Greetings, dear motorists and just amateurs!
It is generally accepted by all of us that when installing wheels of a larger diameter on our car, we have to throw out a few extra hundreds into the exhaust pipe, as the pet starts to eat more.
Every day the thought that this is not leaves me, I know that a lot has been said and retold about this, but now I will try to give my hypothesis about this, I think it will seem to you nonsense of an inexperienced boy who does not understand anything, but I don’t have much I understand and do not know in the car and I ask you the nut and key masters not to condemn if something is wrong, but to fix it.
Take a wheel that rolls 1m along the road in one revolution, we find not by tricky calculations that for 100 km it will rotate 100,000 times.
Take a wheel of a smaller diameter, which in one revolution rolls along the road by 90 cm, by the same calculation we find that for 100 km it will turn 111.111 times (the data is slightly rounded) It turns out that at the same distance, wheels of a larger diameter rotate at a lower frequency, respectively, the shafts, transmission gears and internal combustion engines too.
(Further material from an article from one of the sites) "The speedometer is driven from the transmission by a" flexible shaft "- a special cable that transmits rotation well. Since the same speedometers are found on different cars, a simple gearbox is used in their drive, the gear ratio of which is matched to the car. On a rear-wheel drive, the speedometer usually controls the rotation of the secondary shaft of the gearbox. This means that the readings depend on the size of the tires, the gear ratio of the rear axle gearbox and the intrinsic error of the device. However, the gears of the reducer are not rubber - therefore, there is no perfect match of the speedometer to the tire size, and they still wear out ... The total error of readings up to 10% and even more is a common thing.
Front-wheel drive transverse engine speedometers usually "service" the left wheel drive after the main pair. This means that the effect of rounding the road is added to the error of the speedometer and the influence of the tire size: when cornering to the left, the "indicated speed" is slightly less than in the middle of the car, and to the right - a little more. What is the impact of out-of-order tires? Replacing a 175 / 70R13 tire with a 165 / 70R13 tire or vice versa changes the speedometer reading by 2.5% "
It is clear from the article that when the tire is worn (that is, when the diameter decreases) and when the wheel moves when turning to the right when the left wheel goes along the outer radius, the speedometer winds up excess.
How do we measure the flow? (your car has 14 wheels) We reset the odometer, drive for example 100 km and look at the fuel gauge, let's say it turned out 10 liters, you are happy!
You changed the shoes of your beauty on 16 disks, reset the odometer and drove off, having driven a hundred, you were horrified, your darling swallowed 13 liters. There is no limit to your disappointment!
In my opinion, this is an illusion caused by incorrect readings of the speedometer due to the fact that with a smaller diameter of the wheels the speedometer twists the real mileage and for the odometer to show 100 km you in reality need to drive a shorter distance, and with a larger diameter you actually need to drive a distance exceeding 100 km from here and increased consumption comes out.
If anyone has a desire to check, drive the distance from home to work on the same wheels, change the car and drive along the same path on these wheels (exactly along the same path) and compare the odometer readings, in my opinion the readings will be different.
Once again, I ask if something is wrong, if I am wrong, correct it, but do not criticize, I am not yet experienced.
Thanks to all!
"We all know from childhood that this and that is impossible, but there is always an ignorant who does not believe in it. He makes discoveries." Einstein
How to save on fuel for a car and how tire size affects fuel consumption, an explanation from the Battery Base specialists and a lot of other useful information for car owners on how to take care of your car. We are always glad to see you, come and call!
A large number of drivers plan to fit the widest tires with larger rims to improve the visual appearance of the vehicle. But few people think about the direct effect of tires on gas mileage during use. The main subject of disagreement is the tire rim diameter, as well as their profile width. At the moment, all drivers are divided into two different camps. Some drivers are trying with all their might to prove to others that by buying smaller tires they could significantly increase the fuel economy of their car.
WHAT ARGUMENTS ARE THE DEFENDERS OF THEORY
People who defend the theory offer their arguments that a much greater effort is needed to rotate wheels with an increased diameter. Proceeding from this, an increased amount of fuel is needed for the processes of starting driving and accelerating, nevertheless, the average speed will increase by 10-15 kilometers per hour (which will come in handy for lovers of active driving). Despite the objectivity of the information, it is rather difficult to calculate the exact amount of% of increased fuel losses, since it depends on a large number of various factors (disk weight, technical condition of the car, etc.).
