One of the most important things when setting up a go-kart is an optimal gear ratio. An optimal gear ratio allows you to get the most out of your kart when driving on a circuit. Gear ratio directly affects acceleration and top speed, which is a crucial element in corners and straight sections.
However, finding the optimal translation may not always be that easy and you will definitely need some tools. To help you with this I have created a Go Kart Translation Chart and Speed Calculator. I've also included guides and tips to help you find the optimal gear ratio for your go-kart.
- Gear Ratio and Speed Calculator
- Gear Ratio Chart
- What is a gear ratio?
- How are gear ratios calculated?
- Calculation of maximum speed with gear ratios
- Best gear ratio for go-karts
1. Gear Ratio and Speed Calculator
By entering the engine speed, engine pinion gearing, axle pinion gearing and tire height, you can easily calculate the desired gear ratio and top speed for your go-kart. There is also an option to activate an intermediate shaft if you use a torque converter instead of a clutch.
How to use Gear Ratio and Speed Calculator
There are four values that you must enter or select to allow the calculator to determine your go kart's top speed and gear ratio. If you have an intermediate shaft, two optional values are required. For more information, see the description below.
Required Values:engine speed- The highest RPM value of the engine (e.g. select 3500 if the range is 2800 to 3500). You can find this value in your user manual.engine sprocket(Teeth) - The number of teeth on the engine/crankshaft sprocket. If you are running a clutch, use the number of teeth on the clutch sprocket instead.axle sprocket(Teeth) - The number of teeth on the sprocket that is on your rear axle.tire height(diameter) - The height of yourGo Kart Tires(Take the first number, for example:11x 6.00 - 5). For more information, see the guide onhow to read go kart tire sizes.Optional values:Intermediate shaft input pinion(Teeth) - The number of teeth on your intermediate shaft's input pinion gear (leading from the engine to the intermediate shaft) -OptionalOutput pinion of the intermediate shaft(Teeth) - The number of teeth on the output sprocket of your intermediate shaft (leading out of the intermediate shaft to the rear axle) -Optional
2. Translation table
Here is a comprehensive go kart gear ratio chart that takes into account the most common sprocket sizes. This table shows the gear ratio for engine pinion sizes from 8 - 20 teeth and axle pinion sizes from 50 - 110 teeth.
How to read the translation table
Reading the translation table is relatively easy. The top row refers to the number of teeth on your go kart's motor sprocket. If you're using a clutch, you'll need to refer to the clutch sprocket instead. The range is from 8 to 20 teeth)
The first column on the left indicates the number of teeth on the rear axle sprocket. The range goes from 50 to 110 teeth. To find the gear ratio, locate the number of teeth in both the top and left columns and track the ratio accordingly.
Example:A go-kart with a motor/clutch pinion (12 teeth) and a rear axle pinion (75 teeth) has a gear ratio of6.25or6,25:1.
3. What is a gear ratio on a go kart?
By understanding the importance of optimal gear ratios, you can maximize the efficiency and power output of your go-kart. Finding the right gear ratio also allows you to increase or decrease the go-kart's output torque and top speed.
Let's go into a bit more detail on what a gear ratio is and how you can easily understand the concept. A typical racing go-kart has two sprockets, one on the crankshaft (or clutch) and the other on the rear axle.
Let's go through an example. Both sprockets have the same number of teeth. This would mean that for each revolution of the first sprocket, the second sprocket would turn the same amount since they are exactly the same size. In this example, the rear ratio is 1:1.
Now look at the picture above. The pinion on the engine/clutch (B) has 12 sprocket teeth and the rear axle sprocket (A) has 36 teeth (three times as many teeth). This would mean that the first sprocket would need three full revolutions for the rear sprocket to complete one. Here the translation is 3:1.
Do all go karts have gear ratios?
Every go-kart has an excellent transmission because the engine transfers power from the crankshaft to the rear axle through at least two sprockets. Technically you could have two sprockets of the same size, but that would tear your clutch and chain apart as there is just way too much torque.
As such, go kart racers typically opt for a higher gear ratio so they can effectively balance performance and component wear. You are also able to calibrate go-kart acceleration and top speed (important for corners and straight sections). In general, the lower the gear ratio, the higher the top speed of a go-kart.
4. How are go-kart gear ratios calculated?
Determining the gear ratio on your go kart is easy. All you have to do is divide the number of teeth on the rear axle sprocket by the number of teeth on the clutch/motor sprocket.
transmission ratio= Teeth on axle sprocket / teeth on clutch or engine sprocket
For example, a go-kart has a 12-tooth clutch sprocket and a 54-tooth rear axle sprocket. Simply divide 54 by 12 and you have the gear ratio, which in this case is 4.50:1.
