Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Speedometer shopping experience:
1. Compare - without doubt the biggest advantage that the Speedometer offers shoppers today is the ability to compare thousands of Speedometer at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Speedometer? Wrong! If the Speedometer is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Speedometer then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Speedometer? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Speedometer and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Speedometer wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Speedometer then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Speedometer site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Speedometer, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Speedometer, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
on a
automobile, showing the speed of the
vehicle in
Kilometres per hour. Also shown is the tachometer, which displays the the rate of
rotation of the
engine's crankshaft.
A
speedometer is a vehicle instrument that measures the instantaneous speed.
Traditional automotive speedometers are driven by a flexible, sleeved cable that is rotated by a set of small
gears in the tail shaft of a Transmission (mechanics). The early Volkswagen Beetle and many motorcycles, however, use a cable driven from a front wheel.
The most common form of speedometer relies on the interaction of a small permanent magnet affixed to the rotating cable with a small aluminum cup affixed to the shaft of the pointer. As the magnet rotates near the cup, the changing magnetic field produces eddy currents in the cup, which themselves produce another magnetic field. The effect is that the magnet 'drags' the cup--and thus the speedometer pointer--in the direction of its rotation with no mechanical connection between them.
The pointer shaft is held toward zero by a fine spring. The torque on the cup increases with the speed of rotation of the magnet (which, recall, is driven by the car's transmission.) Thus an increase in the speed of the car will twist the cup and speedometer pointer against the spring. When the torque due to the eddy currents in the cup equals that provided by the spring on the pointer shaft, the pointer will remain motionless and pointing to the appropriate number on the speedometer's dial.
The return spring is
calibration such that a given revolution speed of the cable corresponds to a specific speed indication on the speedometer. This calibration must take into account several factors, including ratios of the tailshaft gears that drive the flexible cable, the final drive ratio in the
differential (mechanics), and the diameter of the driven tires. The speedometer mechanism often also drives an
odometer plus a small switch that sends pulses to the vehicle's engine computer.
Another early form of electronic speedometer relies upon the interaction between a precision watch mechanism and a mechanical pulsator driven by the car's wheel or transmission. The watch mechanism endeavors to push the speedometer pointer toward zero, while the vehicle-driven pulsator tries to push it toward infinity. The position of the speedometer pointer reflects the relative magnitudes of the outputs of the two mechanisms.
The speedometer was invented by Josip Belušić of Croatia in 1888. Modern speedometers are electronics. A rotation sensor, usually mounted on the rear of the transmission, delivers a series of electronic pulses whose frequency corresponds to the rotational speed of the driveshaft. A computer converts the pulses to a speed and displays this speed on an electronically-controlled, analog-style needle or a
digital display, the latter of which is more common nowadays. Pulse counts may also be used to increment the
odometer.
As of 1997, federal standards in the United States allowed a maximum 5% error on speedometer readings (per "Auto Tutor", American Automobile Association of California magazine, Oct. 17, 1997). Aftermarket modifications, such as different tire and wheel sizes or different differential gearing, can cause speedometer inaccuracy.
Speedometers for other craft have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is a
Pitot Tube.
== Error ==Speedometers are not totally accurate, and most speedometers have tolerances of some 10% plus or minus due to wear on tires as it occurs. Modern speedometers are said to be accurate within 5% but as this is legislated accuracy, this may not be entirely correct. This can make it difficult to accurately stay on the speed limits imposed; most countries allow for this known variance when using RADAR to measure speed. Although levels of some 3 km/h, or 3% are also used, where tough enforcement is used. This causes many arguments due to motorists complaining that they were not doing the speed as reported. Revenue Fight Unjust Victorian Speeding Fines. fightfines.info. Retrieved on September 18,
2007. is being increasingly blamed for these stricter measures. There are strict United Nations standards in place but it seems not being enforced leaving this matter in limbo for many countries.
Excessive speedometer error after manufacture can come from several causes but most commonly is due to nonstandard tire diameter, in which case the
percent
error = 100x("standard diameter"/"new diameter" - 1).
Nearly all tires now have their size shown as "T/A_W" on the side of the tire, and the tire's
diameter in inches = TxA/1270 + W.
For example, a standard tire is "185/70R14" with diameter = 185x70/1270 + 14 = 24.196850 in. Another is "195/50R15" with 195x50/1270 + 15 = 22.677165 in. Replacing the first tire (and wheels) with the second (on 15" wheels), a speedometer reads 24.19../22.67..=1.0670139 times the correct speed or 6.7% too high.
GPS
GPS devices may indicate the true speed of travel on the user interface. Unlike instrumental speedometers which provide a continious reading, the GPS speed readouts have a one second update interval.
The reading is based on reception of data from the satellites in orbit, and is therefore independent of the car's transmission components. Discrepancies between the two readings may be caused by instrument error (on the vehicle), or by changing directly influencial factors, such as tire sizes.
See also
References
External links
- Autoblog: Gauging changes
- Visual Tyre Size Calculator with speedometer error
on a
automobile, showing the
speed of the vehicle in Kilometres per hour. Also shown is the tachometer, which displays the the rate of
rotation of the engine's
crankshaft.
A
speedometer is a vehicle instrument that measures the instantaneous speed.
Traditional automotive speedometers are driven by a flexible,
sleeved cable that is rotated by a set of small
gears in the tail shaft of a Transmission (mechanics). The early Volkswagen Beetle and many motorcycles, however, use a cable driven from a front wheel.
