Calculation of gear ratios with Rohloff SPEEDHUB (2023)

New Rohloff users often wonder what size front or rear sprockets to use on a SPEEDHUB 500/14 or how to compare different Rohloff gear setups with a derailleur bike. The SPEEDHUB's internal gear ratios and the size of the front and rear sprockets make it easy to compare Rohloff gears to external gears.

This is what you should do:

Multiply the outer (primary) gear ratio (front sprocket teeth divided by rear sprocket teeth) by the inner gear ratio (from the table below) to get the total ratio for a given gear selection . This overall gear ratio can be directly compared to a specific derailleur or single speed drivetrain combination, provided the same wheel size and crank length are used. If these factors also differ between the two bikes you're comparing, there are other resources below that offer more in-depth powertrain comparisons.

In practice, a comparison of high and low gears is usually sufficient to determine if a particular configuration provides the desired high and low gears. Note that this calculation is the same whether you are using a chain or a strap.

If you are not familiar with the concept of gear ratios, the following articles provide useful background information:

(Video) What's The Ultimate Bicycle Gearbox? Rohloff Hub VS Pinion Gearbox

This diagram shows the internal gear ratio for each of the 14 gears on a SPEEDHUB:

Gang #

internal relationship





























The overall gear range of the SPEEDHUB is 526% (1.467/0.279), which is quite wide and wider than most current derailleurs. This means that when using a Rohloff hub there is a bigger difference between the easiest and hardest gears than on most derailleur bikes. You can choose to have the extra reach on the high or low end, or split the difference based on front and rear sprocket size options.

Calculate high and low ratios in your Rohloff

As an example, let's say you set up your new Rohloff-equipped bike with a 40-tooth front sprocket and a 16-tooth rear sprocket. Your external (primary) gear ratio with such a setup would be 2.5 (40/16 = 2.5). Looking at the graph above, we can see that the internal ratio is 0.279 for the #1 gear and 1.467 for the #14 gear. Multiplying the primary ratio by the internal ratios of the upper and lower gears gives the following high ratios and low:

Highest Ratio: 2.5 * 1.467 = 3.668
Lower ratio: 2.5 * 0.279 = 0.698

(Video) tout terrain Pinion + Rohloff Testing - 3000% gear range

These numbers can now be directly compared to derailleur combination ratios to compare the toughest and lightest gears.

Calculation of transmission ratios with change gears: Example 1x11

Let's say you have a 1x system with a 30t sprocket and a 10-42t cassette. This setup offers 420% overall gear range (42/10), which is less than Rohloff's 526%. To calculate high and low gear ratios with a derailleur system, simply divide the number of teeth on the front sprocket by the largest and smallest cassette sprockets. In this case we obtain the following high and low ratios:

Highest ratio: 30/10 = 3000
Lowest Ratio: 30/42 = 0.714

Comparing these numbers to the Rohloff example above, the Rohloff setup offers a harder/faster gear (3.668 vs 3.0) and an easier/slower gear (0.698 vs 0.714) than the derailleur system.

How do all these numbers affect your choice of sprockets for Rohloff?

If you thought the high gear of the derailleur setup was fast enough (3000) and wanted an easier gear for climbing, downsize the Rohloff system front sprocket from 40 teeth to 33 teeth (2063 primary ratio). It would help to high match the derailleur setup gear and lower the low ratio to 0.575. If the low gear of the derailleur setup was light enough (0.714 ratio) and you want more top end gears, increasing the Rohloff system front sprocket size to 41 teeth (2.563 primary gear ratio) would match Match the low gear ratio of the derailleur setup and increase the high ratio to 3.759.

Another example: Rohloff comparison with 1x12 gears

(Video) Are $199 Shimano Alfine Internal Gear Bicycle Hubs GENIUS or Terrible?

Let's say you have a 1x system with a 30 tooth sprocket and a 10-50 tooth cassette. This gives you 500% overall gear range (50/10), still less than Rohloff's 526%. Using the method described above, we achieve the following high and low ratios:

Highest ratio: 30/10 = 3000
Lowest Ratio: 30/50 = 0.6

Comparing these numbers to the Rohloff example above, the Rohloff setup offers a harder/faster gear (3.668 vs 3.0) but not as low or easier/slower (0.698 vs 0.6) compared to the exchange system.

