If you’re looking to install thumb shifters on drop bars, you may be wondering if it’s even possible.
Afterall, thumb shifters are generally designed for handlebars with a 22.2mm diameter grip area – which is smaller than most modern drop bars.
However, there’s good news! With some tweaking and modifications, you can certainly install thumb shifters on drop bars.
In this article, we’ll delve into several ways you can install thumb shifters on your drop bars and offer some helpful tips and advice to get you started.
Cons Of Installing Thumb Shifters On Drop Bars
Before we learn how to install it, it’s important to be aware of the potential cons:
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The thickness of modern drop bars makes them incompatible with most thumb shifters unless they are modified or alternative models are used.
This can be frustrating for those who want to install their shifters and ride away without any extra work or expense.
Plus, alternative models can be expensive and may outprice entry-level brake-shifters that may be more comfortable to use.
Shifting Only From The Tops
Thumb shifters are designed for flat bars and are typically installed on the tops of drop bars, and are more comfortable.
But, this position requires riders to move their hands away from the brake levers to shift gears, which can impact stability.
Pros Of Installing Thumb Shifters On Drop Bars
Now that you are aware of the cons, let’s take a look at the pros:
Thumb shifters are relatively inexpensive compared to modern brake-shifters, making them a cost-effective way to upgrade a bike’s shifting system.
As long as you don’t opt for exotic models, thumb shifters can be a cheaper option that still delivers a more efficient and reliable shifting experience.
Ditching Retro Shifting Systems
One of the biggest advantages of installing thumb shifters on drop bars is the ability to avoid using outdated shifting systems such as downtube or bar-end shifters.
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Downtube shifters sit on the bike frame’s downtube, and riders have to reach down and shift gears. Bar-end shifters are at the handlebar ends, and riders have to take their hands off the bars to shift gears.
Thumb shifters, on the other hand, can be placed on the flat part of the drops, which makes it easier to shift gears.
Thumb shifters are primarily designed for use with mountain bikes and hybrids, but by installing them on drop bars, you can expand your options for compatible components.
This can give you greater flexibility when it comes to building or upgrading your bike.
How To Install Thumb Shifters On Drop Bars
One of the easiest ways to install thumb shifters on drop bars is by using “thumbies.” These are small adapters that mount on the end of the drop bars and allow you to install flat-bar shifters.
Thumbies come in different shapes and sizes, so make sure to choose one that is compatible with your bike’s shifters and drop bars.
Some popular options include Paul Thumbies, and the Jtek Engineering Shiftmate.
Tips for Installing
Remove the bar-end plugs from your drop bars using an allen key, and slide the thumbie adapters onto the ends of the bars.
Next, tighten the adapters in place with the allen key, ensuring they are angled comfortably for your thumbs.Then, attach your thumb shifters to the thumbie adapters and secure them in place.
Afterwards, test the shifters to ensure they are functioning correctly and adjust the position of the adapters as necessary to ensure an ergonomic fit.
Once you’re satisfied with the placement – secure the shifter cables using electrical tape or bar tape to prevent them from getting in the way.
Find Thumb Shifters That Fit By Default
Another option is to use thumb shifters that are big enough to fit on your drop bars.
For example, the Shimano A050 and Dia-Compe Wing Shifters can fit on 22mm – 24mm grips.
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Filing The Clamps
You can also file down the inside of the shifters’ clamps by 1.6mm so that it fits the thumb shifters. You can do this using a rotary tool.
You could also use a drill with a sanding attachment or even do it manually. But the former is faster.
It’s worth noting that modifying it this way will make the clamp weaker, especially if it’s already thin. Plus it voids the warranty even if the parts aren’t reliant on each other.
Get Thinner Drop Bars
You could try swapping out your drop bars for a thinner version.
Many modern drop bars are designed to be more aerodynamic, which means they may be thicker and less compatible with thumb shifters.
Look for vintage drop bars that have a more traditional shape and a thinner diameter, which will make it easier to install thumb shifters.
Can You Install Shifters On A Handlebar Extender?
Yes, it is possible to install shifters on a handlebar extender – but it is not a good decision and I don’t recommend it.
Using a handlebar extender means that you will have to move your arms away from the handlebars to shift gears, which can be uncomfortable and affect the balance of the bike.
Plus, a cluttered handlebar setup doesn’t look nice, which may be a concern for some cyclists who care about the appearance.
Moreover, you need a shim to secure the shifter in place – because the diameter of the extender is around 20mm, which is smaller than the standard handlebar diameter.
Can You Put Twist Shifters On Drop Bars?
Twist shifters can be installed on drop bars if they fit the required length and diameter, but the rider’s hand position on the drops can cause the shifters to twist and wear out quickly.
Is It OK To Put A Drop Bar On MTB?
While it is technically possible to put drop bars on an MTB, it may not be the most practical or comfortable option because drop bars have a different geometry and riding position than flat or riser bars typically found on MTBs.