engineering

Steering ratio

Steering ratio is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Steering ratio rather than just read about it. In short: Steering ratio refers to the ratio between the turn of the steering wheel (in degrees) or handlebars and the turn of the wheels (in degrees). The steering ratio is the ratio of the number of degrees of turn of the steering wheel to the number of degrees the wheel(s) turn as a result.

Key takeaways

Steering ratio belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Steering ratio to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Steering ratio from memory before moving on to harder problems.

Reference excerpt

Steering ratio refers to the ratio between the turn of the steering wheel (in degrees) or handlebars and the turn of the wheels (in degrees). The steering ratio is the ratio of the number of degrees of turn of the steering wheel to the number of degrees the wheel(s) turn as a result. In motorcycles, delta tricycles and bicycles, the steering ratio is always 1:1, because the steering wheel is fixed to the front wheel. A steering ratio of x:y means that a turn of the steering wheel x degree(s) causes the wheel(s) to turn y degree(s). In most passenger cars, the ratio is between 12:1 and 20:1. For example, if one and a half turns of the steering wheel, 540 degrees, causes the inner & outer wheel to turn 35 and 30 degrees respectively, due to Ackermann steering geometry, the ratio is then 540:((35+30)/2) = 16.6:1. A higher steering ratio means that the steering wheel is turned more to get the wheels turning, but it will be easier to turn the steering wheel. A lower steering ratio means that the steering wheel is turned less to get the wheels turning, but it will be harder to turn the steering wheel. Larger and heavier vehicles will often have a higher steering ratio, which will make the steering wheel easier to turn. If a truck had a low steering ratio, it would be very hard to turn the steering wheel. In normal and lighter cars, the wheels are easier to turn, so the steering ratio doesn't have to be as high. In race cars the ratio is typically very low, because the vehicle must respond to steering input much faster than in normal cars. The steering wheel is therefore harder to turn.

Variable-ratio steering Variable-ratio steering is a system that uses different ratios on the rack in a rack and pinion steering system. At the center of the rack, the space between the teeth are smaller and the space becomes larger as the pinion moves down the rack. In the middle of the rack there is a higher ratio and the ratio becomes lower as the steering wheel is turned towards lock. That makes the steering less sensitive when the steering wheel is close to its center position and makes it harder for the driver to over steer at high speeds. As the steering wheel is turned towards lock, the wheels begin to react more to steering input.

Steering quickener A steering quickener is used to modify the steering ratio of factory-installed steering system, which in turn modifies the response time and overall handling of vehicle. When a steering quickener is employed in an automobile, the driver of the automobile can turn the steering wheel a smaller degree compared to a factory-installed steering system without a steering quickener, to turn the vehicle through same distance. On the other hand, the steering effort needed will greatly increase. If the automobile is equipped with power steering, overloading the power steering pump can also be a concern.

References

Worked examples

Example 1 — a first encounter with Steering ratio

Start with the simplest possible case. Write down what Steering ratio claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Steering ratio before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Steering ratio ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Steering ratio

In research: Steering ratio appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Steering ratio in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Steering ratio is common in secondary-school and first-year university syllabi. It links to neighbouring topics Automotive steering technologies, Engineering ratios, Motorcycle dynamics, so understanding it makes those chapters shorter.
In everyday life: Look for Steering ratio outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Steering ratio in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Steering ratio means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Steering ratio out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Steering ratio in simple terms?

Why does Steering ratio matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Steering ratio?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Steering ratio.