Motorized Bicycles 101: Top End Speed vs Low End Torque

Customized motor-ready bike with 2-stroke engine, high-performance exhaust, and high-performance cylinder head.The top end speed and low end torque of your motorized bicycle are both important factors in determining its overall performance. As a rider, you might have different needs.

Maybe you commute to work in an area with a lot of steep hills. Or maybe you’re part of a competitive racing circuit or off-road club. In any case, it’s important to keep top end speed and low end torque in mind when factoring your motorized bike engine’s performance.

Boosting either speed or torque can be beneficial in different ways, depending on what effect you want to achieve and how you’ll be using your motorized bike.

In this all-in-one guide to top end speed and low end torque, we’ll break down the differences between the two. We’ll also give you some tips for increasing either one of them or both.

Table of Contents

  1. Top End Speed vs. Low End Torque: What’s the Difference?
  2. What Is Top End Speed?
  3. How to Boost Your Motorized Bike’s Top End Speed
  4. What Is Low End Torque?
  5. How to Boost Your Motorized Bike’s Low End Torque
  6. Motorized Bikes: Speed vs. Torque
Alright, let’s talk about speed vs. torque. Once we’re finished here, you’ll know exactly how to get the most out of your motorized bike’s 2-stroke engine!

Top End Speed vs. Low End Torque: What’s the Difference?

Custom-made 2-stroke high-performance motorized bicycle.The difference between a motorized bike’s speed (or horsepower) and torque can be difficult to understand.
  • Top End Speed and Low End Torque — Both speed and torque have to do with the work your 2-stroke engine is doing. In general, scientific terms, that work is the result of a force acting over a distance.
    • When it comes to your 2-stroke motorized bike, the work being done is basically the bike getting from point A to point B. In order to get from point A to point B, your engine exerts a certain amount of force (this is torque) at a certain rate (horsepower), which determines how quickly you get there (speed).
  • Speed Explained — Speed is determined by the horsepower of your engine, which is the rate at which the work is actually done.
  • Torque Explained — Torque comes down to the amount of work your engine is able to exert.
As you can see, top end speed and low end torque are interconnected and affect one another, but they are not the same thing. It’s easier to understand exactly how they differ if we look at the actual definition of both of them, so we’ll go into detail and break them both down.

What Is Top End Speed?

2-stroke motorized bike with custom exhaust system for increased performance.Essentially, the top and speed of your motorized bike refers to the maximum speed it can reach. It’s really as simple as that. While a good amount of torque can give you a boost in your speed, your top end speed really comes down to horsepower: The higher the horsepower, the higher the speed. Your bike’s top end speed will also be affected by its weight and drag force, which is determined by the air and tires. Eventually, your motorized bicycle engine will not be able to work quickly enough to overcome the drag force — that’s when you’ll reach the highest speed you can go. You won’t be able to go faster than that — as such, that is your engine’s top end speed.

How to Boost Your Motorized Bike’s Top End Speed

36 Tooth Rear SprocketDepending on what you’re looking to get out of your motorized bicycle, there are plenty of reasons to increase your top end speed.
  • Motorized Bike Racing Circuit — If you’re going to be racing on your motorized bicycle, you’ll want a fast vehicle. Increasing top end speed will let you get the edge over your competition.
  • Faster Commuting — When you have a lot of ground to cover, or if you just like getting to your destination fast, increased top end speed will work wonders for your commute.
  • Speedy Leisure Riding — Even if you just prefer to get those high speeds to go as fast as you can on your joyrides, you’ll probably want a faster motorized bike. Boosted top end speed will get your adrenaline pumping if you’re just looking for a fast, fun ride.
Blue high-performance carburetor air filter for 2-stroke engines.There are a few ways you can achieve better speeds. This usually requires swapping out your stock components and upgrading to high-performance 2-stroke engine parts. If you want to boost your motorized bike’s top end speed, keep the following tips in mind.
  1. Install a Smaller Rear Sprocket — Gearing up with a smaller rear motorized bike sprocket with fewer teeth will help boost your speed.
    • 36 Tooth Rear Sprocket (Price: $23.95) — A small 36 Tooth Rear Sprocket is the easiest way to get faster speeds. Great if you want a simple installation and instant boost in speed.
    • Note: Gearing up would sacrifice some of your lower end torque, so you’re essentially trading better acceleration for faster speed.
  2. Stainless mesh fuel filter for 2-stroke motorized bikes.Use Fuel and Air Filters — Filters can increase your bike’s top end speed by promoting cleaner air and better intake and flow in your engine.
    • BBR Tuning Speed Carburetor Air Filter (Price: $24.95) — Air filters will allow larger amounts of cleaner air to flow into your engine.
    • Stainless Mesh 1/4 Performance Fuel Filter (Price: $9.95) — Fuel filters will work to purify your fuel before it reaches your engine, giving your bike more efficient combustion.
    • Note: Premium gas is another great option since it naturally runs cleaner and has less debris. That said, it can be significantly pricier than standard gas.
  3. BBR Tuning High Performance Voodoo Muffler Expansion Chamber for 2-stroke engines.Upgrade Your Exhaust System — A high-performance exhaust is great because it can increase both speed and torque. It does so by improving your engine’s air intake and exhaust circulation.
  4. Install Lightweight Parts — Since your motorized bike’s top end speed is affected by its weight, switching to lighter parts is also a good idea. This will decrease the drag force and allow you to go faster as a result.

