Good explanation as always! I have one comment though, about less tire pressure and more grip. I would mention in the video that less tire pressure also increases slip angles, so, even though the contact patch is larger, the tire deforms more and that, if not taken into consideration, can make your car handle poorly.
Hey, just wanted to say ty for giving out easy to understand useful info when we are surrounded by thing like vice, buzz feed, info-graphics in general ect., keep slaying it!
What I've learned from fiddling with pressures at track days is that each tire has unique pressure requirements, to the point that there is no simple rule of thumb. The best I can come up with is that tires with stiffer sidewalls need more air than tires with softer sidewalls. My theory is that as the tire rolls over, if the sidewall is stiff and the tire is underinflated a concave area between the contact patch and the road surface is created, reducing the amount of rubber on the road. So "it depends" is the only right answer.
I made a test on my car years ago. Inflated tires at 32 psi (cold) , and after 4 hours on Highway they were 40psi. Next week, inflated at 38 psi. Same highway for 4 hours and they were the same, 40 psi. I took a security driving course where they told us, if you give the hot air chance to expand, it will. And a way to increase security is raise psi to a level where is not over inflated, but where the hot air finds difficulty to expand and have a hard tire.
The biggest thing out got out of the information was to drive slower on wet roads. This confirms the single car accidents during rain on curvy country roads that I drive.
This is the exact video of where you explain to yourself what you already know and only you (most of the time) gets it. There's just some holes, skips or missing explanation as to why this and that are proportional, related or why it became the answer, etc. The same technique of teaching as what my teachers have always been doing, that I have to do the researching on the internet myself. I like your other videos though.
Yes, please. Even Randal Munroe (xkcd author) made fun of the imperial system in his forword of "What if?"... It was bad enough that Mythbusters couldn't decide which system to use.
Something that was missed is how water affects tire temp which is a far more complex relationship (lots of heat transfer factors ). In autocross speeds are low enough that hydroplaning isn't an issue so typically we lower tire pressures when its wet because the tires don't heat up as much to maintain more contact patch. Since they don't heat up as much the rubber doesn't get as soft and you run a smaller contact patch which gives you less lateral grip which makes you autocross slower. There also is a timeframe factor with autocross since the runs are so short and tires won't heat up quickly internally. For normal freeway driving it makes perfect sense to add extra air when its raining.
Dear Engineering, thank you for this informative video. I've tried to understand whether the recommended tire pressure is like the recommended oil viscosity--which according to another of your videos is "use the recommended oil viscosity". It seems like tire pressure, within reason, is a compromise of grip, wear, efficiency, and ride quality. My question, in this case, is whether we as owners have a working window within which to make some choices, or whether we can only make things worse by not using the recommended pressures. I'm specifically interested in airing up my tires for a little boost in fuel efficiency. Thanks for the wonderful content!
Like he said in the video, when running 1 bar too low, which is significant, they only lost up to 5% in fuel consumption. I'm a bit surprised it was so low but considering this is definitely not worth it to increase the tire pressure any more than recommended.
the external sensor weights 10 grams... wondering if that weight when the car is at highway speed and with centrifugal force may cause tearing the valve stem... what do you think?
No. 10 grams is insufficient at those revolutions. Unless its made out of metal, the stem ages and when you change tires it's always the best idea to change valve stems at the same time. Don't depend on the tire shop automatically replacing them, tell them upfront.
+HockeyLAKings119 Not entirely true. specially 90's Japanese cars. They are some of the best handling cars ever made, and with little modifications like better shocks and tires and or wheels they can feel like a different beast
feels like I am back in school, but that I actually went to class, listened and took notes. and it was informative. I add air when it's 1,2 psi below normal as my car loses about 1.5 every 1 month or 2. my question is how many psi below normal will it starts to affect mileage, tire wear etc. 5,6 psi then you should add air? 1,2,3 doesn't really matter or what?
i noticed that whatever the car suggest it's always better to go overpressure a bit. in my (rip) civic EG instead of the 1.8/2.2 range i went 2.6 and at that point the car really felt more stable and quick in trajectory change, and during hard braking (say 100 to 30kph, no abs and no locking) both the front end diving and the oscillations of the rear axle completely vanished. this is meant for daily use, track racing is a different planet.
3:01 For anyone interested: The formula for this is p=F/A where F is the force (the car's weight times the weight distribution devided by two) and A is the contact patch of the tire.
Biggest time to pay attention to this is when seasons change dramatically (you can skip this part Hawaii and Florida)... that's when drastic enough changes occur to warrant checking and correcting. Personally, I FAR FAR prefer having my tires set to the minimum recommended pressure rather than the maximum recommended pressure, I like em soft, smooth and quiet. :)
I purchased one of those STEELMATE TPMS shortly after putting four new tires on my car. I have 55 series tires and is difficult to detect a tire that is going low or flat. The way I can tell I have a tire problem is that the car will pull in the direction of the low/flat tire. I ruined a tire because it picked up a nail, went flat and I didn't detect it was flat until it was too late.