If the high gear of the derailleur setup was fast enough (3000) and you wanted an easier uphill gear, then downsizing the Rohloff system front sprocket to 33 teeth (2063 primary gear ratio) would match the high 3:1 ratio of the derailleur at the same time. time Reduced the low gear ratio of the Rohloff system to 0.575 (versus the 0.6 gear ratio of the 30/50T derailleur combo).

If the low gear of the derailleur setup was too low and you want more gears on the top end, increasing the front sprocket size of the derailleur system to 35 teeth would match the low gear ratio of the Rohloff setup (0.698 ) and would increase the discharge. derailleur system gear ratio to 3.5.

Another example:

Let's say you have a 3 speed system with 24/34/48 tooth sprockets and an 11-32 tooth cassette. This gives a total gear ratio range of 582% ([48/24] * [32/11]), which is wider than the range of the Rohloff hub, resulting in the following high and low ratios:

Highest ratio: 48/11 = 4,364
Lowest ratio: 24/32 = 0.75

In this example, the derailleur system offers a harder/faster gear (4.364 vs 3.668) and the Rohloff system offers an easier/slower gear (0.698 vs 0.75). If the low gear of your derailleur setup was light enough (0.75 ratio) and you want a higher top end ratio, you can increase the size of the Rohloff system front sprocket to 43 teeth (2.688 primary ratio). to accommodate the low ratio of the To match the front derailleur setup and increase the high ratio to 3.943. If you wanted to match the high gear of the derailleur system (4.364), you would need to increase the front sprocket size to 48 teeth (3,000 primary ratio) to match the high gear of the derailleur system, which would also increase the gear it drops to .837.

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In practice, you're often limited by the available sprocket sizes and need to tune slightly (perhaps 43T isn't available so you should go with 42T or 44T), but in general there are enough sprocket sizes available to achieve almost any combination you want. be practical for cycling. .

General recommendations

If you're not sure where to start, here's a general reference list based on the main translation. You may want to adjust these recommendations for rider strength/fitness, terrain, and payload, but they are a good starting point for those new to using the Rohloff SPEEDHUB 500/14.

1.9-2.3*: mountain biking, fat biking, off-roading with heavier loads
2.1-2.5*: Bikepacking todoterreno
2.4-2.6: Road trips
2.5-2.75: Packing bikes on the road, commuting, riding gravel
2.75-3: Road, fast/fit gravel rider
>3-3.4: fastest/fittest road cyclist

* Please note that Rohloff requires riders weighing more than 100 kg (221 lbs) to use a 2.5 main gear ratio to maintain warranty. All tandems and electric bikes also fall into this category.

online tools

Online gear ratio calculators are helpful in determining what size sprocket to use on the Rohloff SPEEDHUB 500/14. They are programmed to provide gearing information for Rohloff, derailleurs, and other internal systems (shift hubs and gears) and can also be used to compare gear shifting between bikes with different size wheels and/or cranks should you be new in the bike. Consider using a completely new setup. Here are a few we recommend:

We are here to help

At Cycle Monkey, we love helping riders gain a better understanding of the components and gear they use and giving them the chance to experiment and play with their ride setups the way we love. If you have questions about gears, sprocket selection, or how to build a custom bike, write us. If this guide has been helpful, we want to hear from you too! Let us know on ourfacebook site.

(Video) How fast is a bike with an internal geared hub?


How do you calculate gear inches on a Rohloff hub? ›

Here is what you need to do: Multiply the external (primary) gear ratio (front sprocket tooth count divided by rear sprocket tooth count) by the internal gear ratio (from the chart below) to get the overall ratio for a given gear selection.

How many gears does the Rohloff hub have? ›

With 14 gears, it has the same range as a 27 speed Shimano system (which has many doubles). The gears are changed with a grip shift, and different to its counterpart, the gears can be shifted at any time, even while standing. More advantages are: bigger range than a 27 gear system, stronger wheel, low maintainance.

How do you calculate gear range percentage? ›

The percentage figures refer to the gear range of the cassette, or the difference between the highest and lowest available gears. To work out the range of a cassette, you simply divide the largest sprocket by the smallest and then multiply this by one hundred (50 ÷ 10 = 5 x 100 = 500%).

