Gentlelife50:


I still don't believe it

You need to open your mind to strange but factual things.

As a Civil Engr by training, my training makes me imaging things before proving it with mathematics and physics. Not everyone is good at this so if you can't understand it, then its either I try another explanation or give up depending on if you are interested in learning.

At least, if you don't believe me, this should make sense.
www.auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/speedometer4.htm

All speedometers must be calibrated to make sure the torque created by the magnetic field accurately reflects the speed of the car. This calibration must take into account several factors, including the ratios of the gears in the drive cable, the final drive ratio in the differential and the diameter of the tires. All of these factors affect the overall speed of the vehicle. Take tire size, for example. When an axle makes one complete turn, the tire it's connected to makes one complete revolution. But a tire with a larger diameter will travel farther than a wheel with a smaller diameter. That's because the distance a tire covers in one revolution is equal to its circumference. So a tire with a diameter of 20 inches will cover about 62.8 inches of ground in one revolution. A tire with a diameter of 30 inches will cover more ground -- about 94.2 inches.

Calibration adjusts for these variances and is done by the manufacturer, which sets up the speedometer gear to correspond with the factory-installed ring and pinion ratio and tire size. A car owner may have to recalibrate his speedometer if he makes changes that make his vehicle fall out of factory specifications (see the sidebar below). Recalibrating a speedometer can be done by manipulating the hairspring, the permanent magnet or both. Generally, the strength of the magnetic field is the easiest variable to change. This requires a powerful electromagnet, which can be used to adjust the strength of the permanent magnet in the speedometer until the needle matches the input from the rotating drive cable.

Pls note that a diameter of a tire is dependent on rim diameter and aspect ratio. Eg tire size 225/60R17. We are only interested in 60 and R17. So changing the tire width from 225 to 235 or 245 or 255 will not affect the speedometer but changing 60 to 65 or 55 would. Same as the rim size.

adanny01:


You need to open your mind to strange but factual things.

As a Civil Engr by training, my training makes me imaging things before proving it with mathematics and physics. Not everyone is good at this so if you can't understand it, then its either I try another explanation or give up depending on if you are interested in learning.

At least, if you don't believe me, this should make sense.
www.auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/speedometer4.htm



Pls note that a diameter of a tire is dependent on rim diameter and aspect ratio. Eg tire size 225/60R17. We are only interested in 60 and R17. So changing the tire width from 225 to 235 or 245 or 255 will not affect the speedometer but changing 60 to 65 or 55 would. Same as the rim size.

Well you might be right after all

adanny01:


You need to open your mind to strange but factual things.

As a Civil Engr by training, my training makes me imaging things before proving it with mathematics and physics. Not everyone is good at this so if you can't understand it, then its either I try another explanation or give up depending on if you are interested in learning.

At least, if you don't believe me, this should make sense.
www.auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/speedometer4.htm



Pls note that a diameter of a tire is dependent on rim diameter and aspect ratio. Eg tire size 225/60R17. We are only interested in 60 and R17. So changing the tire width from 225 to 235 or 245 or 255 will not affect the speedometer but changing 60 to 65 or 55 would. Same as the rim size.

I don't see how this apply to increasing a car speed.

I don't think that's practical.
In some places they have speed limits, let's say I change my tires to a bigger one. So I will invariably be overspending and will get booked?

Gentlelife50:


I don't see how this apply to increasing a car speed.

I don't think that's practical.
In some places they have speed limits, let's say I change my tires to a bigger one. So I will invariably be overspending and will get booked?

Exactly!

Say the limit is 100km/h and you are driving with bigger tires than specified on this limit, your speedometer will show 100km/h while the police speed gun will show say 105km/h depending on the exact tire size. You know what will happen after that. The police will be right to give you a ticket while you are wrong for modifying your car and not recalibrating the speedometer.

Like I said before, changing an ECU could affect a speedometer if the right ECU is not used. Like using the ECU for LX trim on EX trim.

adanny01:


Exactly!

Say the limit is 100km/h and you are driving with bigger tires than specified on this limit, your speedometer will show 100km/h while the police speed gun will show say 105km/h depending on the exact tire size. You know what will happen after that. The police will be right to give you a ticket while you are wrong for modifying your car and not recalibrating the speedometer.

Like I said before, changing an ECU could affect a speedometer if the right ECU is not used. Like using the ECU for LX trim on EX trim.

Unfounded, that's purely your assumptions. Tires have little to do with the cars speed.

lecturerdabo:
It is even possible for a car doing 100 to overtake you at ur 120 depending on

1. Engine size
2. Age
3. Rpmg(don't know if I got that right sha)
Etc


My belief tho!

