Can You Add Gears To A Single Speed Bike?

Single-speed bikes require that you use more physical strength to tackle challenging terrains. On the other hand, geared bicycles allow you to cover much distance with less stress to the body. So, can you add gears to a single speed bike?

You can add gears to a single speed bike if the bike’s dropouts can accommodate a multiple-speed wheel hub. For dropouts that are 120mm wide, you can use an internal gear hub or cold set the chainstays. Once set, you can install a multi-gear cassette and a derailleur.

In addition, for you successfully change the bike to a multi-speed machine, you will need to buy a new drive train set.

can you add gears to a single speed bike A young woman sitting on a bicycle's top tube

How Can You Add Gears To a Single Speed Bike?

Without a doubt, a single speed bike may be a bit limiting since it requires the rider to use brute force on tougher terrains.

But, on the other hand, bikes with multiple speed gears are energy efficient and have better maneuverability.

So how can you add gears to a single speed bike?

There are several methods that you can apply to add gears to your single speed bike.

However, there is one crucial consideration you have to make. That’s the Over Locknut Dimensions (O.L.D).

Over Locknut Dimension refers to the distance between the outer sides of the locknuts found on either side of the hub.

If your bike’s O.L.D is less than 130mm, then you have two options.

  1. Use an internally geared hub
  2. Cold setting the bike frame

Using An Internally Geared Hub

Since most single gear bikes have an O.L.D of 120mm or sometimes less, they cannot accommodate standard multi-gear cassettes.

Therefore, the easiest way to add gears to a single speed bike is using gear hubs.

As the name suggests, these hubs don’t have a gear cassette, but they have gears installed inside them.

An excellent example of an ideal internal gear hub is the Shimano Nexus Universal Bicycle Hub Kit. It comes with 8-speed gears and works with rim brakes.

However, internal gear hubs can only hold a limited number of gears. Actually, most of these hubs have 2-3 gears since it is difficult to have many gears in such a small space.

Alternatively, if the bike has a steel frame, you can cold set it to accept gear hubs of greater O.L.D.

can you add gears to a single speed bike - bictycle rear gears

What Are The Advantages Of Internal Gear Hubs?

Like we had earlier noted, most single-speed bikes have O.L.Ds of about 120mm. Unfortunately, this width can’t fit a free-wheel gear cassette and a corresponding hub.

Therefore, instead of artificially pushing the dropouts apart, you can go for an internal gear hub. This way, you avoid interfering with your bike’s geometry.

The other advantage of using a gear hub is that it requires little maintenance. Especially during the first stage of usage, it actually needs almost no repairs.

Notably, the standard derailleur system requires regular cleaning of cog and derailleur. On the other hand, an internal gear hub only requires you to keep proper chain tension and periodic lubrication.

In addition, gear hubs keep the bike looking clean since there are few external parts like derailleurs and cogs. Therefore, a gear hub is easier to maintain than a derailleur drive train.

  • Shifts Gears When Stationary

For you to shift gears on a conventional derailleur system, you need to be pedaling.

If you shift when not in motion, the gears won’t change until you start pedaling. Unfortunately, the system will produce disturbing noises.

On the contrary, an internal gear hub allows you to shift gears even when you are not pedaling.

Actually, you can change gears while not in motion. As such, internally geared hubs are excellent for city traffic.

In that case, if you need an excellent internally geared hub for your everyday bike, you can go for the SHIMANO Nexus 5 Speed Internal Gear Hub, which comes with 5 speed and is compatible with disc brakes.

How Do You Cold Set A Bicycle Frame
  • Compatible With Drive Belt

Another advantage of using gear hubs is that they are compatible with a drive belt because it doesn’t require a derailleur.

The main advantage of belts over chains is that they require less maintenance.

Disadvantages Of Using Internal Gear Hubs

Although you can add gears to a single-speed bike using internal gear hubs, they come with a few challenges that you need to consider. They include

  • Internal gear hubs are significantly heavy.
  • They provide a low range of gears.
  • Regular chain tension adjustment due to lack of a derailleur.
  • Difficult tire replacement
  • The gearing system is part of the wheel. This makes the hub replacement process more expensive.
  • Internal gear hubs are complex to repair.

