Monthly Archives: June 2017
When you buy a new vehicle, tires are usually the last thing on your mind. However, tires are important. Nobody wants to become stranded, and they are not exactly cheap to replace. It’s a good idea to know what different types of tires you can purchase.
All-weather tires are most commonly used by drivers who have four mild seasons each year. These types of tires handle torrential rains and slush but are not suitable for black ice or driving through heavy blizzards. These tires are designed to be useful in very low and high temperatures, but not extreme winter conditions. They can easily handle rain and grip well to bare asphalt, slush, and wet roads.
The tread is wider than an average tire but not as wide as winter tires. Their tread pattern increases traction, especially in the rain. All-weather tires feature rubber composites designed for long-term wear.
Unfortunately, during frigid weather, these tires can become as hard as plastic and can be easily damaged and destroyed. This type of tire is not a good choice if the region in which the driver lives drops below 45 degrees Fahrenheit.
Tires created for off-road driving are some of the biggest and most aggressive tires available on the market today. They are made with the strength to drive through deep mud, over boulders, and through canyons. Their size supports heavier loads and tolerates high speeds over a longer duration than other types of tires.
Off-road tires sport deeper treads for rough terrain. The depth of the tread prevents sharp rocks from cutting the tire, and the tires usually have much less pressure than the other categories of tires. The unique knobby tread pattern increases traction, and the tires are built to be durable on any surface with a focus on off-road.
Seasonal tires are best for areas with three seasons and warmer weather. In addition to warmer temperatures, these tires work best in dry conditions.
Seasonal tires contain a much harder compound than other types of tires, to give the tread on the tire longer life. Consequently, if the driver uses these tires in freezing temperatures, traction will be lost very quickly. It is possible to attach chains to seasonal tires and use them in winter weather. The tire chains provide the additional traction needed to get around safely.
The tread pattern on seasonal tires is designed to reduce noise and provide a smooth ride. If you drive through snow or slush, the grooves and channels become clogged.
SUV Tires and Truck Tires
Both trucks and SUV’s require larger than normal tires. These larger tires provide greater ground clearance for the vehicle. The tread pattern is designed for some off-road driving, though not on the same scale as All-Terrain (Off-Road) Tires.
Another difference between these tires and regular tires is that the tread pattern extends all the way to the sidewalls. Plus, the tire pressure is set a little lower to increase traction. On the open highway, this design makes for a bit of a bumpy ride, but on rougher ground, it’s invaluable for smooth handling.
Though similar, there are a few differences between SUV tires and truck tires. Truck tires sport a taller sidewall and carry heavier loads than SUV tires. Lighter truck tires are usually more durable and made with a thicker rubber compound than other tires, but they cost more than passenger SUV tires. Manufacturers market SUV tires as long-lasting and a smoother ride than truck tires.
Winter Tires (Both Studded and Non-Studded)
If you live in a region with wet, winter weather, you might want to keep an extra set of winter tires or snow tires on hand. Snow tires sport wider gaps between the treads for additional traction. They also boast a more flexible rubber. Regular tires and all-season tires become brittle in wet conditions, reducing the traction.
Non-Studded Winter Tires
Winter tires that don’t have studs are still used in harsh winter climates, but won’t perform as well as studded tires. The amount of precipitation and temperature range in your area will determine if studs are required.
The tread pattern on winter tires is called sniping. All winter tires, studded and those without, have an aggressive tread pattern. The only difference is whether or not you have studs.
Studded Winter Tires
Winter tires that are studded are for people who live in extreme winter conditions. Studded winter tires are made to resist deep snow, ice, and heavy amounts of slush. It’s also important to note that the material used to make these rates for temperatures lower than 45 degrees Fahrenheit. Regular tires do not perform well in extreme cold and slide on ice and snow.
The surface of studded winter tires has openings with metal studs pushed deep into them. These studs help grip the icy roads. The metal studs are usually made out of tungsten carbide and should sit approximately one millimeter from the tire to ensure that they function properly.
On each tire, there are usually eighty to one hundred studs. Newer tires feature a design where the studs can retract at the push of a button.
Choosing the correct tires for your vehicle is important for safety. Understand which tires are meant for your weather conditions and plan accordingly. Being prepared for any weather conditions in your area will allow for easier access to roadways in the event of an emergency.