So how does this affect grip while cornering? High pressure in the wet means you will slide easier in the corners, and I have also found that increasing my pressure above manufacturer recommendations helped quite a bit in the dry. Is everything in this video flipped on it's head in the corners?
One thing to keep in mind is that manufacturer recommendations are only accurate for the same tyre profile and same tyre materials. If you are running a different tyre with different material (softer compound or harder) then a different tyre pressure may be required due to different thickness and flex profile of the tyre itself and its behaviour under pressure. Another thing is that higher tyre pressure can lead to an increase in response as there is less flexing of the tyre before the tyre responds to your steering input. This can create an illusion of increased grip without actually increasing grip. Wet behaviour is always harder to gauge. If you're sliding with tyre pressure in the wet then you could be pushing too hard or your tyre pressure is too high, leading to a smaller contact patch, hence it is easier to slip. I find that it's not always best to follow manufacturers instructions. Best way is find a long flat road, preferably a track, and draw a thick line of chalk from your outside shoulder block to inside shoulder block of each tyre. Drive on the track for a lap or do a straight line speed run and see how much chalk was rubbed off, this will tell you about your contact patch and will tell you of you need to increase or decrease your tyre pressure based on current tyre configuration, or even if your camber setting needs to be adjusted.
Definitely need to try that! And yes manufacturer instructions are often set up for comfort and on-purpose understeer so it's best to figure out your own preference either way, I guess. Thanks for the info!
Wonderful information! Looks like I've been bass ackwards about tire pressure and hydroplaning all these years. Whoops! What I'm curious about, is how do you work out the correct inflation pressure for a tire? The sticker on the car is great, but where did that number come from? How does that number change when changing wheel/tire sizes in an aftermarket setup? I've heard so many different things from different tire shops over the years, I honestly don't know what's right and what's wrong!
I wish he covered sidewall protection during very hard cornering. Many people pump up their tire psi during autox events to prevent the tire from rolling on its sidewalls.
Thanks for the video. Really appreciate the things you do. Have been watching from the start. I say THANK YOU again because this video gave me idea about what topic should i start writing research paper on.
You should try to get on with the FIA or try to compete in NHRA/IHRA or get your SCCA license. I work for the Ministry of Transportation of Ontario and I am a race car driver as well.
They have a ring that essentially locks them, and it requires the small wrench shown to remove them. It's possible, but not conveniently easy to steal them.
Engineering Explained thanks for sharing, your videos show high level of quality. I applaud this marketing tool which lets people get answers. Good luck !
+Engineering Explained Wow didn't know I was already enrolled. Great videos,great explanation overall. keep doing what your doing. Really appreciate it
When do we get the printable certificate to show our employers that we took time to educate ourselves in our field of work? That annual review is right around the corner!
My theory on what to inflate tires to on my cars is 2-3 pounds higher that what the car manufacturer recommends. My reasoning is simply that if you inflate them to recommended pressure, they essentially begin their journey immediately to being under inflated. However if you over inflate them 2-3 pounds and monitor them so as not to let them get any lower than 2-3 pounds under the recommended pressure, then overall they are operating in the optimum pressure range. The second observation I have is that a higher pressure tire should in fact reduce rolling resistance, however I've read recently that a couple tire manufacturers in the quest of designing a tire for improved mpg, is they are experimenting with a more flexible tire compound that supposedly allows the tread and sidewall to give under compression then return that energy as they attempt to "spring" back to their original shape. I'm not sold on which design will actually work best, but I'm a bit of a conservative driver and lean more towards hypermiling rather than racing to each red light working the brakes hard then acceleration strongly on a green.
As winter is here and TPMS all over are reading low I wish you would revisit this adding in... Reading differences between old school tire gauges which measure relative to ambient and TPMS which is totally enclosed and I assume calibrated to STP. Is not the goal to maintain tire shape? Is that not based on relative pressure rather than absolute internal tire pressure? What are the affects of elevation change and the less dense air at higher elevations (again the relative pressure concept)? Does tire volume affect temperature/elevation pressure changes? THX
A few questions What would the working pressure be of a tire after 30min of driving and would this be the proper operating pressure? What pressure should you use if a tire is filled with nitrogen as nitrogen does not change with temperature?
I have a question! At 2:50 , does increase in contact patch increase friction??? I think friction only depends on the "Tire Material"-"Road Material" pair and the weight of the car. Could you kindly look this up and explain the facts? As far as I know, wider tires are more grippy because their rubber is softer. And vice versa, if you want a softer compound tire, you need more rubber for making the tire reasonably stable which translates into a wider tire.
I have been running very high tyre pressures, and it seems quite difficult to induce excessive wear of the centre portion of the tread. I presume ye olde steel belted radials are just good at keeping this under control...?
