Actually this prof is wrong he shouldn't multiply the rpms that he saw on the small tyre to the large tyre to get wht the odo will show. What actually will happen is the rpm will be less. As the tyre is larger its circumference is larger thus it needs less rotation to cover the same distance as a smaller tyre. Thus there will be a lower rpm recorded on the wheel. Which the computer will percieve as lower distance and speed. Thus u get a false lower reading. Not high!! So much for a tyre prof😅 i knw he is not a prof.😝 But sure wud pass for one
@@amoghpatil You stated "Thus u get a false lower reading." He did get a false lower reading! His car speedo showed 60 when his GPS showed 62. He may have mis-stated or miscalculated but got the same answer you did. "Not high"
The more important point is that the wrong size of tire can show that your car has more miles on it than it actually has. A smaller tire over 6 years can really mess with the odometer. Not to mention this throws of your service schedule. Oil changes etc. I guess you could put larger tires, notate the difference so you don't speed and keep your cars mileage low. lol. Thanks for the video.
I know for a fact that he didn’t mention was that by going 1 in more higher makes the ride more comfortable because there’s more rubber to absorb the road p.s.I went from 235 60 18 to 235 65 18, much better ride
My truck's stock tires are a 275/60R20 (essentially a 33 inch tire). Next time I buy tires I'm planning to go with a 275/65r20 (essentially a 34 inch tire). May put my speed a hair over what my gauge is reading and my odometer a touch under reality but it's negligible. I believe there's a way on my truck to go into the settings and enter the tire size you're running and it'll recalibrate your speedo to match. Haven't actually gone into the settings to verify this tho...
Why is everyone blowing off about the speedometer readings!? There should be actual talk on upsizing on the same rim with handling issues and clearance etc.,
Thank you! I was wondering if upsizing or downsizing on the same rim would affect my handling and stuff like that. The speedometer is the least of my concerns.
@Milan Latona Tire radius change by +/- 5% should not matter. Provided the Road clearance is not an issue and width remains the same or just the next size. There are comparison calculators on the web which make it easy for everyone
I think the more concerning issue is how the tire size affects the longevity and performance of the car, in my opinion. Also, I heard most cars of today have their speed set lower than what their speedometers display. Using my car app such as Waze, I can notice my speed in some cars to be 2 to 3 miles lower than what is displayed in the dash. So, in this case, should I still get a tire that is bigger than what is specified for my car?
When i read the title i had assumed this would be about the cost that can occur due to mechanical failures of running different size tires on a vehicle . Good video though it makes sense
My car has two different sizes and was manufactured that way. I have wider rims in the rear. I believe that’s to optimize speed by adding more traction to the rear given it’s a RWD vehicle.
Thank you very much for this work. Where am I here in Africa, most of us do not have access to the correct size tires. If the tire can fit the wheel, we go for it. A much bigger problem that we have if inflating the tires to the correct PSI. I have been driving here in Cameroon for 4 years and I'm YET to run into a pump that gives me the exact 35PSI that I need. They are typically inflated at 10PSI overs which, when combined with the aggressive driving habits around me, is the cause of the majority of deadly accidents around me. This is a systemic problem that needs to be resolved to save lives, but the country is "poor" and has far more urgent priorities!
This is good stuff, BUT just the tip of the iceberg as many here are here because we go with larger tires because we're modifying our vehicles to perform better off road and we're curious how to manage the differences with MPH, fuel economy and power..... For instance, I have an '04 AWD Astro van I converted to 4x4 with an s10 transfer case and I have a decent lift on it. My tires are now about 2" taller than stock and my speedometer is off 4mph... There are charts out there that point out the relation to tire size, gearing and rpms - There are "sweet spots" to aim towards, for instance, according to what I've seen you can get better gas mileage but have a loss of power at the same time. This video is great for what it is but most people who go with larger tires already/quickly learn/understand the speedometer is off without needing to understand the math involved (I enjoyed this explanation, anyhow) - What they really want to know is how to reprogram the computer to work with the new tire size so the speedometer in in sinc as well as to get the mpg readings to be accurate - I'll be looking to see if you've done anything on that as I believe you'd probably be the perfect guy to explain all that
Got a BMW 335i. Went through 17 tires in a 3 year period. Therefore, I had zero confidence in the reliability of the vehicle. Well, ironically enough, I garaged the thing for 2 years bc I was sick of driving somewhere, blowing out a tire and then waiting for AAA to come give me a tow bc the vehicle has no spare. Well, after taking it out of the garage recently, I realized that the back tires (which calls for a larger width) was the same as the front. So these dipsticks at NTB we’re sticking on the wrong size for 3 years. No idea how I never caught that. So, shame on me for trusting someone else that should know their job.
Thank you for this, I was just advised to put 195's on my car that should have 175's to run better on an unpaved road I have to travel daily. Immediately realised as I drove off the xtra effort it takes to pull away, not a lot, but still. So by his logic it would also mean that a car would have less miles on it's tachometer than it actually travelled if fitted with bigger tyres, right?
Great info. Just a question though. What if you're switching from highway tires to those all-terrain or rugged-terrain tires with all those biting edges? Not sure if the tire makers all factor those in.
How about the tire size I'm using at the back 215x60 R17 and in the front 225x60 R17, Is there any effect on the performance of the engine car? Please give me advice. Thank you!
