Why is friction a nuisance in a pulley

Without friction, energy transfer would be easier and stopping motion would be more difficult. If there was no friction, there would be no force slowing down motion when two objects rubbed against one another.

Friction can work for or against us. For example, putting sand on an icy sidewalk increases friction so you are less likely to slip. On the other hand, too much friction between moving parts in a car engine can cause the parts to wear out.

Since friction is a resistive force that slows down or prevents motion, it can be a nuisance, because it can hinder motion and cause the need for expending extra energy. Friction can also cause parts in contact to heat up and can cause parts in contact to wear out. The frictional force between two bodies depends mainly on three factors: I the adhesion between body surfaces ii roughness of the surface iii deformation of bodies.

The nature of the surface smoothness or roughness affects the friction. Smooth surfaces have lesser irregularities. The lesser the irregularities, the lesser the tendency to lock. The lesser the tendency to lock with another object, the lesser the friction that is tendency to oppose motion.

So,higher the mass of the object,higher will be the frictional force. Dry friction occurs when two solid objects touch each other. If they are not moving, it is called static friction. If they are moving, it is called kinetic or sliding friction. Friction between moving engine parts increases their temperature and causes the parts to wear down. The bike industry is full of products that claim to make you faster.

Some focus on reducing your aero drag, others trim weight, and some attempt to efficiently transfer the watts from your legs to the road. Many can indeed make you faster, while others perhaps exist because there is profit to be had.

Drivetrain efficiency is an interesting and often overlooked opportunity for going faster. And scarily, that number only gets worse as your power output increases.

Fast chain lube and a clean chain can make a measurable difference here, while other upgrades, such as different bearing seals and lubricant can have a more marginal impact, too. The data suggest the OSPW will indeed save you watts, although that speed is anything but free.

But does it also impact shifting and drivetrain reliability? Is it noisier? CeramicSpeed claims the OSPW can save you between W over a stock Shimano Dura-Ace derailleur cage system at W, 90rpm , and that figure progressively improves the worse your chain maintenance and selection of chain lubricant is or as it wears off and gets contaminated toward the end of a race.

In reality, with an optimised or even well-maintained chain in use, that figure is likely closer to just W — but still, watts are watts. Just as we know using larger cogs and chainrings are more efficient as a result of reduced chain link articulation, the same applies to derailleur pulley wheels.

With regular tooth pulley wheels, each link of a chain must articulate about 33 degrees as it enters and exits each pulley wheel. But with a tooth pulley wheel the largest available in any OSPW , each chain link only needs to articulate 19 degrees. German company Berner was the first to offer an aftermarket derailleur cage upgrade focussed on increasing the pulley wheel tooth count. This is sliding friction.

This is rolling friction. This is fluid friction. How to Melt Tires. How to Calculate the Force of Friction. How to Identify Three Types of Levers. Mechanism Description of a Manual Can Opener. How Does a Suction Cup Work? How to Build a Gyroscope. Sidewall wear is visible, and again, both roll over and groove-hopping is likely. Vertical angular misalignment has either the driver or the driven pulley twisted out of alignment with the other pulley.

For example, if a motor leans inward, the drive sheave, or pulley, is tilted out of alignment with the flywheel, or driven pulley. Once again, users may experience this and believe that banded belts are the answer. They are not. Their use in this application may temporarily mask misalignment, but proper alignment is the remedy. Parallel misalignment has belts misaligned by not having the driver or the driven pulley grooves in a straight line with each other and the v-belts.

By using a string and running it from the far side of a drive groove to the opposite end of a matching driven pulley groove and along a v-belt connecting the groove, installers easily see gaps indicating misalignment.

When used to address misalignment, banded belts often develop torn areas between belts. This, too, indicates misalignment. It is caused by unwanted flexing during normal running time, especially during loading and unloading.

This happens during all three kinds of misalignment listed above. Spin burn is another wear condition. It looks similar to a ruptured cover, except surfaces are smoother, shinier, and glazed. Improper tension is the most common cause. Re-tension the belts, if they are still in usable condition. This makes belts like ever-stretching rubber bands, and they will not properly grip around sheaves and flywheels. They may also hop out of their grooves or roll over.

Vibration is possible with all forms of misalignment. Since belts in this article are designed to operate with a slight bit of slippage during startup, loading, and unloading, belt dressings or other abrasives should not be used. Oil and grease, obviously, cause slippage and should be kept off belts and machine pulley drive surfaces. Use detergent and water to clean the belts and pulley grooves. Keep water and other liquids from splashing onto belts and pulleys.

Flywheels are driven pulleys, and sheaves are driver pulleys. Normal wear can cause v-belt damage. After a long period of operation, in some cases many years, grooves deepen in sheaves and flywheels. New single belts will fit beneath the top of the grooves.

This changes the operating speed, and it increases belt slippage. Belt manufacturers offer inexpensive plastic sheave templates for measuring pulley grooves. Hold a lit flashlight behind the template, and look for light passing between the template and the groove; light indicates wear.