Harley Davidson Motorcycles
|Harley Davidson Motorcycles|
From humble beginnings: Harley Davidson motorcycles
Harley Davidson motorcycles are world renown. These bikes are so well known that if you were to tell an American that you've never heard of Harley Davidson motorcycles, they would not only look at you funny, but probably call their friends and tell them the interesting story about the time they met someone who had never heard of Harley Davidson.
Because the company is so famous and successful now, it is almost impossible to believe that it all started with 2 people in a wooden shed. In 1903, William S. Harley and Arthur Davidson got together in a 10x15 foot wooden shed to create the first ever Harley Davidson motorcycle. They were both 21 and 20 years old respectively at the time and sold their first bike to a childhood friend of Harley, Henry Meyer.
By 1907, Harley Davidson motorcycles had won numerous awards and after William and Walter Davidson, brothers of Arthur Davidson, joined the team, the company was incorporated. They had 18 full time employees at the time and had a new factory. In the 1908 Federation of American Motorcyclists Endurance and Reliability test, Walter Davidson receives a perfect score of 1000 points. Three days later, he would also set the FAM record for economy with 188 miles per gallon. It didn't take long for the news of Harley Davidson motorcycles to spread and the first Harley used for police duty was delivered to the Detroit police department.
From these humble beginnings rose the worlds most popular and well know motorcycles. You aren't considered a collector or enthusiast until you own a Harley. For more information regarding the history of Harley Davidson motorcycles, visit the official web site linked below.
Harley Davidson Motorcycles
Motorcycle Accessories On EBay!
Find virtually any motorcycle accessory, both new and used on eBay!
Motorcycle Accessories Discounted
Save money on all your motorcycle accessory needs.
Harley Davidson Motorcycles
History of Harley Davidson motorcycles.
Today's Harley Davidson Motorcycles Articles
How to Purchase electric scooters online?
The trend of buying the items through the internet has widespread globally. This new revolution has helped people stop going around shop to shop to select an item they exactly look for. The online buying concept helps the customers select the exact item they want and buy the items after paying from home or pay when the item is been delivered at home. This concept has helped even the sellers earn more business without investing money in establishing the retail selling premise in the market areas. Even the manufacturers have started selling their product directly to the customers through online selling. Earlier, the customers never had the knowledge of types, brands and price variation of the item they wanted to buy, because the customers would at the most visit few dealers of a particular area and possibly those dealers would not have a particular item a customer would be looking for, as a result the customer would compromise buying a substitute item. Even if one of those dealers had the exact item the customer would look for, then possibly that dealer would take the advantage of the item being available with him only within that area, so would charge the price more than the price of those dealers in the other areas. The electric vehicles have also mingled with the online sold products and have become the part of the online community. Many manufacturers and dealers have now started selling the electric vehicles including electric scooters directly to the customers through the internet. The online selling system has made the customers smart and alert. Now the customers do not have to go round dealer to dealer looking for the exact item and compromise buying a non-standard or substitute electric vehicle, or pay more to the dealer just because the dealer has the monopoly of a particular brand of electric scooters in particular area. Now the customers can browse through different sites of the companies and dealers dealing in electric vehicles including electric scooters and choose a particular brand or type or design, whatever, they look for in an electric scooter. They also have a wide choice to select from after thoroughly studying and understanding the features of each of the electric scooters. The customers can now gain knowledge of the brands and types of the electric scooters manufacturers and available and also the prices of the types of the scooters so the customers would now not get cheated. When a person thinks of buying an electric scooter or any other electric vehicle for him/herself or for him/her son/daughter, then first of all s/he has to wait for the next week-end. Secondly, s/he has to prepare a plan of where to go to buy the electric scooter and at what time, keeping in mind that his/her other week-end programmes or commitments are not disturbed. Then, if going by car, s/he has to find out whether there is any parking place and also find the route to get to the electric vehicle market. If the person decides to go by public transport or by train to the electric vehicle market, then s/he has to get the information on were to get the bus/train, where to change and were to get down and how long s/he has to walk to reach the market after getting off the public transport. Obviously, such buying would cost delay in buying an electric scooter, time and physical stress. Instead, if a person decides to get an electric scooter for his/herself or for any of his/her beloved ones, then s/he could immediately start browsing the websites and search for the electric scooters. You may also visit the website of www.bernsonev.com and choose one from the wide range of electric scooters the site sells online, of various popular brands at unbeatable price. The online buying facility can save up to 75% of the time and buying cost of the buyers.