Out of all of the systems controlling your car, one of the most important is the transmission. This mechanism transmits the power from the engine to the wheels.
To better understand how a transmission works, first you need to understand a few key terms.
Transmission gear refers to the set of toothed wheels that function together to alter or determine the relationship between the speed of the wheels and the engine speed of the vehicle. This term also describes the ratio of the gears selected by the driver on the output and input shafts.
The gear ratio refers to the ratio at which the output and input gears rotate (i.e. 3:4 ratio).
A clutch is a mechanism for connecting and then disconnecting the engine from the transmission system of the vehicle.
The shift lever refers to the control lever first used by the driver to manage the gear range of the transmission.
An H-Pattern is used to describe the arrangement of gears designated on the knob of the shift lever, which is where the placement falls in a parallel row series.
Once you understand the terminology, then it is easier to grasp the function and mechanics of a transmission.
Types of Transmissions
Cars are manufactured with a variety of transmission types. These types include:
- Manual Transmission (MT)
- Dual-clutch Transmission (DCT)
- Automatic Transmission (AT)
- Semi-Automatic Transmission (SAT)
- Continuously Variable Transmission (CVT)
The automatic transmission is by far the most popular variety, but the manual transmission with its simpler function and construction is also an old-time favorite.
A manual transmission includes a set of gears and a pair of shafts, the output shafts and input shafts. During an engagement, the gears on one shaft mesh with the other gears on the other. The overall gear ratio results between the engaged gear on the output shaft and the selected gear on the input shaft. Overall, the manual transmission is fully operated by the driver without any computer controls which makes it the most exciting for an auto enthusiast.
The function of the dual-clutch transmission is almost the same as a manual transmission, but the difference lies in the control system. The dual-clutch transmission features a computer control. As it bridges the gap between automatic and manual transmissions, then it is becoming widely popular among customers. The biggest advantages of the dual-clutch transmission are its fuel economy, ease of operation, and shift times.
The automatic transmission is the most popular type of transmission. One of the main differences between a manual transmission and an automatic transmission is that the automatic transmission doesn’t have a clutch. The automatic transmission uses a torque converter to couple or decouple the gear set with the engine.
The automatic transmission can be further sub-categorized into the semi-automatic transmission and continuously variable transmission.
A semi-automatic transmission is a system that uses electronic processors, actuators, and sensors for gearshifts on the driver’s command. With the semi-automatic transmission in use, there isn’t any need to use a clutch pedal for changing gear. In this system, electronic equipment actuates the clutch, synchronizing the torque and timing required for smooth and quick gearshifts. Semi-automatic transmissions are popular in many vehicles.
Continuously Variable Transmission
A continuously variable transmission, or a single-speed transmission, is a type of automatic transmission that can move seamlessly through gear ratios falling between a minimum and maximum value. It is one of the best features of the CVT, as other mechanical transmissions offer a finite number of gear ratios. It is because of its flexibility that the input shaft then maintains a consistent angular velocity.
How a Transmission Works
When the driver shifts to select gears in the manual transmission, then the shifter engages a linkage which controls the gears movement along the input shaft. On moving the lever, backward or forward, the driver selects between the two gears given on a linkage. Note that the car with four gears uses two gear links while the model with five speeds uses three gear links. By moving the shift lever right and left, the driver makes changes between the linkages.
First, the driver disconnects the engine from the transmission’s input shaft by pushing the clutch pedal. When he does, then it engages the gear in the manual transmission. The disconnection frees the input shaft gears to move. Then, the gears on the shaft are engaged when the engine sends torque through it. Once the clutch disconnects the power to the transmission from the engine, then the driver chooses the appropriate gear while releasing the clutch which re-engages the power of the engine to the input shaft. Finally, this process propels the vehicle using the chosen gear ratio.
As in the manual transmission, the mechanics of the automatic transmission use one concentric shaft. The gears on this shaft work as the ratio of output to input gear speed changes. The process involves engagement of one gear with another. Here, a complex hydraulics system is present which controls the mechanism and not a shift lever. This system includes a set of planetary gears, engaged at a given time. An electronic control unit programmed to suit the engine, which in turn, controls this hydraulic control system.
The gear sets are connected by a series of internal clutches to the motor’s input. These move as the hydraulic system moves and determine the gear ratio of the output to the drive shaft.
