A 50/34 crankset can be combined with an 11-36 cassette provided that the rear derailleur of the bicycle has the needed capacity to reach the largest cog. The combination is not common but offers the following benefits.
- Top Speed
The largest gear of this combination is 50/11 and comes with a 4.54 gear ratio. The gear ratio indicates the number of rotations that the rear cog and respectively the rear wheel make per 1 complete revolution of the cranks/chainring(s). In this case, the rear wheel makes 4.51 rotations per 1 crank spin.
The gear ratio is an important property because it directly impacts the maximum speed that a chainring and cog combination can produce. The other two factors are RPM (rotations of the cranks per 1 minute) and wheel circumference.
If two bikes with identical wheels are pedaled at the same RPM, the bike that has a higher gear (larger gear ratio) will be faster because each revolution of the cranks will result in more spins of the rear wheel and a greater travel distance in the same time frame. (Speed = Distance/Time).
If two bikes have identical gearing and wheel size, then the bicycle pedaled at a higher RPM will be faster because the rear wheel will make more rotations in 60 seconds and thus travel a greater distance.
If two bikes have identical gearing and are pedaled at the same RPM, the bike with the larger wheels will be faster because each revolution of the rear wheel will result in a greater travel distance.
The table below shows the maximum top speed that a 50/11 gear can generate at different RPMs when the bike has standard 700×25 wheels.
|RPM||Wheel Size||Speed kph||Speed mph|
50×11 offers a very high top speed (50km/h or more) that will be enough for most people. Spinning out can occur only during extreme descents.
FAQ: What is “spinning out”? Spinning out happens when the wheels of a bike are already rotating faster than the speed that the rider can reach by pedaling. At that point, pedaling is useless as it doesn’t contribute to forward movement.
- Very Low Gear
The lowest gear in this case is 34/36 and provides a 0.94 gear ratio. This means that the rear wheel will make slightly less than a full turn per 1 spin of the cranks. The lower the gear ratio, the easier is to pedal and consequently to climb precisely because each pedal stroke results in a very short forward travel.
34/36 is not nearly as low as what we could find on an MTB or a hybrid with a 3x drivetrain (e.g., 22/36), but very low for a road bike.
Road bikes have lower rolling resistance and are designed for paved roads. Thus, they don’t require the low gearing of an MTB.
For trained cyclists, the gearing will be needlessly low. If you’re a strong cyclist and/or you don’t conquer hilly terrain regularly, you can benefit from a smaller cassette.
34/36 is also a good gear for commuters as it reduces the effort needed to climb. This is beneficial when you want to minimize energy expenditure on your way to work.
The Downsides of Running 50/11 + 11/36
- The Gearing Could Be Needlessly High
Even though it’s awesome to have a high gear, sometimes it’s simply not necessary. Many casual cyclists won’t be able to take advantage of 50/11, at least not in “high cadence mode”. Thus, it could be beneficial to look into a set of sub-compact cranks, for example.
- Large Jumps Between the Rear Cogs
Large first gears result in larger transitions between the cogs. In other words, the size difference between each cog is greater. This is problematic because it becomes more difficult to maintain a smooth cadence since each shift throws you onto a notably different gear ratio.
The table below contains the gradations of 11-speed 11-25, 11-28, 11-30, 11-32, 11-34 and 11-36 cassettes.
The smallest jumps on an 11-36 cassette are 2 teeth. The last two shifts have 4 teeth difference between the cogs. The discrepancies are large enough to disrupt one’s ability to pedal smoothly at high RPM.
Of course, the difference isn’t massive, and most casual cyclists wouldn’t care. However, those who want to have smaller jumps between the gears allowing them to maintain the smoothest possible cadence will benefit from getting a cassette with a smaller large cog.
The trade-off is that you will lose the bail-out gearing that comes with the 36T cog.
- Won’t Work With Many Derailleurs
The vast majority of road derailleurs are limited to a 32-34T large cog. And if the derailleur has a short cage even that could be problematic. To make an 11-36T cassette it will be necessary to get a derailleur with a long cage and/or a derailleur hanger extender.
Summary: What You Need To Know
- A compact 50/34 crankset is a fine choice for cyclists who plan on riding seriously.
- Combining a 50/34 crankset with an 11-36 cassette is acceptable because the rider acquires a decent gear range.
- For some people, a 36T cog may be needlessly large, especially if the terrain is mostly flat.
- It may be necessary to replace the existing derailleur with one designed for a larger first gear.
- The jumps on an 11-36T cassette are large enough to hurt the rider’s cadence.