I picked one up, certainly is fun info to have on hand, question is what is an acceptable tire pressure different between tires? So as each tire warms or cools different, what wold consider to be to far of a gap between them to start being unsafe or cause issues? Also should the tire be re-balanced with the increase wait of these monitor systems? and will they affect cars with monitoring systems inside the wheels?
I like my tires a bit over the top recommended pressure as it feels more responsive and also helps with saving the wheels when one hits a pothole or a speedhump... Yes the UK is covered in the things! :/
Engineering Explained I was just taught to always look things over every once in a while. Hard learned lesson taught by my father. He used to have an '89 mustang GT(beautiful car, Porsche red paint job, fully built at nearly 500bhp, he put over 200k miles on it), and my uncle would always harp on him about looking under the hood every once in a while just to poke around. He never did, and sure enough, radiator had broken free from all the mounts, and after smashing around for god knows how long had leaked everywhere on him. Always best to be preventative to avoid expensive repairs
Ian: Not really, just monitoring pressure is fine. You're far more likely to notice one tire's pressure fluctuating/lowering much more than the others than you are to actually see the nail in the tire.
I’ve probably got 1-3 psi too much because the contact on tread bar 1&3 show 3/32 and 2 is at 3/64 on the front of my Scion tC. But the rears are 9/32 on tread bar 1-3. Been getting 24mpg from 17mpg in the city using the bsfc video you uploaded a while back. Freeways I’ve been getting around 29-33mpg. I think I’m doing ok on economy but I have notice my fuel economy has gone down as the tread has gone down.
With modern radial tires increasing the pressure won’t cause center to wear much more. Even running tire from new to legal limit with 30% over the suggested pressure will wear the center less than 1mm or about 1/32” more than sides.
Request: Can you make video of Transmission oil and how it affects transmission and why you shouldnt drive with fifth gear at low speeds and high loads
An increase in tyre pressure results in a smaller contact patch which means more pressure exerted on the wet ground so the tyre can displace the water more effectively, however, a smaller contact patch means less tread is exposed to displace the water? Confused...
Think of it as skipping stones on water. Skip the flat side against the water and it'll bounce off. Skip the edge against the water and it will slice through.
Ive been meaning to ask this for some time, when you do a fuel economy run on any of the vehicles you are testing do you use techniques such as hypermiling or drafting? Do you also drive with the intention to get as food of mileage as possible like ac off, heated seats off, shifting under a certain rmp or are you driving how you would drive normally? I'm just curious as to your methodology behind that. Thanks for making great content.
Decreasing pressure increases grip? Top gear did a race on the salt flats in some older season where they decreased pressure but got a slower time. Are there other factors besides contact patch that would affect the performance of the car? Maybe less force against the wall so it has more of a flex? Or something like that?
with bicycle tires there is a point at which more pressure makes rolling resistance worse again. does this happen with cars, and if so at what psi does it tend to occur?
I removed the stock 17 in rims from my Forester and installed 15 in rims with BFG K02 tires. Switching from a passenger metric tire to a light truck tire. How do I find the best tire pressure for normal highway driving to get the best tread wear and contact patch?
Great video! Like the info. I laughed a bit at the remarks about degrees C. Most countries that I know of that use Celcius don't use "pounds per square inch" ;) We use bar or, in other words, (k)pa.
Will you do one on tire pressure differences between manufacture recommendation and over sized tires? My tire discounter store reccomended 10psi less than manufacture recommendation. I don't know if that is accurate.
Hi. Could you make a video where you explain how the tire pressure, the surface in contact and other parameters affect the friction between the tire and the road, please?
would you make a video about how the total amount of gears in your transmission effects the driving-charateristics of your car. for example: imagine two cars with the same HP/weight/acceleration...etc. but one with 5gears and the second one with 7 or 8 gears
Great info, thanks! My Sienna SE came with P235/50R19 Dunlop Sport 7000 tires. Reading reviews they don't look great for wet traction. I don't know if I should just swap them out for some better tires, or if they'll be okay with optimum inflation. The max pressure is 51psi, and the placard in the van says 36psi front and back. Would 38 or 40psi likely be an optimum pressure to not lose dry traction but to maximize wet traction? Also, I have to drive .25 miles on a rough dirt road every time I leave the house. Thanks for these well-presented and informative videos!
Great work on your videos! Q: What about the difference between what the manufacturer recommends for the vehicle vs. What the tire manufacturer lists as a max pressure? I tend to keep my tires closer to the max/higher than vehicle manufacturer...
Usually, half between OEM and tire max is a safe bet if you want to go higher. On most cars, the door sticker pressure is a bit low. I had to go 6PSI above to get even tread wear.
Yeah you wouldn’t want to keep it close to max. Anything above maybe 40 psi, depending on the car of course, probably isn’t going to be yield any benefits
What is tire size and pressure relation to car weight? I feel like 2,5 bar is too low for Nissan leaf which cyrb weights about 1730 kiloes. Often cars as such has 235-245 wide tires but Leaf has 215/50R17. I drive 2.8 bar and it decreases aquaplaning a lot and does not effect grip in summer. On winter i will go 2,5-2,7 since its for better grip.