Nice to see your method of displaying the calculations. I myself have simply ignored my car's dinosaur terrestrial speedo'... for over 15 years, in favour of GPS! Reason: my '91 seven seater FrontWheelDrive (FWD) mazda's speedo has an inbuilt inaccuracy far beyond what I personally deem practical; for example at Speedo 100kmh, I am doing GPS 92kmh. At Speedo 80, I am doing GPS 73kmh etc etc. The vehicle has only one size on it's manufactures' chart - being 185/70-14. I'd like to go for 185/75-14 instead. ( I don't want to go 195/65-14 etc etc) I want to achieve a longer rolling distance; smoother ride From the above figures: PROs: I will have no need to worry the Speedo will ever under-read, compared to the GPS' as according to calcs' I would expect to see a 3% increase in Rolling Distance with the 75% tyres on. I can see I would achieve a softer ride; lower RPMs for any given GPS speed; I don't need to worry about larger wheel rim width changes; I would achieve a higher area of footprint for better hold, for, when applying power I therefore expect to never again have to suffer the tyre skid when accelerating from standstill. This being due to the extra rubber on the road, from the larger Diameter. CONs: There might be some small compromise to tyre wall deformation upon hard cornering? An Insurer might refuse to pay out, if the tyre is not exactly as stipulated on the Plate? My Mazda seven seater is FWD, and is well known for the tyre skid upon acceleration from standstill. Most of it due to being FWD, but I also have long blamed the original diameter of a 185/70-14 contributes to it. A more modern vehicle's ECU would report to the owner that it's next due Servicing Schedule would for example come due at 97000km instead of 100000km
I have a 1999 Trans Am. To give the car a better look I put on a set of C6 Corvette wheels . 18X9.5 front and 19X10 rear. I have noticed that the ABS light comes on at highway speeds. What can I do to fix this and keep these wheels?
My 2020 Mitsubishi Outlander PHEV OEM's are 215/70r16. I changed it to 225/70r16 AllTerrain tires (I do a lot mild off-road, gravel roads and snow). I am very happy with the change but I lost about 20% of EV range and fuel consumption went slightly up. I will be performing 1.2inch (about 3cm) lift and I am planning to install even bigger 225/75r16 tires to increase the tire side wall and ground clearance even more. Do you think this is good idea or this is too much?
My car, the 2021 Impreza had 7 trims but 3 different wheel/tire sizes. I bought the sport 🤣, which has the same engine in all trims, so I am wanting to change my P225/40R18's to P205/65R16's for an smoother ride.
What about tire compression under vehicle weight. I think an inch higher in height(side wall) would in reality not be up to an inch because more sidewall means more compression under weight right. I hope someone can help me out on this
That might appear that way. But in Reality, the factory tire size that comes with a vehicle is thoroughly tested to be the best possible for the vehicle, engine, aerodynamics of vehicle and offcourse driver comfort. If increase diameter increase mpg, then all companies will fit bigger tyres lol, to increase mpg. The tyres with bigger diameter cost more engine power thats why truck and suv with bigger engine has bigger diameter tyre than sedan. If u install suv size tyre in a sedan with 40mpg, the mpg will drop cause taller tyre will push engine to use more power and therfore use more fuel. And yes top speed of vehicle will decrease as well. The handling might also be bad.
I own a mazda 3 automatic that came with 205/60R16 and I have an issue with my gearing ratio where the car does not downshift on the highway when I have to slow down and speed up again (for eg. coming up behind a slower vehicle ahead of me and then having to accelerate to pass the car). It stays at 5th gear and does not downshift to 4th. I asked the mazda dealership and they told me the gearing software is set for fuel economy. thats why it does not downshift in those situations. So I have to manually downshift to get the acceleration. would getting an overall taller or shorter tire diameter help?
After punctured the tire (pothole) I was in need to install spare tire, so I could only get in that situation 225/50/17 tire (other three are 215/50/17). One wider tire installed on the rear right position. I'm in the process of finding the same 215/50/17 tire, and occasionally driving with one wider tire (and with different pattern), and I didn't notice any change in control, balance, braking, also in 6th gear on highway. Do I really need to match one wider tire ASAP? What are the symptoms of driving with one tire wider 10mm than others on the system? Thanks.
i had the opposite issue, think it was after getting a plug in my tire and getting a get throttle body, could be that my tire pressure was lower than needed be but finally getting accurate odometer and speed, but now getting tire/axle ratio out of range it's weird. ECM was replaced and completely reprogrammed a year ago around same time but was about 1 week after the throttle body was swapped.
I just had two sizes bigger tyres fitted on my car. Was advised to do that to better handle an unpaved road I have to travel daily. I immediately noticed I needed to give it more gass to pull away and that the fuel consumption is a little worse, not too much, but noticeably so. The ride comfort improved, which is what I needed, and I have less road noise, but all other aspects remain unchanged. Cornering , braking etc. But then again, Iam just driving normally, didnt do any top gear style performance tests.
I can't say confidently one way or the other. With taller tires, your vehicle will work a little harder, but go a little further. I'm not certain which way would yield the best MPG. But thank you for your comment and for checking out the video. I might have to investigate that in a future video.
This is an old question but I'll answer it for the next guy because its a good question. Short answer is Yes. If you have mis-matched tire sizes on the driven axel (front wheel drive/rear wheel drive) it could definitely cause problems. If you have two different sized tires they will have to spin at different speeds to cover the same distance, kinda like when you go around a corner, the outside tire has to spin faster than the inside tire. This is why cars have differentals. If youve ever driven a car with a Locked/Welded Diff and go around a tight corner it basically forces the inside tire to do a supsr slow burn out to keep up with the outside tire. So it'll probably burn up the Diff before the transmission? I cant imagine a front wheel drive with an automatic transmission would fair very well either. Its absolutely necessary to have 4 matching tires with any All Wheel Drive system where its AWD all the time. Subarus are kinda notorious for making people change all four tires at once even if you just had a random flat in one tire for fear that putting a brand new tire on one corner when the other three are maybe only halfway thru their thread wear. BMW X-drives ive heard similar. So really as long as the two drive tires are Same size, the actual size is basically irrelevant.
Thanks a lot for all the efforts and calculations to explain this..... it's really informative and I understand why my brothers car's speedometer isn't accurate. Appreciate your good work man!! 👍👍👍
I own Honda Jazz 1st gen and drive 175/65/r14 tyres in the front and 185/60/R14 back tyres.Honda recommend to drive with 175/65 tyres but i have made mistake and mounted brand new 185/60r14 on the back wheels. Cons-The braking distance increased.I feel like i need to push the gas little more than before to gain speed.Steering is little heavier. Pros-car feels really stable,especially when turning at higher speed.Suspension feels softer and bumps are less noticeable. Will i cause damage to the engine and suspension if i continue driving with this tyre combination?
I got a 2007 Jeep JK with 344k and it had 35" MT tires....is it possible that the odometer is reading higher than what it actually has? 7 weeks in now im at 348k....thats 4k i seven weeks?
