop crying

    • @ONeA2122
      @ONeA2122 11 місяців тому +1

      @@DutchVanDerLindo i thought they are spears too at first, but then i realized how tf would a person be able to handle suck a big and heavy wheel and also jacking up a loaded truck

  • @barrycrosby8602
    @barrycrosby8602 Рік тому +187

    Here in the UK nearly all tractor units are the 6×2 configuration ie 6 wheels 2 wheels powered with a lift axle on the middle, the lift axle will only lift if the weight on the drive axle is below the maximum axle weight, we operate double deck trailers and you have to run with the lift axle down at all times as lifting the axle could cause the suspension plates or the rear bumper to ground, running with the axle raised increases the height so the trailers could be above 16"6" which is the legal height limit in the UK and potentially cause a bridge strike but this would be rare as most bridges are about 17" on main trunk roads

    • @brianb-p6586
      @brianb-p6586 Рік тому +12

      The automatic control is important. Without it, drivers would drive with high load and the axle lifted, causing excessive load on the non-lifting axle. This is the reason that the use of lift axles is restricted in western Canadian provinces - the regulators don't trust drivers to avoid overloading by incompetent or reckless operation.

    • @fredfrederickson
      @fredfrederickson Рік тому +5

      Only 17”?! Holy moly that’s short

    • @brianb-p6586
      @brianb-p6586 Рік тому +3

      Obviously the heights were supposed to be 16'7" and 17',@@fredfrederickson

    • @fredfrederickson
      @fredfrederickson Рік тому +5

      @@brianb-p6586 So they built them all nearly 16 feet short of the height they’re supposed to be? That’s even worse!

    • @Cdaragorn
      @Cdaragorn Рік тому

      @@brianb-p6586 If you think you have to force people to do what they should you've already failed as a manager/regulator. The entire US is literally proof that you don't.

  • @Nyootnyooot
    @Nyootnyooot Місяць тому +109

    my dumbass idea is it was spare tires

    • @malikkimanimaasai3703
      @malikkimanimaasai3703 Місяць тому +5

      Yep, you are not the only one😂

    • @johngeiger3770
      @johngeiger3770 Місяць тому

      Same here until saw it pushed down by the weight and start rolling.

    • @MexicanBagpiper96
      @MexicanBagpiper96 27 днів тому

      That's what I used to think when I was a kid. I once asked my uncle, who owned his own truck, why some trucks had so many spare tires.

  • @jimBobuu
    @jimBobuu Рік тому +9

    Ive been wondering this for YEARS. Like since 1982! I just never thought to ask or even look it up.
    Thank you, almightly algorithm!

  • @111jacare
    @111jacare Рік тому +44

    Back in the old days, pre July 1979, the lift axles were known as Tax Axles, due to the Road Maintenance (Contributive) Tax that was applied in all jurisdictions. They were set up on spring suspensions with a single air bag which was inflated to raise the tax axle. This was generally the rear axle of a tandem group on a rigid, or appropriate axles on a tandem or tri-axle.

  • @Silentguy_
    @Silentguy_ Рік тому +27

    So cool little bit of side info. Since these wheels are raised and lowered with airbags, most trucks allow you to adjust the pressure in the airbags to maintain proper ground pressure for weight distribution and traction.
    Too much pressure and you can actually put too much weight on these tires leading to excessive wear and even blowouts and you can even make it to where the drive wheels don’t have enough traction. While too little pressure can effectively mean they aren’t even doing anything.
    Also a fun little side story, I was doing first time inspection on a truck we bought that had a set of these wheels. I found out the pressure regulator was actually broken for the airbags and when I went to drop the wheels the airbags were so over pressure that you actually couldn’t drive the truck while it was empty because it completely lifted the drive axel about an inch off the ground. Had to basically rebuild the system for the drop wheels because of this

    • @sergeantspeed5941
      @sergeantspeed5941 11 місяців тому

      That's literally fake news. I won't say 100% of all trucks, but almost every single truck is equipped with a dump valve. Not a pressure regulator.. we can't just adjust pressures on the fly. Trucks have ride height adjusters though, but they're completely independent from the drivers seat.
      It's just a lever that moves up and down with the weight of the load that adds or subtracts pressure from the bags to maintain proper height. Has nothing to do with tire ground pressure, or anything else. Strictly a way to maintain the same height regardless of load.

    • @KilnGuyBob
      @KilnGuyBob 11 місяців тому

      @@sergeantspeed5941 Yeah he thinks that truck axles still use spring and only the tag axles have air bags. Also this garbage video thinks that they actually provide power for some reason because "2?" trucks do.

    • @KilnGuyBob
      @KilnGuyBob 11 місяців тому

      Sooooo, no. The axles that lift up when not needed have springs to lift them up. When the driver needs them their air bags are tied into the entire truck airbag suspension system to make sure the bullshit you are saying can never happen. And to be clear, The amount of engineering, and cost per truck, it would take to make the tag axles an entire independent system would make it more difficult to use is an order of magnitude more than just tying it into all the other airbags on the drive axles. You obviously have no idea how trucks actually work.
      You're an idiot.