Roadgear H20-Tec Waterproof Gloves Review
Basic gloves with minimal padding and insulation for touring riders.
How to Buy a Pocket Bike
A pocket bike is getting to be more and more popular for people. With so many of the manufactures bringing new ideas to the bike trend, there are so many bikes to choose from to fit your style. When you are buying a pocket bike, you have to do a little research before you agree on one certain kind. One of the most important facts about buying a pocket bike is to find a high quality product at a great price. You want to get the most for your money and have a bike that will last a long time for anyone to have. There are gas and electric pocket bikes to choose from. You need to determine what style and brand that you want and then do the shopping to find the best prices around. Do not let anyone pick your pocket bike for you. This is something that you want to use and you should pick the right one for you. You want to check how powerful the bike is going to be. If the bike is for you or another adult, then the more horse power the better. If it is for a child, then you may want to tone it down a little bit more for safety. Think about how heavy the rider is going to be and where they will be riding it. The atmosphere is so important to the size and the kind that you decide on. Make sure that the bike is made from durable materials and put together in sturdy way. You should inspect the bike thoroughly so that you do miss any imperfections or mistakes. You want your ride to be as safe as possible. You should also check the store where you are buying he pocket bike. Think about their creditability and how safe it is. If you are buying online, you should do a lot of research on the company to make sure that you are buying from a store that has a good reputation. Also check the return policy of the store where are buying the pocket bike. Make sure that you can return the pocket bike if it does not meet your expectations. You should ask about this policy before you decide to purchase the bike. Understand all of the fees that you may be responsible for if you do decide to return the bike. Check to make sure that you are allowed to ride the pocket bikes in your area. Do this before you purchase your bike because it may not be legal for you to ride your pocket bike and you will not be able to return it later for this reason. You will have to decide on the bike that you want. Do not buy one just because it is the cheapest one for you. You should make sure that you are happy with the bike so that you can enjoy as much time on the pocket bike as possible. This is your investment and you will be the only one to determine the one that you want. Once you choose the perfect pocket bike for you, you will have nothing but fun riding it.
Copyright 2006 - Ivar Rudi. Ivar suggests you find great market for less by shopping online today. For more information and resources about this subject check out: http://www.pocketbikes-guide.com/ and also: http://www.mini-chopper.org/
Why I Like Classic Car & Cycle People!
While watching the TV news, I was appalled at how many people can't just get along, to quote Rodney King. It is truly a very sad situation. Then I thought about all the different types of people we have at our event and how well they all get along. In the 18 years we have been doing our events, we have never had any trouble with the participants at our shows. Bikers, Low Riders, Classic Cars, Hot Rodders, Sports Cars types and Tuner owners, they all attend our classic car & cycle show and all of them have a great time. Don't get me wrong, they all have different likes and dislikes, but they are tolerant of their fellow gear heads. The world could learn a lot from Gear Heads! Learn to appreciate the other person's point of view. Low Riders always draw a crowd when they put their vehicles through their "dance". Now I'm not at all interested in having a car that hops, but I sure can appreciate the work and engineering that goes into allowing thousands of pounds of Chevy to bounce six feet off the ground. I also don't want a car with 1000 horsepower with a blower sticking out of the hood. but I sure do enjoy checking out those types of cars at the car shows. The way I see it, we are all different and we should revel in these differences not curse them. Diversity makes the world an interesting and fun place to live in. It's a shame that some people feel its either their way or the highway. Whether its religion, politics or drive trains, we all need to love our neighbors and that which makes them unique. If the world was made of Classic Car and Cycle People, what a wonderful place it would be! See Ya There! Ray Taylor Owner of the San Diego Auto Swap and the Classic Cars Net Free Classifieds http://www.CarsNet.com http://www.SanDiegoAutoSwap.com
Ray Taylor is the owner of the real world San Diego Car & Cycle - Show & Swap. He also owns www.CarsNet.com, www.SanDiegoAutoSwap.com
Motorcycle Reviews Page
You asked for it! A new page that lists all of our motorcycle reviews, ride reports, information and specifications.
British Motorcycle Gear Rapido Gloves Review
Super quality and full protection at a fraction of the cost of other race gloves.
Gas Scooters Safety Rules For Staying Alive!
By following a few safety measures gas scooters can be as safe as any vehicle on the road. However, taken lightly, gas scooters can cause serious injury or even death.