Not true, that's what Nigerians believe. Unfortunately even mechanics and experienced drivers think so.
Most times the bigger the engine the more durable, not necessarily because of racing.
Trucks have big engines same with SUVs but most times when it comes to racing cars have an edge over them.

Plasmbob1:
A car moving at 120km/h will not overtake any object also moving at 120km/h. Be it another car(weaker or stronger), a hawk or a stone.

In as much as they're moving at the same speed. They will continue to cover the same distance at the same time.

Horsepower only determines how fast it can reach the said speed, traction etc.

Well said

.

I believe there an angle the op is asking this question from
We are all going physics and theory.but I would have loved this question to get a practical answer.
I believe that if am going at same speed with u and I want to move past you without increasing my speed above the agreed speed,things like gear come into play for manual cars.
Am subject to corrections but am just thinking out of theory.

guy30stainless:


Unfounded, that's purely your assumptions. Tires have little to do with the cars speed.

Just because you are ignorant does not mean facts are unfounded.

Lack of knowledge can also be said to be lack of will to know and vise versa. I suggest you go find out what the fact is then explain to me how wrong i am so that i can see where i went wrong. As it is now, you are just living in denial.

alfa0:
I believe there an angle the op is asking this question from
We are all going physics and theory.but I would have loved this question to get a practical answer.
I believe that if am going at same speed with u and I want to move past you without increasing my speed above the agreed speed,things like gear come into play for manual cars.
Am subject to corrections but am just thinking out of theory.

You cant move pass anyone when both of you are on the same speed.

100km/h is the same every where.

Final gear ratio only affects the engine RPM at a certain level of speed.

Say a 5 speed car with fifth gear ratio of 0.65 at 100km/h will have an RPM of say 2800 but a 6 speed car with 6th gear ratio of 0.55 at 100Km/h will have an RPM of 2600. This mostly increases the fuel efficiency and increase tge durability of the emgine.

Its possible oh ...abi u won compare v8 engine speed to V6

Kayode12345:
Its possible oh ...abi u won compare v8 engine speed to V6

V6 speed and V8 speed are the same. Even W12 speed is the same.

The difference is acceleration.

adanny01:


Just because you are ignorant does not mean facts are unfounded.

Lack of knowledge can also be said to be lack of will to know and vise versa. I suggest you go find out what the fact is then explain to me how wrong i am so that i can see where i went wrong. As it is now, you are just living in denial.

Tire sizes gat nothing to do with speed Br

adanny01:


V6 speed and V8 speed are the same. Even W12 speed is the same.

The difference is acceleration.

Exactly, that's common with Nigerians.

alfa0:
I believe there an angle the op is asking this question from
We are all going physics and theory.but I would have loved this question to get a practical answer.
I believe that if am going at same speed with u and I want to move past you without increasing my speed above the agreed speed,things like gear come into play for manual cars.
Am subject to corrections but am just thinking out of theory.

Speed is the rate at which you change position as measured.as far as this is same and constant nothing changes i n time.

erico2k2:

Speed is the rate at which you change position as measured.as far as this is same and constant nothing changes i n time.

I wonder ooo

guy30stainless:


Tire sizes gat nothing to do with speed Br

During my undergraduate days, machine drawing class to be precise, we were taught that you have to have a very sound imaginative mind to be a good engineer. Structural engineering for example deals with alot of abstract forces that cannot be seen, you can only imagine them and work with them using imaginations and mathematical expressions.

How does speed relate to tire size? I have imagined it an translated it to the mathematical expression. For another person to understand it he has to view, understand the mathematical expression then imagine it. Some where along the line, you failed. Not my fault.

adanny01:


During my undergraduate days, machine drawing class to be precise, we were taught that you have to have a very sound imaginative mind to be a good engineer. Structural engineering for example deals with alot of abstract forces that cannot be seen, you can only imagine them and work with them using imaginations and mathematical expressions.

How does speed relate to tire size? I have imagined it an translated it to the mathematical expression. For another person to understand it he has to view, understand the mathematical expression then imagine it. Some where along the line, you failed. Not my fault.

Oga all things been equal two cars at the same speed whether it is Bugatti and golf can't overtake each other

guy30stainless:


Oga all things been equal two cars at the same speed whether it is Bugatti and golf can't overtake each other

Did i say anything otherwise?

adanny01:


V6 speed and V8 speed are the same. Even W12 speed is the same.