  • @EyebrowsMahoney
    @EyebrowsMahoney Рік тому +22

    Front lift axles (ahead of drive axles) are often called "Pusher axles" as well. This is because your driveline "pushes" the axle along, rather than "tagging" along the rear.
    Some trucks also have "steerable" pusher/tag axles. They lock out when retracted.

  • @phillipmoore6295
    @phillipmoore6295 Рік тому +12

    BTW you must pay for those axles when using a toll road, whether up or down. I found out a long time age, when towing a truck with lift axles. I had to pay for the wreckers axles and ALL of the trucks axles "including" the lift axle.

  • @kevinhoward9341
    @kevinhoward9341 Рік тому +12

    I drove auto transport trucks for almost 30 years, some of the trucks had a "Tag Axle" some a "Lift Axle". The tag axle was an air suspension axle that when the air was released would still ride on the ground but not carry any weight. The lift axle when no air was applied would lift off the ground.

    • @GAZZA55
      @GAZZA55 Рік тому

      yes i know the ones you mean very common in new zealand .

  • @deserteagle7032
    @deserteagle7032 Рік тому +52

    Actually the real reason for lift axles is toll tax. You pay per axle/wheel on the road. Trailers also have lift axles. When not loaded the axles are lifted to save costs ie, tax. They also have another benefit in that they reduce rolling resistance and save fuel.

    • @tr1bes
      @tr1bes Рік тому +3

      I was wondering about the axel payments billboard as I pass through the tollway. It listed as 2 axel payment (regular vehicles) a certain amount and then 3 axel+ payment.

    • @deltaxcd
      @deltaxcd Рік тому

      that is dumb. I think it is not like it works you should pay not per axle but per road load using more axles should reduce the amount you pay not increase it because by using fewer you are loading the road more
      as I know you need ot use more axles not to exceed the allowed axle limits that are often measure by police or automatically

    • @Jimmy_CV
      @Jimmy_CV Рік тому

      you beat me to it, used to work for a garbage company, we only ever deployed the push axel before hitting the weigh station, then pulled em up as soon as you were off the scale.

    • @davidawaters
      @davidawaters Рік тому +2

      The funny thing is that the tax (per axle) is justified by damage done to the road. By running fewer axles, they pay less tax, but the pressure on the road increases accelerating road wear.

    • @deltaxcd
      @deltaxcd Рік тому +3

      @@davidawaters Yes exactly, an idea to tax per axle which is down is beyond stupidity of even average politician, it can be true that they passed such law fo real.

  • @obtrunco
    @obtrunco Рік тому +66

    Thanks for this. I always saw construction trucks with a raised axle which puzzled me. The only explanation in my head, was that it helped as a form of support for when the truck climbed onto mounds at a site to dump its contents.

    • @TruckTropia
      @TruckTropia  Рік тому +5

      👍

    • @trueriver1950
      @trueriver1950 Рік тому +6

      My imaginative explanation was that if the truck got a flat tyre the driver could drop the lifted axle and raise the one with the flat. I didn't really believe it but it was the best I could think of.
      Many thanks to the channel creator for solving the mystery for me. Definitely a like 👍👍🌟

    • @Rose-yx6jq
      @Rose-yx6jq Рік тому +6

      I actually asked my dad that about a dump truck (I think I was around 10) and I think he said that it was for when they were going over train tracks so it didn't scrape the underside if it was a little too high of an angle. I'm starting to think he made that up on the spot.

    • @deltab9768
      @deltab9768 Рік тому +1

      Yeah this is what I thought. I thought they were fixed in place and only there to help drive over uneven surfaces.

  • @neru10183
    @neru10183 Рік тому +113

    It's 3 AM, wtf am I doing here

    • @Just_Prob
      @Just_Prob 8 місяців тому +7

      Same 😂😂

    • @souvikbiswas284
      @souvikbiswas284 7 місяців тому +5

      Actually it's 4 am now🙂‍↕️

    • @goofycat676
      @goofycat676 7 місяців тому +4

      Same for me lol

    • @dalmar5567
      @dalmar5567 7 місяців тому +4

      You're lonely

    • @leechjim8023
      @leechjim8023 Місяць тому

      Too much caffeine!!?😮🤪🤪

  • @DNV75
    @DNV75 Місяць тому +1

    I swear I'm not lying. This is the first time the algorithm actually answered a question I just asked myself yesterday. I can smile the rest of the day.

  • @ianrastoski3346
    @ianrastoski3346 Рік тому +8

    Take a drink every time he says "distribute the load evenly."

  • @sanjogkarki
    @sanjogkarki Місяць тому +12

    5:44 you are welcome

  • @jasonrabe1664
    @jasonrabe1664 Рік тому +59

    I have a drop axle on my freightliner. They are more prevalent in the Pacific Northwest and upper midwest. Nonexistent anywhere else on tractor trailers except for Heavy Haul applications with duals. Used for spreading weight out on drive axle group when you have more than 80,000 gross vehicle weight as the norm. Helps to take weight off drive axles rather than go the the trouble of sliding tandems or fifth wheel. Flip switch and work is done.