Gas motor scooters are often thought of as toys, innocent and cheap fun. But it's exactly that type of thinking that can get a gas scooter driver into deep trouble. First and foremost scooters are motor vehicles just like motorcycles and automobiles. They share the road with other cars and trucks and are subject to similar laws and regulations. And although they are an object of desire for many they can be dangerous for the unexperienced or unprepared.
As a general rule gas powered scooters are regulated by state laws as either motorcycles or mopeds and are subject to similar regulations as these other motor vehicles. By staying alert and using caution many accidents can be avoided. Most accidents arise due to carelessness. By paying attention to what is going on around you and what other drivers are doing you can feel relatively safe out on the highway.
There are two things that cause the majority of accidents, speeding and following too closely to the vehicle ahead. Driving safely is all about giving other drivers enough reaction time. If another driver wants to change into your lane directly in front of you it may cause you to lose control if you are speeding and haven't enough time to react. Without enough time to slow down this maneuver by the other driver may require you to move into another lane to avoid him. This can affect other drivers in other lanes which is the beginning of many accidents.
Another major mistake that many gas scooter drivers make is following too closely. When the person ahead of you suddenly slams on the brakes you need enough time to slow down comfortably. Ramming into the back of someone's car is not what you want to do, especially when you are driving a small scooter without any protection around you. By following the speed limits and giving yourself enough room to slow down if something unexpected should happen in front of you most accidents can be prevented.
The third problem arises when gas powered scooters are purchased for use by children and teenagers who do not even possess a valid driver's license. Drivers with licenses may not be any safer on the road than unlicensed drivers, but at least they have had some training and experience behind the wheel of a car. Children and teenagers without any training can be an accident waiting to happen when it comes to motor scooters. Without any experience or training children and young teenagers can quickly find themselves in positions that experienced drivers normally would not.
Kids have been known to throw caution into the wind, darting in and out of traffic without a clue as to the dangers. On gas scooters that are so small they can't be seen well by other drivers, and without much driving experience or training, kids will pose a hazard to both themselves and the other motorists they come in contact with.
Parents should be strongly cautioned to have their children receive the proper amount of training on their gas power scooters before they are allowed onto the busy city streets. Find a deserted road and put them through a training session. The life a parent saves may be his own children's. Only after a parent feels comfortable with his child's driving skills should they allow the child onto the busier streets. By making sure that our children know the safety rules of the road we are decreasing their chances of being involved in a serious accident. Before we can legally drive a car on the highway we must all pass certain tests. Why should it be any different for younger kids?
Gas or electric scooters are wonderful little vehicles that are fun to drive, cheap to buy and are very handy for traveling short distances around the neighborhood to perform errands. They usually have larger storage room than a motorcycle and are very inexpensive to operate. There are many reasons for owning a gas scooter, but in the hands of the untrained and inexperienced they can be deadly.
The ATV, go carts, dirt bikes and mini bikes are other vehicles that are often owned and operated by younger drivers. But they are usually not seen on the city streets as scooters are. Go karts are typically driven on tracks specifically designed for the go cart. And the mini bike, dirt bike or ATVs are typically driven off road. These other vehicles avoid many of the dangers that scooter drivers must face, namely traffic on the busy highway.
Gas scooters are quite popular these days, especially among the younger market who are too young to drive cars yet. Without proper training for these kids it opens the door to possible serious accidents. As the worldwide popularity of gas scooters grows we need to make sure that people's awareness of driving and safety regulations keeps pace, especially among the kids that have no previous drivers experience.
Kids often think of gas scooters as toys, not as potentially dangerous vehicles. But a scooter is not a toy. It is a motor vehicle that is subject to certain laws and regulations. People need to be aware of the potential scooter dangers and remain alert while driving at all times. They should not drive erratically, but be predictable and courteous to other drivers on the road. They should follow the speed limits and remain a safe distance behind other vehicles. Kids should receive proper training before being allowed on the busier streets. By taking these few safety precautions we can help ensure a fun safe driving experience for all.
J Larry Alan is an enthusiast of <a href="http://www.my-gas-scooters.com">gas scooters</a>. He enjoys riding motorcycles and <a href="http://www.my-gas-scooters.com">gas powered scooters</a>. He also enjoys promoting gas scooter safety. For more information visit his site about <a href="http://www.my-gas-scooters.com">gas motor scooters</a>.
