The Advantages And Disadvantages Of Straight Cut Gears

A gearbox is the main part of a vehicle as without it you can’t operate a car for the torque and speed. A gearbox is responsible for providing you that torque and amount of speed as per the surface you drive on. Such as in hilly areas or on incline terrains, you need less speed and more torque; the opposite is true on the plane surfaces. A gearbox fulfills all these requirements and lets the driver have the amount of speed and torque as per the situation. Now, when we talk about gears, there are several types of them. The widely used ones are straight cut gears and helical. Many people get confused that if straight cut gears are useful as helical gears seem to hold a more positive image. So, today we are going to diminish your doubts about the straight cut gears.

Straight Cut Gears: Advantages And Disadvantages

The straight cut as its name contains the teeth that are cut in straight form instead of the helical or spiral shape. Straight cut gears are widely used in racing cars than regular cars. The reasons are many that why straight cut gears are preferred. So let’s discuss the same and understand the advantages and disadvantages.

1. Advantages of Straight-Cut Gears

Straight cut gears are known for producing no axial load like helical gears. As there is no axial load, there is no restriction applied on the torque. Hence, the straight cut gears are used in racing cars as torque is an aspect that is much needed in racing.

The elimination of thrust force in straight cut gears protects the output shafts and other bearings from tearing apart. This away, the straight cut ensures safety as well as torque even at a great force.

A straight-cut transmission does not produce any heat due to its absence of axis load. The axis load is responsible for increased friction and heat and decreased energy which happens in the helical gears system.

Due to the simple nature of straight-cut gears, they always come easy to assemble. Plus, as there is no axis load, no bearings and output shafts are needed. This, as a result, decreases the overall loads and slims down the engine, and that comes as a huge advantage in racing cars. Due to the decreased weight, racing cars perform efficiently and well every time.

Spur gears or straight-cut gears charge less money also. It comes beneficial, especially in the reverse gear part where three gears are needed to perform the reverse action. Since they come cheap, they are used for the reverse gear operation. Straight cuts gears do not need any synchronizers as well, and that makes them even cheaper.

straight cut gears- explained here for you
Everything you need to know about straight cut gears (Photo Source: carfromjapan)

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Advantages in Brief:

  • Straight cut gears make the drive lightweight
  • They produce no axial force
  • They provide more torque
  • Easy to assemble
  • Slims down the overall engine space
  • Built for racing cars
  • Cheaper in price

2. Disadvantages Of Straight-Cut Gears

Nothing is an exception to drawbacks, and so straight cut gears have their downsides too. Due to the straight cut, they mesh each other all at once, and this creates a hell lot noise out of them. Thus, they are not used for regular cars as they are not known for silent operation.

straight cut gears- understanding it all
Straight cut gears (Photo Source: petermayengineering)

As the straight gears meet their parts all at once, they tap on each other, and thus they produce the whining sound. They are less smooth and efficient than helical gears which come together in small segments, and thus they produce no instant tapping. With the increasing speed, the tapping increase too, and the noise carries on. Hence, you now know why those racing cars are so noisy while in motion.

Plus, the straight cut gears are not meant to carry heavy loads which helical gear can carry effortlessly. It happens because of the distributed force due to the spiral teeth of the gears. Want to know if you can drive with a bad motor mount? Here are the Maintenance Tips.

Disadvantages In Brief:

  • Noisy driving
  • Not meant to carry heavy loads
  • Not good for city cars
straight cut gears- explained
What you need to know about straight cut gears now? (Photo Source: carfromjapan)


More and more sports cars have been adopting the concept of helical gears with advancements of technology so the torque won’t be compromised. There are still cars that use straight cut gears gracefully and let the driver complete the racing in full charm. So, as long as you do not mind noise while driving, straight cut ears are not that bad of a transmission.

Even there are motor enthusiasts who prefer converting their gear system into a straight-cut gear mechanism for improved efficiency and speed. At last, it all depends on the preferences whether you want to go with smooth ride and silence or power and noise.