    • @CanCobb
      @CanCobb Рік тому +2

      Finally a comment with the interesting and necessary information. Also the Pacific Northwest has a ton of cross border deliveries, and the weight limits are all different in Canada. For trucks that have to comply with both sets of regulations, it's very useful to have a couple of different drop axles, including to take weight off the steer axles as well. Steerable drops are not allowed in Canada, so the weight limits end up being higher in the US. The added expense was justified by being able to charge higher than standard rates in order to take a couple of extra units across the border.
      Fun fact: Idaho has an entire worksheet that a truck driver must complete in order to operate in that state. There are some VERY tight hairpins in some places, and truckers are given the specific roads that they are permitted to drive on based on this worksheet.

    • @moparjr89
      @moparjr89 Рік тому

      ​@CanCobb wrong I live in Idaho and got my cdl in Idaho as well as drove trucks with lift axles Idaho has no special sheet requirements. Only difference with an 8axle truck over a 5axle truck is making sure your weights as well as length are within legal limits which applies to every truck in every state its called bridge law

    • @jasonrabe1664
      @jasonrabe1664 Рік тому

      Might be referring to truck registration, not company driver responsibility. There are tight roads in Idaho mts I'm sure.

    • @musicauthority674
      @musicauthority674 Рік тому +1

      80.000LBS is the maximum weight for all highways in the US. and anything more than that requires tag axles plain and simple.

    • @jasonrabe1664
      @jasonrabe1664 9 місяців тому

      Wrong. Some states like Washington allow for 105,500 lb. You don't even need a permit you just have to pay extra tonnage on the registration. You would need extra axles to accommodate the weight though. 80,000 lb is for five axle truck.

  • @allanweaverling730
    @allanweaverling730 Рік тому +2

    Drove a coal hauler dump truck. Had a high side dump box and carried 22 tons. Axle in front of the drive axles helped take the load of the front axle. Had to raise them when making a tight turn

  • @MicraHakkinen
    @MicraHakkinen Рік тому +7

    Another benefit of lifting a tag axle is a reduced turning radius. Some Volvo trucks allow you to lift the tag axle at low speed even with a heavy load, and will automatically lower it again when you exceed 30km/h.

  • @Chicken-x6q6d
    @Chicken-x6q6d Рік тому +4

    I used to work on a rigid refuse truck which had an extra axel like that at the back in front of the main rear one, it lowered automatically once you reached a certain load weight (typically around 22000 KG) though you could also lower it yourself with the onboard computer. I’m not sure if Dennis Eagle makes those types any more. All the later models I used have the single wheel axels behind the main rear axle and they are connected to the steering, thus always down.

  • @twicedemita2151
    @twicedemita2151 Рік тому +6

    In Australia with trailers axles raising up is only when empty but if full loaded they’ll lower it down

  • @SmashMasterQ
    @SmashMasterQ Рік тому +4

    I was just thinking about this question and this video showed up. How perfect.

  • @Zarkonem
    @Zarkonem Рік тому +5

    I felt like i already knew the answer to this, and to an extent i did. I knew the floating axle was for when the truck had heavier loads and figured it was for better weight distribution on the suspension. What i didn't know was that they could be lowered dynamically. I thought they activated when the suspension sunk far enough for the floating wheels to touch the ground. Now i know better, all because i didn't let my hubris skip over this video i thought i already knew the answer to.

  • @DefenDefault4
    @DefenDefault4 9 місяців тому +2

    I didn't even know they can be lowered and lifted manually. I thought it's only use is when the the truck gets so heavy that the real axles get squished which makes the lifted one touch the ground. Also another use I thought is when the truck is going in a vertically very curved road.

  • @benjisgarbagetrucks
    @benjisgarbagetrucks Рік тому +18

    Great explanation! With garbage trucks, they put tag axles on the jumbo garbage trucks and lower the tag or tandem axle when the load is too heavy.

  • @caleblarsen5490
    @caleblarsen5490 Рік тому +2

    You can also shrink your turning radius a little by picking up an axle. Not by much, but every little bit helps.

  • @andrefortuin4554
    @andrefortuin4554 Рік тому +8

    Here in South Africa we call our Trucks "Horse and trailers" or the ones with two trailers we call "Super-links" and our are have always two drive axles at the rear(*6x4). Trucks that are 6x2 or 4x2 are considered smaller trucks. The only region or country with bigger trucks than S.Africa is Australia with their Roadtrains

  • @MF175mp
    @MF175mp Рік тому +2

    The Finnish Sisu trucks are legendary for their axles that can be lifted even when fully loaded and higher than most other brands, enabling you to drive out of that spot where a Scania, MB or Volvo would get stuck.

