Introduction: Gravitybike HQ

Picture of Gravitybike HQ
Brett Phillips - Gravitybike HQ

A Gravity Bike is a specialised two wheeled bicycle propelled by nothing other than gravity. Without pedals or a chain, Gravity Bike riders rely on steep gradients and gravity to reach incredibly fast speeds. Historically, Gravity Bikes evolved from modifying a traditional BMX where a rider would add weight, alter seating and handlebar positions and change a bikes aerodynamic characteristics in the pursuit of greater speeds. More recently, Gravity Bikes have evolved to become highly specialised and purpose built machines capable of reaching speeds over 130kph from a standing push start.

Gravity Bikes are ultimately built for speed. The steeper and more technical a road or dedicated racing circuit, the greater the adrenaline rush for riders. Fitted with full protective gear including leathers, helmets, gloves and boots, Gravity Bike riding combines the thrill of speed with a love of bicycles.

In 2009, I designed and built this purpose built and highly specialised Gravity Bike. The first of its kind, the bike is a quantum leap in Gravity Bike design and fabrication. The bike is a combination of hand fabricated and CNC (computed numerically controlled) components. The bike was designed from scratch and had to accommodate existing components such as 20'" wheels and mountain bike brakes. The bike has reached speeds of 136kph from a standing push start and assisted me to win the 2009 World Gravity Bike Championships. The only Australian to do so to date. I hope you guys like the build!

For more:


IndexGlobal made it! (author)2016-08-29

Hey guys! Test your builds out with Global Speed Index to get your speed, and check other Gravity Bike Gear and riders from around the world. Global Speed Index is an App for Gravity Bikes and Action Sports. Check it out @ - one you register, get a free month subscription to PRO Services, just send us a message via Contact Us in settings screen with GBIKE in the body. Happy building, and happy riding!

cedric.royblanchard (author)2015-05-01

What are those 6 pistons brakes?

Great project by the way!

ZacharyL2 (author)2015-02-03

so who made the very first gravity bike??

ZacharyL2 (author)2015-02-03

so who made the very first gravity bike??

The nerdling (author)2012-12-26

i see your in australia, do you know lithgow?
if you do, there is a huge steep windy highway there, which would be great for this, but, there is a cliff on the edge, not too high but still a cliff

jeffconnelly (author)2012-07-26

"The first of its kind, the bike is a quantum leap in Gravity Bike design and fabrication."

You're probably going to want to change that. A quantum leap is the smallest measurable change.

Atomic Electron Transision 

Aron313 (author)2012-05-19

Can you say it in mph?

Bjorgulf (author)Aron3132012-07-09

just divide by 1.6 ;)
or multiply with 5/8 if that suits you better

Aron313 (author)Bjorgulf2012-07-12

Ok thanks.

Oldbear (author)2012-07-08

Odd question - but do you have to counter steer at a certain speed? (my motorbikes have been anywhere from 25kmph to 35)

mr fat (author)2012-04-06

Is there any gravity bike racing in Queensland?

Dedlee (author)2011-09-08

I want to find someone to build me a gravity bike. As of now I ride a BMX doing downhill. Any suggestions?

gravitybike (author)Dedlee2011-09-11

Hey Dedlee
shoot me a email at brett(at)gravitybike(dot)com(dot)au and we can have a chat about it! cheers Brett

Simba8400 (author)gravitybike2011-10-02

how much would you ask for one built just like that?

afleming2 (author)2011-10-01

looks comfortable

calcooper5 (author)2011-06-22

This would be cooler if you put up some instructions on how to build this bad boy

evindrews (author)calcooper52011-08-27

there IS one.

calcooper5 (author)evindrews2011-08-28

ive seen that one but it is a completely different grav bike. i would love to build THIS one

tyoung6 (author)2011-07-27

whats the song

TheMaker888 (author)2011-06-22

dont get pulled over for speeding mate haha
nice bike too, you build it?

russvan (author)2011-06-09

that is amazing

TwistyTIE (author)2011-06-08

oh my that design is just asking for a small bike engine to be put on it :P

Ceiling cat (author)2011-05-23

I love that you're wearing Converse high-tops in the video. Probably some of my favorite shoes. I've been wearing mine a lot lately.

gravitybike (author)Ceiling cat2011-05-23

Hey CC, they are the best shoes and have followed me all over the world on the bike! :)

rimar2000 (author)2011-05-20

WOW! That is wonderful! It is a pity that my area be totally plain.

The bike seems very strong. Good design.

notingkool (author)rimar20002011-05-20

muy diferente a la planilandia de La plata, no se puede andar ni en patineta, por el empedrado.

rimar2000 (author)notingkool2011-05-20

Sí, la pendiente más alta y pronunciada que tengo a 200 kilómetros a la redonda es el acceso a la autopista...

notingkool (author)rimar20002011-05-20

jajaja, es verdad. Aunque descubri que todas las calles son planas hasta que te subis a la bici y te das cuenta que estan todas en subida.

notingkool (author)2011-05-20

is awesome, i wish i live in a place with that road. it's ideal to longboard and to back home without efford

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