The taller wall tires will give more comfort. One will have to bear in mind that the actual road speed will be about 3 to 5 percent higher than the speedometer reading. I think as long as the wheel well can fit, upsizing the whole tyre is doable.
most car speedometers are calibrated to show 5-8% more than your actual speed so people can't blame the speedometer when they care caught speeding. so an inch up should really not make a big difference since you would still be traveling slower than the speedometer says. If you want to measure precise speed GPS is the way to go.
@@Ggorazzi the speedometer gauge dosnt even show actual speed if you look at scan data the computer shows the speed more accurate usually the speedometer is already off by 1 or 2
No, you should be fine. The ABS system looks at the wheel speeds in relation to each other. You'll still have a little difference in actual vehicle speed compared to the speedometer, but no ABS issues.
I just bought some tires 315 40 21 and replacing the old 315 30 21, will I have issues with ABS? I realize I may have to adjust the computer for new tires.
I do understand the millage and speed difference and that is not a concern. Do I lose anything essential otherwise and my question is actually for a reverse scenario, say using an aspect ratio of 65 instead of your 70, with the aim to bring the center of gravity a bit lower in a sporty car and not a truck, for better cornering? Will, I jeopardize something significantly, or am I at fault by a liability on any major issue?
@Bippolas Beige Can you explain farther? Is this Fed or State law? I say that because many cars for eg WRX from Subaru comes with many choices s.a. 17 or 18" rim directly from the factory. Also, what are low riders then?
Have a question for you? I bought a Brand new 2022 Mercedes-Benz Metri van I now have 38,000 miles on the van time to change tires, original tires and rims on the van factory, have not been changed. I discovered from factory the van has 17" rims on the driver's side and 16" rims on the passenger side. Mercedes say they will buy me two new 16" rims, but they want the old 17" rims back. My question is do you think with this being a rear wheel drive there is any drive Trane concerns?
I have 2001 Proton Wira sedan. My OEM wheel and tires size 185/65/14, i change to 185/70/14 tires to increase ride height, fill wheel gap and more smoother ride on uneven rod.
Hello sir I have a question My tires in front should be 245/40 r20 But I only found 245/45 r20 Does that extra 5 height harm the car by the way my car is bmw 740li 2013
As far as fitment goes, they would very likely fit just fine. Those tires will be just shy of 1 inch taller than the tires you should have. My concern is that you said the front, which makes me think you are talking about only replacing the front. You want to avoid putting different sized tires on the same vehicle unless it was designed to be that way. While the tire might fit and work fine, the different size will make those wheels turn slower, and having that happen can cause a number of ABS issues as the ABS constantly monitors all wheel speeds and uses that info, along with other input information, to determine if the wheels are locking up. In addition to that, I thought thoust 740li's were AWD, or at least some of them were. If it's AWD, you absolutely never want to put different sized tires on unless you're putting all 4 on. On AWD vehicles, you'll tear up the drivetrain if you have the front and rear axles trying to turn different speeds due to different tire sizes. I would suggest either finding the recommended size for your front tires, or replacing all 4 with the 245/45/20 tires you found.
@@DIYAutoHomeschool my front tires should be 245/40 r5 And rear is 275/35 r20 Do u think that I only found for the front 245/45 The rear also should be 275/40 1 inch hiegher. That way is it balanced now? Do u think one inch hiegher in both rear and front will harm the car Currently I have one inch higher in both front tires from 40 to 45 but the rear still 35 do I have to put 40 now Thanks for your help and replying and please reply to my new questions
What would happen if i put on my toyota truck with limited split differential. on the back differential the stock tire 31x 10.50 R 15 and in the other side i put a 265/75 R16??
I got hpnda crv 2019 my tire size is 235/60r18. If i use a tire sizes of 235/55r18 will it affects the awd system or does it may cause some trouble on the awd system in the future? Thanks
I have an factory 225R 40 18 and im wanting to change over to a 225R "45" 18. I have plenty of clearance on my Subaru Impreza. Do you think this will work?
The dealer put 225 65R17 on my car when it calls for 225 60R17. I think this is the reason my AWD light is flashing. I'm going to do more research. I'm trying to get them to replace the tires. Thank you for the video!
Thank you for taking the time to watch the video and for your comment. If they put those tires on the vehicle, but not on all 4 wheels, then it absolutely could cause your AWD system to act funny, and to drive funny. It can also cause damage to your AWD system. If all for wheel had the same size put on, it's less likely that it would cause problems, but some vehicles are capable of detecting when the incorrect tire size has been installed. Best of luck and I hope it turns out well for you.
@@DIYAutoHomeschool Thanks for the reply! All 4 tires are the same size! They originally thought it was something else and replaced some struts and sway bar links, but 20 minutes into the drive back from the shop, the AWD light start flashing again. The manual just says it's a tire rotation problem/difference between the front and back tires. Maybe they aren't all the same tread or maybe I need to add air. I don't know! >_< I've been reading everything I can on the Nissan forums and everyone says for my year vehicle, the tires should be the 60R17 and not the 65. Thank you again for the video because without it, I wouldn't have even thought to check the tire sizes for the make/model/year for my vehicle. Back to the drawing board!
What if you have two tires the wrong size (back or front not side to side)? Say the front tires are the correct size and the back tires are incorrect, or vice versa?
I have a question I have a 2019 Nissan frontier 2.5 King cab. The tires are small with the s model the SV King cab with 4.0 V6 have bigger tires. I just wanted to see if I can go up a little higher like the SV model of the King cab Nissan frontier but I'm kind of skeptical about doing it after seeing these videos. I just want a more rugged look because it sits low to the ground and I would like it to sit a little higher
I have Renault Duster it Has 215/60/16 on tha Front and 215/65/16 on tha back! Just tell me this! Can I run the car in this size tire Sir! Plz Answer me !
Rainier Dagdag. Ok, with just a quick check, you should come out close to the same diameter if you use 175/50/R17 tires. Your stock size is 175/70/14. This is if you want to stick with the same width of tire. But that's a rather odd size and finding tires that size and buying them may be more hassle than you want. Another thing to consider with putting aftermarket wheels on is the offset. Most aftermarket wheels carry a different and greater offset than your stock wheels. This means the centerline of the wheel will be at a different place than with your stock wheels and tires. If the difference is too much, you can end up with wheels that rub the liner or suspension parts on turns. I'm not trying to talk you out of aftermarket wheels, just do a lot of research to make sure they'll work the way you want them to once you purchase them.