  • @richs4878
    @richs4878 Рік тому +23

    Never really puzzled me. I figured it was for heavier loads and gave the ability to lift and save the tires from wear when not needed. If truck tires are so expensive that they retread them then this must save a lot of money.

  • @geehammer1511
    @geehammer1511 Рік тому +7

    Thank you for making this video, after many hours playing ETS2 & ATS I've always wondered what use having a liftable axle had, maybe now I'll convert some of my game trucks to have the chassis for them.

  • @williamblack5101
    @williamblack5101 Рік тому +3

    I drove a tri-drive for years. Had a few drivers tell me my tag axle was down. Then had to educate them on how tri-drives work.

    • @joecummings1260
      @joecummings1260 6 місяців тому

      Not many tridrives around here at least. I worked on Macks in the Philly area and I can remember maybe 3 of them running around. All dumps

  • @halobloksmexico4980
    @halobloksmexico4980 11 місяців тому +1

    I speak about trucks like once a year, last time it was two days ago and exactly about this topic as we crossed a truck that was raising an axle of tires. I was asked about it, answered (by live voice, not even text or voicenote) and now I have this video at the top of my home page...

  • @lilg8017
    @lilg8017 Рік тому +10

    0:12 thanks for the reassurance. It was really freaking me out!

  • @venonat80
    @venonat80 Рік тому +1

    For the longest time I thought the wheels off the ground were the spares for the truck. One day I saw a truck lower the wheels that were previously in the air. Still I thought it was for the purpose of changing the tires since it lifted the other axels up higher off the ground.
    Now know why. Great informational video.

  • @Lothclutch
    @Lothclutch Рік тому +3

    I was playing snowtires. My friend bought a truck with this axel we talked about it and this video popped up on my recommendation. LoL

  • @Khemani_RL
    @Khemani_RL Рік тому +2

    I saw a truck on my way to College today with its axle raised up, and it intrigued me. I didn’t even search for this video and somehow my UA-cam algorithm recommended this to me coincidentally 😅

  • @russvoight1167
    @russvoight1167 Рік тому +8

    Lift axles ahead of the drive axlels are called pusher axlles

  • @mn815048
    @mn815048 Рік тому +1

    I have a lift axle on my truck solely for heavy loads. It's a 4 axle truck, and the first axle in the drive group (closest to the cab) can be lowered to meet the bridge law requirements. The pressure in the airbags can be adjusted to shift weight between the steer axle and the drive axle group. Adding another full axle allows an additional 20,000 pounds to be permitted on the drive group, up to 60k on 3 axles (in most places).
    I also run a RGN trailer with 3 fixed axles and a pin-on flip. 4 pins hold the last axle onto the trailer. 2 pins can be removed and the axle can be flipped up when not needed. Or all 4 pins can be removed and the axle comes off.

  • @Bulvan123
    @Bulvan123 Рік тому +5

    I assumed it was save tire wear (seened an expensive way to "save" money.) Also for tolls if they only charge for axles touching the road. My issue is id say 97% of lift axles i see are lifted all the time. Im wondering does the average driver really calculate axle weight & raise & lower it as needed? Or is it lifted on day one & never actually put in use?

    • @DonGorgen
      @DonGorgen Рік тому

      It's every truckers responsibility to know you're within weight regulations. Either by knowing the weight of your cargo or drive onto a weight station, and then lower the tag axle if needed.
      The money you save by trying to cheat the system is not enough to cover even a fraction of the fine you risk if you get busted with overweight.

    • @Bulvan123
      @Bulvan123 Рік тому

      @@DonGorgen i agree, but I'm really talking about the dump trucks making local runs where they're not gonna be stopped for weighing or anything else (at least not where I live). I rarely if ever see the lift wheels down. I don't think local drivers really care to bother with calculations & all that.

    • @ernestdesimone2234
      @ernestdesimone2234 Рік тому

      That may be because you are only noticing the ones that are up in the air and not rolling. When that axle is lowered we all tend not to even notice it.

  • @MarcusRefusius
    @MarcusRefusius Рік тому +1

    I drove Heavy Trash Trucks in National Parks for 25 years WAY UP in the Mountains.. Front Loaders and Rolloffs. Tag axles are great. Two added tons of payload. When you’re 60 miles from a landfill that comes in handy. The added braking really helped too.

    • @LuckyCharms777
      @LuckyCharms777 Рік тому

      What a great “office” location. You were a lucky guy.

  • @amunra8510
    @amunra8510 Рік тому +8

    The question I always wanted to figure out but never took the time to look up. Thank you!

  • @Sefhen
    @Sefhen Рік тому +2

    In european trucks, we have had "automatic" axles for years now, when a sensor measures enough weight on one axle, it will drop down lift axles to balance them out. Also nowadays they have automatic balancing feature too so the liftable axle isn't pushing down with full force but instead just enough so that the drive axle is at full legal maximum load.