The most common form of speedometer relies on the interaction of a small permanent magnet affixed to the rotating cable with a small aluminum cup affixed to the shaft of the pointer. As the magnet rotates near the cup, the changing magnetic field produces
eddy currents in the cup, which themselves produce another magnetic field. The effect is that the magnet 'drags' the cup--and thus the speedometer pointer--in the direction of its rotation with no mechanical connection between them.
The pointer shaft is held toward zero by a fine spring. The torque on the cup increases with the speed of rotation of the magnet (which, recall, is driven by the car's transmission.) Thus an increase in the speed of the car will twist the cup and speedometer pointer against the spring. When the torque due to the eddy currents in the cup equals that provided by the spring on the pointer shaft, the pointer will remain motionless and pointing to the appropriate number on the speedometer's dial.
The return spring is calibration such that a given revolution speed of the cable corresponds to a specific speed indication on the speedometer. This calibration must take into account several factors, including ratios of the tailshaft gears that drive the flexible cable, the final drive ratio in the differential (mechanics), and the diameter of the driven
tires. The speedometer mechanism often also drives an
odometer plus a small switch that sends pulses to the vehicle's engine computer.
Another early form of electronic speedometer relies upon the interaction between a precision watch mechanism and a mechanical pulsator driven by the car's wheel or transmission. The watch mechanism endeavors to push the speedometer pointer toward zero, while the vehicle-driven pulsator tries to push it toward infinity. The position of the speedometer pointer reflects the relative magnitudes of the outputs of the two mechanisms.
The speedometer was invented by
Josip Belušić of Croatia in 1888. Modern speedometers are electronics. A rotation sensor, usually mounted on the rear of the transmission, delivers a series of electronic pulses whose frequency corresponds to the rotational speed of the
driveshaft. A computer converts the pulses to a speed and displays this speed on an electronically-controlled, analog-style needle or a digital display, the latter of which is more common nowadays. Pulse counts may also be used to increment the odometer.
As of 1997, federal standards in the
United States allowed a maximum 5% error on speedometer readings (per "Auto Tutor", American Automobile Association of California magazine, Oct. 17, 1997). Aftermarket modifications, such as different tire and wheel sizes or different differential gearing, can cause speedometer inaccuracy.
Speedometers for other craft have specific names and use other means of sensing speed. For a boat, this is a
pit log. For an aircraft, this is a Pitot Tube.
== Error ==Speedometers are not totally accurate, and most speedometers have tolerances of some 10% plus or minus due to wear on tires as it occurs. Modern speedometers are said to be accurate within 5% but as this is legislated accuracy, this may not be entirely correct. This can make it difficult to accurately stay on the speed limits imposed; most countries allow for this known variance when using RADAR to measure speed. Although levels of some 3 km/h, or 3% are also used, where tough enforcement is used. This causes many arguments due to motorists complaining that they were not doing the speed as reported. Revenue Fight Unjust Victorian Speeding Fines. fightfines.info. Retrieved on September 18,
2007. is being increasingly blamed for these stricter measures. There are strict United Nations standards in place but it seems not being enforced leaving this matter in limbo for many countries.
Excessive speedometer error after manufacture can come from several causes but most commonly is due to nonstandard tire diameter, in which case the
percent
error = 100x("standard diameter"/"new diameter" - 1).
Nearly all tires now have their size shown as "T/A_W" on the side of the tire, and the tire's
diameter in inches = TxA/1270 + W.
For example, a standard tire is "185/70R14" with diameter = 185x70/1270 + 14 = 24.196850 in. Another is "195/50R15" with 195x50/1270 + 15 = 22.677165 in. Replacing the first tire (and wheels) with the second (on 15" wheels), a speedometer reads 24.19../22.67..=1.0670139 times the correct speed or 6.7% too high.
GPS
GPS devices may indicate the true speed of travel on the user interface. Unlike instrumental speedometers which provide a continious reading, the GPS speed readouts have a one second update interval.
The reading is based on reception of data from the satellites in orbit, and is therefore independent of the car's transmission components. Discrepancies between the two readings may be caused by instrument error (on the vehicle), or by changing directly influencial factors, such as tire sizes.
See also
References
External links
- Autoblog: Gauging changes
- Visual Tyre Size Calculator with speedometer error
speedometer from FOLDOC
speedometer. A pattern of lights displayed on a linear set of LEDs (today) or nixie tubes (yesterday, on ancient mainframes). The pattern is shifted left every N times the ...
Speedometer - Wikipedia, the free encyclopedia
A speedometer (commonly misspelled spedometer) is a device that measures the instantaneous speed of a land vehicle. Now universally fitted to motor vehicles, they started to be ...
USB Speedometer Speed Handy Gadget Type Typists Track Fast Typing Word ...
USB Speedometer Speed Handy Gadget Type Typists Track Fast Typing Word Words Amount Each Day Game Novelty Gift Home Work Office Touch Typing Skills UK Buy
Speedometer
Speedometer Home Page
Welcome to the online home of europe's most authentic funk band, Speedometer. Follow the links in the navigation bar at the top of the page for further information on recorded ...
Internet Connection Speedometer - How Fast is Your Internet Connection ...
Internet Connection Speedometer - How Fast is Your Inernet Connection? - McAfee ... Now you can find out how fast or slow your Internet connection is with our Internet Connection ...
Mcafee Speedometer
McAfee.com - Internet Connection Speedometer
McAfee.com Online Applications. Learn about or get to all of our online application services here.
Speedometer & Odometer Repairs — Overseas Speedometer
Repairs electronic and mechanical speedometers, odometers and quartz clocks.
AskOxford: speedometer
speedometer /spee domm it r/ • noun an instrument on a vehicle’s dashboard indicating its speed. Perform another search of the Compact Oxford English Dictionary
