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Choosing A Dropper Post

Posted by TranzX Components on



With all of the options available choosing the correct dropper post can be challenging - we're here to help. Between riding styles, cable routing requirements, dropper length options, seat post diameters, and bike fit droppers can end up a confusing mix of specs for a seatpost. First we'll cover riding style to get a basic feel of where to look, and then delve into a handy flow chart of cable routing and sizes of our current product line to help you choose. 

dropper box

Riding Style

Mountain bikes - Mountain bikes tend to have more seat post showing out of the frame than a road or gravel bike and can accommodate a longer length travel dropper post. If your bike has a factory installed hole at the base of the seat tube it can accommodate internal dropper post cable routing, otherwise you will need to choose an externally routed post. Most mountain bike riders will want to look at the long travel 125-170mm drop (depending on model / fit) Kitsuma Air, Kitsuma, and Skyline dropper posts. 

Gravel bikes - Most gravel bikes have a more traditional road-like frame with a taller front triangle than a mountain bike and require a shorter drop post, though some taller riders may be able to use mountain length dropper travel posts depending on bike fit. If your gravel bike has a factory installed dropper port at the base of the seat tube to accommodate internal dropper post routing you will want to look at the short travel 50mm drop Hot Lap post. If your bike requires external cable routing we unfortunately do not currently make an externally routed Hot Lap but the externally routed Kitsuma post may fit. 

Commuter / Dirt Jump / Cargo Bike / Rail Trail - Dropper posts can be very useful on a variety of bikes, whether to put your feet down at a stop light easily, get on and off without having to swing your leg as high, or raise the seat for the ride to and from the bike park without tools. The Jump Seat has a lever under the nose of the saddle to adjust the dropper to any height within its travel, and has an easy installation that doesn't require any cables whatsoever. 


Flow Chart 

To navigate the flow chart you will need three pieces of information: required cable routing, seat post diameter, and long or short travel dropper. 

Required cable routing - Your bike can either accommodate internal dropper cable routing through a port installed at the factory at the base of the seat tube, or it requires external cable routing for a handlebar mounted dropper lever. Forgo the cables and the installation hassle altogether with the Jump Seat. 

Seatpost Diameter - TranzX makes 27.2mm, 30.9mm, and 31.6mm diameter dropper posts. The seatpost diameter that your bike requires should be printed at the bae of the seatpost that came stock with your bike, available on the manufacturer's website, or can be carefully measured with calipers. 

Dropper Travel - Droppers come in different length travels to accommodate different fit and riding styles. Most mountain bike riders are going to want long travel posts, most gravel riders are going to want short travel posts. 

dropper flow chart

Dropper Bike Fit

All of our dropper post product pages feature a chart with technical measurements to help you make the correct decision on a dropper for your bike fit. We will cover these measurements in more detail in a future post. 

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