  • @owlenderg
    @owlenderg Рік тому +4

    From my experience in Snowrunner,
    Keeping the axle lifted helps with traction more for some reason, even though it should be the opposite

    • @nimruil337
      @nimruil337 Рік тому +11

      Less wheels carrying the weight => more weight on each wheel. More weight => more traction. Hope it helps

    • @Patty-qy8qh
      @Patty-qy8qh Рік тому

      The lowered non driven axle also prevents the driven axles from digging into lose ground where the tyres can reach some traction, because it's just sitting on top

    • @owlenderg
      @owlenderg Рік тому +1

      The issue is though, it doesn't seem to be that effective in Snowrunner
      Occasionally it's helpful, but usually I can go through mud faster if the wheels are raised
      It's the opposite to what I'd expect

    • @Cdaragorn
      @Cdaragorn Рік тому

      @@owlenderg Sounds like what you're describing isn't traction, but reduced friction. Assuming you don't need the extra pulling power having fewer wheels on the ground will mean less friction to push against.

    • @williamdouglas2549
      @williamdouglas2549 Рік тому

      I always raise my tractor tag when it snows. It drops my steer down to 10k when I'm loaded and tag down. I can get 3 to 4 k more on my steers by raising my tag. Really helpful for turning in slick conditions

  • @bm5906
    @bm5906 Рік тому +1

    This was one of the most interesting and informative videos I've ever seen on UA-cam. On the high side of 60, I've wondered about this for decades. Thank you.

  • @brianb-p6586
    @brianb-p6586 Рік тому +4

    Miscellaneous clarifications, corrections, and additions:
    A "lift axle" is any axle which can be lifted, regardless of position (despite the suggestion that they are only ahead of the rear drive axles).
    An axle can be both a drive axle and a steer axle - they are different characteristics, not exclusive types.
    A *tag* axle is any unpowered axle behind the rear drive axles... whether it lifts or not. An unpowered axle ahead of the rear drive axles is often called a *"pusher"* axle.
    Unpowered axles in the rear (ahead of or behind the drive axles, so pushers or tag) can be passively steered (castered) or actively steered (linked mechanically, hydraulically, or electronically to the main steer axle).
    Lift axles are used on both trucks (including highway tractors) and trailers.
    The word is tire "wear", not "ware".

    • @maxi5778
      @maxi5778 Рік тому +1

      There's also lift axles (usually tag axles) that are powered

    • @Ronald.Golleher
      @Ronald.Golleher Рік тому

      @maxi5778 how does a powered lift axle work?
      Edit: What I mean is how a lift axle can be powered? What keeps it from receiving power while lifted?

    • @jasonrabe1664
      @jasonrabe1664 Рік тому

      Air bags push them up. Reverse air direction and they deflate while full size bags inflate pushing axle to ground.

    • @rikardandersson7288
      @rikardandersson7288 Рік тому +1

      ​@@Ronald.Golleherbasically works as a normal tandem drive, when you want tandem drive you lower it and activate the power divider. Disconnect power divider and lift the axle when not needed. I dont know how much of the process is automated (ie. The tandem drive most likely automatically disconnects if you lift the axle) but the principle is more or less the same as for a normal non liftable tandem drive

    • @Ronald.Golleher
      @Ronald.Golleher Рік тому +1

      @@rikardandersson7288 ah that makes sense, assuming either the power is disconnected or the wheels are braced against something so they can't turn.

  • @derby2510
    @derby2510 Рік тому +1

    Love watching trucks. Like to see them on the different roads. Can’t beat a truck for heavy loads.

    • @krane15
      @krane15 Рік тому

      Really? What's use to deliver trucks to market? I'm thinking ships and rail.

  • @brocktonhaught5347
    @brocktonhaught5347 Рік тому +5

    5:40 YOUR WELCOME

  • @alooga555
    @alooga555 Рік тому +1

    Thank you for making this video. You have answered the questions I had about this going back 30 years.

    • @cristibaluta
      @cristibaluta 11 місяців тому

      You could have googled it

  • @rogersmith7194
    @rogersmith7194 Рік тому +7

    Nice vid. It was very informative about something I’ve always noticed on the road, but about which I’ve only speculated as to why. It’s nice that this vid helped to validate why I thought larger semis and dump trucks have this feature. Thank you.

  • @God.Almighty
    @God.Almighty Рік тому +1

    i didn't really need this info but youtube insisted and now it'll live in my head forever.

  • @USArmyVet91
    @USArmyVet91 Рік тому +4

    This has been something that has bugged me for years. I came up with the brilliant solution that an axle was lifted only when making sharp turns, then dropped once on the straight and narrow... I have only seen it them on Dump Trucks, not the Big Rigs. So yeah I feel a bit silly, but also a bit smarter thanks to your explanation. Thank you. 👍👍

    • @Rigel_Chiokis
      @Rigel_Chiokis Рік тому +1

      You are not wrong. They do raise the extra axles, especially the ones that are on trailers, making turns at intersections. Otherwise, they end up dragging those wheels sideways through the turn which risks damage to tires or even popping a tire of the rim. But, if the vehicle is loaded, you don't want the axle up for too long or the weight might blow one of the tires that's still on the ground. It's a balancing act!