The difference is acceleration.

adanny01:


During my undergraduate days, machine drawing class to be precise, we were taught that you have to have a very sound imaginative mind to be a good engineer. Structural engineering for example deals with alot of abstract forces that cannot be seen, you can only imagine them and work with them using imaginations and mathematical expressions.

How does speed relate to tire size? I have imagined it an translated it to the mathematical expression. For another person to understand it he has to view, understand the mathematical expression then imagine it. Some where along the line, you failed. Not my fault.

All these back and forth. Okay, oga let me rephrase the OP's question. Or simply put, can my v8 for instance overtake your i4 (4 cylinder) if both of us are doing 120k/h on the same highway assuming our tires are company specifications?

ableguy:


All these back and forth. Okay, oga let me rephrase the OP's question. Or simply put, can my v8 for instance overtake your i4 (4 cylinder) if both of us are doing 120k/h on the same highway assuming our tires are company specifications?

He is trying to tell you that
In basic physics, the answer is no so a VV16 bugatti doing 120km/h is same as an i3 Kia piano doing 120km/h

In advance physics, the answer is complicated because you can only achieve such feat with a computer assisted driving.

The complicated issue is there are external forces acting in a body that you can't see and unless you are able to take control of such, it is possible.

nurey:


He is trying to tell you that
In basic physics, the answer is yes

In advance physics, the answer is complicated because you can only achieve such feat with a computer assisted driving.

The complicated issue is there are external forces acting in a body that you can't see and unless you are able to take control of such, it is possible.

Bro its not that hard, there are clear facts to verify such, its the simplest physics ever
check this out .
two cars VW golf and Range rover sport
Range rover sport does 0 to 60 km/h in 5 secs while golfe does 0 to 60 km/hr in 20 secs.
how long will it take A Range rover to get from A to B then B to C then whats the total time from A to C
How long will it take VW golf to travel from A to B then from B to C then the total time from A to C
PS once at point B they maintained 60km/h same speed.


get this answer then this question by the Op can be put to rest once and for all.

erico2k2:

Bro its not that hard, there are clear facts to verify such, its the simplest physics ever
check this out .
two cars VW golf and Range rover sport
Range rover sport does 0 to 60 km/h in 5 secs while golfe does 0 to 60 km/hr in 20 secs.
how long will it take A Range rover to get from A to B then B to C then whats the total time from A to C
How long will it take VW golf to travel from A to B then from B to C then the total time from A to C
PS once at point B they maintained 60km/h same speed.


get this answer then this question by the Op can be put to rest once and for all.

I know all this basics as I was a science student in school and I taught physics during my NYSC.

The question is if two cars A and B are going at same speed in motion (they are already in motion side by side not just starting from rest) will one pass the other if they are both at same speed.

In basic physics the answer is no but in advance physics the answer is yes, let me use a general rule in physics as example.

The gravitational speed is 9.8ms so if you throw two objects from the top of building, the gravitational pull will be 9.8ms so they are expected to reach the ground at same time but it's not always so as mass also plays a role in determining this so a feather and a brick thrown from same height will not reach the ground at same time because the wind will act on the feather giving it a zip zag pattern to reach the ground.

Same for two different cars traveling at same speed side by side, aerodynamics will determine, wind speed, tire size, gear ratio, road pattern etc

nurey:


I know all this basics as I was a science student in school and I taught physics during my NYSC.

The question is if two cars A and B are going at same speed in motion (they are already in motion side by side not just starting from rest) will one pass the other if they are both at same speed.

In basic physics the answer is no but in advance physics the answer is yes, let me use a general rule in physics as example.

The gravitational speed is 9.8ms so if you throw two objects from the top of building, the gravitational pull will be 9.8ms so they are expected to reach the ground at same time but it's not always so as mass also plays a role in determining this so a feather and a brick thrown from same height will not reach the ground at same time because the wind will act on the feather giving it a zip zag pattern to reach the ground.

Same for two different cars traveling at same speed side by side, aerodynamics will determine, wind speed, tire size, gear ratio, road pattern etc

you got this all completely wrong, and also gravity has nothing to do with this as nothing is at a free fall here, the only impending force here is friction caused by wind and this is where Aerodynamics comes into play.That aside, check what I gave up there, if you can give an answer then we have solved this back and forth once and for all, there was a reason i gave an initial start up point and an average speed.This is to compensate for different gear ratio and tyre size, as you can see, my illustration covers all angle.
use this as guide Average speed=Distance/time plz.

ableguy:


All these back and forth. Okay, oga let me rephrase the OP's question. Or simply put, can my v8 for instance overtake your i4 (4 cylinder) if both of us are doing 120k/h on the same highway assuming our tires are company specifications?

