Firefighters were five times more susceptible to a range of cancers because of their work, Mr Rush said.
The last two rides raised $45,000 each and by yesterday more than $15,800 had been raised.
The ride begins on November 6 and is set to finish on November 14 or 15.
Two other Wanganui firefighters will be joining the ride at some point. The core group of 20 will be picking up others as they travel up the country.
Wanganui Fire Service training data administrator Bryan Barkla joined part of the ride on a 50cc scooter, Mr Rush said.
Suzuki NZ is also getting involved this year, supplying a spare motorcycle and a support vehicle and trailer, so anyone who breaks down or gets a flat tyre doesn't have to be left behind.
"That was extremely generous," Mr Rush said. "We just really appreciate the support from Suzuki."
He said the camaraderie during the ride was "fantastic".
"I have to say, the support we've got from people, it's really humbling. What people do and say and give us is just really humbling.
"It's quite a rewarding thing to do."
Mr Rush said he was diagnosed with cancer in about 1985.
"I knew something was wrong so I went and got it looked at and they cut a huge lump in my leg. They've cut a whole lot of lumps out of me since!"
He said getting early treatment was the key to survival.
People who want to donate to the cause can go to rideforcancer.org.nz to pay by credit card, or make electronic payments to 06 0501 0024342 00. They can also come into the fire station in Gilberd St to make a payment, or phone the station on 06 348 0103 and ask for someone to pick up their payment.