So I have heard (and read somewhere I think) that it is not good for your valve stems to deflate them with an object such as a ballpoint pen. Do you know what should be used, or if this should be done at all?
Could you please answer and explain this; Does more contact area on the tire (wider tires) equal to more grip in the corner, on a smooth, dry road? My friends and I are arguing over this for days!
basically, lower pressure is more surface area. more surface area is more grip, so less tire spin, but more grip to overcome. think of it this way, if you glue one finger to a table, it takes less effort to pull off than if you glued your entire hand to the table
yes the tire pressure increase will increase the pressure of the tire pressing against the ground but not how he explained it. higher tire pressure results in a smaller contact patch. we know pressure P = Force / Area . The force being the weight of the car with gravity pushing downwards, and the area being the contact patch. Now it's easy to understand why the higher tire pressure works against hydroplaining.
I was wondering what is an under over inflated tire, like how much psi? My SUV has the tire specs say all tires should be at 26 psi. Currently I inflated them to 35 psi because I am doing a lot of highway driving with my new job. I have yet to see the fuel economy lost or gained as I still want to do another couple weeks of driving to know for sure. Would 26 psi be under inflated? Or would the 35 psi be over because it over the specs?
What, nothing about cornering? Don't under inflated tires experience more lean during cornering? Not sure on the term there... might be roll out/off - basically the tendency for the contact patch to momentarily move off-center from the rim.
Hydroplaning isn't anything compared to the effect of under-inflation on winter tires. Their grippy magic on snow/slush goes away if not inflated enough. Now if driving on loose sand or soft dirt/mud, letting air out isn't too bad an idea. That'll spread out the tire some and help keep it from digging in.
Good explanation as always! I have one comment though, about less tire pressure and more grip. I would mention in the video that less tire pressure also increases slip angles, so, even though the contact patch is larger, the tire deforms more and that, if not taken into consideration, can make your car handle poorly.
Oooh, that tire pressure gauge is perfect for track days so you can get your hot temps! Great vid as always. :)
Hey, just wanted to say ty for giving out easy to understand useful info when we are surrounded by thing like vice, buzz feed, info-graphics in general ect., keep slaying it!
im glad I've learnt ideal gas law before this video. cheers thewhiteboard-man
Do a video on tyre shape (wide/thin tracks, thick/thin sidewalls) vs speed and economy
Wow , you have answered my age old question of what happens if you drive with low pressure tire.. brilliant and exceptional
What I've learned from fiddling with pressures at track days is that each tire has unique pressure requirements, to the point that there is no simple rule of thumb. The best I can come up with is that tires with stiffer sidewalls need more air than tires with softer sidewalls. My theory is that as the tire rolls over, if the sidewall is stiff and the tire is underinflated a concave area between the contact patch and the road surface is created, reducing the amount of rubber on the road.
So "it depends" is the only right answer.
great work with your videos!
Thanks Tommy!
I made a test on my car years ago.
Inflated tires at 32 psi (cold) , and after 4 hours on Highway they were 40psi.
Next week, inflated at 38 psi. Same highway for 4 hours and they were the same, 40 psi.
I took a security driving course where they told us, if you give the hot air chance to expand, it will. And a way to increase security is raise psi to a level where is not over inflated, but where the hot air finds difficulty to expand and have a hard tire.
was hoping for more details in the grip part
Metric system please...
Sincerely,
Rest of the world
USA: idk maybe later
I already knew about some of those, but never thought about hydroplaning. awesome video I love the equation breakdown! Thanks!! 👍👍
The biggest thing out got out of the information was to drive slower on wet roads. This confirms the single car accidents during rain on curvy country roads that I drive.
This is the exact video of where you explain to yourself what you already know and only you (most of the time) gets it. There's just some holes, skips or missing explanation as to why this and that are proportional, related or why it became the answer, etc. The same technique of teaching as what my teachers have always been doing, that I have to do the researching on the internet myself. I like your other videos though.
Coming from a guy who knows nothing about cars (but would love to learn), this is cool! Especially learning about the fuel consumption lol
I am in school to become a Service Tech. This is very helpful, thank you.
Please use the metric system :D
No. :D
+Reus The imperial system doesn't make any sense
I agree, hearing those imperial units is pain in the ass for non-US guy. Or if Jason at least put some figures on screen in metric units.
Really doesn't make any sense using the imperial one...
Yes, please. Even Randal Munroe (xkcd author) made fun of the imperial system in his forword of "What if?"...
It was bad enough that Mythbusters couldn't decide which system to use.
Great vid! Easy to share with friends and very easy to understand. Thanks!
Happy to hear it, thanks for watching, and a double thanks for sharing!