Motorcycle Tire Basics
This is the first in a series of articles exploring motorcycle tire basics and various basic dynamic characteristics of the handling behavior of motorcycles. Overall this is a very complex subject and needs a good level of mathematics and physics to properly understand what's happening. However, in these articles I'll try and explain the basics with the absolute minimum of mathematics, but where this is unavoidable I'll not go beyond simple trigonometry. For those that are unhappy with any mathematics at all, don't worry, just skip those parts and the rest should still prove useful. I'll try and illustrate the mechanics with many sketches and graphs. It seems incredible that just two small contact patches of rubber, can support our machines and manage to deliver large amounts of power to the road, whilst at the same time supporting cornering forces at least as much as the weight of the bike and rider. As such the tires exert perhaps the single most important influence over general handling characteristics, so it seems appropriate to study their characteristics before the other various aspects of chassis design. When Newton first expounded to the world his theories of mechanics, no doubt he had on his mind, things other than the interaction of motorcycle tires with the road surface. Never-the-less his suppositions are equally valid for this situation. In particular his third law states, "For every force there is an equal and opposite force to resist it." or to put it another way "Action and reaction are equal and opposite." Relating this to tire action, means that when the tire is pushing on the road then the road is pushing back equally hard on the tire. This applies equally well regardless of whether we are looking at supporting the weight of the bike or resisting cornering, braking or driving loads. What this particular law of Newton does not concern itself with, is which force is the originating one nor indeed does it matter for many purposes of analysis. However, as a guide to the understanding of some physical systems it is often useful to mentally separate the action from the reaction. The forces that occur between the ground and the tires determine so much the behaviour of our machines, but they are so often taken for granted. tires really perform such a multitude of different tasks and their apparent simplicity hides the degree of engineering sophistication that goes into their design and fabrication. Initially pneumatic tires were fitted to improve comfort and reduce loads on the wheels. Even with modern suspension systems it is still the tires that provide the first line of defence for absorbing road shocks. To explore carcass construction, tread compound and tread pattern in great detail is beyond the scope of this book. Rather we are concerned here with some basic principles and their effects on handling characteristics. Weight Support The most obvious function of the tire is to support the weight of the machine, whether upright or leaning over in a corner. However, the actual mechanism by which the air pressure and tire passes the wheel load to the road is often misunderstood. Consider fig. 1, this sketch represents a slice through the bottom of a rim and tire of unit thickness with an inflation pressure of P. The left hand side shows the wheel unloaded and the right hand side shows it supporting the weight F. When loaded the tire is compressed vertically and the width increases as shown, perhaps surprisingly the internal air pressure does not change significantly with load, the internal volume is little changed. At the widest section (X1) of the unloaded tire the internal half width is W1, and so the force normal to this section due to the internal pressure is simply 2.P.W1 . This force acts upwards towards the wheel rim, but as the pressure and tire width are evenly distributed around the circumference the overall effect is completely balanced. This force also has to be resisted by an equal tension (T) in the tire carcass. The loaded tire has a half width of W2 at it's widest section (X2) and so the normal force is 2.P.W2 . Therefore, the extra force over this section, when loaded, is 2.P.(W2 â€" W1) but as the tire is only widened over a small portion of the bottom part of the circumference, this force supports the load F. The above describes how the inflation pressure and tire width increase produce forces to oppose the vertical wheel loading, but does not completely explain the detail of the mechanism by which these forces are transferred to the rim. The bead of a fitted tire is an interference fit over the bead seat of the wheel rim, which puts this area into compression, the in-line component of the side-wall tension due to the inflation pressure reduces this compression somewhat. This component is shown as F1 on the unloaded half of F1 = T.cos(U1). The greater angle U2 of the side-wall when loaded means that the in-line component of the tension is reduced, thereby also restoring some of the rim to tire bead compression. This only happens in the lower part of the tire circumference, where the widening takes place. So there is a nett increase in the compressive force on the lower rim acting upward, this supports the bike weight. The nett force is the difference between the unloaded and loaded in-line forces, F = T.