The most ardent defenders of the theory are convinced that fuel consumption increases nonlinearly, therefore it directly depends on the selected speed mode. In the process of driving at low speeds, the increased consumption of gasoline will not be significant, but with an increase in speeds of more than 40-50 kilometers per hour, its consumption increases sharply.
SECOND PARTY CONSIDERATIONS
In search of the truth about which wheel size affects fuel consumption, most experts resort to a science called physics. Due to this, there is a theory according to which the minimum fuel losses will be the cause of the increased number of engine revolutions, because the work will be equivalent. Fuel consumption will mainly depend on the weight of the vehicle and aerodynamic braking.
There is a "theory of auto" which implies the presence of a special formula, which can be used to calculate the track fuel consumption Qs, which makes it possible to neglect the dynamic indicators of the radius. In this case, it is worth considering the applied tire profile height: the higher the profile height, the higher the fuel consumption.
PROFILE WIDTH AND ITS ROLE IN FUEL EFFICIENCY
Most likely, everyone understands that wheels with a wider profile require high gasoline costs, because the weight of this wheel will be large. Plus, the engine needs increased efforts to move the car from place. In addition to weight, the contact patch area usually becomes larger, and with it rolling resistance and acoustic noise.
The fact that the car consumes much more fuel than stated by the manufacturer: the standard driving cycles, until recently, were very different in terms of load from actual operation. But sometimes the fault lies with the driver.
Wider tires with a larger bore on heavier rims lead to a noticeable drop in dynamics and an increase in fuel consumption. Well, I don't need to explain how pressure and fuel consumption are related. It is not for nothing that in recent years TPMS pressure monitoring systems have become standard equipment on all machine classes. And in the US and Europe from 2014, all new passenger cars must be equipped with a similar system.
I will not open America: the higher the pressure in the wheel, the lower the fuel consumption. True, it does not decrease linearly; after a certain threshold, fuel consumption remains almost unchanged. But the negative phenomena associated with pumping are becoming more and more noticeable. And this is not only a loss of comfort, but also a deterioration in the grip of the tire, and a general deterioration in handling due to a violation of the frequency characteristics of the tire-suspension ligament.
For this reason, tires have a recommended pressure, which the manufacturer always indicates in the documentation. Typically, for basic tires, the data can be found on the information decals on the body. The optimal pressure indicated on the decals is determined by experiment and depends on the characteristics of a particular tire model. Exceeding it without understanding the processes occurring with the tire is not worth it.
An increase in the contact area of the tire with the road surface is usually associated with an increase in the width of the tire. But an increase in the outer diameter is also a fairly effective measure. And this is understandable: the larger the outer diameter, the larger the contact patch. Unfortunately, the large wheel also has disadvantages, first of all - the increased mass of the tire and rim.
Downloading further!
In practice, fuel efficiency and grip do not mix well in a single tire model. To achieve the lowest fuel consumption, a separate line of ContiEcoContact rubber is produced. It is distinguished by lower rolling resistance, lower weight, and lower resource. And, of course, maximum efficiency, even when compared to the ContiPremiumContact 6.
But in the line of tires of quite classic dimensions and appearance, there is also one completely new model. Don't be surprised, its dimension is 195/55 R20. I did not describe, the landing diameter is exactly 20 inches, and the tire width is 195 mm.
Remember what I wrote above about the relationship between the working pressure of the tire, its width and diameter, fuel consumption and grip? It looks like engineers have found a new way to reduce fuel consumption. This path is not easy, it includes several solutions at once.
Firstly, the new tire material makes the wheel grip more efficient.
Secondly, the large outer diameter of the wheel improves traction even more. But the width of the tire has been reduced to reduce rolling resistance.
And most importantly, don't forget about the pressure! The developed tread material allows you to maintain grip at a higher internal tire pressure, which, as you already understood, gives a benefit in economy.
Although it is often impossible to significantly reduce the average fuel consumption of a car, it is quite possible to save on fuel consumption by using high-quality energy-efficient tires. What tires are we talking about? What is behind this concept?