Simply awsum sir , following u frm last 3 years
Something that was missed is how water affects tire temp which is a far more complex relationship (lots of heat transfer factors ). In autocross speeds are low enough that hydroplaning isn't an issue so typically we lower tire pressures when its wet because the tires don't heat up as much to maintain more contact patch. Since they don't heat up as much the rubber doesn't get as soft and you run a smaller contact patch which gives you less lateral grip which makes you autocross slower. There also is a timeframe factor with autocross since the runs are so short and tires won't heat up quickly internally.
For normal freeway driving it makes perfect sense to add extra air when its raining.
Dear Engineering, thank you for this informative video. I've tried to understand whether the recommended tire pressure is like the recommended oil viscosity--which according to another of your videos is "use the recommended oil viscosity". It seems like tire pressure, within reason, is a compromise of grip, wear, efficiency, and ride quality. My question, in this case, is whether we as owners have a working window within which to make some choices, or whether we can only make things worse by not using the recommended pressures. I'm specifically interested in airing up my tires for a little boost in fuel efficiency. Thanks for the wonderful content!
Like he said in the video, when running 1 bar too low, which is significant, they only lost up to 5% in fuel consumption. I'm a bit surprised it was so low but considering this is definitely not worth it to increase the tire pressure any more than recommended.
the external sensor weights 10 grams... wondering if that weight when the car is at highway speed and with centrifugal force may cause tearing the valve stem... what do you think?
No. 10 grams is insufficient at those revolutions. Unless its made out of metal, the stem ages and when you change tires it's always the best idea to change valve stems at the same time. Don't depend on the tire shop automatically replacing them, tell them upfront.
Hey can you explain stancing a car? I would like to know how it affects the tires, suspension, etc.
He has. Go look. Camber, scrub radius, wheel spacers, go watch
you shouldn't lower or raise a vehicle, engineers do all the calculations, and how it comes out of the factory is how it runs best.
+HockeyLAKings119
Not entirely true. specially 90's Japanese cars. They are some of the best handling cars ever made, and with little modifications like better shocks and tires and or wheels they can feel like a different beast
+Alejandro Ochoa Yes, I know that, and completely agree, but I thought we were talking about standing a car here, not new tires and shocks...
feels like I am back in school, but that I actually went to class, listened and took notes. and it was informative.
I add air when it's 1,2 psi below normal as my car loses about 1.5 every 1 month or 2. my question is how many psi below normal will it starts to affect mileage, tire wear etc. 5,6 psi then you should add air? 1,2,3 doesn't really matter or what?
Thank heavens for the Internet. This smart, useful video (with MATH!) gives good reason for UA-cam to exist.
So to get the most use out of my tires I should over inflate them until the center is worn, then under inflate them until the sides are worn?
Haha absolutely not - unsafe to do.
Don't worry, this was only a joke. :)
Bahahahaha. 😂 This comment made my morning lolll
i noticed that whatever the car suggest it's always better to go overpressure a bit. in my (rip) civic EG instead of the 1.8/2.2 range i went 2.6 and at that point the car really felt more stable and quick in trajectory change, and during hard braking (say 100 to 30kph, no abs and no locking) both the front end diving and the oscillations of the rear axle completely vanished. this is meant for daily use, track racing is a different planet.
Currently a high school senior looking to do a physics final project relating to vehicles, ideas? Love your videos by the way!
You did a great job explaining how tire pressure effect wet conditions but what about dry conditions?
3:01 For anyone interested:
The formula for this is p=F/A where F is the force (the car's weight times the weight distribution devided by two) and A is the contact patch of the tire.
Contact patch expressed in width (205mm example) or area?
@@Fabio_T26 Area
Biggest time to pay attention to this is when seasons change dramatically (you can skip this part Hawaii and Florida)... that's when drastic enough changes occur to warrant checking and correcting. Personally, I FAR FAR prefer having my tires set to the minimum recommended pressure rather than the maximum recommended pressure, I like em soft, smooth and quiet. :)
awsmmm... Reallly nevr thought dat tire pressure is going to effect the fuel economy. Thnks for d uploading.Bro.
I purchased one of those STEELMATE TPMS shortly after putting four new tires on my car. I have 55 series tires and is difficult to detect a tire that is going low or flat. The way I can tell I have a tire problem is that the car will pull in the direction of the low/flat tire. I ruined a tire because it picked up a nail, went flat and I didn't detect it was flat until it was too late.
So how does this affect grip while cornering? High pressure in the wet means you will slide easier in the corners, and I have also found that increasing my pressure above manufacturer recommendations helped quite a bit in the dry. Is everything in this video flipped on it's head in the corners?
One thing to keep in mind is that manufacturer recommendations are only accurate for the same tyre profile and same tyre materials. If you are running a different tyre with different material (softer compound or harder) then a different tyre pressure may be required due to different thickness and flex profile of the tyre itself and its behaviour under pressure.
Another thing is that higher tyre pressure can lead to an increase in response as there is less flexing of the tyre before the tyre responds to your steering input. This can create an illusion of increased grip without actually increasing grip.