(cos( U1) -cos(U2)) The left hand side shows half of an inflated but unloaded tire, a tension (T) is created in the carcass by the internal pressure. To the right, the compressed and widened shape of the loaded tire is shown. The in-line components (F1 & F2) of the side-wall tension are reduced by factors equal to the cosines of the angles of the side-wall. This reduction is greater with the loaded tire resulting in a greater compressive force on the lower part of the rim. This is the principle but not the only mechanism which passes force from the wheel to the ground, the above ignores the effects of the flexure stiffness of the carcass itself, in addition to supporting the tension forces as outlined, the side-walls also have some bending resistance which can resist small wheel loads without any internal air pressure. Suspension Action In performing this function the pneumatic tire is the first object that feels any road shocks and so acts as the most important element in the machine's suspension system. To the extent that, whilst uncomfortable, it would be quite feasible to ride a bike around the roads, at reasonable speeds with no other form of bump absorption. In fact rear suspension was not at all common until the 1940s or 50s. Whereas, regardless of the sophistication of the conventional suspension system, it would be quite impractical to use wheels without pneumatic tires, or some other form of tire that allowed considerable bump deflection. The loads fed into the wheels without such tires would be enormous at all but slow speeds, and continual wheel failure would be the norm. A few figures will illustrate what I mean:--Assume that a bike, with a normal size front wheel, hits a 25 mm, sharp edged bump at 190 km/h. This not a large bump. With no tire the wheel would then be subject to an average vertical acceleration of approximately 1000 G. (the peak value would be higher than this). This means than if the wheel and brake assembly had a mass of 25 kg. then the average point load on the rim would be 245 kN. or about 25 tons. What wheel could stand that? If the wheel was shod with a normal tire, then this would have at ground level, a spring rate, to a sharp edge, of approx. 17-35 N/mm. The maximum force then transmitted to the wheel for a 25 mm. step would be about 425-875 N. i.e. less than four thousandths of the previous figure, and this load would be more evenly spread around the rim. Without the tire the shock loads passed back to the sprung part of the bike would be much higher too. The vertical wheel velocity would be very much greater, and so the bump damping forces, which depend on wheel velocity, would be tremendous. These high forces would be transmitted directly back to bike and rider. The following five charts show some results of a computer simulation of accelerations and displacements on a typical road motorcycle, and illustrate the tire's significance to comfort and road holding. The bike is traveling at 100 km/h. and the front wheel hits a 0.025 metre high step at 0.1 seconds. Note that the time scales vary from graph to graph. Three cases are considered: Â· With typical vertical tire stiffness and typical suspension springing and damping. Â· With identical tire properties but with a suspension spring rate of 100 X that of the previous. Â· With tire stiffness 100 X the above and with normal suspension springing. So basically we are considering a typical case, another case with almost no suspension springing and the final case is with a virtually rigid tire. Structural loading, comfort and roadholding would all be adversely affected without the initial cushioning of the tire. Note that the above charts are not all to the same time scale, this is simply to better illustrate the appropriate points. This shows the vertical displacement of the front wheel. There is little difference between the maximum displacements for the two cases with a normal tire, for a small step the front tire absorbs most of the shock. However, in the case of a very stiff tire, the wheel movement is increased by a factor of about 10 times. It is obvious that the tire leaves the ground in this case and the landing bounces can be seen after 0.5 seconds. These curves show the vertical movement of the C of G of the bike and rider. As in Fig 1 it is clear that the stiff tire causes much higher bike movements, to the obvious detriment of comfort. Demonstrating the different accelerations transmitted to the bike and rider, these curves show the vertical accelerations at the C of G. Both of the stiffer tire or stiffer suspension cases show similar values of about 5 or 6 times that of the normal case, but the shape of the two curves is quite different. With the stiff suspension there is little damping and we can see that it takes a few cycles to settle down. The second bump at around 0.155 seconds is when the rear wheel hits the step, this rear wheel response is not shown on the other graphs for clarity. Front wheel vertical acceleration for the two cases with a normal tire. The early part is similar for the two cases, the suspension has little effect here, it is tire deflection that is the most important for this height of step. As in Fig 5 the lack of suspension damping allows the tire to bounce for a few cycles before settling down. As in these curves are of the wheel acceleration, the values of the normal case are overwhelmed by the stiff tire case, with a peak value of close to 600 G compared with nearly 80 G normally. Again note the effects of the landing bounces after 0.5 seconds. This high acceleration would cause very high structural loading. As the tire is so good at removing most of the road shocks, right at the point of application, perhaps it would be worth while to consider designing it to absorb even more and eliminate the need for other suspension. Unfortunately we would run into other problems. We have all seen large construction machinery bouncing down the road on their balloon tires, sometimes this gets so violent that the wheels actually leave the ground. A pneumatic tire acts just like an air spring, and the rubber acts as a damper when it flexes, but when the tire is made bigger the springing effect overwhelms the damping and we then get the uncontrolled bouncing. So there are practical restraints to the amount of cushioning that can be built into a tire for any given application. Effects of Tire Pressure Obviously, the springing characteristics mentioned above are largely affected by the tire inflation pressure, but there are other influences also. Carcass material and construction and