New world record: 100 laps of pump – 20″ style

This weekend I rocked the Intense Factory Alloy 20 on The Fix pump track, and the results were surprising.

If you apply the correct force to a solid patch of ground, IT’S ON!

I’ve had the sweet new 20″ for about a week, and I’ve ridden it three times. This bike is unbelievably quick and responsive. It rewards perfect timing with turbo braaap. Imperfect timing … uh, never mind.

Where: The Fix pump track, Boulder, CO. This track is neither smooth nor perfectly built. When I rode the 20 there this week, I was forcing it, and the rocks were beating me to death.

Protocol: 10 laps clockwise with my right foot forward. One minute rest. 10 laps counterclockwise with my left foot forward. One minute rest. Repeat five times for a total of 100 laps.

20 vs. 26: When I figure this out fully, I will publish diagrams galore. For now I’ll say the 20 gives you a smaller but more focused window of pump. The backsides start and end a bit sooner than with 26″ wheels. Small wheels force you to be even more pro-active, which is a good thing.

The experience: One great thing about endurance pump track riding — it forces you to relax and find smoothness. I fought the bike at first, but after 20 laps or so I relaxed and found my timing. I kept my weight in my feet and tried to keep my arms loose unless they were pulling or pushing. Cool: I found some nice pump on a few little bumps that I’d been avoiding. One good corner-hop-to-roller-backside and the bike was up to mach speed. Turbo braaap.

The results: I didn’t feel fast, but — dude — the stopwatch said my riding time was only 26 minutes. My BMX cruiser time was 33 minutes. My last P.3 time was 35 minutes.

Why? There are a million variables, but that 20″ time blows everything else out of the water. Possible explanations:

– Conditions? The track was hardpacked and fast today. But it usually is.

– Fitness? It’s the end of the summer, and I feel decent. But I’m usually about the same, pump-wise.

– Skill? I’ve learned A TON working with top racers on the BMX book, but I think I’m still in the phase where the new knowledge is balling me up. It isn’t automatic yet.

– Longer recovery? I usually rest 30-40 seconds between sets. Today I gave myself a full minute of recovery. BMX coach Greg Romero, whose athletes earned two medals at the Olympics, says longer recoveries are required for high-intensity work. The longer rest felt good, but I was still beat at the end — and the total time, including rest, was still lower than with the other bikes.

– The bike? That is the clearest variable. Are 20s just plain faster than 24s and 26s? The experiments will continue …

— Lee

For the record:

Intense 20 : Sept. 7, 2008
Total: 35:19
Rest: 9:00
Riding: 26:19

Intense Cruiser : Feb. 3, 2008
Total: 41:22
Rest: 7:54
Riding: 33:30

P.3 : July 23, 2007
Total: 41 minutes
Rest: 6 minutes
Riding: 35 minutes

14 replies
  1. Chris says:

    “Are 20s just plain faster than 24s and 26s?” IMHO? Yes, proven by experimentation.

    Once upon a time in a country far, far away, I wondered what was the fastest way through the last straight on a certain BMX track: roll, manual or jump the doubles? I would stand at the top of the berm (this bmx track was built lower than the surrounding land) and without pedalling my BMX roll down and try different variations on the final straight and see how far I could roll up the gentle slope that came after the finish line (answer was to manual, for me). I then tried the same thing on my MTB (STP with K-Rads, pumped up hard) and I could not get as far up the slope as I could on my BMX. Not even close. Also, on the second last straight, there was a gap that needed warp factor nine and achieving the necessary speed in the preceding tight and relentless rhythm section was easier on my BMX than my MTB. And my life flashed before my eyes trying it on a 4″ Trance.

  2. Neil says:

    Sounds like fun!
    I picked up a 20″ a few weeks ago and couldn’t agree more with how fast they are. DJing is a whole new experience as well!

  3. Fred says:

    I’ve noticed what your talking about with the “window of pump.” the 20 is a more forgiving about when/how you pump then the 26, and more so the smaller the roller is. this really shows when it comes to endurance 20vs26.
    I also noticed, before reading this, that I get more boost when i tried to start my pump sooner, like you where saying about the backsides starting and ending sooner. I think the key to explain this lies in the tire’s angle of attack, ie: the reason 29ers rock in the rough is the same reason 20s brapp the smooth.

  4. Jeremy says:

    What about the gearing were all three bikes geared the same? Some of it could be the track,it maybe faster for the 20. I know there are times when a 26 is the faster ride, there are alot of variables sometime a full is faster and it maybe that you are better on a 20. On my track we refer to as the hog pen a cruiser is hands down the faster ride.

  5. Jeremy says:

    I do some XC, bmx and a little road racing. I quess you would say I am a expert generalist. I would like to try some 4X but there is not a track around close.

  6. Bomber says:

    maybe this will sound weird, but can the presure difference in the tires (20″vs26″) could explain the difference in speed? I would like to try the new KHE 26″ light weight tires with 8 Bar in them on my 26″

    just my thoughts, cheers

  7. leelikesbikes says:

    Great point!

    Air pressure could indeed make a difference. On a smooth track, high pressure would usually be faster. On a rough track, lower pressure would probably have less overall resistance.

    For The Fix pump track, I run both my P.3 and my 20 at about 50 psi, so that’s a wash.

  8. Bomber says:

    Hi Lee,

    This matter could not leave my head :p Your speaking about a smaller “window of pump” i dont realy know how you meant this, but with 20″ you have more time to pump and push, due to shorter wheelbase (20″vs26″) So basicly the rollers are bigger on 20″ then with 26″ and therefor you get more pump out of the rollers/berms with 20″. Just my thoughts 😉

    Cheers Sjors

  9. MattPatt says:

    I wonder if your 26″ bikes have suspension forks, clearly the 20 doesn’t, and I have to assume that pumping is more efficient when fully rigid 😉


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