Thanks a lot sir for explaining so easily and briefly, i was wondering why my bike speedometer showing slow when i am feel going fast one question: in this case our total distance covered in odometer will be less than we actually covered? right?
Hello. I drive a 2005 mercury grand marquis. Stock tire size is 225/60r16 and is what I have on right now, can I put on 215 65r16? I have them in my garage and my 225's threads are almost done.
Ok so if I take a truck with a 30” tire already on it and that tire rotates 622 times in a mile. That same truck I put on 50” tire that rotates 404 times a mile. But of course because the bigger tire has a bigger diameter, the engine struggles and the Speedo is wrong. What if I put on portal axles with a low gear ratio to counteract this? Then my speedo is correct and my engine has the same mechanical advantage with the 50” as it did with the 30”. Yes I know the 05” will be heavier and cause the engine to struggle more, but I’m ignoring that for the time being. What do y’all think?
Local Salvage store has new Good Year tires for $35 each. Only problem is my car takes 215/55/R16 and these tires are 215/60/R16…. Can the new tires be used?
I wanted to do this my car calls for 245-40-19 & I wanna do 245-45-19 or 245-50-19 for more cushion, m y question is will this ruin the cars components in any way?
I have Toyota Sienna 2013SE. I got 215/50/R17 winter tires and rims, Can I put this tires to my Sienna? I currently I have 235/50/R19 all season tires.
Yes, the odometer will be affected, you will be going further than your vehicle thinks you are, so you're odometer will show less miles than you've actually driven. And mileage is a factor in the algorithm to determine oil life on most vehicles, so it's possible that it could affect that as well. However, the affect on that would likely be negligible.
I have a 97 k1500 with the right tires/rims (265/75r16) amd I'm driving at 60 and I'm getting told I'm going 50 to 55 mph??? I'm thinking of putting 285/75r16s on
i bought a clio mk3 uk----on front i have noticed 2 differant sizes of tyres-on n/s 195/50/15-o/s 185/55/15-garage says its ok what is your opinion?-is it safe as my daughter drives it?
Any thoughts on why my 2001 GMC Jimmy 2 door 4wd indicates two different OEM tire size? When I go to tire sellers websites it lists both 235X70XR15 and 235X75XR15 as proper fitment. It seems strange that there would be more than one OEM size listing. For 90% highway and city street driving which would you recommend?
Did this RUclipsr answer your question? In my opinion, I would go with the one with the higher tire or one with the greater diameter. But, then again, I just looked up you model. It seems the tire with 70 height is listed more. Looks like your wheel size is 15×7, with that 7" width size you could even go to 225/70 R15 , in my opinion. Considering most of your driving is highway (or freeway also) driving, I would favor the taller tire for comfort but better performance and shorter tire for performance and handling. The only thing I noticed unusual about the OEM tires you listed were that the only the height of the second was tire was taller. I usually notice when the second tire is shorter, than it is usually has a wider tread.
That’s all well and good how do you recalibrate it I have a 91 suburban I’m putting 17 inch rims on it and a tall rear tire P235/70 R17 to be exact. Speed sensor? What do I do what do I change. these gizmos that I see on RUclips don’t fit my truck. Any advice would be very much appreciated.
Looking at getting decent snow tires for the first time this year, rather than decent all season, and have R45 - 18" performance summers on - thinking downsizing to 17" with higher R75 exactly for this reason but without understanding the math, which isn't ny strongest suit! Thanks for this - but still a bit creepy to think my phone seems to know what I'm thinking!! 😉
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+1” tire height (roughly) = 2 mph actual speed over the gauge. Great geek work, thank you!!!
Real question is what happens if you put on a 19" rim instead of the oem 17"...
Actually this prof is wrong he shouldn't multiply the rpms that he saw on the small tyre to the large tyre to get wht the odo will show. What actually will happen is the rpm will be less. As the tyre is larger its circumference is larger thus it needs less rotation to cover the same distance as a smaller tyre. Thus there will be a lower rpm recorded on the wheel. Which the computer will percieve as lower distance and speed. Thus u get a false lower reading. Not high!! So much for a tyre prof😅
i knw he is not a prof.😝 But sure wud pass for one
@@amoghpatil did you watch till the very end?
@@dpeagles yea.. i have
@@amoghpatil You stated "Thus u get a false lower reading."
He did get a false lower reading! His car speedo showed 60 when his GPS showed 62.
He may have mis-stated or miscalculated but got the same answer you did. "Not high"
The more important point is that the wrong size of tire can show that your car has more miles on it than it actually has. A smaller tire over 6 years can really mess with the odometer. Not to mention this throws of your service schedule. Oil changes etc. I guess you could put larger tires, notate the difference so you don't speed and keep your cars mileage low. lol. Thanks for the video.
Thank you for this, this comment is very helpful and what I was looking for.
@@jgthe2nd202 lol so you getting bigger tires?
That's a bloody lie
@@wildestcowboy2668 how is it a lie??
Tire lesson and math in one video, brilliant !
I've totally learned something new. Thank YOU!!!
I know for a fact that he didn’t mention was that by going 1 in more higher makes the ride more comfortable because there’s more rubber to absorb the road p.s.I went from 235 60 18 to 235 65 18, much better ride
Just done the same, better ride.😅
My truck's stock tires are a 275/60R20 (essentially a 33 inch tire). Next time I buy tires I'm planning to go with a 275/65r20 (essentially a 34 inch tire). May put my speed a hair over what my gauge is reading and my odometer a touch under reality but it's negligible. I believe there's a way on my truck to go into the settings and enter the tire size you're running and it'll recalibrate your speedo to match. Haven't actually gone into the settings to verify this tho...
Why is everyone blowing off about the speedometer readings!? There should be actual talk on upsizing on the same rim with handling issues and clearance etc.,
Thank you! I was wondering if upsizing or downsizing on the same rim would affect my handling and stuff like that. The speedometer is the least of my concerns.
@Milan Latona Tire radius change by +/- 5% should not matter. Provided the Road clearance is not an issue and width remains the same or just the next size.