the properties and tread pattern of the outer layer of rubber all have an effect on both the springing properties and the area in contact with the ground (contact patch). Under and over inflation both allow the tire to assume non-optimum cross-sectional shapes, additionally the inflation pressure exerts an influence over the lateral flexibility of a tire and this is a property of the utmost importance to motorcycle stability. Manufacturers' recommendations should always be adhered to. The influence of tire pressure on the vertical stiffness of an inflated tire, when loaded on a flat surface. These curves are from actual measured data. Note that the spring rate is close to linear over the full range of loading and varies from 14 kgf/mm. at 1.9 bar pressure to 19 kgf/mm. at 2.9 bar. The effective spring rate when the tire is loaded against a sharp edge, such as a brick, is considerably lower than this, and is more non-linear due to the changing shape of the contact area as the tire "wraps" around the object. This spring rate acts in series with the suspension springs and is an important part of the overall suspension system. An interesting property of rubber is that when compressed and released it doesn't usually return exactly to it's original position, this is known as hysteresis. This effect is shown only for the 1.9 bar. case, the curve drawn during the loading phase is not followed during the unloading phase. The area between these two curves represents a loss of energy which results in tire heating and also acts as a form of suspension damping. In this particular case the energy lost over one loading and unloading cycle is approximately 10% of the total stored energy in the compressed tire, and is a significant parameter controlling tire bounce. Vertical stiffness of a standard road tire against a flat surface at different inflation pressures. This data is from an Avon Azaro Sport II 170/60 ZR17. The upward arrows indicate the compression of the tire and the 2nd line with the downward arrow (shown only at 1.9 bar for clarity) shows the behaviour of the tire when the load is released. The shaded area between the two lines represents a loss of energy called hysteresis. This acts as a source of suspension damping and also heats the tire. (From data supplied by Avon tires.) The lateral stiffness of the same tire measured at two different pressures. In both cases the tire was loaded vertically with it's maximum rated capacity of 355 kgf. The lateral spring rate is less than half that of the vertical rate at 7.7 and 7.3 kgf/mm. at 2.9 and 2.5 bar respectively. It is interesting to note that at the higher pressure the tire saturates or loses adhesion at the lower figure of 460 kgf. compared to 490 kgf. at the lower pressure. Saturation is indicated when the curve more or less becomes horizontal, this is when the tire cannot support an more lateral force and it displaces or slides sideways, with an approximately constant force. The contact patch area and pressure produced at the lower air pressure has allowed more static grip. However, these tests are done with the artificial case of an upright and non-rotating wheel and hence it would be risky to extrapolate this grip characteristic to a moving machine. Although not shown, the lateral deformation would also be subject to some hysteresis and this damping and the lateral flexibility exert an important influence over the weave stability. Lateral stiffness of the same tire shown in fig. 9. The vertical load was constant at 355 kgf. and the wheel was kept vertical. As expected the tire is somewhat stiffer with the higher inflation pressure but loses grip or saturates at the lower lateral load of 460 kgf. compared to 490 kgf. at the lower pressure. (From data supplied by Avon tires.) Contact Area The tire must ultimately give it's support to the bike through a small area of rubber in contact with the ground, and so "contact patch area = vertical force Ã· average contact patch surface pressure". This applies under ALL conditions. The contact patch surface pressure is NOT however, the same as the inflation pressure, as is sometimes claimed. They are related but there are at least four factors which modify the relationship. Carcass stiffness, carcass shape, surface rubber depth and softness, and road surface compliance. If we have an extremely high carcass stiffness then inflation pressure will have a reduced influence. Let's look at this in a little more detail and see why: If a tire was made just like an inner tube, that is from quite thin rubber and with little stiffness unless inflated, then the internal air pressure would be the only means to support the bike's weight. In this case the contact patch pressure would be equal to that of the internal air pressure. For an air pressure of 2 bar and a vertical load of 1.0 kN. Then the contact area would be 5003 sq.mm. If we now increased the air pressure to say 3 bar the area would fall to 3335 sq.mm. Let's now imagine that we substitute a rigid steel tubular hoop for our rim and tire, the area in contact with the ground will be quite small. If we now inflate the hoop with some air pressure, it doesn't take much imagination to see that, unlike the inner tube, this internal pressure will have a negligible effect on the external area of contact. Obviously, a tire is not exactly like the steel hoop, nor the inner tube, but this does show that the carcass rigidity can reduce the contact surface area as calculated purely from inflation pressure alone. On the other hand, let's now imagine that we cover the previous steel hoop with a layer of thick soft rubber. Now, the actual contact area will be considerably increased and the average contact patch pressure will be reduced. Substitute this mental picture back to a real tire and we see that the tread layer of rubber will give us a greater contact area and lower contact pressure than that of the inflation pressure alone. It is this compliance