Wet behaviour is always harder to gauge. If you're sliding with tyre pressure in the wet then you could be pushing too hard or your tyre pressure is too high, leading to a smaller contact patch, hence it is easier to slip.
I find that it's not always best to follow manufacturers instructions. Best way is find a long flat road, preferably a track, and draw a thick line of chalk from your outside shoulder block to inside shoulder block of each tyre. Drive on the track for a lap or do a straight line speed run and see how much chalk was rubbed off, this will tell you about your contact patch and will tell you of you need to increase or decrease your tyre pressure based on current tyre configuration, or even if your camber setting needs to be adjusted.
Definitely need to try that! And yes manufacturer instructions are often set up for comfort and on-purpose understeer so it's best to figure out your own preference either way, I guess. Thanks for the info!
Wonderful information! Looks like I've been bass ackwards about tire pressure and hydroplaning all these years. Whoops!
What I'm curious about, is how do you work out the correct inflation pressure for a tire? The sticker on the car is great, but where did that number come from? How does that number change when changing wheel/tire sizes in an aftermarket setup? I've heard so many different things from different tire shops over the years, I honestly don't know what's right and what's wrong!
It's been worked out by the vehicle manufacturer. Just use what they suggest.
I wish he covered sidewall protection during very hard cornering. Many people pump up their tire psi during autox events to prevent the tire from rolling on its sidewalls.
Thanks for the video. Really appreciate the things you do. Have been watching from the start. I say THANK YOU again because this video gave me idea about what topic should i start writing research paper on.
So basically just need to be at the recommended tire pressure and you'll be fine :D Nice video though, very informative :)
The part about hydroplaning was very interesting. The rest I'd figured out myself without engineering. Now, I have science to support what I've known.
You should try to get on with the FIA or try to compete in NHRA/IHRA or get your SCCA license. I work for the Ministry of Transportation of Ontario and I am a race car driver as well.
You give the pressure drop information for °celsius... but you give it in PSI. Nice one m8 :D
it's a pretty nice device , but in spain probaly the people steal the black things that go in the tyres :(
what about Venezuela? a country that was... and is no more. Pitty Vzlan Government
They have a ring that essentially locks them, and it requires the small wrench shown to remove them. It's possible, but not conveniently easy to steal them.
hey! thanks for the info , probably i get one this summer
Gofrin Bicelis yep, saddly corruption stinks in both countrys
Engineering Explained thanks for sharing, your videos show high level of quality. I applaud this marketing tool which lets people get answers. Good luck !
So when are you opening your own school???
Opened it June 2011 on UA-cam, free for everyone to enroll! :)
+Engineering Explained
Wow didn't know I was already enrolled.
Great videos,great explanation overall. keep doing what your doing. Really appreciate it
+Engineering Explained idk how I'm still in the class. I thought I would be dropped by now.
When do we get the printable certificate to show our employers that we took time to educate ourselves in our field of work? That annual review is right around the corner!
i think we actually learn more here in youtube than at an institute. No lie
My theory on what to inflate tires to on my cars is 2-3 pounds higher that what the car manufacturer recommends. My reasoning is simply that if you inflate them to recommended pressure, they essentially begin their journey immediately to being under inflated. However if you over inflate them 2-3 pounds and monitor them so as not to let them get any lower than 2-3 pounds under the recommended pressure, then overall they are operating in the optimum pressure range.
The second observation I have is that a higher pressure tire should in fact reduce rolling resistance, however I've read recently that a couple tire manufacturers in the quest of designing a tire for improved mpg, is they are experimenting with a more flexible tire compound that supposedly allows the tread and sidewall to give under compression then return that energy as they attempt to "spring" back to their original shape. I'm not sold on which design will actually work best, but I'm a bit of a conservative driver and lean more towards hypermiling rather than racing to each red light working the brakes hard then acceleration strongly on a green.
Okay. Do us a favor then, would you? Travel in the right lane. Thank you.
As winter is here and TPMS all over are reading low I wish you would revisit this adding in... Reading differences between old school tire gauges which measure relative to ambient and TPMS which is totally enclosed and I assume calibrated to STP. Is not the goal to maintain tire shape? Is that not based on relative pressure rather than absolute internal tire pressure? What are the affects of elevation change and the less dense air at higher elevations (again the relative pressure concept)? Does tire volume affect temperature/elevation pressure changes? THX
A few questions
What would the working pressure be of a tire after 30min of driving and would this be the proper operating pressure?
What pressure should you use if a tire is filled with nitrogen as nitrogen does not change with temperature?
Hi, would pls make a video on tyre & wheel weight rotational effects. Keep up the great videos. Thanks.
Always informative.
I have a question! At 2:50 , does increase in contact patch increase friction??? I think friction only depends on the "Tire Material"-"Road Material" pair and the weight of the car. Could you kindly look this up and explain the facts? As far as I know, wider tires are more grippy because their rubber is softer. And vice versa, if you want a softer compound tire, you need more rubber for making the tire reasonably stable which translates into a wider tire.