The functioning of a semi-automatic transmission and continuously variable transmissions is far better than that of traditional automatic transmissions. As mentioned earlier, with semi-automatic transmissions there isn’t any need for shifting the gears manually, as the transmission’s computer handles the job. Semi-automatics retain a clutch like a manual transmission controlled by electro-hydraulic systems.
Dual Clutch Transmissions
The dual-clutch transmission uses two different clutches, each at even and odd gear sets. It almost seems like two manual gearboxes placed into a single housing. Typically, the dual clutch transmissions operate in the same way as a standard automatic transmission with no clutch pedal and a PRND gear selector. They may also function like an automatic transmission, where the gears can be shifted automatically via a separate gate or paddle shifters on the gear selector.
Several components work together to move your vehicle. If any one of them is out of alignment, then the car won’t travel. Getting the clutch and gears to operate smoothly can be difficult, but with proper maintenance, your transmission should hold up. First, check your transmission fluid when you change your oil. Then, take your car to a transmission shop if you feel it shifting hard or there is a lack of power. The transmission is an extremely important system within any vehicle.
There’s a popular misconception that there are no speed limits on the Autobahn. About 40% of the German Autobahn system is speed regulated. However, did you immediately catch the significance of that? If 40% is regulated, that means 60% is NOT.
Today’s German Autobahn system stretches 8,047 miles across most of Germany. They post speed limits on the Autobahn near cities and across stretches with a history of accidents. However, even then, the speed limit stays a fast 81 mph.
History of the Autobahn
In 1929, Germany built its first Autobahn link between Opladen and Dusseldorf. After seeing the benefits of this high-speed road system, Adolf Hitler started a program to build two east-west and north-south links. However, despite the propaganda of the time, the Autobahn was not built for military purposes. Before the horrendous acts that led to World War II began to occur in the late 1930s, the Autobahn helped bring Germany out of the depression. The road system allowed Germany to promote economic growth by generating additional jobs in construction.
Initially, the limited-access road was used by the Mercedes-Benz Grand Prix racing team for high-speed record attempts. Rudolf Caracciola set one of the highest speeds for a public roadway during this time. The racing came to an end in 1938 with the tragic death of a popular German race driver, Bern Rosemeyer. Shortly after, when the War broke out, they used the roads for military transport.
After WWII, new sections of the system were added onto the existing Autobahns. Each decade saw additions to the roads until they reached their current span just after the turn of the Millennium.
“The Autobahn” is a Misnomer
Often, foreigners will refer to the German road system as “The Autobahn” when in fact it forms a series of connected roads. Similar to the interstates found in America, these roads have multiple lanes of traffic flowing in two directions. Often, they have a central barrier and shoulders to the side.
In 1974, The German government adopted an autobahn numbering system. Each road identifies itself by a capital “A” followed by a number. Larger autobahns that cross the country have single digits, while shorter roads have double digits.
Some very short stretches of road exist which they designed only for local traffic. Each of these roads uses three digits. They base which digits they use on the direction of travel (e.g. east to west, north to south).
The Speed Limit on the German Autobahns
The autobahns serve as the German freeways. As we already stated, over half of these roads do not post set speed limits. The ones that do serve heavily congested areas near cities. Also, certain stretches of road with dangerous curves have posted regulations.
During inclement weather, parts of the Autobahn system come under speed regulation and they enforce limits set in construction zones.
Posted “recommendations” for speed limits show on the roads where no official speed regulation exists. If a car exceeds the recommendation and causes an accident, they might have liability for damages. However, it’s pretty common to see a Porsche or BMW flying down the road at over 100 mph.
In the late 1990’s, one of Germany’s political parties took up the cause of environmentalism. They claimed that the high speeds were contributing to air pollution and pushed for a national speed limit. They were unsuccessful at imposing the national limit, but they did manage to pass regulations in forested areas.
Autobahn Accident Statistics
Over the past decade, traffic fatalities across all of the European nations have seen a decline. However, a good number of accidents still occur on the Autobahn.
- Out of the total accidents that occurred on the Autobahn, 67% of them happened in areas that featured no posted speed limit.
- Rural road deaths that occurred on the Autobahn were 5 times more than the deaths that occurred in automobile accidents.