of the surface rubber that gives us more contact with the road when we increase tire width and diameter, but this must be balanced against the opposing effects of the carcass stiffness. Radial and bias or cross ply tires exhibit quite different characteristics in this regard. The properties of the road surface are also important, a soft surface, mud and sand for example, will obviously give support over a wider area of the tire and so reduce the contact pressure. On a hot day with softened tarmac, even a normal road will deflect significantly enough to affect the contact patch. To get a feeling for the degree of departure of the contact patch pressure from the inflation pressure, consider a completely flat tire, in this case the rubber area will probably be no more than 3 or 4 times, at most, the area when inflated correctly. Based on the notion that rubber pressure = inflation pressure, we would expect the rubber area to be much higher, infinite in fact. Another extreme case to consider: Imagine a knobbly tire with very few knobs such that only one knob supports the bike. In this example the rubber pressure is simply the weight divided by the area of the one knob, this is regardless of the inflation pressure. These are extreme examples of course but should still demonstrate the lie in the proposition that rubber contact pressure = inflation pressure. The following describes some simple measurements that I made to check out the actual relationship between load, inflation pressure and contact area. I did 2 sets of tests. For the first I kept the tire inflation pressure constant at 2.4 bar and varied the tire load between 178 and 1210 N. (allowing for the weight of the glass and wooden beams). Secondly, I keep a constant load of 1210 N. and tried varying the inflation pressure between 2.4 to 1 bar. Even with a generous allowance for experimental error the effects are clear. The graphs show that the results appeared to fit reasonably well to a smooth line, there wasn't much scatter. Point (1) on the curve with constant inflation pressure, shows how the actual contact patch pressure is lower (just over half) than the inflation pressure, or in other words the contact area is greater. This is due to the rubber surface compliance, thus this is more important at low vertical loads, whereas carcass stiffness became more important as the load rose as shown by points (3) to (6) where the actual contact pressure is higher than the air pressure, i.e. reduced area of contact. Measurement setup. Various weights were placed on the end of a beam, which also loaded the tire via a thick plate of glass. The beam was arranged to apply the load to the tire with a 4:1 leverage. So a 25 kgf. weight would load the tire with 100 kgf. By tracing over the glass the contact area was determined. Tracings of tire footprint for different loads and pressures. The numbers relate to the data points below. The top plot shows the measured contact patch pressure at various wheel loads for a constant inflation pressure of 2.4 bar. The lower curves show the contact pressure at various inflation pressures for a fixed load of 1210 N. The numbers at the data points correspond with the contact area tracings in the previous sketch. The plain line on each plot shows the case of the contact patch pressure being equal to the inflation pressure. The carcass stiffness helps to support the machine as the air pressure is reduced, the contact patch pressure being considerably higher than the inflation pressure. It looks as though the two lines will cross at an air pressure of about 3.5 bar. (although this was not tested by measurement), at which point the surface rubber compression will assume the greatest importance. This is as per the steel hoop analogy above. We can easily see the two separate effects of surface compliance and carcass stiffness and how the relative importance of these varies with load and/or inflation pressure. These tests were only done with one particular tire, other types will show different detail results but the overall effects should follow a similar pattern. Area Under Cornering Does cornering affect tire contact area? Let's assume a horizontal surface and lateral acceleration of 1G. Under these conditions the bike/rider CoG will be on a line at 45Â° to the horizontal and passing through the contact patch. There will a resultant force acting along this line through the contact patch of 1.4 times the supported weight. This force is the resultant of the supported weight and the cornering force, which have the same magnitude, in this example of a 45Â° lean. The force normal to the surface is simply that due to the supported weight and does NOT vary with cornering force. The cornering force is reacted by the horizontal frictional force generated by the tire/road surface and this frictional force is "allowed" by virtue of the normal force. Therefore, to a first approximation cornering force will NOT affect the tire contact area, and in fact this case could be approximated to, if we were just considering the inner tube without a real world tire. However in reality, the lateral force will cause some additional tire distortion to take place at the road/tire interface and depending on the tire characteristics, mentioned above, the contact area may well change. Another aspect to this is of course the tire cross-sectional profile. The old Dunlop triangular racing tire, for example, was designed to put more rubber on the road when leant over, so even without tire distortion the contact patch area increased, simply by virtue of the lean angle. Next month we'll look at other aspects of tires, such as friction, grip, drifting, under- and over-steer, and tire construction and materials. by Tony Foale http://www.CarsNet.com/motorcycle
Ray Taylor is the owner of the real world San Diego Car & Cycle - Show & Swap. He also owns www.CarsNet.com and www.SanDiegoAutoSwap.com
How to purchase best electric bicycles online?
