What is Downshifting?
Put simply, downshifting on a motorcycle is when you shift into lower gears. However, rather than to slow the car down, downshifting is typically done to preserve speed when cornering and, if done right, ensures that you have maximum power to accelerate again after turning the corner.
Therefore, downshifting is the process of shifting your motorcycle into lower gears to lose as little speed as possible during cornering. But how does it work?
To understand how downshifting works to preserve speed, we need first to understand how a motorcycle’s transmission system works. Lower gears, like first or second gear, provide more torque, and hence more power, but lower top speed. Conversely, higher gears, like fourth or fifth gear, provide less torque, hence less power, but greater top speed.
Therefore, your motorcycle can very quickly reach around 30mph when in a lower gear but cannot exceed this. The higher the gear, the slower the vehicle will accelerate, but the speed it will maintain will be higher.
A motorcycle can hence travel at 30mph in both second and third gear. However, the RPM (revolutions per minute) at second gear will be around 4000, while at third gear, it will be around 1500 RPM.
Therefore, downshifting is a way of bringing your transmission system into a higher RPM without slowing down. For this reason, there is a right way of downshifting and a wrong way. To perform downshifting correctly, you will have to understand rev-matching.
Downshifting vs. Engine Braking
Many people use the terms downshifting and engine braking interchangeably. However, these two terms are different in a very important way.
Downshifting is the process of shifting into lower gears to preserve speed while cornering. Lower gears have more power and hence allow the motorcycle to quickly accelerate once again after cornering.
On the other hand, engine braking is the process of disengaging the throttle to slow down your vehicle without using the brake pads.
These two terms are often confused with one another because downshifting incorrectly can cause engine braking, which is an unnatural way to slow down and can be harmful to your motorcycle.
What is Rev Matching?
As mentioned, downshifting is a way of shifting your motorcycle into a lower gear, or a higher RPM, without losing too much speed. However, to perform downshifting correctly in a way that does not harm your vehicle, you must also perform rev-matching.
Rev matching is the process of cranking up your RPM using the throttle in preparation to downshift your motorcycle. Rev matching is the correct way of downshifting because it ensures that the RPM of your vehicle is high enough for the lower gear to take over in a smooth transition. This prevents unnatural locking of the engine, which causes jerking.
In technical terms, rev-matching is a way to match the rotation speed of the clutch disk with the rotation speed of the pressure plate that is bolted up to the flywheel. The clutch disk rotates with the transmission while the pressure plate rotates with the engine.
Therefore, by cranking up the throttle and increasing the RPM of the pressure plate in preparation for downshifting, you are essentially matching the RPM of the pressure plate with the RPM of the clutch disk in the lower gear, thereby allowing the two speeds to line up in a smooth transition.
Pros and Cons of Downshifting
The main pro of downshifting has already been established in this article: it helps to provide sufficient power after cornering to accelerate again quickly. Meanwhile, downshifting has no cons as long as it is done correctly (read: with rev-matching).
Having said that, there are some other pros and cons of downshifting that need to be considered, especially when compared with regular braking.
Pros of Downshifting
Here are some of the pros of downshifting:
Saves the Brake Pads
By leaving the braking pressure to the engine and the transmission, you are saving your brake pads from doing any work and, are hence, ensuring that you won’t need to replace them for a while.
Maintains the Gear
Downshifting keeps your motorcycle in gear at all times, which means you can quickly accelerate in the middle of slowing down in the event of an emergency.
Great for Downhill
Regular braking when going downhill can cause brake pads to overheat. Meanwhile, downshifting while driving downhill is a much safer way to maintain a lower speed.
Cons of Downshifting
Here are some of the cons of downshifting:
If done incorrectly, downshifting will put unnecessary pressure on the clutch disk, thereby causing potential damage.
Clutch Replacement Difficulties
Repairing or replacing a clutch disk is much more difficult than doing the same for brake pads.
Clutch Issues Often Remain Undetected
While brake pads are expected to be replaced every so often, the same cannot be said about the clutch disk. Usually, clutch damages remain undetected, thereby making total clutch failure a possibility while riding.
About THE AUTHOR
Russ currently owns a Yamaha FZ6N and KTM RC 390. When it comes to vintage bikes, his favorite motorcycle is the feisty BMW R32. He also holds a particular interest in the LAMS segment and triple cylinders. Himself a riding enthusiast, Russ has had experience with racetracks from around the world including Willow Springs Raceway in California and the Imola Circuit in Italy.Read More About Russ Crowley