What Is Low End Torque?

2-stroke stretch motorized bike with high-performance cylinder head and exhaust.When we talk about torque in a motorized bike engine, we’re referring to the engine’s rotational force. In other words, the amount of force required for your engine to rotate, and therefore the amount of force that is available at the engine’s crankshaft.

Torque comes down to the amount of work your bicycle engine is able to exert and how much force it can produce. As previously mentioned, this isn’t the same as speed, but it does have a lot to do with acceleration.

That’s because torque measures the amount of force your engine needs to reach a certain speed, and how easily it can produce that force. The more torque an engine produces, the more ability it has to perform work.

When it comes to low end torque specifically, that has to do with how much force your engine can exert in order to produce a rotation at lower revolutions per minute (RPMs).

That said, it will eventually level off. This is the alternative to high end torque, which gives you less of a boost in lower RPMs but increases over time and speed.

The stronger your low end torque is, the faster you can accelerate when you first start riding, because it’s able to exert more initial force right away. This is especially helpful for everyday leisure riding or getting around town (as opposed to racing) because it gives you higher torque within the RPM range you’ll typically be riding at. It’s also really beneficial for off-roading on hilly, uneven terrains.

How to Boost Your Motorized Bike’s Low End Torque

54 Tooth Sprocket for motorized bikes.There are a lot of benefits to having a motorized bike with strong low end torque. Good torque allows you to accelerate faster at lower RPMs. This is great for a number of reasons and suits a lot of different needs.
  • Going up Inclines — If you ride on hilly terrain frequently, you should try to get more low end torque out of your engine rather than boosting your top end speed. This is because low end torque can give you the boost and acceleration necessary to take on steep inclines. The ability to accelerate at lower RPMs will help you get over hills even if you aren’t going at high speeds.
  • Off-Roading — The more low end torque your bike has, the more responsive it is to throttle. Stronger torque will give you the most beneficial boosts while on loose gravel or other types of off-road terrain.
  • BBR Tuning Dual Ended Torquer Up Exhaust Pipe MufflerSteady Riding and Commuting — With the right components, you won’t have to rev up too much or go very fast in order to reach your bike’s peak. Torque also prevents you from having to shift gears as often as you normally would. That makes for a more relaxed and enjoyable riding experience if you’re just going for a cruise. It’s also great for fuel efficiency.
You have a few different options when it comes to parts that will help increase your motorized bike’s low end torque. Note the following tips and components if you want to increase acceleration on your motorized bicycle.
  1. Install a Larger Rear Sprocket — Gearing down with a large sprocket that has a lot of teeth is one of the most sure-fire ways to improve your motorized bike’s torque.
    • 54 Tooth Sprocket (Price: $29.95) — A large rear sprocket changes your gear ratio to improve your motorized bike’s acceleration.
    • Note: Gearing down will result in an overall loss of top end speed.
  2. BBR Tuning Reed Valve Kit - 40MM for 2-stroke motorized bikes.Upgrade Your Exhaust and Intake Systems — Another thing you can do to increase torque is upgrade your motorized bike’s exhaust and intake systems. You can do this with a reed valve, muffler, header, or manifold. The key is to get the air that enters your engine as clean as possible.
    • BBR Tuning Dual Ended Torquer Up Exhaust Pipe Muffler (Price: $75.99) — This exhaust system is a huge step up from your motorized bike’s stock pipe. By using up excess exhaust that would otherwise be wasted, it provides a boost to your ride that you’ll notice immediately.
    • BBR Tuning Reed Valve Kit (Price: $31.95) — A reed valve controls the air/fuel mixture that flows to your bike’s cylinder by opening and closing on the engine’s vacuum, thus preventing engine blowback to the carburetor. This will also work to improve your engine’s top end speed, so it’s a win-win if you’re looking to increase torque without sacrificing speed.

Motorized Bikes: Speed vs. Torque

Custom-made 2-stroke motorized bicycle.The difference between speed and torque may take a little work to understand at first. Once you know how they both function, though, you can start working on making the necessary changes in order to get the best possible performance out of your motorized bicycle. There’s no reason you shouldn’t have a motorized bike that meets all your riding needs, no matter how you plan to use it. Maybe you want to reach top speeds to beat the competition in a race. Or perhaps you want to take on steep inclines and hilly rides. Or who knows? Maybe you just want a motorized bike with top notch performance to ensure you get to work quickly. Whatever the case may be, with the information in this article, you’re now equipped with the knowledge to adjust your bike’s 2-stroke engine so that it works exactly how you want it to.

Leave a comment

All comments are moderated before being published