- In 2013, deaths on the Autobahn rose by 8% over those in 2012.
For drivers who want to go fast, the Autobahn is perfect. Large stretches of the road have no posted speed limits and other drivers understand how to navigate speeding traffic. With over 8000 miles of road before you, you can drive for days.
How fast can you drive on the Autobahn? As fast as your car can go.
When the wheels of a vehicle lock up on a slippery or wet road, skidding is often the result. Anti-lock braking systems (ABS) keep your wheels in constant tractive contact with the road which prevents skidding. ABS works on the principles of the cadence and threshold braking systems. However, it does the job with more control and at much faster rate.
Components of Anti-Lock Braking Systems (ABS)
Anti-lock braking systems (ABS) feature four main components:
- Wheel Speed Sensors
Each of these components works together to keep your car from going into a skid.
The controller works as an ECU unit in the vehicle. It receives information from the wheel speed sensors which send a signal to the controller if a wheel loses traction. The controller then limits the braking force as well as activates the ABS modulator which further activates the braking valves.
The pump in the anti-lock braking system restores the pressure released by the valves to the hydraulic brakes. At the first detection of wheel slip, the valve releases when the controller sends the signal. The pump restores the desired amount of pressure released by the valve to the braking system. The controller modulates the status of the pumps to provide the amount of pressure desired to reduce slipping.
Each brake controlled by the ABS includes a valve in its brake line. The valve in some systems has three positions. In the first position, the valve is open. The pressure is passed right from the master cylinder to the brake. In the second position, the valve blocks the brake line which isolates it from the master cylinder. This valve position doesn’t allow the pressure to increase. In the third position, the valve releases pressure from the brakes.
Wheel Speed Sensors
Wheel Speed Sensors determine the acceleration and deceleration of a wheel. The speed sensors use a Hall Effect sensor and a magnet, or an electromagnetic coil and a toothed wheel for generating a signal. The differential or rotation of the wheel creates a magnetic field around the speed sensor. The magnetic field fluctuation generates a voltage in the speed sensor.
The Working of the Anti-Lock Braking System
The anti-lock braking system works with the regular braking system by pumping them automatically. The controller of the Anti-Lock Braking system monitors the sensors at all times. It looks out for any unexpected decelerations in the wheels. If a deceleration is sensed, the ABS system works to stop the vehicle evenly and quickly.
Such a rapid deceleration isn’t possible without reducing the amount of pressure to that brake until the brake reaches the point of acceleration. The controller then increases the pressure until the vehicle decelerates again. ABS handle this before the wheel can change the speed. As a result, the speed of the wheel slows down. At this point, the brakes keep the wheels close to the lock up threshold. This provides maximum braking power to the system.
Does the Anti-Lock Braking System work?
Yes, the anti-lock braking system helps stop a vehicle safely. The system prevents the wheels of the vehicle from locking up and stops the vehicle in the shortest distance possible, even on the slippery surfaces.
According to a study conducted in 1996 by the Insurance Institute, cars equipped with ABS were involved in fewer fatal accidents than the cars that didn’t feature this system. The study stated that although vehicles equipped with ABS were less likely to encounter fatal accidents involving other cars, they were more likely to meet fatal accidents than others. There are a number of speculations for this.
According to some, the drivers operating the cars equipped with ABS used the system incorrectly, either by releasing the brakes or pumping the brakes.
Nevertheless, the recent reports state that the accident rate for cars fitted with an ABS is improving. Regardless, the effectiveness of this system cannot be disregarded. It does work as intended when driver error does not come into play.
When used correctly, a vehicle with ABS slows down more quickly than a vehicle equipped with simply a threshold braking system. It is wise to know how to apply the ABS and how to drive in inclement conditions to maximize safety.
The Dos and Do Nots of Using ABS
- Do apply the brakes as hard as possible and hold until the ABS completes its job to stop the vehicle.
- You should have your ABS system inspected on a regular basis to ensure maximum safety.
- Do steer and brake at the same time as ABS allows for this functionality, unlike threshold brakes, increasing the chance to avoid an accident.
- Don’t ever pump the brake pedal in a vehicle fitted with ABS as this isn’t required.
- Don’t ever take your foot off of the brake pedal if you need to quickly stop as this will increase the likelihood of an accident occurring.