How does tire pressure affect braking performance?

[@largebills337]

I love how you guys jump from practical automotive advice to off the wall projects like building a car out of logs in the forest. Many channels do one or the other but you guys do both very well.

[@azrobbins01]

A lot of your videos are just crazy and only for fun, but this topic is extremely important and informative!

[@petej.8676]

I think if our world leaders had discussions in their garages over an engine bay...things would be a helluva lot better.✌️

[@SuperFGeeT]

At least we know there be a child sacrifice nearby. Satire

[@MadScientist267]

Manufacturers are imposing anti "right to discuss" policies.

[@MadScientist267]

Oh wait no. That's social media

[@willterry1212]

Must be some model t that would never run

[@GrantJohnston-dr9rt]

Then they would argue about what oil to use! Greetings from Montreal!

[@charleswelch249]

I've been telling people that for years now working in the tire busses, thank you for providing honest results to keep people safe.

[@angrysocialjusticewarrior]

Busses have other important proprieties other than braking. Busses also have to consider weight rating (how much weight each tire can support) to avoid tire bursts or tire overheating. Same goes for large trucks. But for normal cars, this video is correct.

[@winstonsmasterplan]

You should do a 4th test each time with manufacturers tyre pressure spec to verify the first run

[@EvrttGrn]

That's what I was thinking as well.Some of the extra distance could have been from brake fade or glazing due to the hard braking.

[@operator8014]

​@@EvrttGrnor the tires getting hotter and more worn out, or the surface getting scrubbed, revealing newer cleaner rubber beneath.

[@winstonsmasterplan]

@@PREDATEURLT the fact they are similar is reason to do a 4th test to rule out heat soak and glazing. What’s the harm?

[@ckl8a]

unless they do a 4th run at recommended pressure, we can't rule out brake fade, which makes their findings irrelevant, although interesting and entertaining to watch!

[@KenFullman]

@@EvrttGrnI doubt that's happening but they could have just done all the tests again but in the reverse order (ie over inflated, under inflated THEN just right).

[@fangthewarrior]

Tire tread and overall condition is also just as important! Good tires can decrease stopping distance, prevent hydroplaning, be more resistant to punctures, and most of all prevent a blowout. You can check a tire's tread easily by feeling for the wear indicator, when it's flush to the rest of the tread its recommended to replace it. Be sure to go through the entire tire's width. Check your sidewalls for cracks from rot or gashes that aren't cosmetic. Check the date of the tire the newer the better, example would be 0923 9th week of 2023. Any imperfections such as cracks, bubbles.. Really anything that seems off should be looked into, doing these simple inspections could save your and or others' lives

[@youxkio]

Yes, add the rubber softness/hardness or summer/winter/ all weather tires to this experiment.

[@tomaspetrik8953]

You really didn't understand the point of the experiment. This experiment was about varying tire pressure and its effect on braking distance.

[@mediocreman2]

I would only recommend going to the wear bars in warm/dry climates. Otherwise it's not enough tread for rain, and especially not snow.

[@mann_idonotreadreplies]

Cool story bro

[@Miles7955]

The age of the tires 'allegedly' plays a roll in grip as well. I did notice that the Lancer tires were dry rotted. Tire quality as well as wear also would affect the distances tested. Great video, but in order to do a direct comparison, all vehicles would have to have the same brand/model of tire fitted, their date codes being within 3 months of each other, have a wheel alignment, last but not least; have the tires worn in 500-1500km on the car prior to the test.

[@trm4life]

I've had arguments with friends about the recommended tire pressure, vs the tire maximum pressure too many times to count! Thank you for finally making a video that shows the data clearly! I want more of this with suvs, trucks, and crossovers!!

[@angrysocialjusticewarrior]

There is no need to have arguments. Simply tell them to go read their car owner's manual and then come back to you to apologies for disagreeing with you. If you try to hold a debate with them right there and then, they won't listen to you.

[@ranger178]

you should change the order of testing to see if is fading with heat after each braking a smaller change would be more interesting to see if it makes any diference.