How much torque can a Rohloff hub handle? ›

Limit G510 for Rohloff max torque of 130nm.

How do you calculate hub spacing? ›

If you are unsure of your frame spacing or have an older bicycle, measure the hub width to ensure a proper fit. To do this, remove the rear wheel and use a pair of calipers or a ruler to measure the distance between the inner surfaces of the dropouts.

How long does a Rohloff hub last? ›

Rohloff hubs should get you through a minimum of 100,000km riding before failure; many people have been known to cover far more. The only maintenance that you need to complete is an oil change every 5000km.

Can you put a Rohloff hub on any bike? ›

The main reason I have refrained from compiling this list is that Rohloff hubs can be retrofitted to almost any bike – so any bike can technically be a Rohloff bike! There are many ways to tension the chain, manage the cables or secure the hub in any frame. That said, a dedicated Rohloff bike is very nice to have.

Is Rohloff worth the money? ›

Having used the Rohloff speedhub on my bike now for over nine years, I can honestly say that I am very happy with it. It's one of those bits of gear that has a higher upfront cost, but repays itself over the long run.

How do you calculate gear ratios examples? ›

To calculate the 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 from RPM? ›

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.

How do you calculate overall drive ratio? ›

By simply dividing the ring gear tooth count by the pinion gear tooth count, the ratio is determined. For example, if we divide a ring gear with 41 teeth by a pinion gear with 10 teeth we find that the gear ratio is 4.10:1 (41/10 = 4.10). Tire diameter will also have an effect on a vehicle's final drive ratio.

How fast is a 8000W hub motor? ›

speed of 8000W hub motor is 115km/h. 2) The recommend max. speed is 100km/h at battery voltage 72V. The repair rate is the lowest at this speed configuration.

How fast can a 1000W hub motor go? ›

1000W Ebike can do as little as 22mph as top speed and as much as 45mph! There are different types of 1000w systems.

Are Rohloff hubs noisy? ›

Different noises are noticeable whilst freewheeling depending on which gear you have currently selected. This is due to different parts of the gear mechanism rotating within the hub. It should be also noted that a new Speedhub 500/14 is typically noisier than one that is run in after the first 500-1000 kms.

What is the formula for gear speed? ›

For two given gears, one of number of teeth A and one of number of teeth B, the speed ratio (gear ratio) is as follows: (Speed A * Number of teeth A) = (Speed B * Number of teeth B) When two gears are touching, the force of one gear's teeth exerts force on the teeth of the other gear.

Does hub bore size have to be exact? ›

Wheel hubs, located between the drive axle and brake drums, connect the wheels to the body of the car. Therefore, in order to fit the new wheels correctly, it is important that the car's wheel hub size perfectly matches the wheel's centre bore.

Can I use a 32 hole hub on a 36 hole rim? ›

The hole counts must match. You need to order a 32-hole rim or a 36-hole hub. I recommend the latter. 36-spoke wheels are noticeably stronger than 32-hole ones.

How much play should a hub bearing have? ›

For context, the tolerable end-play for truck wheel bearings is the same: 0.001 to 0.005 inches, also expressed as 1 to 5 mil or 0.025 to 0.127 mm. In other words, it's perfectly acceptable to adjust wheel bearings so that they are just a little bit loose, but not too loose.

How much weight does Rohloff add? ›

– A Rohloff hub is 400 grams heavier than a 2x or 3x drivetrain. – There isn't a big weight difference between 2x and 3x because you need practically the same amount of parts.

Is a louder hub better? ›

In many cases, a louder hub signifies faster engagement, which is part of the reason that those extra decibels are desirable.

Is the Shimano Alfine 11 speed hub filled with oil? ›

The Shimano Alfine Inter 11 internal gear hub uses oil for lubrication. It is recommend you perform this procedure for a new hub after the first 500 kilometers of riding. After this every two years, or 5000 kilometers.

Are ratchet hubs better than Pawls? ›

Ratchet systems are generally spoken stronger, more reliable and need less maintenance compared to traditional pawl systems. Biggest reason for this is that the power transferred from the drivetrain to the wheel is spread of a larger surface. In general hubs that are "louder" usually have more engagement points.

