But before you start searching for your missing wheels, think again. The two Australian Defence Force Academy cadets haven't been involved in a spate of stealings.

The young Canberrans are collecting unwanted bicycles to repair and ship overseas to disadvantaged communities.

They hope to pack 500 bikes into a shipping container by August as part of their backyard project, Bikes4Africa, an initiative sending unwanted bikes from around the capital to people who would otherwise walk miles for clean water and medical supplies.

So far they have 100 sets of wheels stored at the academy.

Officer Cadet Skene said a few trips to southern Africa a number of years ago had spurred the project.

"I've been able to experience firsthand the distances disadvantaged communitiess in rural Africa need to travel in order to obtain food, water and medical supplies," he said.

"Bikes presented a really practical way of contributing to these communities."

He started contacting businesses and individuals around Canberra about five years ago in the hope of collecting as many secondhand bicycles as possible for what was then a school project.

That first shipment in 2010 saw 250 bicycles donated to people in southern Africa.

"I repaired them all just in my backyard, much to my parents' displeasure, and I purchased a 20 foot shipping container and put it on my front lawn," he said.

"Slowly, over the course of a year, I repaired all the bicycles, loaded all the bikes into the container, and then I got in contact with a non-government organisation based out of Cape Town, South Africa, the Bicycle Empowerment Network ... to take care of the distribution and logistics."

Officer Cadet Skene met Midshipman Guilmartin at ADFA in 2013 and together the cadets hope to see the Bicycle Empowerment Network distribute 500 bicycles on their behalf.

Midshipman Guilmartin said they were also fundraising for bike parts and tools and the cost of purchasing a larger shipping container, all of which will be donated with the bicycles in September.

"When a shipping container is taken there they'll actually turn it into a bike shed for the community there," he said.

"They'll have one or two permanent staff that will stay there to run it like a bike shop, and they'll do repairs, creating employment opportunities in that community.

"Any leftover money or tools will go to buying extra things like spare tubes and bike tools to chuck in the container to aid [the project's] effectiveness over there."

The pair hopes to see Bikes4Africa grow to become an academy bi-annual project.

"I definitely want to see it become a project the Australian Defence Force Academy takes on with the support of the cadet body here," Officer Cadet Skene said.

For more information or to donate, visit www.gofundme.com/bikes4africa or email mikesbikes4africa@gmail.com.