Buying an electric bicycle remaining at home is a great idea, thanks to the new internet marketing business trend. Those who could not spare time for shopping can browse through various sites sitting at home, while doing their personal or office work on the computer. Online selling business has now so wide-spread that sometimes people find it hard to select an item because of wide options they get to select an item from the websites of different companies. It is so easy to buy an item online, that even you can bargain the way you do when you visit any shop personally. Also the customers get the discount online. Buying anything online is very much beneficial. Online purchasing could reduce purchasing time and costs by more than 75 percent. The Internet is a valuable tool for buying electric bicycles by the customers across town or around the world. It also provides an abundance of buying and cost saving opportunities. When you decide to buy an electric bicycle for yourself or for your child, both of you can sit at home, browse through various sites including www.bernsonev.com. You can find a wide collection of electric bicycles at www.bernsonev.com. You can even compare the prices, makes, brands and features and finally select one and make the deal online with www.bernsonev.com. The payment options are also given on the site. Select the suitable payment options, pay for the selected electric bicycle and wait for the same to be delivered at your home. Those who have purchased electric bicycles through the internet are much satisfied since they have gained several benefits while purchasing viz, fast sources, better comparison, overall low purchasing costs, opportunity to check the lowest price and lot more benefits. The professional buyers can get a wide range of online buying forums with different features, designs and cost from the web. Since most of the websites are US based including www.bernsonev.com, the sites could be visited by the electric bicycle buyers from whole over the world. The website of www.bernsonev.com provides all those services the buyer would seek to procure for an electric bicycle. The Bernsonev E.V. company has launched a free website with detailed background information on their company including the list of the electric bicycles they sell online along with the price tags and services they offer.
Tips On Buying That New Motorcycle
You've made up your mind and you have finally decided to buy a new motorcycle! What a thrilling time this can be especially when you go into a dealership with a little bit of knowledge! It is important to know what you want, and to make sure your motorcycle fits your needs. Do your homework and understand completely what you're looking for before you talk to a salesperson. There is a great web site called http://CycleBuy.com where you can find out the dealer invoice price and obtain a report on each bike. Remember the dealer is in business to think money and he will try and make at least 10% profit on your sale. Some of the more common fees are set-up fees, documentation fees, destination charges and taxes. It is difficult sometimes to find out what a dealership's profit margin is, but it is somewhere between 5 and 15%.
Also know that the salesman will always try to sell you extra items including an extended warranty and all the accessories, because, as you may well know, the dealer makes money on this as well. You may not want any extras and if so, don't let a salesman talk you into anything you don't want.
If you are doing a trade-in, remember to do your homework. Check out this web site, http://www.kbb.com (Kelly Blue Book), as this will tell you what the price of the vehicle is when either selling it outright or trading it in. Try keeping mind that the dealer always wants to make at least 10% profit on each deal, so doing your homework means you may be able to talk them down quite a bit.
Most dealers like cash deals, however, if you are financing try to put down a good portion of that in cash. You may want to use a personal line of credit or get a pre-approved loan from a lending institution before approaching a dealer. Some dealers may have low percentage loans they can offer you on certain models, and this may definitely influence your decision. If you sell your bike privately rather than trading it in, you will usually get more for it. Remember, the dealer wants to work with you so play hardball with him. Give them some of your other business such as riding gear and accessories as this can be used as a bargaining tool. After you finalize the deal, you can almost always get them to sweeten it a bit more by throwing in the helmet or a jacket, since the salesperson has spent a lot of time and doesn't want to lose the sale.
Sintilia Miecevole, Administrator of <a href="http://www.hkmotorcycle.com" title="http://www.hkmotorcycle.com" target="_blank">http://www.hkmotorcycle.com</a> provides you with information or resources from motorcycle, motorcycle accessories, clothing and gear to parts, rallies, events and more. Be sure to visit <a href="http://www.hkmotorcycle.com" title="http://www.hkmotorcycle.com" target="_blank">http://www.hkmotorcycle.com</a> for further information.