Can you use throttle only on a mid-drive ebike? ›

Yes, you can retrofit a throttle to most e-bikes IF they have a hub-mounted motor and compatible controller, BUT, you will struggle to fit a throttle to an ebike that has a mid-drive motor as it relies on the rider to pedal before the motor would kick in.

Can I put a 7 speed freewheel on a 6 speed hub? ›

If your bike has friction shifting , it will definitely work with either 6 or 7.

Are Alfine gears any good? ›

Shimano Alfine hubs are excellent, and for many people out there, I think they're actually a better option than a Rohloff hub. This is because they're cheaper, quieter and employ trigger or neat drop bar shifters. I especially like the drop bar electronic shifters.

What are Rohloff dropouts? ›

Rohloff Speedhub dropouts.

This set allows you to fit a Rohloff Speedhub in conjuction with Rohloff OEM axle plates – therefore avoiding the need to use Torque arms or Speed bones. Thus creating a VERY neat and economic Speedhub set-up. Rohloff ADS plates are compatible with all current Identiti ADS frames.

How do you calculate rear gear ratio? ›

Count the number of teeth on the pinion gear and count the number of teeth on the ring gear. Divide the ring gear teeth number by the number of teeth on the pinion. The result is your gear ratio.

How do you check gear ratio without pulling cover? ›

With the transmission in neutral, rotate the rear driveshaft by hand. Count the number of driveshaft revolutions required for one revolution of the tire. If the driveshaft turns approximately 3-1/2 times, you have a 3.54 ratio, etc.

How do you find gear ratio with acceleration? ›

Calculating the acceleration of a car
  1. calculating the torque on the wheels: Te/G (engine torque / Gear ratio)
  2. Calculate the Force exerted on the ground: T_w/r (wheel torque / wheel radius)
  3. then finding the acceleration using F=ma.
Mar 24, 2013

How to calculate ratios? ›

Ratios compare two numbers, usually by dividing them. If you are comparing one data point (A) to another data point (B), your formula would be A/B. This means you are dividing information A by information B. For example, if A is five and B is 10, your ratio will be 5/10.

What is the formula for gears? ›

The gear ratio i=d2/d1. d1 and d2 refer to the reference diameters of 2 mating gears (gear 1 is the driving gear, and gear 2 is the driven gear).

Do you add or multiply gear ratios? ›

The compound gear ratio between the driven and driv- ing gears is then calculated by multiplying the gear ratios of each of the individual gear pairs.

How do you calculate axle gear ratio? ›

Divide the number of the ring gear's teeth by the number of the pinion's teeth. This will give you the axle ratio.

What gear ratio is best for 35 inch tires? ›

That's why I run a 4.56 gear ratio with 35″ tires. This gives me decent fuel efficiency at highway speeds, and enough low end power to throttle through difficult obstacles. Below I've outlined a gear ratio chart that cross compares tire size to gear ratio for the ideal RPM.

How fast can a 10000w ebike go? ›

How Fast Does a 10000w Electric Bike Go? An 10000w electric bike can reach speeds of 85mph (137kph) on flat terrain, if no speed limiter is in place.

How fast is 72V 8000w ebike? ›

8000w 72v Adult Electric Off Road Dirt Bike Bomber Mountain Ebike Fast 60 MPH+

How fast is a 5000w hub motor? ›

Top speed: 100-80km/h(65-50mile/h) with 26inch wheel or 29in 700c mountain bike wheel; Huge torque, 155N./M, good ability to climb hills; LCD display shows battery power level, time, speed, mileage, gear.

Is 52V faster than 48V? ›

The Difference Between 48V and 52V Batteries

The difference between the two is power and performance: A 52V battery delivers better performance. A higher-voltage battery provides greater efficiency, with the battery using less electricity to provide the same or better power for the bike.

How fast is 72 volts in mph? ›

The 72-volt battery allows us to keep the same (40 mph) top speed we are known for while maintaining the full torque potential of our new motor system.

How fast can a 3000w hub motor go? ›

It is about 50 mph (80 km/h), a 3000w e-bikes can reach speeds of more than 50 mph.