There are comparison calculators on the web which make it easy for everyone
This is teaching. Clear and simple
I think the more concerning issue is how the tire size affects the longevity and performance of the car, in my opinion.
Also, I heard most cars of today have their speed set lower than what their speedometers display. Using my car app such as Waze, I can notice my speed in some cars to be 2 to 3 miles lower than what is displayed in the dash.
So, in this case, should I still get a tire that is bigger than what is specified for my car?
One of the best youtube mechanical videos I've ever seen!
If it is then you need to watch more mechanical videos...
Darren Davenport which ones?
When i read the title i had assumed this would be about the cost that can occur due to mechanical failures of running different size tires on a vehicle .
Good video though it makes sense
My car has two different sizes and was manufactured that way. I have wider rims in the rear. I believe that’s to optimize speed by adding more traction to the rear given it’s a RWD vehicle.
Thank you very much for this work. Where am I here in Africa, most of us do not have access to the correct size tires. If the tire can fit the wheel, we go for it. A much bigger problem that we have if inflating the tires to the correct PSI. I have been driving here in Cameroon for 4 years and I'm YET to run into a pump that gives me the exact 35PSI that I need. They are typically inflated at 10PSI overs which, when combined with the aggressive driving habits around me, is the cause of the majority of deadly accidents around me. This is a systemic problem that needs to be resolved to save lives, but the country is "poor" and has far more urgent priorities!
This is good stuff, BUT just the tip of the iceberg as many here are here because we go with larger tires because we're modifying our vehicles to perform better off road and we're curious how to manage the differences with MPH, fuel economy and power..... For instance, I have an '04 AWD Astro van I converted to 4x4 with an s10 transfer case and I have a decent lift on it. My tires are now about 2" taller than stock and my speedometer is off 4mph... There are charts out there that point out the relation to tire size, gearing and rpms - There are "sweet spots" to aim towards, for instance, according to what I've seen you can get better gas mileage but have a loss of power at the same time.
This video is great for what it is but most people who go with larger tires already/quickly learn/understand the speedometer is off without needing to understand the math involved (I enjoyed this explanation, anyhow) - What they really want to know is how to reprogram the computer to work with the new tire size so the speedometer in in sinc as well as to get the mpg readings to be accurate - I'll be looking to see if you've done anything on that as I believe you'd probably be the perfect guy to explain all that
Very precise and informative video
Does taller sidewall provide more cushion for suspension components?
Got a BMW 335i. Went through 17 tires in a 3 year period. Therefore, I had zero confidence in the reliability of the vehicle. Well, ironically enough, I garaged the thing for 2 years bc I was sick of driving somewhere, blowing out a tire and then waiting for AAA to come give me a tow bc the vehicle has no spare. Well, after taking it out of the garage recently, I realized that the back tires (which calls for a larger width) was the same as the front. So these dipsticks at NTB we’re sticking on the wrong size for 3 years. No idea how I never caught that. So, shame on me for trusting someone else that should know their job.
The numbers don’t lie.
I had to put slightly smaller tires on my truck. I just drive it around town, in light traffic, doing errands, so I think everything's ok.
What size did you start with and what size did you go to? I'm curious because I'm looking into doing the same with my truck
Dose it effect milage ? Fuel economy ?
Thank you for this, I was just advised to put 195's on my car that should have 175's to run better on an unpaved road I have to travel daily. Immediately realised as I drove off the xtra effort it takes to pull away, not a lot, but still. So by his logic it would also mean that a car would have less miles on it's tachometer than it actually travelled if fitted with bigger tyres, right?
Great info. Just a question though. What if you're switching from highway tires to those all-terrain or rugged-terrain tires with all those biting edges? Not sure if the tire makers all factor those in.
How about the tire size I'm using at the back 215x60 R17 and in the front 225x60 R17, Is there any effect on the performance of the engine car? Please give me advice. Thank you!
Thanks for sharing with us about this..... I just bought the wrong size tire ...and I will get a close look about the speed
Awesome math skills ! 😊
in thesis - Trip recorder/tachometer would be off too i believe.. thank you for sharing
Nice to see your method of displaying the calculations.
I myself have simply ignored my car's dinosaur terrestrial speedo'... for over 15 years, in favour of GPS!
Reason: my '91 seven seater FrontWheelDrive (FWD) mazda's speedo has an inbuilt inaccuracy far beyond what I personally deem practical;
for example at Speedo 100kmh, I am doing GPS 92kmh.
At Speedo 80, I am doing GPS 73kmh etc etc.
The vehicle has only one size on it's manufactures' chart - being 185/70-14.
I'd like to go for 185/75-14 instead. ( I don't want to go 195/65-14 etc etc)
I want to achieve a longer rolling distance; smoother ride
From the above figures:
PROs: I will have no need to worry the Speedo will ever under-read, compared to the GPS' as according to calcs' I would expect to see a 3% increase in Rolling Distance with the 75% tyres on.
I can see I would achieve a softer ride;
lower RPMs for any given GPS speed;
I don't need to worry about larger wheel rim width changes;
I would achieve a higher area of footprint for better hold, for, when applying power I therefore expect to never again have to suffer the tyre skid when accelerating from standstill.
This being due to the extra rubber on the road, from the larger Diameter.
CONs: There might be some small compromise to tyre wall deformation upon hard cornering?
An Insurer might refuse to pay out, if the tyre is not exactly as stipulated on the Plate?
My Mazda seven seater is FWD, and is well known for the tyre skid upon acceleration from standstill. Most of it due to being FWD, but I also have long blamed the original diameter of a 185/70-14 contributes to it.
A more modern vehicle's ECU would report to the owner that it's next due Servicing Schedule would for example come due at 97000km instead of 100000km
Hey, Thanks for checking out the video. I hope you liked it. Feel free to ask any questions you have and leave your thoughts or feedback.
thanks for your video and the info...
What would be then the effect on the car's gearbox (if any?)
I have a 1999 Trans Am. To give the car a better look I put on a set of C6 Corvette wheels . 18X9.5 front and 19X10 rear. I have noticed that the ABS light comes on at highway speeds. What can I do to fix this and keep these wheels?
My 2020 Mitsubishi Outlander PHEV OEM's are 215/70r16.