5. Maximum speed calculation with gear ratios
If you know the gear ratio, RPM and tire height, you can also calculate the top speed of your go-kart. I'll spare you the somewhat complicated calculations, but you can use thoseGear Ratio and Top Speed Calculatorthat I created for this. Here's a quick summary of the information you'll need:
- Engine/clutch sprocket teeth
- Rear axle sprocket teeth
- tire height (diameter)
- Maximum engine speed
You can also use the go kart speed calculator and work backwards to find the optimal gear ratio. This means you can see the desired speed you are aiming for and adjust the sliders on the sprockets to determine which gearing you should go for. Make sure to activate the jackshaft function when using a jackshaft on your kart.
A word of caution! You also need to consider the additional stress on your go-kart parts the lower you configure your gear ratio. While a lower gear ratio equates to higher top speeds, you don't want to ruin your kart. Therefore, it is best to take small steps through trial and error.
6. What is the best gear ratio for go karts?
Here's the thing, there's no such thing as a "golden gear ratio" that everyone can give you. However, there are certain areas where it will be most likely. The reason for this is that every go-kart is different.
The optimal gear ratio for go-karts not only depends on the engine speed, the tire height and the number of teeth on both pinions, but also on your gearbox and go-kart type as well as the construction of your go-kart and what purpose it serves.
For racing go-karts, you can use the table below as a general reference.
|2-Stroke Engine||18:1 bis 15:1||15:1 bis 12:1||12:1 bis 8:1|
|4-Stroke Engine||10:1 bis 8:1||8:1 bis 6:1||6:1 bis 4:1|
I want to reiterate that you should do all your testing in small increments and keep a close eye on your go-kart's performance and parts. The best results come from practice, attention to detail, and lots of trial and error. All the best!
How do you calculate go-kart gear ratio? ›
To determine your gear ratio, simply divide the rear axle sprocket by the clutch sprocket, so in the case of the above example, 60 divided by 12.What is the best gear ratio for go karting? ›
A buzzword in go-kart gear ratios is the 6:1 ratio. While this isn't optimal for every track, a 6:1 gear ratio provides your go-kart with enough top speed on the long straights and acceleration on the exit of tight corners.How fast will a 13hp go-kart Go? ›
13hp top speed of up to 100km/h.How fast is a 23 hp go-kart? ›
The motors can rev up to 14,000 rpm and reach speeds of 110km/h plus up the straight.What is a 5.2 1 gear ratio good for? ›
The low gear ratios like 5.2:1 and 5.3:1 are great for fishing baits that pull hard like deep crankbaits, big swimbaits, and deep water spinnerbaits. The low gear ratio helps you reel the bait slower, keeping it in the strike zone longer when fishing moving baits in the deep water.How fast is 169cc go-kart? ›
The RPS 200 169cc Falcon Go Kart features a 169cc, single-cylinder, four-stroke, horizontal type, air-cooled motor. It has CDI ignition and an automatic transmission with belt and chain drive. Top speed on the Falcon Go Kart is 37 mph on 21” front tires and 22” rear tires.Can a go kart go 100 mph? ›
Karts vary widely in speed and some (known as superkarts) can reach speeds exceeding 161 kilometres per hour (100 mph), while recreational go-karts intended for the general public may be limited to lower speeds.Is 50 mph fast for a go kart? ›
Most karts max out around 40-50mph, while this is a maintained speed that is safe and as controlled as you can be. It's a speed that is comfortable in the sense of you wont fly off the track, and hurt other racers or patrons. At LVGP ours max out at around 45mph.How fast is a 7.5 hp go kart? ›
The Cheetah 8 equips with 208cc, 7.5 HP horizontal OHV Engine; Torque converter CVT transmission allows this beast takes off with ease. Its top speed can reach up to 32M/H. The manual choke allows this unit to start easy even under cold temperatures.How fast is a 9.5 hp go kart? ›
