We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Hypoid Gear?

By Allan Robinson
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A hypoid gear is a spiral bevel gear with an axis that does not intersect with the axis of the meshing gear, or pinion. Its primary application is in the differential drive of a wheeled vehicle, where the drive shaft must be at a right angle to the wheels. The helical teeth in this gear produce less vibration than a gear with spur-cut or straight-cut teeth. Hypoid gears are manufactured in pairs and should be replaced in pairs.

A right-hand hypoid gear is one in which the outer half of the teeth are inclined in the clockwise direction as one looks at the face of the gear. Similarly, a left-hand one has the outer half of its teeth inclined in the counterclockwise direction. The gear and its pinion usually have opposite handedness. This type of gear also can be classified according to its spiral angle — the angle between an element of the pitch cone and the tooth trace.

A hypoid gear has the shape of a revolved hyperboloid, meaning that its pitch surface forms a hyperbolic surface. Its pinion is off-axis with respect to the ring gear, also known as the crown wheel. This allows the pinion to be larger than the hypoid gear, which causes the pinion to have greater contact with the gear.

This type of gear is generally stronger and quieter than an ordinary spiral bevel gear. It can also handle a higher reduction ratio. The teeth experience some sliding, causing friction, which means that the gear requires special oils to lubricate it under very high pressure.

A larger offset in the hypoid gear increases its torque at the expense of efficiency. Its most common use is in older rear-drive vehicles, especially trucks, since the greater torque is most beneficial in larger vehicles. Designers of modern automobiles have tended to value the greater efficiency of an ordinary spiral bevel gear.

A spiral bevel gear must be much larger to provide the same torque as a hypoid gear. This generally means that a spiral bevel gear has less ground clearance, and it produces a greater hump in the floor of passenger cars. It's normally impractical to replace a hypoid gear with a more efficient spiral bevel gear.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.