    • @USArmyVet91
      @USArmyVet91 Рік тому

      @@Rigel_Chiokis Thank you for that. I feel less silly now. 👍👍

    • @Pesmog
      @Pesmog Рік тому

      For yard work in places where low speed tight maneuvering is needed a driver might lift the axles to reduce tyre scrub, but it does depend upon the axle configuration of the vehicle.

    • @moparjr89
      @moparjr89 Рік тому

      ​@@Rigel_Chiokiswrong axle and tire ratings are higher then the dot allows for example the drive axles on a semi are legal for 34k but they are rated for 40k by manufacturers. So lift axles are solely there to make sure the truck stays dot legal on weight. The weight ratings are set by the government as the max allowed weight per axle and tire as to provide best service life of roads

    • @Rigel_Chiokis
      @Rigel_Chiokis Рік тому

      @@moparjr89 my country doesn't have a DOT and our rules are different. :)

  • @504RoadTrips
    @504RoadTrips Рік тому +1

    I always wondered about those, and had an idea of what they were for, but this video explained it in detail in a language anyone could understand.

  • @UrvineSpiegel
    @UrvineSpiegel Рік тому +7

    All these years, I thought they were spare tires

    • @Kevon-m8b
      @Kevon-m8b Місяць тому

      😂😂😂no joke bro

  • @ronaldpainting5614
    @ronaldpainting5614 11 місяців тому +1

    In the 70s i drove a Volvo F86 with a raised axel configuration. Great for farm deliveries in Scotland in winter.

  • @DefundTheFringes
    @DefundTheFringes 6 місяців тому +4

    Grammar fix: "Why Do Some Truck Tires Don't Touch The Ground?" Remove "Do" or change "Don't" to "Not."

  • @deant876
    @deant876 Рік тому +1

    That was a pretty good explanation, but you missed one big reason for the lift axle. Here in Michigan, we can run 160,000 pounds. That will require a total of 11 axles to carry the weight. It you do not have the steerable lift axles, When you are fully loaded and have the axles down and you have to make a tight turn (like 90° on to a street), you have to raise the axles. If you do not, you will end up dragging tires sideways. That will stall your truck, damage you tires, or tare up the pavement.

  • @jacka55six60
    @jacka55six60 Рік тому +5

    Next time you see some biker riding a wheelie down the highway, remember, he is saving the environment.

  • @kdigitalproductionservices6581

    3:31 Lifting or lowering axles to comply with mass regulations? Can you explain this better?
    Whether you lift or lower an axle won't change the overall mass of the vehicle, whether it's overloaded or not.
    Overloaded vehicles cannot change their mass by adjusting which axles are touching the ground.

    • @pontiacg445
      @pontiacg445 Рік тому

      Mass per square inch of contact is what they care about. More axles with the same load means less mass per square inch. It's pretty much that easy.
      Have you ever seen a bridge weight limit sign with multiple trucks and higher weight limits for the bigger trucks? It'll say something like 4T with a two axle box truck, 6T with a common semi trailer config with three axles, and then a pic of a tractor pulling doubles with 4 total axles and a 8T limit.
      If you do the math, you'll find that that means the bridge is rated to hold 2 tons per axle.

  • @VM15
    @VM15 Рік тому +30

    “Have you ever driven a truck …” -No

    • @HirukaArunathilaka
      @HirukaArunathilaka 4 місяці тому

      ETS2 players be like : ...

    • @MrDannyDetail
      @MrDannyDetail Місяць тому +1

      He said 'have you ever driven BY a truck?'. So, have you ever gone past one?

  • @marh122
    @marh122 Рік тому +1

    THANK YOU ! Since I was a kid my lifelong question is now answered

  • @riffdex
    @riffdex Рік тому +3

    1:55
    The video: “Well, actually…”
    Me: “Well, axelly…” 🤓

  • @RAMROD1847
    @RAMROD1847 Рік тому +2

    Sometimes we forget just how beautiful machinery is.

  • @TheEmperor000
    @TheEmperor000 Рік тому +2

    LOL, I always thought it was the spare tires!

  • @geodude7116
    @geodude7116 Рік тому +1

    I always subconsciously wondered why. Thanks for this explanation.

  • @jmaus2k
    @jmaus2k Рік тому +11

    Lift axles in front of driven axles are pushers. In the video they were referred to as just lift axles. There is another version not mentioned too, the steerable pusher, usually added as a second pusher.
    A more concise reason for lift axles is to allow trucks to stay under the maximum weight per axle limit on some roads or bridges.