[@peglor]

I'd love to see the same test done in wet conditions. Low tyre pressure could make a genuine improvement to wet weather braking as dry friction (Which is independent of tyre contact area) plays almost no part in wet braking as the layer of water between the tyre and the road will act as a lubricant, so hysteresis (Tyres grip on the roughness of the road surface by turning the energy required to make it flex into the roughness of the road surface into heat) in the tyre rubber becomes the sole source of grip. For this reason more rubber in contact at lower tyre pressure should mean more braking friction in the wet. It also means more aquaplaning in standing water though, so the recommended pressure is still the value to go for in the real world.

[@busyguy7479]

Always a pleasure watching these videos ,something to help with stress thanks guys.

[@Andrew-eh1bj]

very interesting. never taught that underinflated tires will brake worse, because the rolling resistance should increase. you can do the exact test for acceleration. I think it will be also interesting to

[@will24655]

I thought this too. Increased contact patch and all that.

[@zeropointzero]

​@@will24655underinflated radial tires actually have less contact patch than when properly inflated. The design of them causes the tread to cup inwards at the center.

[@serhisidorov486]

@@zeropointzero if talking about extremes... slick tires are used in drag racing

[@zeropointzero]

@@serhisidorov486 yes, but drag slicks are bias ply. Totally different structure.

[@antibrevity]

5:39. "The car has stopped." Vlad is awesome, but I couldn't help but chuckle at this observation ;). I was half-expecting to afterward hear, "the door is ajar."

[@billynomates920]

i was a victim of low tyre pressure once. didn't check. had 15 pounds in the front left when i put the vehicle shiny side down. keep a tyre inflator in the boot and one of those pressure sticks in the centre console cubby hole - not in the ashtray just in case out of sight is out of mind again.

[@GHOOGLEMALE]

Mmm - good test BUT, you were all over the shop with braking start point. The differences more than enough to seriously skew those results. I suggest taller cones or signals at braking start point so you can nail the braking accurately.

[@2coolwheels139]

What a great lesson on proper inflation!

[@federsbgh1]

With ABS the lock reading error increases, with maximum braking the flexibility of the tire is added (more delay in reading locked ). try without abs

[@dilysi156]

Clever comment, but this would happen on the road as well, which makes this experiment not too inaccurate

[@gsestream]

instead of stopping distance, you could just measure surface friction of the wheels, remove nonsense variables like user performance. both overpressure and underpressure remove surface friction from the tires to ground.

[@telluridecolorado8918]

Two suggestions for you guys: Add a 2nd brake caliper to all 4 wheels, will it make a difference braking? and how many alternators can you attach to an engine? Some people have 2 on their trucks, but can you use 5, 10 or more?

[@operator8014]

Two starter motors too!

[@nathanieljames7462]

Competition car audio. Those vehicles sometimes have several alternators often outputting 350amps a piece at 16V

[@5.43v]

​@@operator8014that's pointless

[@damiangillett6443]

Very educational video for safety. Well done Info learned I am in Australia

[@themetalslayer2260]

first car 185/70/R14....exactly like on my car. This experiment is worthwhile. Citroën is known for its good braking performances (last time i drove a Citroën i nearly kissed the windshield after barely touched the brake pedal) and is avaible in Russia, why don't do this test with a Citroën (in the 70's and early 80's Citroën had the world record for the shortest braking distance at 160km/h and was fighting against Porsche in the same event)

[@zakburnett6690]

With drum breaks you have to jolt the breaks in reverse to adjust them you'll stop better with properly adjusted drum breaks and yes they're supposed to just work themselves but if you don't break hard a few times going backwards they don't actually do anything if you don't break hard enough whenever you back up

[@michaeljucius9509]

Apocryphal. But trying to explain to someone who can't even spell brakes properly how they work isn't worth the effort.

[@zakburnett6690]

@@michaeljucius9509 don't be a dick your life isn't worth the effort

[@davidcovington901]

​@@michaeljucius9509Not apocryphal to those of us who have worked on drum brakes. There is a "self-adjuster" that works when braking while traveling in reverse. Study a torn-down drum brake, and when you see some parts that even you don't understand, that'll be it. You're welcome.

