How a Sequential Transmission Works

Sequential Transmission works


Sequential transmission works is similar to manual transmission but it’s a bit different. Sequential transmission is a type of non-synchronous manual transmission used in a variety of vehicles but is highly used in motorcycles and high-performance racing cars.

If you have ever ridden a motorcycle you know that the manual transmission in a motorcycle is nothing. You shift hears by clicking a lever up or down with your toe. It is a much faster way to shift. This type of transmission is called a sequential gearbox or sequential manual transmission.

How to change gears in Sequential Manual Transmission?

In a car with a manual transmission, you shift the car through the gears in each pattern. The top left position is first and then you move straight down to the second. To get the third you shift up to the right and up again. The fourth gear is straight down from the third. Another right and upshift for the fifth gear and down for the reverse gear. This is exactly what you do in the manual.

But in sequential transmission gears must be selected in order as it will not allow you to skip any gear like a traditional manual transmission. The method of switching gears is unique to this transmission where a selector shaft is used to upshift or downshift. In a vehicle with a sequential gearbox, you just hit a lever or a paddle to click through each of the gears in order of whether you are upshifting or downshifting.

Difference between the manual and sequential manual transmission:

A sequential gearbox works the same way as a regular manual gearbox. There is still a set of gear selector forks that move collars to engage gears. The only difference is the way the control rods operate. In sequential, the h pattern is eliminated and replaced with a different motion. In vehicles, with a sequential gearbox, the driver either pushes the lever forward or pulls backward to shift up or shift down it depends on the type of gearbox of the vehicle.

How to shift gears in sequential manual transmission:

If you are in second gear and you want to go to third gear you simply need to pull the shift lever backward and to go from third to fourth you need to pull the lever backward again. To go from fourth to fifth you press it backward again. It is the same motion every time you change gears. To drop back down a gear say from fifth to fourth you push the lever forward. In formula one cars there are two paddles on the sides of the steering wheel instead of a shift lever. The left paddle upshifts while the right paddle downshifts. On a motorcycle, you do the same thing but instead of moving a lever back and forth with your hand, you move a lever up and down with your foot.

Why do race cars use sequential manual transmission?

There are four main reasons for this preference.

  1. The sequential shift is quicker. For example, if you want to go from second gear to third gear on the H pattern you have to push the lever up over and up again which takes time but on a sequential transmission works you simply push the lever up for every gear you change.
  2. The sequential shift is consistent you don’t have to think let’s see we are in second gear so we have to go up over up to get to third. It’s confusing sometimes but in sequential you simply push the lever forward. It’s the same motion for every gear you change.
  3. The sequential shift has no surprises. If you miss a shift with the H pattern in a race for example downshifting to second when you meant to go to fourth. It is possible to blow up the engine that can never happen with a sequential gearbox.
  4. The other advantage is that the sequential shift lever takes up less space in the car cockpit. You only need space for the forward and backward motion of the lever not left and right.

Nearly all race transmissions use the sequential shift approach the drum is rotated manually by a lever in the cockpit or it is rotated by solenoid pneumatics or hydraulics that are activated electronically. In the electronic case, the driver has a pair of paddle switches on the steering wheel to control the machine and never has to move his hands from the steering wheel. Because of the advantage of the sequential approach this type of transmission is starting to appear on cars in the high-end tuner market.

A sequential manual transmission is not to be confused with a Trip tonic sort of automatic transmission. The trip tonic system duplicates the shift lever motion of the sequential gearbox. However, a trip tonic transmission is an automatic transmission at its core. It still has the torque converter and usually does not shift as quickly.

How do sequential works in bikes?

Sequential transmission works are the norm with motorcycles but they are quite rare with cars. Most motorcycles have a non-synchronized 5 or 6-speed gearbox with a manual clutch. The gearbox is operated with a gearshift lever which is moved with your foot. So to shift up a gear you open the clutch put your foot under the lever and pull it upwards until it stops then you release the clutch again. To shift down a gear you push down the lever.

If you are a little bit experience shifting up is also possible without the clutch just put some load on the lever then briefly close the throttle. The dry train gets unwinds for a moment and the next gear kicks in. to shift down without a clutch, you need to have a very much feeling for adjusting the motor speed. For that reason, the industry has developed quick shift mechanisms which allow shifting up and down without a clutch.

A sequential gearbox has one odd problem. You cannot see which gear is engaged by the position of the gearshift lever but most modern bikes have a gear indicator in the cockpit which shows the gear that is currently engaged.

Are sequential better than others?

As you can see many high-performance cars uses dual-clutch transmission that’s because they offer smooth performance and lightning-fast shifts, especially at high speeds.

Sequential is faster than DCT transmission. Sequential is significantly lighter and often more compact and most important the dual-clutch uses helical style gears and a sequential has straight cut gears meaning less power loss traveling through the transmission into the axles. It also uses dog teeth connectors to get from one gear to another forcing the gears together instead of smoothly transitioning from one to another. Dog gears reduce less power than synchromesh ones.

Because of these benefits, sequential transmissions work are still commonly used in racing. Also, every manual-shifting motorcycle has a sequential gearbox.

You can also read this: How does a Differential Work

Advantages of sequential manual transmission:

  • Shifting gears is easier.
  • The sequential gearbox does not require you to stop or slow down to change gears. Thus you can increase or decrease your speed without stopping or experiencing a drop in speed.
  • The mechanism is uncomplicated.

In an H pattern shifter, you have to be extremely dexterous to operate the gears.

  • In a sequential gearbox you simply push the lever upwards or downwards and the gear will have changed.
  • You do not have to overthink and keep the gears in mind because of the simplicity of the mechanism.
  • Gears changes occur sequentially.
  • Jumping gears is impossible since you do not have direct access to each gear as in a manual transmission
  • Smoother shifting.

A sequential gearbox also prevents you from jumping gears when you are upshifting or downshifting. With a manual transmission, you can skip right from to fourth gear if you want though you will likely get some pushback from the car.

  • With a sequential gearbox you have no choice but to skip gears.
  • You have to move through each gear and you will enjoy much smoother shifting and performance.

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