Frame Cold Setting To Add Gears To A Single Speed Bike (Using Derailleurs)

Besides using a gear hub for bikes with dropout widths less than 130mm, you can use frame cold setting to fit a standard cassette.

Cold setting is the art of tactfully spreading the dropouts until they accept a wheel with a derailleur gear system.

All the same, one major limitation with cold setting is that it is only ideal for steel frames. This is because steel yields high tensile strength that makes it withstand substantial stress before getting deformed.

There are two popular ways of cold setting a bike’s frame, but the easiest and safest is using a threaded rod and nuts.

For you to get e around the task easily you need to have several tools with you. All the same, a tool kit like the 23 Piece Bicycle Repair Tool Box (View on Amazon) has all the required tools.

How Much Does It Cost To Put Gears On A Bike

Advantages of a Derailleur System

Definitely, when you use a derailleur drivetrain, there are pros that you will enjoy overusing a gear hub. Some of the benefits include:

  • Derailleurs Are Easy To Repair

Unlike gear hubs which are too complicated to repair, derailleur drivetrains are easy to fix using essential bike tools. When touring, a derailleur system is the friendliest drivetrain.

  • They Are More Efficient

Derailleurs have a greater mechanical advantage than gear hubs. Technically, gear hubs lose a lot of drive power as energy goes through multiple gears.

  • Derailleurs Are Cheaper

The whole derailleur groupset goes a few hundred bucks. Actually, compared to low-end gear hubs, a mid-range derailleur drive set is cheaper by almost 50%.

So if your budget is tight, a derailleur set such as the SHIMANO Cassette X.T. 9-Speed 11-34 Sprocket will do just fine.

  • Wider Gear Range

Notably, most common derailleurs systems have up to 30 speeds. As a result, you can choose the optimal speed for your terrain.

  • Derailleurs Are Lighter And Faster

Compared to geared hubs, derailleurs are lighter in weight. Therefore, it adds less weight to the bike, and as a result, you can accelerate faster and attain high speeds since the system is power efficient.

Disadvantages of Derailleur setup

  • Derailleurs are fragile
  • Can’t work with belt drives
  • Easily affected by elements
  • Can’t shift gears when not pedaling
  • Derailleur chains don’t last long
  • Requires frequent maintenance

How Do You Cold Set A Bicycle Frame?

At times, your bike dropouts and the hub’s O.L.D may have a slight difference. As such, it is possible to slightly spread the frame and install the wheel without the need to cold-set the frame.

Although this method is tempting, it may leave the dropouts misaligned, leading to constant chain tensioning. In addition, removing the wheel becomes quite inconvenient.

Using A Threaded Rod And Nuts 

Using a threaded rod and nuts to cold set a bike’s frame is the safest way. As you thread the nuts, they push the dropouts outwards in equal measure. This video by R.J. The Bike gives an exemplary demonstration.

How Much Does It Cost To Put Gears On A Bike?

For you to add gears to a single-speed bike, you need to change the whole drive set. Therefore, adding gears to a single-speed bike is not as straightforward or cheap as it would sound. Instead, it requires significant investment in terms of labor and replacement parts.

If you won’t personally do the job, labor costs $60 – $100. But, again, the cost may vary from town to town.

Also, the cost will depend on whether you are for an internal gear hub or a derailleur gear system. Actually, an internal gear hub of reputable quality will cost about $1200.

On the other hand, a good derailleur gear system will cost about $200 – $500.

Also, Read: How to install a rear derailleur on a mountain bike.

Final Take : ”Can You Add Gears To A Single Speed Bike”

Can you add gears to a single speed bike without damaging your bike? Yes, there are safe ways that you can use to add gears to your bicycle.

First, your bike has a small O.L.D; you can go for an internally geared hub. The main drawback will be the limited gear range since most gear hubs come with 2-3 gears.

On the other hand, you can cold set your bike’s frame for the dropouts to accommodate an ordinary gear cassette and its hub.

However, for you to cold set the frame, make sure it is made of steel or else, you will damage your bicycle.