4 Stroke engine about 9.5 hp and almost zero engine maintenance. Ages 7 to Adult - 60 MPH Top Speed.
Can a go kart go 70 mph? ›
The top speed of a go-kart is around 50-80 mph (80-129 km/h), but some go-karts can reach speeds up to 140 mph (225 km/h)! Even my Supermoto bike doesn't go that fast. A go-kart's top speed, however, is impacted by several factors, like the engine size, the kart's weight, and the aerodynamics.How fast is a 100 hp go kart? ›
The fastest go-karts in terms of speed are 250cc 2-stroke superkarts. These come with a 2-cylinder engine, and they can produce up to 100hp. They have a top speed of 130-140mph (209-225 km/h), but some have reached higher speeds when tuned.What gear ratio gives more speed? ›
A lower (taller) gear ratio provides a higher top speed, and a higher (shorter) gear ratio provides faster acceleration. . Besides the gears in the transmission, there is also a gear in the rear differential. This is known as the final drive, differential gear, Crown Wheel Pinion (CWP) or ring and pinion.Does a smaller rear sprocket make you go faster? ›
A bigger rear sprocket/ smaller front sprocket will give you an increase in acceleration but decrease your top speed. A smaller rear sprocket/bigger front sprocket will reduce you acceleration but increase the top speed.What gear ratio is best for acceleration? ›
Shorter gears (higher numbers) are much better suited for accelerating, such as 3.55, 3.73, 3.91's, 4.11's etc. Always remember, for very “give” there is a “take”. If you take lower gears to accelerate quickly from 0-60, you will give top-end speed.What is a 7.0 1 gear ratio good for? ›
So, buying a reel with a 7.0:1 gear ratio, which retrieves line pretty quickly, might be good for covering lots of water with a spinnerbait to locate active fish.What is a 6.2 1 gear ratio good for? ›
6.2:1 to 6.5:1 – We personally use this speed range anytime we are tossing spinnerbaits, throwing jerkbaits, shallow running and lipless crankbaits, early season swim jigs, vibrating jigs and swimbaits / umbrella rigs.What is a 7.5 1 gear ratio good for? ›
7.5:1 Reel - With my 7.5:1 gear-ratio reel, I like to use this reel when I'm fishing single-hook lures like a buzzbait, a spinner bait, bladed jigs and a frog.How fast is a 1000w go kart? ›
Not only just have fun on the fast speed up to 20 mph, but also enjoy that sense of smooth while parking. FRP go karts for kids offer you a smooth ride & parking experience with a foot brake & disc brake.How fast is a 250 cc go kart? ›
250 National is for single cylinder karts with five- and six-speed boxes. Typically these karts produce 48 kW (65 hp) and are capable of 210 km/h (130 mph).
How fast is a 120cc go kart? ›
And last but not least we have our 120cc Biz Cadet Karts capable of speeds up to 39mph.What is the easiest way to determine gear ratio? ›
Divide the number of driven gear teeth by the number of drive gear teeth. In our example, it's 28/21 or 4 : 3. This gear ratio shows that the smaller driver gear must turn 1,3 times to get the larger driven gear to make one complete turn.How do you calculate gear ratio with rpm and speed? ›
Here's the formula for calculating gear ratio: (RPM x Tire Diameter Inches) / (Final Drive Ratio x Transmission Gear Ratio x 336) = Actual numerical gear ratio to the ground from every revolution of the engine.What is the formula for speed ratio? ›
The Speed Ratio (arm/plate) is therefore often defined as(4.1)Speed Ratio=Major Axis(rpm)Major Axis(rpm)−Major Axis(rpm)Thus if the minor axis speed reading on the machine is 15 rpm and the major axis speed is 12 rpm, then the Speed Ratio (arm/plate speeds) is 4:1, which is a common ratio.What gears for what speed? ›
First gear—0 to 10 mph. Second gear—10 to 20 mph. Third gear—20 to 30 mph. Fourth gear—30-40 mph.Is it better to have a higher or lower gear ratio? ›
Gear ratios can be boiled down to a single statement: Higher ratios (with a lower numerical value) give better torque/acceleration and lower ratios allow for higher top speeds and better fuel economy. Higher ratios mean the engine has to run faster to achieve a given speed.How many rpm is each gear? ›
Generally, you should shift gears up when the tachometer is around “3” or 3,000 RPMs; shift down when the tachometer is around “1” or 1,000 RPMs. After some experience with driving a stick shift, you'll be able to figure out when to shift by the way your engine sounds and “feels.” More on that below.What is the ratio of rpm and speed? ›
To convert from gear rpm to gear speed in rad/s: multiply gear rpm by π/30. Gear rpm indicates how many rotations a rotating object makes per minute. To convert from gear speed in rad/s to gear speed in rpm: multiply gear speed in rad/s by 30 / π 30/\pi 30/π.What is a 5 to 1 gear ratio? ›
The driving gear has fewer teeth than the driven gear. For example, if a motor drives a 12T gear to a driven 60T gear on an arm, the 12T driving gear has to rotate 5 times to rotate the 60T driven gear once. This is known as a 5:1 ratio.How do you calculate speed from rpm and wheel size? ›
Vehicle speed = Wheels RPM × Tire diameter × π × 60 / 63360 , where: π is the circle constant; it represents the ratio between the tire's perimeter and its diameter; 60 is the number of minutes (from "rounds per minutes") in an hour (from "miles per hour"); and.
What are the 3 formulas for speed? ›
The formula can be rearranged in three ways: speed = distance ÷ time. distance = speed × time. time = distance ÷ speed.What are the 3 equations for speed? ›
The three equations are, v = u + at. v² = u² + 2as. s = ut + ½at²What is the formula for fastest speed? ›
The general speed formula for an object is given as [Speed = Distance ÷ Time]. SI units of speed is m/s.