Updated on March 16, 2023
A bicycle sliding dropout is a type of rear frame dropout on a bicycle that allows the wheel to be removed without having to first remove the derailleur or chain. This type of dropout is common on BMX bikes and single-speed/fixie bikes. They are also found on some mountain bikes, although they are becoming less common as frame designers move away from sliders in favor of thru-holes that can accommodate press-fit bottom brackets.
A slider is a metal plate that is mounted to the frame and over which the wheel axle passes. The slider has two small “ears” that fit into correspondingly shaped notches in the frame’s dropouts. A bolt or quick-release skewer holds the wheel in place by clamping down on both the frame and the axle.
To remove the wheel, the bolt or skewer is loosened and the slider is pulled back (away from the front of the bike). This disengages the ears from the dropouts, allowing the wheel to be removed. To install the wheel, the process is reversed.
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Sliding dropouts have a few advantages over traditional horizontal dropouts. First, they make chain tension easier. Second, they allow for minor wheel adjustments without having to remove the wheel from the frame. And third, if you’re using a threaded hub, they provide extra protection against stripping out the threads.
Disadvantages of Sliding Dropout
The main disadvantage of sliding dropouts is that they can be finicky to adjust. The ears need to be perfectly aligned with the notches in the dropouts, or else the wheel won’t go in (or will come out unexpectedly). And if the slider isn’t positioned correctly, it can rub on the tire and cause problems with braking. So while sliding dropouts can be a great option, they’re not for everyone. If you’re not comfortable making adjustments to your Rear frame dropout, you might be better off sticking with a traditional horizontal dropout.
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What is a horizontal dropout on a bike?
A horizontal dropout is a type of bike frame that has a slot on the side where the rear wheel axle slots in, as opposed to a vertical dropout which has a hole at the end of the fork.
Horizontal dropouts are found on many vintage road bikes and track frames. They allow you to easily remove and install the rear wheel without having to fiddle with adjusting or tightening skewers. This is convenient if you need to change a flat tire or transport your bike in a car. However, they can be more prone to getting bent out of shape since they’re not as strong as vertical dropouts.
There are a few different types of horizontal dropouts. The most common are solid axle and quick release. Solid axle dropouts have a slot for the axle that is the same width as the axle itself. Quick-release dropouts have a wider slot that allows the quick-release skewer to pass through.
Some horizontal dropouts also have a derailleur hanger. This is a small tab that protrudes from the side of the frame and provides a place to attach your rear derailleur. Derailleur hangers can be removable or permanent, depending on the frame design.
If you’re looking for a new bike frame, check out our selection of horizontal dropout frames! We’ve got something for everyone, from vintage road bikes to modern track frames.
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What are the benefits of a vertical dropout over a horizontal dropout?
Vertical dropouts offer a number of advantages over horizontal dropouts. First, they’re stronger and less likely to get bent out of shape. Second, they provide more wheel support since the axle is closer to the frame. And third, they’re easier to adjust since you don’t have to worry about aligning the axle with the dropout slot.
The main disadvantage of vertical dropouts is that they can be more difficult to remove and install the rear wheel. This is because you have to thread the axle through the hole in the frame. If you’re not careful, it’s easy to cross-thread the axle and damage the frame. For this reason, many people prefer horizontal dropouts for their convenience.
Austin Jacobs is a passionate cycling enthusiast who has over five years of experience in bike repair and maintenance. He is an avid mountain biker and loves tinkering with bikes for hours on end to make sure they are running at their optimum performance level. Leland’s blog, which focuses on bike repairs and tips to keep them in good running order, was created out of a desire to share his knowledge and help fellow cyclists stay safe while enjoying the outdoors. He covers topics such as preventive maintenance, troubleshooting common issues, basic tools and supplies needed for repairs, and more.