I changed it to 225/70r16 AllTerrain tires (I do a lot mild off-road, gravel roads and snow).
I am very happy with the change but I lost about 20% of EV range and fuel consumption went slightly up.
I will be performing 1.2inch (about 3cm) lift and I am planning to install even bigger 225/75r16 tires to increase the tire side wall and ground clearance even more.
Do you think this is good idea or this is too much?
You should explain how you got numbers/increments of the tires
I.e. 265 is the width, 70 is 70% of the width of the tire.
My car, the 2021 Impreza had 7 trims but 3 different wheel/tire sizes. I bought the sport 🤣, which has the same engine in all trims, so I am wanting to change my P225/40R18's to P205/65R16's for an smoother ride.
What about tire compression under vehicle weight. I think an inch higher in height(side wall) would in reality not be up to an inch because more sidewall means more compression under weight right. I hope someone can help me out on this
Will running tires with a higher diameter result in better fuel efficiency (MPG), and why?
That might appear that way. But in Reality, the factory tire size that comes with a vehicle is thoroughly tested to be the best possible for the vehicle, engine, aerodynamics of vehicle and offcourse driver comfort.
If increase diameter increase mpg, then all companies will fit bigger tyres lol, to increase mpg.
The tyres with bigger diameter cost more engine power thats why truck and suv with bigger engine has bigger diameter tyre than sedan.
If u install suv size tyre in a sedan with 40mpg, the mpg will drop cause taller tyre will push engine to use more power and therfore use more fuel. And yes top speed of vehicle will decrease as well.
The handling might also be bad.
Damn never thought I’d use math from school cool
I own a mazda 3 automatic that came with 205/60R16 and I have an issue with my gearing ratio where the car does not downshift on the highway when I have to slow down and speed up again (for eg. coming up behind a slower vehicle ahead of me and then having to accelerate to pass the car). It stays at 5th gear and does not downshift to 4th.
I asked the mazda dealership and they told me the gearing software is set for fuel economy. thats why it does not downshift in those situations.
So I have to manually downshift to get the acceleration.
would getting an overall taller or shorter tire diameter help?
Oh man Im in big shit my stock 1995 landcruiser had 265/70R16 what equates to 31.6" and I went to 40s everything has been really good.
Thanks, anyway is it ok to odd tire width from 205/70/15 to 225/70/15?
Thanks for showing me that,i leaned you are good,subcribed and liked.
Your very smart Sir ... nice math ...I always wandered how that worked.
After punctured the tire (pothole) I was in need to install spare tire, so I could only get in that situation 225/50/17 tire (other three are 215/50/17). One wider tire installed on the rear right position.
I'm in the process of finding the same 215/50/17 tire, and occasionally driving with one wider tire (and with different pattern), and I didn't notice any change in control, balance, braking, also in 6th gear on highway.
Do I really need to match one wider tire ASAP?
What are the symptoms of driving with one tire wider 10mm than others on the system?
Thanks.
i had the opposite issue, think it was after getting a plug in my tire and getting a get throttle body, could be that my tire pressure was lower than needed be but finally getting accurate odometer and speed, but now getting tire/axle ratio out of range it's weird. ECM was replaced and completely reprogrammed a year ago around same time but was about 1 week after the throttle body was swapped.
So does aftermarket rims and tires make the same affects
Great Video, thanks 🙏🏻
hi as per your example will there be any effect on the drivability and steering feedback
I just had two sizes bigger tyres fitted on my car. Was advised to do that to better handle an unpaved road I have to travel daily. I immediately noticed I needed to give it more gass to pull away and that the fuel consumption is a little worse, not too much, but noticeably so. The ride comfort improved, which is what I needed, and I have less road noise, but all other aspects remain unchanged. Cornering , braking etc. But then again, Iam just driving normally, didnt do any top gear style performance tests.
Does change of height affect the fuel consumption?
What app do you use to check car speed?
Excellent video, is there any effect on actual MPG, for gas only vehicles. Thanks!!!
I can't say confidently one way or the other. With taller tires, your vehicle will work a little harder, but go a little further. I'm not certain which way would yield the best MPG. But thank you for your comment and for checking out the video.
I might have to investigate that in a future video.
DIY Auto Homeschool that would be a great video.
@@DIYAutoHomeschool Looking forward to your investigation on its effect on MPG.
Do TIRE differences harm a transmission?
This is an old question but I'll answer it for the next guy because its a good question.
Short answer is Yes.
If you have mis-matched tire sizes on the driven axel (front wheel drive/rear wheel drive) it could definitely cause problems.
If you have two different sized tires they will have to spin at different speeds to cover the same distance, kinda like when you go around a corner, the outside tire has to spin faster than the inside tire. This is why cars have differentals. If youve ever driven a car with a Locked/Welded Diff and go around a tight corner it basically forces the inside tire to do a supsr slow burn out to keep up with the outside tire.
So it'll probably burn up the Diff before the transmission? I cant imagine a front wheel drive with an automatic transmission would fair very well either.
Its absolutely necessary to have 4 matching tires with any All Wheel Drive system where its AWD all the time. Subarus are kinda notorious for making people change all four tires at once even if you just had a random flat in one tire for fear that putting a brand new tire on one corner when the other three are maybe only halfway thru their thread wear. BMW X-drives ive heard similar.
So really as long as the two drive tires are Same size, the actual size is basically irrelevant.
Thanks a lot for all the efforts and calculations to explain this..... it's really informative and I understand why my brothers car's speedometer isn't accurate. Appreciate your good work man!! 👍👍👍
I own Honda Jazz 1st gen and drive 175/65/r14 tyres in the front and 185/60/R14 back tyres.Honda recommend to drive with 175/65 tyres but i have made mistake and mounted brand new 185/60r14 on the back wheels.
Cons-The braking distance increased.I feel like i need to push the gas little more than before to gain speed.Steering is little heavier.
Pros-car feels really stable,especially when turning at higher speed.Suspension feels softer and bumps are less noticeable.
Will i cause damage to the engine and suspension if i continue driving with this tyre combination?
I got a 2007 Jeep JK with 344k and it had 35" MT tires....is it possible that the odometer is reading higher than what it actually has? 7 weeks in now im at 348k....thats 4k i seven weeks?
