BMX shifter bike!

Our man Chris Powell is too smart for his own good, and here is his latest creation.

The racers didn’t gear up on the hyper-fast OTC track. They sprinted, spun, tucked and pumped.

Why don’t BMX bikes have gears?
Over the years, BMX racers (including Brian Lopes) have experimented with multiple gears, but they have never taken off. Possible reasons:

– BMX racers are immensely powerful. Narrow chains, ramped cogs and derailleurs aren’t as secure or durable as an old-fashioned single speed chain and non-ramped gears.

– Stuff happens in BMX. You don’t need to be bending your derailleur hangar in your first moto. Dude — can you imagine racers aiming for each other’s derailleurs? “I so Dura-Aced that guy in the first turn …”

– BMXers can accelerate. They train for strength and power, and they are up to speed in just a few cranks. Coach Greg Romero measures these guys at 2,000 watts off the line.

– BMXers learn to spin. A good BMXer can spin at 180 rpm. Jason Richardson has been measured at 225 rpm — and he can squat more than 500 pounds. That’s a very wide powerband. Why shift?

– Bandwidth. On the first straight of a BMX race, a whole lot happens in a very short time. Thinking about shifting would detract from the other priorities: 1) power, 2) power and 3) power.

– Tradition. Nobody is using gears.

Why did Chris build this thing?
Mr. Powell does most of his riding at the Olympic Training Center in Chula Vista, CA. That course is BIG and FAST.

Chris, also a pro mountain bike racer, student and soon-to-be husband, sees no need to squat 500 or spin 225. Shifting is easier.

Nice and clean.

Mandatory chain guide.

Note the Saint cranks. Chris actually bent a pair of XTRs casing the second double on the OTC track.

That looks like two speeds: braaap and BRAAAP!!!

10 replies
  1. Eric says:

    Ok, I’m not a pro racer nor can I squat 500lbs (anymore :))but I have raced BMX and running a mtn. bike in place of a cruiser on a track with gears you end up have them skip and not really shifting much anyway. I tried a two speed setup before and while it had less gear jump issues…I still don’t see the need.

    BMX is a sprint race, you hammer out of the gate and then how well you can pump and jump determines where you’ll place more than having an easier/harder gear to go to. It’s over in 40 SECONDS.

    Gears on BMX bikes? Why not gears on Track/Velodrome bikes? They at least race longer time and distance.

  2. leelikesbikes says:

    Eric — I don’t think Chris is optimizing for BMX racing action. I think he wants to boost those 40-foot doubles without spinning his patellas off their mounts.

  3. leelikesbikes says:

    From Chris Powell:

    “As for shifting at the track: Easy gear for a start, shift at the kink (near where the light is) and then leave it in the diesel gear all the way around. Perfect for me, I’m not the best at spinning because MTB has programmed my legs to shift after a certain rpm.”

  4. Chris says:

    Sean is right. Hammerschmidt is equivalent going up or down a front ring (10 teeth). Unusable for BMX.

    Hammerschmidt is a beefier, inelegant copy of the Schlumpf. Both are 1:1 or 1:1.6. I rode a Schlumpf around the Sea Otter XC course on a gorgeous steel Spot 29er and it blew my mind. You press a button on the crank bolt with your heel so no shifter pod. Singlespeed simplicity.

  5. Eric says:

    Lee and Chris, I know the theory behind it (ie easy gear for holeshot, harder for rest of the track) but especially if you aren’t racing, sorry don’t see the point. Your bike has a nice setup though! I do wish I could do some laps on the Olympic track, even though I wouldn’t be doing 40ft dubs ;D

    I could see a Hammerschmidt type setup working well IF the gear gap wasn’t huge. That would actually be pretty slick seeing as how you could shift while not pedaling.

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