How many gears does a Rohloff have? ›

The 14 gears are evenly spaced out over this range in 13.6% increases. Through the choice of chainring and sprocket in use, the Rohloff SPEEDHUB 500/14 can be tuned for the specific riding purpose. The Rohloff SPEEDHUB 500/14 comes standard with a 16 tooth sprocket.

How many gears are in a Rohloff? ›

Very simply, a Rohloff Speedhub is a system of 14 gears completely sealed within the rear hub – doing away with the need for front and rear derailleurs, multiple chainrings and rear cassette.

What is the formula for calculating gears? ›

The gear ratio is calculated by dividing the output speed by the input speed (i= Ws/ We) or by dividing the number of teeth of the driving gear by the number of teeth of the driven gear (i= Ze/ Zs).

How is gear module measured? ›

How to Calculate Module of a Gear? Divide the pitch diameter (in millimeters!) of a gear by its number of teeth to get the module of a gear. Alternatively, 25.4 divided by the diametral pitch of the gear will also give you its module.

How is spur gear size calculated? ›

Root Diameter (df) is the diameter of the root circle; its value is: df = m (z – 2.5) or df = de – 2h. Center Distance (dc) is the distance between the shafts of the gear and the pinion; its value is: dc = (D + d) / 2, where “D” corresponds to the pitch diameter of the gear and “d” to the pitch diameter of the pinion.

How do you calculate gear design? ›

The gear ratio i=d2/d1. d1 and d2 refer to the reference diameters of 2 mating gears (gear 1 is the driving gear, and gear 2 is the driven gear).

How do you find gear ratio with speed and RPM? ›

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 speed ratio formula? ›

The speed ratio is defined as the ratio of the large to small pulley size and can be calculated simply by dividing the number of teeth in the large pulley by the number of teeth in the small pulley.

What is gear module formula? ›

m = d / z. Since the unit of the pitch circle diameter is mm, the unit of the module obtained by dividing the pitch circle diameter by the number of teeth is also mm, but in practice, modules are often used with only a number after the m symbol, such as m1, m2, or m4, instead of adding mm to the module.

What is the gear ratio? ›

A gear ratio is the ratio of the number of rotations of a driver gear to the number of rotations of a driven gear. A colon is often used to show a gear ratio: gear ratio = rotations of a driver gear : rotations of a driven gear. For every rotation of the 45-tooth gear, the 15-tooth gear must rotate 3 times.

What is gear contact ratio? ›

The contact ratio is a measure of overlapping tooth action which is necessary to assure smooth, continuous action. For example, as one pair of teeth passes out of action, a succeeding pair of teeth must have already started action. The hunting ratio is the ratio of the number of gear and pinion teeth.

How do you calculate the spur gear contact ratio? ›

The contact ratio will be the length of this segment divided by the “length” of a single tooth. This is why the contact ratio is called a ratio–because it is calculated as the ratio of two lengths. Nevertheless, it is also the average number of teeth in engagement between meshing gears.

What is the ratio of spur gear? ›

Spur-gear terms (Fig.

The gear ratio is the ratio of the number of teeth in the gear to the number of teeth in the pinion, the pinion being the smaller of the two gears in mesh.

How do you calculate the velocity ratio of a spur gear? ›

Velocity ratio = number of teeth on driven wheel / number of teeth on driving wheel.

How do you calculate rack and pinion gear ratio? ›

Calculating Rack-and-Pinion Gear Ratio

Measure the distance from the end of the rack to an arbitrary point, turn the pinion one full revolution and then measure the distance again. The difference between the two is the gear ratio.

How is gear depth calculated? ›

Spur Gear Calculator and Geometry Generator - Download DXF, SVG, csv file.
Spur Gear Design Calculator.
To FindEquation
Pitch DiameterD = N / P D = (N p ) / π
Root DiameterDR = D - 2b
Whole Deptha + b
Working DepthaG + ap
9 more rows

How do you calculate bevel gear ratio? ›

The 90° case is called “bevel gear in right angle drive”. When Σ = 90°, Equation (4.20) becomes : Miter gears are bevel gears with Σ = 90° and z1 = z2. Their transmission ratio z2 / z1 = 1.


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