Can you please make a video about the JZ motors? Like what is 1,5 JZ, why are they as good as for example v8 , pros, cons, etc. Thanks!
Love your videos. Thank you! I just really wished you used metric. It would certainly help with the mental math a little. 😊
I have been running very high tyre pressures, and it seems quite difficult to induce excessive wear of the centre portion of the tread.
I presume ye olde steel belted radials are just good at keeping this under control...?
I picked one up, certainly is fun info to have on hand, question is what is an acceptable tire pressure different between tires? So as each tire warms or cools different, what wold consider to be to far of a gap between them to start being unsafe or cause issues?
Also should the tire be re-balanced with the increase wait of these monitor systems? and will they affect cars with monitoring systems inside the wheels?
The ideal gas law also does not model ambient air very well. Are you assuming all sorts of nitrogen?
I like my tires a bit over the top recommended pressure as it feels more responsive and also helps with saving the wheels when one hits a pothole or a speedhump... Yes the UK is covered in the things! :/
I drive old school cars so they don't come with tyre pressure sensors. I just make it a habit to check the pressures manually once a week or so.
i do the same, no big deal, also gives me a chance to look around the car to make sure everything is in order
Seriously, good on you! More people need to monitor. This device just makes it super easy, but either way keep checking!
Engineering Explained I was just taught to always look things over every once in a while. Hard learned lesson taught by my father. He used to have an '89 mustang GT(beautiful car, Porsche red paint job, fully built at nearly 500bhp, he put over 200k miles on it), and my uncle would always harp on him about looking under the hood every once in a while just to poke around. He never did, and sure enough, radiator had broken free from all the mounts, and after smashing around for god knows how long had leaked everywhere on him. Always best to be preventative to avoid expensive repairs
+Engineering Explained you should also check for damage and foreign objects like small rocks nails etc
Ian: Not really, just monitoring pressure is fine. You're far more likely to notice one tire's pressure fluctuating/lowering much more than the others than you are to actually see the nail in the tire.
Good stuff mate. Could you do a video about more advanced vehicle aerodynamics? Can't really find about it anywhere
plz do an episode on tiyer pressure in pro drifting. us it better to have low pressure when drifting for more grip ?
Good explaination ,Great video,Just keep doing that .
Awesome video!!
I’ve probably got 1-3 psi too much because the contact on tread bar 1&3 show 3/32 and 2 is at 3/64 on the front of my Scion tC. But the rears are 9/32 on tread bar 1-3. Been getting 24mpg from 17mpg in the city using the bsfc video you uploaded a while back. Freeways I’ve been getting around 29-33mpg. I think I’m doing ok on economy but I have notice my fuel economy has gone down as the tread has gone down.
Hi, Can you go over how the age of the tire affects its grip?
With modern radial tires increasing the pressure won’t cause center to wear much more.
Even running tire from new to legal limit with 30% over the suggested pressure will wear the center less than 1mm or about 1/32” more than sides.
can you do a video on how the Acura nsx has combustion and electric motors and how they work together
Request: Can you make video of Transmission oil and how it affects transmission and why you shouldnt drive with fifth gear at low speeds and high loads
can you do a video on the structural integrity of a convertible,
im thinking of doing a pick up truck conversion on a 2001 vw cabriolet
An increase in tyre pressure results in a smaller contact patch which means more pressure exerted on the wet ground so the tyre can displace the water more effectively, however, a smaller contact patch means less tread is exposed to displace the water? Confused...
Think of it as skipping stones on water. Skip the flat side against the water and it'll bounce off. Skip the edge against the water and it will slice through.
Nice analogy :)
Ive been meaning to ask this for some time, when you do a fuel economy run on any of the vehicles you are testing do you use techniques such as hypermiling or drafting? Do you also drive with the intention to get as food of mileage as possible like ac off, heated seats off, shifting under a certain rmp or are you driving how you would drive normally? I'm just curious as to your methodology behind that. Thanks for making great content.
Super sweet. Thanks for the heads up and helping me understand what is going on. Now my Honda in the game and Real life handle way better :)
Hello! Would you do a video on different suspension designs and their characteristics?
Good information
Where I can get this Steel Mate tyre pressure monitoring system?
Decreasing pressure increases grip? Top gear did a race on the salt flats in some older season where they decreased pressure but got a slower time. Are there other factors besides contact patch that would affect the performance of the car? Maybe less force against the wall so it has more of a flex? Or something like that?
By a Scangauge scanner instead of this tire pressure monitor reader. Scangauge can read many ODB parameters and it is probably less expensive.
with bicycle tires there is a point at which more pressure makes rolling resistance worse again. does this happen with cars, and if so at what psi does it tend to occur?