NO

This a 2016 thread o. Besides, i answered this question few post above on this page.

adanny01:


You cant move pass anyone when both of you are on the same speed.

100km/h is the same every where.

You are still talking about same issues when you have been answered over and over and over again. This was your first correct answer.

Plasmbob1:
A car moving at 120km/h will not overtake any object also moving at 120km/h. Be it another car(weaker or stronger), a hawk or a stone.

In as much as they're moving at the same speed. They will continue to cover the same distance at the same time.

Horsepower only determines how fast it can reach the said speed, traction etc.

I didnt want to comment and reply the obvious answer then, until i reached the misunderstanding of Sultaan's posts where you and ericko2k2 didnt get his point so i tried to explain his point which is actually a deviation from your question.

He was trying to explain that speedometer in 2 cars should not be used as separate instruments in the same speed test. The speedometer differences he mentioned could be caused by tire size or calibration.

I wrote my first comment on this thread to expatiate on his point which i have been doing. That doesnot take away the fact that speed is speed or change my opinion on speed.

My point basically is if you rely on speedometer in a car, say car A and B racing on the same track and both are looking at their speedometer and both claiming they are going 100km/h, because of calibration and other errors, their actual speed might be different and 1 may overtake the other based on errors. These errors will be eliminted if one speed gun is used to read speed of both cars and its the same, then one car can never pass the other.

erico2k2:

you got this all completely wrong, and also gravity has nothing to do with this as nothing is at a free fall here, the only impending force here is friction caused by wind and this is where Aerodynamics comes into play.That aside, check what I gave up there, if you can give an answer then we have solved this back and forth once and for all, there was a reason i gave an initial start up point and an average speed.This is to compensate for different gear ratio and tyre size, as you can see, my illustration covers all angle.
use this as guide Average speed=Distance/time plz.

OK the range gets to B in 300secs
The VW gets to B in 1200secs

Both will get to C from B at 7200secs adding that to the first lap

Range Rover gets from A to C in 7500secs
Vw gets from A to C in 8400

So the question the op asked was related from their trip from B to C let's just leave it at that and let's say every other thing is standard and controlled.

nurey:


He is trying to tell you that
In basic physics, the answer is no so a VV16 bugatti doing 120km/h is same as an i3 Kia piano doing 120km/h

In advance physics, the answer is complicated because you can only achieve such feat with a computer assisted driving.

The complicated issue is there are external forces acting in a body that you can't see and unless you are able to take control of such, it is possible.

Just right. You get the point.

erico2k2:

Bro its not that hard, there are clear facts to verify such, its the simplest physics ever
check this out .
two cars VW golf and Range rover sport
Range rover sport does 0 to 60 km/h in 5 secs while golfe does 0 to 60 km/hr in 20 secs.
how long will it take A Range rover to get from A to B then B to C then whats the total time from A to C
How long will it take VW golf to travel from A to B then from B to C then the total time from A to C
PS once at point B they maintained 60km/h same speed.


get this answer then this question by the Op can be put to rest once and for all.

The op's question has been put to rest since.

The question didnt ask for a yes or no answer so additional info was added to it. That seems to be the confusion, but the answer has been given severally right from page 0.

nurey:


OK the range gets to B in 300secs
The VW gets to B in 1200secs

Both will get to C from B at 7200secs adding that to the first lap

Range Rover gets from A to C in 7500secs
Vw gets from A to C in 8400

So the question the op asked was related from their trip from B to C let's just leave it at that and let's say every other thing is standard and controlled.

Exactly

nurey:


OK the range gets to B in 300secs
The VW gets to B in 1200secs

Both will get to C from B at 7200secs adding that to the first lap

Range Rover gets from A to C in 7500secs
Vw gets from A to C in 8400

So the question the op asked was related from their trip from B to C let's just leave it at that and let's say every other thing is standard and controlled.

FAILED !( I was assuming the speed its no achievable but 4 illustration)
this is why you guys get it all wrong, how can the range get from A to B in 300 secs when it has the force to accelerate from 0 to 60km/hr in 5 secs?
and to the rest of us here we dey dodge this question abi? and you all claim you did physics dey broke big big oyibo
and to the gentleman saying speed gun, plz note a speed gone can only be used to measure one car speed at a time not two as it functions like a two way radio.

ableguy:


Exactly

FAILED!
Chey una say una do physics