Hey, that’s great, but is there any physical harm using your example?
The taller wall tires will give more comfort.
One will have to bear in mind that the actual road speed will be about 3 to 5 percent higher than the speedometer reading.
I think as long as the wheel well can fit, upsizing the whole tyre is doable.
most car speedometers are calibrated to show 5-8% more than your actual speed so people can't blame the speedometer when they care caught speeding. so an inch up should really not make a big difference since you would still be traveling slower than the speedometer says. If you want to measure precise speed GPS is the way to go.
@@Ggorazzi the speedometer gauge dosnt even show actual speed if you look at scan data the computer shows the speed more accurate usually the speedometer is already off by 1 or 2
Great information, Thank you
185/65/r15 is the stock, im planning to upgrade 195/65/r15, will it mess the ABS?
No, you should be fine. The ABS system looks at the wheel speeds in relation to each other. You'll still have a little difference in actual vehicle speed compared to the speedometer, but no ABS issues.
I just bought some tires 315 40 21 and replacing the old 315 30 21, will I have issues with ABS? I realize I may have to adjust the computer for new tires.
Thank you so much for this information.
Good job! Thanks!
I do understand the millage and speed difference and that is not a concern. Do I lose anything essential otherwise and my question is actually for a reverse scenario, say using an aspect ratio of 65 instead of your 70, with the aim to bring the center of gravity a bit lower in a sporty car and not a truck, for better cornering? Will, I jeopardize something significantly, or am I at fault by a liability on any major issue?
@Bippolas Beige Can you explain farther? Is this Fed or State law? I say that because many cars for eg WRX from Subaru comes with many choices s.a. 17 or 18" rim directly from the factory. Also, what are low riders then?
Have a question for you? I bought a Brand new 2022 Mercedes-Benz Metri van I now have 38,000 miles on the van time to change tires, original tires and rims on the van factory, have not been changed. I discovered from factory the van has 17" rims on the driver's side and 16" rims on the passenger side. Mercedes say they will buy me two new 16" rims, but they want the old 17" rims back. My question is do you think with this being a rear wheel drive there is any drive Trane concerns?
Tyre with higher rpm is good or with lower rpm?
tiresize.com/comparison/
Use this website, it's really helpful.
nice...other than speed...any performance issues? thinking to change my tires from 245 / 40 R19 to 245 / 45 R19.
Can different tire size causes trouble code? I'm getting v-signal not plausible error.
I have 2001 Proton Wira sedan. My OEM wheel and tires size 185/65/14, i change to 185/70/14 tires to increase ride height, fill wheel gap and more smoother ride on uneven rod.
Did this increase your fuel consumption?
Hello sir I have a question
My tires in front should be
245/40 r20
But I only found
245/45 r20
Does that extra 5 height harm the car by the way my car is bmw 740li 2013
As far as fitment goes, they would very likely fit just fine. Those tires will be just shy of 1 inch taller than the tires you should have.
My concern is that you said the front, which makes me think you are talking about only replacing the front. You want to avoid putting different sized tires on the same vehicle unless it was designed to be that way. While the tire might fit and work fine, the different size will make those wheels turn slower, and having that happen can cause a number of ABS issues as the ABS constantly monitors all wheel speeds and uses that info, along with other input information, to determine if the wheels are locking up.
In addition to that, I thought thoust 740li's were AWD, or at least some of them were. If it's AWD, you absolutely never want to put different sized tires on unless you're putting all 4 on. On AWD vehicles, you'll tear up the drivetrain if you have the front and rear axles trying to turn different speeds due to different tire sizes.
I would suggest either finding the recommended size for your front tires, or replacing all 4 with the 245/45/20 tires you found.
@@DIYAutoHomeschool my front tires should be
245/40 r5
And rear is
275/35 r20
Do u think that I only found for the front 245/45
The rear also should be
275/40
1 inch hiegher. That way is it balanced now?
Do u think one inch hiegher in both rear and front will harm the car
Currently I have one inch higher in both front tires from 40 to 45 but the rear still 35 do I have to put 40 now
Thanks for your help and replying and please reply to my new questions
What would happen if i put on my toyota truck with limited split differential. on the back differential the stock tire 31x 10.50 R 15 and in the other side i put a 265/75 R16??
I got hpnda crv 2019 my tire size is 235/60r18. If i use a tire sizes of 235/55r18 will it affects the awd system or does it may cause some trouble on the awd system in the future? Thanks
Excellent clear explanation,good video 👍👍👍👍
Great video. Thank you for you information
I have an factory 225R 40 18 and im wanting to change over to a 225R "45" 18. I have plenty of clearance on my Subaru Impreza. Do you think this will work?
Excellent math.
The dealer put 225 65R17 on my car when it calls for 225 60R17. I think this is the reason my AWD light is flashing. I'm going to do more research. I'm trying to get them to replace the tires. Thank you for the video!
Thank you for taking the time to watch the video and for your comment.
If they put those tires on the vehicle, but not on all 4 wheels, then it absolutely could cause your AWD system to act funny, and to drive funny. It can also cause damage to your AWD system.
If all for wheel had the same size put on, it's less likely that it would cause problems, but some vehicles are capable of detecting when the incorrect tire size has been installed.
Best of luck and I hope it turns out well for you.
@@DIYAutoHomeschool Thanks for the reply! All 4 tires are the same size! They originally thought it was something else and replaced some struts and sway bar links, but 20 minutes into the drive back from the shop, the AWD light start flashing again. The manual just says it's a tire rotation problem/difference between the front and back tires. Maybe they aren't all the same tread or maybe I need to add air. I don't know! >_< I've been reading everything I can on the Nissan forums and everyone says for my year vehicle, the tires should be the 60R17 and not the 65. Thank you again for the video because without it, I wouldn't have even thought to check the tire sizes for the make/model/year for my vehicle. Back to the drawing board!
danger! YOU will kill of car diferencial,becose Your car 4weel drive must to by factory size all4 tires same!
What if you have two tires the wrong size (back or front not side to side)? Say the front tires are the correct size and the back tires are incorrect, or vice versa?