[@lesklower7281]

A very good experiment as for the tyre pressures suggested by the vehicle manufacturer they are the safest

[@Undertaker1134Tx]

The heating of the breaks is causing the longer distance after each pressure change, and time to cool down. Need to run more than one try per inflation amount.

[@GLH8]

👍 Could you try using a compressed air tank as a method of forced induction

[@Spirit_Lanayru]

Unless they can get an extremely large tank of air, a given 2 liter engine at idle (assumed to be idling at 1000 RPM) will process/require 1000 liters of air per minute, or 35.3 cubic feet per minute (a common air density measurement used with engine intakes). Assuming a redline of 6000 RPM, the same engine will suck 6000 liters of air per minute, or 211 CFM. The standard half inch air impact requires a measly 5-8 CFM at 90 PSI, and using one of them will drain a 20 gallon tank quite rapidly, as 20 gallons translates to 2.67 cubic feet. Granted, compressing air does change its density, but a standard 20 gallon tank compressed to 90 PSI releasing its pressure at a regulated 20 PSI of "boost" would still need to release that pressure at a volume that would empty the tank quite quickly in order to appropriately feed the engine. As for how I figure that, I'm dividing the RPM by two to account for "half strokes" where no air is moving (compression and power strokes), and then multiplying that result by the overall displacement (2 liters to make it easy) This works because each cylinder moves its air between two revolutions of the crankshaft (suck-squeeze, then bang-blow) Remember!! Engines themselves are air pumps, so the problem arises when you're trying to feed a 2,000 CC pump (engine) with a 150cc pump (air compressor)

[@Storm11711]

they have already done that they started with a propane sized tank and ended up with 2 oxygen tanks it is on there video list

[@darthvirago]

Should try over on one side and under on the other side and see if it stops in a strait line.

[@mwbgaming28]

You need to let the brakes cool before each test, overheating brakes massively increase stopping distance, and an emergency stop from 80kph puts a LOT of heat into thr brakes

[@mann_idonotreadreplies]

Cool story bro

[@4BillC]

I definitely expected the larger contact patch of the low tire would have made stopping distance better, not worse.

[@keilveil9153]

Yeah I dont get it either

[@johnnyblue4799]

@@keilveil9153 They lowered it way too much. .2, or .3 bar at the max will probably outbrake the recommended tire pressure, but not by much. There are too many variables involved (tire carcass rigidity, tire temperature, surface conditions, tire wear, tire profile etc) and the test was too simplistic. Plus the tires were junk. You could see the Mitsubishi's tires with cracks all around the rim. Those tires are cooked.

[@timothybayliss6680]

Radial tires do really bad things when underinflated. If they tried a skidpad test it would have been dramatic

[@willjohnsonjohnson]

The middle of the tire curves up when the pressure is that low. The car bounces a bit too.

[@dimitar4y]

@@keilveil9153 it's some advanced science, it has to do with the PSI - pressure per area. The car is only so heavy, distributed among all 4 wheels, the total pressure forcing the rubber into the road is "less" than what is required to make the rubber bite into the ground. Essentially the flatter tyre acts like a large ski board. And, too inflated, acts like ice skates - just glides on the floor.

[@danbhakta]

A bit of information I'd like to know is how they normalized brake fade. Was the first factory recommended figures run multiple times?

[@Madpegasusmax]

Nice video . I only have added the race logic to show the speedometer error between under/ ok / over pressure

[@anibalbabilonia1867]

I always keep my eyes on my tire pressure’s! Very important indeed! Specially when gasoline prices are so high! Great video!👌😎👍

[@mariuscostelmiron6082]

Nice... Well done. Keep it the good way

[@mediocreman2]

8:15 "Don't mind me, I'm just taking my tires for a walk!" 😅

[@SerPurple51]

I wouldn't necessarily say the test for the Lancer is accurate given how bad those tires are dry rotted, which means the compound is probably harder than when new. But still very informative for the most part!

[@volvo09]

They aren't testing max braking performance, just the difference between pressure... Old tires / new tires, there will still be differences.