    • @kikixchannel
      @kikixchannel Рік тому +3

      Your more concise reason for lift axles is simply not a reason for lift axles. In fact, this is the problem I had with this video as well. Most of what was told has nothing to do with the lift itself.
      No, lift axles are NOT there to distribute the weight across more axles or to deal with weight regulations. That is what an extra AXLE is for. If it was permanently lowered type, there would be literally zero difference for any of these purposes.
      The lift part is there strictly to save money on things like fuel and wear when the extra axles are NOT needed. Nothing more and nothing else.
      Remember, a non-lift axle is the default! Therefore reasons for a 'lift axle' is reasons to add a lift mechanism to a non-lift axle, and NOT a reason to add additional axle!

    • @jmaus2k
      @jmaus2k Рік тому

      @kikixchannel Lift axles take weight off the driven axles to meet the local and state road axle limits. Most states only allow 34k lbs on tandem axles. You can haul more by putting a lift axle down. Lift axles are rated by the weight they lift. Tags are usually 13.5k lbs and pushers are 12-20k lbs. Truck designers add lift axles to keep all axles when loaded under the axle weight limits for areas they are traveling.

    • @kikixchannel
      @kikixchannel Рік тому +2

      @@jmaus2k You do not understand the point of my post...
      I know that putting the lift axle spreads the weight between larger surface and more axles. However, this is not a trait of the LIFT axle, but of an AXLE altogether. If you have eight axles and two are lift axles, when they are down, the distribution is exactly the same as when you have four axles and none are lift axles. Therefore, the 'lift' function in the axle has literally zero effect on the adherence to the regulations.
      The lift is NOT added for adherence to legal limits. It is added so that you can save on running costs by not having to go for full load capacity at all times.
      Basically, you are putting the cart before the horse. Again, a standard axle is the default, the lift is an add-on. Don't make the lift the default when it's not.

    • @jmaus2k
      @jmaus2k Рік тому

      @@kikixchannel You can't easily add solid axles that are down all the time in front of tandems. In fact there are no solid axle options for the center frame mounting of trucks because the driveline is in the way. To avoid scrubbing tires when turning you also can lift up lift axles. So it is the most reasonable way to add weight capacity to a truck. And of course, they can be lifted when empty to save fuel. They can also be lifted where roads are less strict. Primarily the reason to buy a lift axle option on a truck is to gain weight capacity(after you get past tandem axles).

  • @gwiyomikim5988
    @gwiyomikim5988 Місяць тому +1

    Maybe I missed it, but do lift axels have their own hub odometers? Seems like a necessity to schedule maintenance and assess wear & tear.

  • @Siklebider
    @Siklebider Рік тому +5

    I'll watch anything the algorithm gives me at 3am

  • @Noone-g5z
    @Noone-g5z Рік тому +1

    Finally the answer to the question I've been thinking about for my whole life

  • @darshan.sk37
    @darshan.sk37 Рік тому +62

    This could have been a 60 sec video

    • @shinobicl
      @shinobicl 7 місяців тому +6

      60 secs is not long enough for proper procrastination

    • @CountBaton
      @CountBaton Місяць тому +7

      This ain’t TikTok

  • @marcusmajors6196
    @marcusmajors6196 Рік тому +2

    What are the trucks that have 2 axles in the front and 2 in the rear

  • @jjroyal8530
    @jjroyal8530 Рік тому +2

    Tracey have a great Christmas 😊😊😊❤😮😊

  • @scarcesense6449
    @scarcesense6449 Рік тому +2

    If lowered axles increase grip and improve safety, is there an automatic deployment option under emergency braking/steering? Seems there should be.

    • @sergeantspeed5941
      @sergeantspeed5941 11 місяців тому

      No because when empty, the more tires you have, the less pressure per square inch is applied to the ground i.e you skid the tires much easier.
      When loaded, yes because at full brake, you still can't skid, but benefit from the extra wheels braking.

  • @VanWeeden420
    @VanWeeden420 Рік тому +4

    Don't forget axel rose

  • @ephraimemmanuelmuwema3444
    @ephraimemmanuelmuwema3444 Рік тому +1

    I had the dumbest idea - thought they were spare Tyres.
    👍🏿Informative

  • @billr3053
    @billr3053 Рік тому +3

    0:40 - “Axels are connected to the wheels by bearings”. Nope. Axels are connected to the wheels very rigidly via bolts, making a solid unit. The axels, near the wheels, are connected to the suspension system via roller bearings allowing free rotation of axel & wheel combination.

  • @markpritchard
    @markpritchard 11 місяців тому +1

    I drive a Volvo with a tag axle. Some times i lift it when i'm fully loaded when i'm in a tight space as the truck turns better with the axle lifted. We also have a lifting front axle on are trailers which reduces tyre scrubbing when making tight turns and again makes it alot easier to turn. On the bad side if you drive an empty tag axle it makes the ride very bouncy when its lifted. I sometimes drop the axle down if its a really bad road and again in windy conditions. Inside my hairy little head a tiny bit of extra tyre rear is much better then putting the truck on its side.

  • @scheimong
    @scheimong Місяць тому +3

    This video gives me high school English class vibes... In that you have to write a 500 words essay, but you really only have 5 sentences to say.