I have a question I have a 2019 Nissan frontier 2.5 King cab. The tires are small with the s model the SV King cab with 4.0 V6 have bigger tires. I just wanted to see if I can go up a little higher like the SV model of the King cab Nissan frontier but I'm kind of skeptical about doing it after seeing these videos. I just want a more rugged look because it sits low to the ground and I would like it to sit a little higher
I have Renault Duster it Has 215/60/16 on tha Front and 215/65/16 on tha back! Just tell me this! Can I run the car in this size tire Sir! Plz Answer me !
You can but cannot drive 4x4 with central diff block
I have 14 inch rim on my Hyundai Accent sedan 2017, what size of tire can I use on 17 inch mag wheels after market?
Rainier Dagdag. Ok, with just a quick check, you should come out close to the same diameter if you use 175/50/R17 tires. Your stock size is 175/70/14. This is if you want to stick with the same width of tire. But that's a rather odd size and finding tires that size and buying them may be more hassle than you want.
Another thing to consider with putting aftermarket wheels on is the offset. Most aftermarket wheels carry a different and greater offset than your stock wheels. This means the centerline of the wheel will be at a different place than with your stock wheels and tires. If the difference is too much, you can end up with wheels that rub the liner or suspension parts on turns. I'm not trying to talk you out of aftermarket wheels, just do a lot of research to make sure they'll work the way you want them to once you purchase them.
I wanted to change my 265/50r20 to275/50r20 what do you think?
Thanks a lot sir for explaining so easily and briefly, i was wondering why my bike speedometer showing slow when i am feel going fast
one question: in this case our total distance covered in odometer will be less than we actually covered? right?
Yes you got it
Hello. I drive a 2005 mercury grand marquis. Stock tire size is 225/60r16 and is what I have on right now, can I put on 215 65r16? I have them in my garage and my 225's threads are almost done.
Professor Tire thanks for explaining.
Ok so if I take a truck with a 30” tire already on it and that tire rotates 622 times in a mile.
That same truck I put on 50” tire that rotates 404 times a mile.
But of course because the bigger tire has a bigger diameter, the engine struggles and the Speedo is wrong.
What if I put on portal axles with a low gear ratio to counteract this?
Then my speedo is correct and my engine has the same mechanical advantage with the 50” as it did with the 30”.
Yes I know the 05” will be heavier and cause the engine to struggle more, but I’m ignoring that for the time being.
What do y’all think?
My uncle upsized his tires and then they started rubbing his splash guards.🤪 What a dumb butt move.
Local Salvage store has new Good Year tires for $35 each. Only problem is my car takes 215/55/R16 and these tires are 215/60/R16…. Can the new tires be used?
I wanted to do this my car calls for 245-40-19 & I wanna do 245-45-19 or 245-50-19 for more cushion, m y question is will this ruin the cars components in any way?
my question is would i throw off the abs and traction control sensors
I have Toyota Sienna 2013SE. I got 215/50/R17 winter tires and rims, Can I put this tires to my Sienna? I currently I have 235/50/R19 all season tires.
1:08 how was 185.5mm computed?
so basically taller tires add more miles to your meter right?
does this have a negative effect on thr break system?
Please if u can answer me , I have 3 tire with this number ,215/50/17,,,,, so can i ued with just one different one number 215/55/17
What about length meter.... Does it affects....?
Oil change time
Yes, the odometer will be affected, you will be going further than your vehicle thinks you are, so you're odometer will show less miles than you've actually driven.
And mileage is a factor in the algorithm to determine oil life on most vehicles, so it's possible that it could affect that as well. However, the affect on that would likely be negligible.
@@DIYAutoHomeschool thx alot...
I have a 97 k1500 with the right tires/rims (265/75r16) amd I'm driving at 60 and I'm getting told I'm going 50 to 55 mph???
I'm thinking of putting 285/75r16s on
Thanks for the info you helped me a lot.
Question! If I let air out of the tire. (30psi) vs 35psi would that matter in tire height? And by how much
Your tire would no longer be round. Flat at the bottom increasing roll resistance and gas mileage. Keep the air in your tires.
My stock tire 255/60 18 would like putting 260/60 18 just to have a wider look. Would it fit ?
i bought a clio mk3 uk----on front i have noticed 2 differant sizes of tyres-on n/s 195/50/15-o/s 185/55/15-garage says its ok what is your opinion?-is it safe as my daughter drives it?
so lets say I want to install a larger wheel onto my car. what would i have to do to sync my speedometer with the wheel. (66 mustang inline 6 200)
Reprogram the computer and if it don't have one I don't remember
Any thoughts on why my 2001 GMC Jimmy 2 door 4wd indicates two different OEM tire size? When I go to tire sellers websites it lists both 235X70XR15 and 235X75XR15 as proper fitment. It seems strange that there would be more than one OEM size listing. For 90% highway and city street driving which would you recommend?
Did this RUclipsr answer your question? In my opinion, I would go with the one with the higher tire or one with the greater diameter. But, then again, I just looked up you model. It seems the tire with 70 height is listed more. Looks like your wheel size is 15×7, with that 7" width size you could even go to 225/70 R15 , in my opinion. Considering most of your driving is highway (or freeway also) driving, I would favor the taller tire for comfort but better performance and shorter tire for performance and handling. The only thing I noticed unusual about the OEM tires you listed were that the only the height of the second was tire was taller. I usually notice when the second tire is shorter, than it is usually has a wider tread.
That’s all well and good how do you recalibrate it I have a 91 suburban I’m putting 17 inch rims on it and a tall rear tire
P235/70 R17 to be exact. Speed sensor? What do I do what do I change. these gizmos that I see on RUclips don’t fit my truck. Any advice would be very much appreciated.
What about tire width?
great explanation.. good job... thanks :)
Hi is it possible to change from 225/65R17 to 235/65R17?
Looking at getting decent snow tires for the first time this year, rather than decent all season, and have R45 - 18" performance summers on - thinking downsizing to 17" with higher R75 exactly for this reason but without understanding the math, which isn't ny strongest suit! Thanks for this - but still a bit creepy to think my phone seems to know what I'm thinking!! 😉
Well, your phone and google do listen to us secretly :P
Hey man, how do you think this effects mpg? Better or worse? Great vid! Thanks
Definitely worse, bigger tires requires more power to role it