I removed the stock 17 in rims from my Forester and installed 15 in rims with BFG K02 tires. Switching from a passenger metric tire to a light truck tire. How do I find the best tire pressure for normal highway driving to get the best tread wear and contact patch?
Great video! Like the info. I laughed a bit at the remarks about degrees C. Most countries that I know of that use Celcius don't use "pounds per square inch" ;) We use bar or, in other words, (k)pa.
Excellent, Keep it up 😊
Will you do one on tire pressure differences between manufacture recommendation and over sized tires? My tire discounter store reccomended 10psi less than manufacture recommendation. I don't know if that is accurate.
Hi. Could you make a video where you explain how the tire pressure, the surface in contact and other parameters affect the friction between the tire and the road, please?
I think you'll find this helpful: ua-cam.com/video/kNa2gZNqmT8/v-deo.html
Thank you a lot!
What is the right pressure for a track day?
would you make a video about how the total amount of gears in your transmission effects the driving-charateristics of your car.
for example: imagine two cars with the same HP/weight/acceleration...etc. but one with 5gears and the second one with 7 or 8 gears
Thanks for uploading.
What time of the day should we pump our tires since temperature affects the pressure level?
I really learned something! :)
Great info, thanks! My Sienna SE came with P235/50R19 Dunlop Sport 7000 tires. Reading reviews they don't look great for wet traction. I don't know if I should just swap them out for some better tires, or if they'll be okay with optimum inflation. The max pressure is 51psi, and the placard in the van says 36psi front and back. Would 38 or 40psi likely be an optimum pressure to not lose dry traction but to maximize wet traction? Also, I have to drive .25 miles on a rough dirt road every time I leave the house. Thanks for these well-presented and informative videos!
I watched it to the point Chris Fix said you go buy this tool then immediately updated my wishlist lol
Great work on your videos!
Q: What about the difference between what the manufacturer recommends for the vehicle vs. What the tire manufacturer lists as a max pressure?
I tend to keep my tires closer to the max/higher than vehicle manufacturer...
I'd always go with what the manufacturer recommends.
Usually, half between OEM and tire max is a safe bet if you want to go higher.
On most cars, the door sticker pressure is a bit low. I had to go 6PSI above to get even tread wear.
Yeah you wouldn’t want to keep it close to max. Anything above maybe 40 psi, depending on the car of course, probably isn’t going to be yield any benefits
What is tire size and pressure relation to car weight? I feel like 2,5 bar is too low for Nissan leaf which cyrb weights about 1730 kiloes. Often cars as such has 235-245 wide tires but Leaf has 215/50R17. I drive 2.8 bar and it decreases aquaplaning a lot and does not effect grip in summer. On winter i will go 2,5-2,7 since its for better grip.
Great video. What are your thoughts on tire rotation provided that tire pressure is ideal?
Doesn't the ambient (atmospheric) pressure cancel put since it's also pushing on the outside of the tyre?
So I have heard (and read somewhere I think) that it is not good for your valve stems to deflate them with an object such as a ballpoint pen. Do you know what should be used, or if this should be done at all?
While using imperial units, wouldn't be easier to use Rankine instead of Kelvin?
Could you please answer and explain this; Does more contact area on the tire (wider tires) equal to more grip in the corner, on a smooth, dry road?
My friends and I are arguing over this for days!
Typically yes, here's why: ua-cam.com/video/kNa2gZNqmT8/v-deo.html
basically, lower pressure is more surface area. more surface area is more grip, so less tire spin, but more grip to overcome. think of it this way, if you glue one finger to a table, it takes less effort to pull off than if you glued your entire hand to the table
Engineering Explained
Ups, I somehow missed that video, thanks a lot!
yes the tire pressure increase will increase the pressure of the tire pressing against the ground but not how he explained it.
higher tire pressure results in a smaller contact patch. we know pressure P = Force / Area . The force being the weight of the car with gravity pushing downwards, and the area being the contact patch. Now it's easy to understand why the higher tire pressure works against hydroplaining.
I was wondering what is an under over inflated tire, like how much psi? My SUV has the tire specs say all tires should be at 26 psi. Currently I inflated them to 35 psi because I am doing a lot of highway driving with my new job. I have yet to see the fuel economy lost or gained as I still want to do another couple weeks of driving to know for sure. Would 26 psi be under inflated? Or would the 35 psi be over because it over the specs?
Nice video! Is it necessary a wheel balance after installing a TPMS retrofit kit?
What, nothing about cornering? Don't under inflated tires experience more lean during cornering? Not sure on the term there... might be roll out/off - basically the tendency for the contact patch to momentarily move off-center from the rim.
Hydroplaning isn't anything compared to the effect of under-inflation on winter tires. Their grippy magic on snow/slush goes away if not inflated enough.
Now if driving on loose sand or soft dirt/mud, letting air out isn't too bad an idea. That'll spread out the tire some and help keep it from digging in.
Awesome vid
Comon. Ive learned english. Isnt that enough. just say everything with metric data...