[@jeremymcadam7400]

Yeah its relative to itself, so the test is good

[@whyjnot420]

I honestly would have thought that the larger contact patch created by lower pressure would allow for quicker stopping. I wonder what would happen without ABS on each of these.

[@angrysocialjusticewarrior]

Underinflating tires actually creates a smaller contact patch. When you underinflate a tire, the sides of the contact patch will have good grip but the center will have less grip because the tire has too little air to push the whole contact patch properly onto the road. When a tire is overinflated, the opposite happens. Having too much air creates a "balloon" effect where the contact patch is slightly rounded. This means the center will have the most grip while the sides will barely touch the road. Following the recommended pressure on the door sticker will ensure the tire has enough pressure to for the whole contact patch to properly grip the road.

[@whyjnot420]

@@angrysocialjusticewarrior Thanks for reading the wikipedia entry on tire pressure. I'll be sure to mention this to the places I learned auto repair at... over 20 years ago. It depends on how much a tire is over or underinflated as well as the type of terrain it is on and even the temperature it operates at. You forgot to mention things like that.

[@angrysocialjusticewarrior]

@@whyjnot420 The things you mention are not relevant to the discussion. Temperature is not relevant because the recommended pressure displayed on the door placard already accounts for temperature. Terrain is also not a factor since the recommended pressure provides optimal contact patch for both road and offroad conditions. It is only in niche circumstances where you would deflate tires to avoid getting stuck on an extremely muddy trail.

[@johnnypolex]

I brought my toyota 4runner to a used tire shop to mount my new tires. All of my tires were pumped to about 75psi (5.2 bar) or more! I asked the guy why he pumped it so high. He pointed to the max pressure on the sidewall lol. And once i brought my lotus exige to the lotus and exotic car dealership for a recall. I picked it up with the tires pumped up another 15psi (1 bar) over what I had ser it to. They even forgot to bolt the battery back down. I took the lotus to the track and almost wiped out on the warm up lap. And then the battery got thrown around and damaged my fiberglass body and spilled acid everywhere in the trunk Lesson learned

[@Mike-qh7sh]

I was actually wondering a day ago and today if you guys have a video about this subject

[@CapnCrunchESO]

Who else wants them to put a turbo on a lada and keep upping the boost until the engine blows?

[@Z_732]

It all boils down to maintain your vehicle. Basically. Good vid you all!

[@dilysi156]

Love how this channel is getting better, more precise and scientific over time. We, carguys, we love FACTS about cars. Keep going though ✌️

[@marcoavila2426]

@ Garage 54 -did you happen to see what the maximum pressure was on any of these tires? When you say “over inflation” is this past the max pressure value for the tire, not the label in the door jamb? I would be curious to know how a tire performs at Maximum tire pressure, which may not be considered “over inflation”.

[@glencalhoun9544]

I have a very Very good feeling that if you wouldnt have dropped the pressure to extreme levels and would have only dropped it in smaller increments you would have seen enhanced braking as you dropped pressure until you got to where the tread is rounding on its contact patch. Slightly lower pressure will increase braking but also increase fuel consumption. Higher pressure give better fuel economy being less rolling resistance with higher pressure being a harder tire, and thats also what causes higher pressures to brake worse. Because the tire is harder with less road contact.

[@TheRattyBiker]

G54 always testing the important stuff 👍 check your tyre pressures lads.

[@NipponSpeedWorks]

Love your channel!!

[@thanos9973]

Odličan test. Svaka čast na trudu.

[@Mackze]

I would have expected best braking with the underinflation cause of the increased surface area touching the ground

[@ChieFChalinOLarssoN]

I was totally certain that it would be better grip with less air in the tyres!

[@alisteeaiken7667]

Just make sure your tyre pressures are correct!, though just wondering where do all these right hand drive come from in eastern Europe

[@ViceCityMasta]

How do you know the results weren't affected just by the brakes heating up?

[@joshuagibson2520]

Vlad is a genius.

[@Iowa599]

Monitor tire pressures with an IR temperature gun, change them to fit your personal use. Those temperature measurements also should be used to monitor wheel algnment, specifically toe & camber (thus caster). It works for me. I double the mileage out of tires & great mpg…of course, that also requires frequent attention…almost every stop & adjusting toe in parking lots…

[@Chappomusic]

9.37 : this car suits you. You found your match ❤.