  • @NLBassist
    @NLBassist Рік тому +2

    In Europe you see those smaller lifted wheels too, opposed to the normal sized lifted wheels. The small ones on Mercedes Benz trucks are called Rudy Wheels.

    • @Pesmog
      @Pesmog Рік тому

      Yes good point, you tend to see those on tanker and bulk load trucks. They reduce the annual taxation cost but also do not rob the truck of as much payload as a full sized lifting axle and wheel does.

  • @fireaza
    @fireaza Рік тому +4

    I always thought it was because the tires get tired, so they take it in shifts.

  • @PLPlolol1
    @PLPlolol1 Рік тому +1

    The box trucks we have at work have 3 axles with the last one being a lift axle
    often we lift it for taking tighter turns but it also helps with grip on slopes
    another reason to put it down again is stability on highway since these trucks have such a short wheelbase
    our trucks automatically lower the 3rd axle when a certain amount of weight is loaded tho even on heavy loads you can still lift the axle for a moment

    • @Skelterbane69
      @Skelterbane69 Рік тому

      Same here. The legal limit for the driven axle is 11.5 tons here, so the boggie will automatically lower if you go above that.
      However, if you use the press button, you can overcome this.
      I once had a really slippery road where I had to reverse my trailer and to get grip I had to fully press the axle with 15 tons lol, but only for a few seconds.

    • @Anotaren
      @Anotaren Рік тому

      @@Skelterbane69Been driving with over 17 tons a few times on my Scanias drive axle on horrible winter days, no problems at all, people in norway press them over 18 tons without any problems

    • @Skelterbane69
      @Skelterbane69 Рік тому

      @@Anotaren Scania power

  • @thatpersonwithamlpiconwhos2861

    As a kid I always thought these were just spare tires lol

    • @kennethsprouse77
      @kennethsprouse77 Рік тому

      Up until now. I did too.. I'm 40. 😂 makes more sense that it was a lift able axle now though. You'd need some serious tools to change one of those tires.

  • @Cypher791
    @Cypher791 Рік тому +1

    With a rigid vehicle, if it has a lift-able rear “tag axle” that can distribute weight more evenly, but can make it difficult to make a tight turn, even if it’s a rear steering axle, the tyres will scrub across the ground when trying to do an extremely tight turn so it’s best to lift that when driving in towns or cities with lots of sharp turns.

  • @dcentral
    @dcentral Рік тому +3

    I always thought they were just spare tires.

  • @sebbes333
    @sebbes333 Рік тому +2

    I thought "lift-axles" was "stationary axles" that was built to be a bit higher up, but low enough that when a heavy load was placed on the truck, it would push it all down so the "stationary axle" would come into contact with the ground & therefore take up some of the weight, I didn't expect them to be movable, even if that makes more sense, but creates more parts that can break.

  • @martinkuliza
    @martinkuliza Рік тому +5

    0:04 Yeah i have, it's called a lazy axle

  • @steevod6608
    @steevod6608 Рік тому +1

    Stumbled across this video & it's been a question I've always wondered my whole life. Ty for the explanation

  • @gd.ritter
    @gd.ritter Рік тому +5

    Why spend 5 minutes on lift axels and barely say anything about tag/boogie axels. How does a tag axel help?

  • @Normal1855
    @Normal1855 Рік тому +1

    I wasn't looking for this video, but I watched it. Very informative.

  • @JamesPiteo
    @JamesPiteo Рік тому +4

    It should read Why Doesn't it touch the ground?

  • @forzer456
    @forzer456 Рік тому +1

    Hey can I ask why most front truck wheels are indented out while the back rims are indented in? I have always wanted to know.

    • @whyjnot420
      @whyjnot420 Рік тому +1

      If you look, you will find that the outer rims on the back are simply just facing the other way. I.e. inwards towards a second rim. You will find this to be true on just about anything with dualies, i.e. two tires per side on a single axel.

  • @samurai4766
    @samurai4766 Рік тому +2

    I've always wondered why multi-axle U.S. trucks don't have an additional steerable axle like Volvo or Scania have done ?

  • @TheRealJoeMama1
    @TheRealJoeMama1 Рік тому +5

    What's the purpose of the music? To distract? To annoy?

  • @alopezjr
    @alopezjr 26 днів тому

    Thanks for the explanation. I’ve seen this on trash trucks and wondered why those set of tires that are not even touching the ground.

  • @gordospeti
    @gordospeti 11 місяців тому +2

    I love semi-trailer trucks and your vids, thanx for your content! I wonder considering the 6x2 config which is better. Is it better to have the steerable lift axle after the driven axle or before it? Hope you will once cover the topic of steerable semitrailers. That would be cool. Keep on the nice work, good luck to you!

  • @solomonshv
    @solomonshv Рік тому +1

    there is also the issue of road tolls. some roads charge trucks PER AXLE, like the Verrazzano bridge in NYC. having less axles on the ground when not in use can save thousands of dollars a year in tolls.