# Difference between pump and jump



## axolotl (Apr 24, 2008)

I am wondering what the build differences between a pump track bike and a dirt jumper are? Seems like dj's come with taller and narrow bars - built strong to take abuse. Can anyone enlighten me here?


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## False (Feb 18, 2011)

I would go with a more BMX geometry than a DJ geometry for strictly pump track riding.


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## Jason B (Aug 15, 2008)

More info...
http://forums.mtbr.com/showthread.php?t=680543


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## climbingbubba (Jan 10, 2007)

It just depends on how you like your bike set up. Bar height will be personal preference. 

If you want both a DJ and a pump track bike then just build one up how you want it for DJ and it will work great on a pump track. If its strict pump track then you can go a little lighter on some parts.

I have never ridden a BMX bike on a pump track so i can't comment on how it would be (although im sure it would rip). I already don't like going from one bike to another so going from one wheel size to another doesn't seem fun at all. Also im building a pumptrack to work on my mtb skills (mainly DH racing) so having the feel for 26" wheels seems like the best option.


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## cmc4130 (Jan 30, 2008)

axolotl said:


> I am wondering what the build differences between a pump track bike and a dirt jumper are? Seems like dj's come with taller and narrow bars - built strong to take abuse. Can anyone enlighten me here?


First of all, there is no specific thing recognized as a "pump track bike" : You could ride 20" wheel BMX, 22" wheel BMX, 24" wheel BMX, 24" dirt jumper aka MTBMX, or 26" DJ/MTBMX.

The trend in DJ bikes is actually towards wider bars (like 28" ish) like in BMX, so I'm not sure why you think they are narrower. Also, DJ bikes have also gotten lighter, so I wouldn't necessarily say they have to be heavy duty any more--although, yeah, they're still definitely heavier than xc.

The better distinction is what is NOT a pump track bike:

1) Full-suspension is terrible for pump tracks. It's doable if you super-pump up your rear shock...but it's really counterproductive. Most of your pump comes from your feet and rear triangle. (That's why a suspension fork is fine for pump track). Full-sus is designed to soak up bumps on a trail.....

2) Full-size XC bike are generally bad pump track bikes, for the reason that the seat tube is too high (even when you slam the seat all the way down, it's still too high). Also, wheelbase is usually long and awkward, and stem reach puts your stance too far forward. That said, it is possible to take a very small XC bike and build it with DJ parts--not advisable, but doable. A guy around here took a 13" hard rock and made a pretty rad dirt jumper out of it. That's essentially what the early Specialized P bikes were..... Although now, geometry-wise, dirt jumpers are a blend of mtb and bmx cruiser. The back end is short, the bottom bracket sits a little higher, top tube lower, etc.

I personally think a new school dirt jumper 26" hard tail (Blackmarket, NS, Doberman, Superco, Atomlab, Haro Steel Reserve, etc.) is an ideal pump track bike, 
Lastly, I would also point out that some builders (such as myself) build a style of pump track that has dirt jumps in it--or, said another way, a style of dirt jump building that has pump track elements to it.....for a fun blend.... This is an old video of our spot, but you'll see the mix of bikes riding: 



Here's a slightly newer vid: 




You should read LeeLikesBikes.com . He has a ton of different articles on pump tracks.


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## False (Feb 18, 2011)

That looks like so much fun. I gotta find something like that here in GA.


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## WaveDude (Jan 14, 2004)

False said:


> That looks like so much fun. I gotta find something like that here in GA.


Look in your shed or garage. See that wheelbarrow, buckets, and shovel? THERE IT IS--the pump track you've been looking for.


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## False (Feb 18, 2011)

I mean, I know where you're going with, but I actually don't have a wheelbarrow or shovel and since I just started riding DJs I haven't really met anyone who could help or know an area good for it. Once I get some experience I'll probably start digging.


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## cmc4130 (Jan 30, 2008)

False said:


> I mean, I know where you're going with, but I actually don't have a wheelbarrow or shovel and since I just started riding DJs I haven't really met anyone who could help or know an area good for it. Once I get some experience I'll probably start digging.


Start by finding out if there is a BMX race track near you. The ABA is open to all wheel sizes. Except for the long straight-sways and huge radius turns that require cranking, a Bmx track IS a pump track !


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## False (Feb 18, 2011)

Oh I've ridden race tracks for the last decade, but none that flow-y.


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