Contents
Jump Bikes Introduction
Jump bikes are a type of hybrid bike, somewhere in-between BMXs and standard mountain bikes. As the name suggests, they are mainly used for jumping stunts, although there is also a wide selection of tricks that a jump bike rider can pull off.
While initially, it may seem as though they are similar to a mountain bike, if you look closer you will find that there are a lot of differences in the design of a jump bike. They are smaller, more mobile, and are specifically designed to handle the stress of repeatedly landing on their tires from great heights.
Jump bikes feature several characteristics that separate them from other bike types:
Lower, reinforced frames: The upper tube of a jump bike frame slopes upward from the seat post, giving the rider more room to maneuver. The frames themselves tend to be stronger than regular bike frames so that they can withstand the large forces involved when landing stunts – they are built for rugged use
Smaller wheels: Jump bikes feature small wheels; around 24” to 26” wheels is considered best.
Firm suspension: To help to deal with high jump bike tricks, most frames have a suspension forks for the front wheel. They are typically set to the least springy setting to give the bike a better feel.
Fewer gears: High torque gear ratios are all that is needed to flip the jump bike up fast and give the rider instant control over the bike’s balance.
There are two main styles that involve the use of jump bikes:
Urban jump riding takes its name from the streets, with riders performing all manner of skillful tricks and jumping using everyday objects such as benches, stairs, walls, and so on. A street jump bike has a lot of similarities with trial bikes.
Dirt jump biking is a relatively new sport where jumps are done in parks, woods, and trails, with ramps specifically designed to get as much height as possible for the rider. Competitions involve high or long jumps where the riders of jump dirt bikes are graded on the difficulty of the tricks performed.
Jump bikes may be a new type of hybrid bike, but their popularity is increasing every day with more manufacturers releasing specific models all the time. Mountain bikes enjoyed rapid growth when they first appeared – expect the same from jump bikes!
Types Of Jump Bike
While you have probably seen the trick videos on YouTube, not everyone is aware dirt jumping can be done on almost any type of bike. What, even mountain bikes? I hear you ask. Yes, even common bike types can be used, but it would be much more difficult due to the bike being geared towards racing. Even so, it can still be used, along with BMXs, and other bike types (with a little bit of modification).
Here is a list of bikes and their suitability as for dirt jumping:
Jump Bikes: These are the ones that are designed especially for the sport. Similar at first glance to a mountain bike, these bikes feature a lower seat to enable the rider to easily perform tricks without it getting in the way. They also tend to have much more rugged frames and wheels, which makes them better prepared for the intensity of forces that result from vertical stunts. Specially built bikes are designed for a balance between being as light as possible and being strong enough to endure repeated jump bike tricks. They almost always have front-only suspension to make the bike a twitchier ride, which gives the rider more control.
Mountain Bikes: As previously mentioned, it is possible to use a modified type mountain bike for dirt jump biking. Hardcore enthusiasts use small mountain bike frames with front suspension shocks and smaller wheels than normal. Front suspension is not always used, but it does help!
BMX Bikes: Modified versions of BMX frames exist which are geared towards dirt jumping. They tend to have an extended top tube to put more if the rider’s weight over the back wheel, making the bike easier to wheelie and ollie. BMX jumping bikes also have a shorter chainstay to further change the weight balance. Just like other trick bikes, road slick tires are abandoned in favor of wider, treaded tires that are inflated to a low PSI to further help in absorbing hard landings.
Since dirt bike jumping is a relatively new sport, makers of trick bikes have no real standards to follow as yet. Maybe this is one of the reasons why it is common to see many other types of custom bikes. Whatever the reason, it won’t be long until jump type bikes for sale are seen in shops and stores and given equal footing as a separate category of bicycles.
Jump Bikes: Sizing Information
It can be a lot trickier than with other bicycle types to find a jump bike that is the correct fit for your height. Ideally, you are looking for the seat of the jump bike to be as low as possible without it hitting the seat, allowing you to squeeze out as much mobility as possible when tricking out.
To get a favorable reference frame for your height, the basic rule of thumb is to take the frame size that you would normally ride on a mountain bike and subtract 2-3 inches. So if you usually ride a 19″ Mtb frame, jump bikes with a frame size of 17″ or lower would be a good place to start. Generally, large jump bikes have a 17″ frame, medium 15.5 to 5″ and small 14″ to 15″ – these are the manufacturer’s recommendations.
Despite this, many tall riders prefer a smaller frame than the manufacturers suggest. A smaller frame requires less effort to spin and pull tricks on, due to the rotational mechanics involved. In reality, a suitable frame side for a jump bike is only limited by how close your feet are to the front wheel – you will know when a frame size is too small for you when your feet are hitting off it!
So with this in mind, it is worthwhile having a good idea what kind of use you expect to get out of the bike – will it be used for racing or for tricking out on? Racing jump bikes will perform better with a longer top tube length since this gives the rider added stability when cornering. Dirt jump bike riders will prefer a frame with a shorter top tube since this will make it a lot edgier when spinning and attacking jumps mid-air. Not all manufacturers list the top tube length in their catalogs so the local bike shop is your friend. If you are looking for some suggested models that can be found ‘off the peg’, have a look at the P1 jump bike made by Specialized, or any of the Kona jump bikes.
If you are looking to buy your first dirt jumping bike, start by going for a bike frame 2 inches less than the size of the mountain bike frame you would usually ride. Next, depending on what kind of rider you are, select a top tube length to suit your style of riding. There are a couple of good makes of jump bike available in shops these days, so the best thing to do is to go out and test them before buying – there is nothing worse than getting a new bike delivered only to discover it’s an unsuitable size!
Jump Bikes Buying Guide
Picture the scene – your new custom jump bike has just been delivered, and you are full of excitement. You can’t wait to wield the handlebars and take her out for a quick spin. You push off and start pedaling furiously down the street, only to find your shoulders are hunched up and your feet hitting the front wheel with every turn – you stop, angered by your realization – the frame size is too small, the handlebars too close, the suspension is as hard as a marshmallow.
Such a mistake can easily be avoided by knowing what to look for before making a purchasing decision. Jump bikes are relatively new to bike shops, and because of this, it is hard to find good advice over what features to look for. Here’s what to bear in mind:
Correct size: If you are approaching 6 feet, it is important to consider the length of the top tube on the bike before buying. Too short and you may find that the frame is too small for you, and your feet may hit the front wheel while doing slow turns. The lower the seat is the better since you will have more room between you and the frame. Try to test one out before buying.
Suspension: Strength and firmness are the key factors to consider when it comes to suspension systems. Jump bikes need to have reinforced shocks to absorb the high impact landings – they are similar to the ones used on mountain bikes but they have slightly thicker posts. It is preferable to have firm shocks with not a lot of movement as this affords the rider more control during tricks. If you are going to be dirt jumping over high air gaps you might want slightly spongier shocks with more travel, but they should still be pretty solid.
Gears: Gearing on dirt jumping bikes is not essential but if you are going to be using it for other purposes then it can be useful to have. A lot of models are single speed which is a lot more robust and makes it a lot less likely that the chain will fall off during landing. Single-speed bikes tend to require less maintenance too since there is no derailleur to take care of.
You can now buy a good selection of ‘off the peg’ bikes at local bicycle shops, which wasn’t the case a few years ago. This means that you can try before buying, although the shop owner may be hesitant about letting you out of the shop to do tricks! You can also get some good bargain second-hand jump bikes by looking at eBay and Gumtree, the latter being preferable as you can again try them out.