[@jonathanbrown1120]

I would go back to the original pressure to make sure nothing changed from slamming on the brakes. And to see if it stops on the same cone. It’s odd that less pressure and a larger surface area doesn’t stop faster. I guess it’s the way tires treads are designed it may be different on completely bald tires.

[@jonrob4675]

Thank you

[@busyguy7479]

Have you guys ever thought about a hover craft of some kind ? put a downward thrust engine on a frame with a skirt around the edge just a thought.

[@dimitar4y]

before watching, my theory, lower pressure = better braking as more surface area hugs the road fully inflated would reduce surface area but improve efficiency/steering.

[@gigante6627]

As you were testing back to back the brakes were heating up and after each test the brakes were performing worse

[@Blanchy10]

Interesting. Tyre dealers where I live always over inflate the tyres. They claim the manufacturers run them lower for ride quality. I have always reset them to the manufacturers recommended level as I feel they do testing not just working off a hunch.

[@theilige]

i wonder if "reverse piston rings" would work, where instead of having the rings on the piston, you install them in the chambers ?

[@peglor]

They'd work, but the pistons would have to have a uniform cylindrical cross section for the whole stroke length of the engine for the rings to seal on them, so it wasn't as practical a solution as having the rings move with the piston.

[@theilige]

@@peglor i was thinking, youd have to weld some kind of bus bar onto the rings to make sure the piston doesnt catch on the up/down motion

[@theilige]

even though its never going to happen, but if anybody could come up with a way to do it, it would be those guys

[@BIGBaNANaBender]

This is a very good education video 🎉🎉🎉

[@White_Fang2102]

This is my New knowledge , in the past i thought drop tire pressure will reduce brake distance.

[@dimitar4y]

after video: So, there's a coefficient of friction, too inflated or underinflated makes the tyre have less than optimal ground resistance, losing braking performance; and also the ABS is doing its own thing making it worse.

[@jimnyplayer]

乗員が1人〜フル乗車、荷物が空荷〜フル積載、燃料が空〜満タン、ドライ路面〜ウエット路面まで、自動車メーカーはすべてテストして平均点を指定空気圧にしているはずです。 なので至極真っ当なテスト結果と言えるでしょうし、条件が変わればベストな空気圧は僅かに違うとも言える。

[@soulsbourne]

Put big deep puddle of water and you can see high tyre pressure prevents hydroplaning at high speeds

[@ukaszrugaa104]

How about warming of the brakes it self, did u do it in the same temp of them?

[@ogunsanyaolusegun3051]

Can tyre pattern influence the braking system?

[@AlexanderTan2263]

You forget to wait till the disk n drum to get cold...

[@waynesteinmacher9794]

DEAR garage 54 if you read comments? i hope this one gets your attention i was watchin one of your videos? and got to thinking what would happen if you were to force pure oxygen from like a scuba tank into the the intake of a car ? or if you replaced nitros with oxygen what would happen

[@vitaminwaterdaisuki]

Please try doing 6 cycle engine!!!

[@Aleks_Mechanics]

Notification squad Have a nice weekend!🔥🔥🔥

[@robertdagge]

Wouldn't stopping distances change more as the tyres heat up too?

[@Cherokee2005]

This is makes interesting content, but how do you know your applying consistent pressure on the brake pedal on each test phase?!?!?!

[@peglor]

By pushing the pedal until the ABS kicks in (It was noted at the start of the video that all cars have ABS) you're guaranteeing that the car is braking hard enough to lock the wheels. If there's less grip, less pedal pressure is needed to lock the wheels, but more pedal pressure won't stop the car any quicker, so it's not a useful thing to keep constant in the experiment in the first place.

[@SimplyTakuma]

The Nissan Sunny is right in the middle of all.

[@yacinealg152]

I always put my polo 6r at 3-2.8kg of tire pressure I drive slowly, i want maximum efficient and less friction and wear of my vehicle

[@jamesglavich1426]

Was there a cool down period between the different stops? Maybe some of the stopping distance was due to brake heat (fade), as the stops got progressively longer each time.

