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>Gravity Bike

Compared with some of the other projects that we have become involved with, building a gravity bike is a real doddle.

We followed Dr. Neil Farrow through the process of building a Gravity Bike. The completed bike worked so well, Neil clinched a third place position in the Highland Extreme 2002!

How to build a Gravity Bike...

Neil Farrow was able to purchase a used 20" BMX bike for £50, which was in good condition and was advertised locally. This proved to be a good machine to base the project on however you could opt for a new BMX bike instead of purchasing used.

According to Neil "if I were to build a gravity bike again, I would seriously consider buying a new BMX bike with some good v-brakes already fitted, and perhaps some front suspension. I've seen them on sale for about £120, which is a good deal."

Any ways here is how Neil built his Gravity Bike

 

Start with a BMX...
The costs to date (£UK):
1 Used BMX bike 50
2 V-brakes 30
3 Mounting plates (brakes) 20
4 Tyres (incl. inner tubes) 30
5 Seat (mountain bike) 12
6 Handle bars (had spare) n/a
7 Knee rest (home made) 2
8 Rear foot pegs (came with bike) n/a
9 Steering dampener (had spare) n/a
10 Bearings (orig. OK) n/a
11 Wheels straighten 8
12 Welding (D.I.Y.) 5
The total to date: £157
Gravity bike link:
Gravity Bike.com
Gravity bike racing photos:
Link to us

Before

After

 
Work still to do...  

Frame flip: Neil would like to try flipping the frame back to its origional position to see if it makes the bike more stable (its a bit twitchy at speed).

Steering dampener: Neil would also like to install one of the steering dampeners from his racing motorcycles to help make the front end more planted.

 
What we learnt this time...  

Consider buying a new BMX bike with good V-brakes, or disk brakes and possibly a suspension if the price is right. Remember a cheep suspension might not be up to the job so budget for rebuilding or replacing.

Disk brakes are recommended if you are going to be racing on courses where heavy breaking is required or in hotter climates. As with all bikes, something like 95% of your braking power is from your front brake, so if you can afford just one brake upgrade, make sure you invest it in the front.