What are Energy Saving Tires
Let's dwell on the concept of energy-efficient tires. By this is meant tires that have a sufficiently low rolling resistance. This creates little resistance or minimal friction in relation to the rest of the tires. Energy saving in tires occurs due to a decrease in the heating of the rubber in contact with the road surface and the rim of the wheel rim.
Rolling resistance as an example of the Michelin Enegy Saver
Rolling resistance and grip
There is a rather big difference between the two. Although at first glance, these concepts are closely related, but they are not interdependent. This means that even if the rolling resistance decreases, the overall grip performance will remain the same.
Manufacturers of durable and reliable tires strongly advise to refrain from saving on such tires, because we are talking about safe driving and even someone's life.
Rolling resistance and pressure
In order to be guided by this indicator when buying tires, it is worth learning one unshakable rule - stiff tires have less rolling resistance. Therefore, it is very important to carefully monitor that the air pressure in the tires is always optimal. Regardless of the rubber used, it is important that the pressure is always correct so that you can count on fuel economy.
If this parameter is always observed at the proper level, then the fuel economy can be from 0.3 to 0.5 liters for every 100 kilometers. Too low tire pressure increases the rolling resistance by changing the shape of the rubber itself. And if the car gets into extreme conditions on the road, then this further affects the complications associated with handling. If the pressure is optimal, then this is a guarantee that the rubber will run easily on the roadway, thereby reducing the amount of harmful emissions from the car as a whole.
If there is free rolling, then it is quite normal to talk about the car's fuel economy. In order for fuel consumption to be uniform and economical, it is important to develop the most optimal driving style and manner. By avoiding aggressive driving, as well as sudden jerks of the car or emergency braking, you will be able to use fuel in the minimum amount and evenly.
How rolling resistance is measured
Although this is not specifically specified anywhere, if the rolling resistance of the tire is reduced by 10%, then the fuel economy increases to 2%, but everything will depend on both the car model and the quality of the tires.
Since 2012, the European government has mandated tire manufacturers to label new tires with a fuel efficiency mark that is directly related to rolling resistance. A whole staff of professional engineers tests various product models and compares them with each other. In the experiment, the amount of forces that are needed for rolling on 1 dynamometer is determined, taking into account that the speed of the car will be ~ 80 km / h. The tire is then graded from A to G, with the top letter representing maximum economy.
22.11.2015
Many drivers strive to fit the widest tires with large rims to improve the visual appearance of the car. However, few people think about the direct impact of tires on fuel consumption during operation. The main subject of disagreement is the tire rim and profile width. To date, all drivers are divided into two directly opposite camps. One part of drivers is trying unsuccessfully to prove to others that by purchasing smaller tires they have been able to significantly improve the fuel efficiency of their car.
Arguments of the defenders of the theory
Advocates of the theory offer arguments that much more effort is needed to spin larger wheels. Accordingly, for the processes of starting movement and acceleration, an increased amount of gasoline will be required, however, the average speed will increase by 10-15 km / h (which will play into the hands of lovers of an active driving style). Despite the objectivity of the data, it is extremely difficult to calculate the exact percentage of increased fuel losses, since it depends on a number of very diverse factors (disk weight, technical condition of the machine, etc.).
The most ardent defenders of the theory are sure that fuel consumption increases non-linearly, therefore it directly depends on the selected speed mode. In the process of driving at low speeds, the increased fuel consumption will not be significant, but with the development of speeds above 40-50 km / h, its consumption will increase sharply.
Opponents' arguments
In an attempt to find out the truth about the effect of wheel size on fuel consumption, most experts resort to knowledge of physics. Thanks to this, there is a theory according to which small fuel losses will cause an increased number of engine revolutions, because the work will be performed equally. Gasoline consumption will mainly depend directly on the mass of the vehicle and aerodynamic braking.
The existing "theory of the car" implies the presence of a special formula, which can be used to calculate the directional consumption of gasoline Qs, which makes it possible to neglect the dynamic values of the radius. In this case, it is necessary to take into account the used tire profile height: after all, the higher the profile height, the greater the fuel consumption.
Profile width and its role in fuel efficiency
Probably everyone understands that wheels with a wider profile require more fuel, because the weight of such a wheel will be large. In addition to this, the engine will require increased effort to move the machine. In addition to weight, the contact patch area usually increases, and with it rolling resistance and acoustic noise.