[@Braydenclark]

That's what I was thinking. Did they think about brake fade

[@6Twisted]

The problem with low pressure is that the tyre overheats which effects its grip. Do this test again but drive around on the tyres for a while first.

[@rian0xFFF]

Less pressure per area

[@AlienLivesMatter]

Heated tire increases its own operating temperature

[@youxkio]

Well, what type of tires you use?

[@accurategranite9268]

привет Влад, Производители шин советуют накачивать до одной спецификации. автопроизводители в другой спецификации. насколько велика разница в безопасности и экономии топлива между ними. я накачиваю немного меньше, чем указывают производители шин.

[@carlosvdroidxx]

Whats the brand and model of the third car?

[@crown674]

Nissan Sunny B14

[@Nickwillfixit]

You should have tried the tyres at totally different from left to right.

[@TOM-C.]

This example would have been far better if you had replicated real world pressures. If the tires were recommended to have 32 lbs pressure, you should have filled them to 28/29 lbs instead of half or less tire pressure which is obviously going to be worse.👍😎✌🗽

[@MattyEngland]

The difference would be too small to properly measure it

[@TOM-C.]

@@MattyEngland 2.2 bar equals 32 lbs of pressure. Lowering it to 1 bar is dropping the air pressure to less than half recommended pressure, around 15 lbs. If they had dropped the pressure to 28 lbs which is 4 lbs under recommended, it would represent real world tire pressures. Not many people ignore their tire pressures when they get as low as one bar which I would estimate being about 15 lbs, because the tires will be noticeably flat. Plus, I'd like to see if underinflating a tire by a few lbs would actually decrease braking distance.👍😎✌🗽

[@Mr.Humphrey60]

Great info thank you guys Greetings from U.S.A. MUCH RESPECT

[@zgamer9442]

glad there are no lada's

[@justinfurman9267]

Brakes could have just been getting hot and fading. Wish they would have done a 4th run back at recommended pressure..

[@CzarnobylPL]

I wonder what would be the difference when you only just slightly changed the pressure, like idk .2, .3 bar

[@dimitar4y]

So try the same experiment but put stupidly thin tyres, like bicycle tyres :D

[@limepineda6192]

hey can i request use the gear box of motor cycle and put it in car. thank you

[@Universal.G]

I've noticed that you guys haven't done any experiments regarding top speed or high speed tests. Maybe something to consider? Get a car, and see what you can do to make it reach higher top speeds. Keep making changes to go faster.

[@jusb1066]

They mostly used ladas which can barely do 60, which is a good thing because look at the state of everything

[@peglor]

They'd need a much better track with longer straights and plenty of run off areas to do that even slightly safely. The chance of killing someone rises dramatically as speed increases too, especially given the cars they use have no crash safety to speak of. You're literally asking them why they're not trying to kill themselves for your entertainment.

[@nathanwest2304]

did the guys from garage 54 ever talk about the war? like, do they even know what's happening? how can they escape being drafted?

[@Nomad_za]

I miss my 2004 Mitsubishi Lancer 1.6

[@netalantan4609]

Should have tried more times with the same pressure, will never be the same...

[@cossiedriverrs]

When you went to get in the Note for the first time Vlad, did you think the steering wheel had been stolen? 🙂

[@thomasphillips8180]

A chirping tire stops best. Best not to fully apply brake for this.

[@karl_toffel]

The lancer had totally cracked and old tires

[@dand5593]

somehow failed test, the differences are due to breakes heating more and more...it will be nice to see a 4'th control trest wit the right pressure.

[@MrVainia]

Now try this on gravel and snow

[@Nickwillfixit]

The Lancers tyres need to be replaced they have some serious wall crazing so are perished I would take it straight to a tyre suppliers and replace them before winter sets in.

[@MattyEngland]

Cracks will probably close up when it hits -30C 😂

[@twilliamrc4wd]

Try that again without using ABS braking

[@Kacper-sd6rx]

Cool

[@YouThinkAboutThis]

Remember when myth busters were paid to show incorrect tire pressures were bad? Hope this is real.