John 'Zac' Brennan

7years All Star
John 'Zac' Brennan
Cancer is the biggest killer of kids from disease in the USA, 38 children die every week. Please donate now and support my challenge to fight kids' cancer!
I've Ridden 327.6 mi My goal is 500 mi
My Rankings
  • National: 213th
  • State: 7th in CO
  • My Team: 4th
I've raised $4,259 My goal is $4,500 Donate Now

I'm Riding For

Kahleesi

Kahleesi

Kahleesi ride your cool bike! Have fun❤️

My Story

26 Sep 2026

This September 2026 I am taking part in the Great Cycle Challenge to fight kids' cancer!

Cancer research funding has been recently defunded by the current administration in Washington. Now, more than ever the children née our help.

Why? Because right now, cancer is the biggest killer of children from disease in the United States. Over 15,700 children are diagnosed every year, and sadly, 38 children die of cancer every week. Kids should be living life, not fighting for it.

So I am raising funds through my challenge to help these kids and support Children's Cancer Research Fund to allow them to continue their work to develop lifesaving treatments and find a cure for childhood cancer.

Please support me by making a donation to give these kids the brighter futures they deserve. I'm also riding for myself. In Vietnam in the Army I was exposed to Agent Orange herbicide and now at 76, have Stage IV prostate cancer.

Your support will change little lives.....and mine too!

Thank you.

John Zac Brennan

My Legacy

Here's my personal impact over 7 years to fight kids' cancer and save little lives.
  • 514 mi Ridden
    $2,077 Raised
    2020
  • 465 mi Ridden
    $1,695 Raised
    2021
  • 519 mi Ridden
    $2,266 Raised
    2022
  • 546 mi Ridden
    $6,000 Raised
    2023
  • 565 mi Ridden
    $4,500 Raised
    2024
  • 534 mi Ridden
    $4,240 Raised
    2025
  • 328 mi Ridden
    $4,259 Raised
    2026
7years
3,471 mi
Ridden
$25,037
Raised

My Challenge

  • 30.4 mi ride - Hayden Power Plant pump house - Sunday, September 27, 2026
    Logged this ride 2 days ago
  • 25.6 mi ride - Bartholomew Lane Loop - Saturday, September 26, 2026
    Logged this ride 3 days ago
  • 4.9 mi ride - Post surgery ride - Friday, September 25, 2026
    Logged this ride 3 days ago
  • 8.1 mi ride - Urgent Care - Tuesday, September 22, 2026
    Logged this ride 7 days ago
  • 12.6 mi ride - Flat Tire - Sunday, September 20, 2026
    Logged this ride 7 days ago
  • 25.6 mi ride - Thursday, September 17, 2026
    Logged this ride 7 days ago
  • 1.0 mi ride - Wednesday, September 16, 2026
    Logged this ride 7 days ago
  • 20.4 mi ride - Into the sunset - Wednesday, September 16, 2026
    Logged this ride 13 days ago
  • 25.3 mi ride - Bartholomew Lane - Monday, September 14, 2026
    Logged this ride 14 days ago
  • Saturday, September 12 ride
    13 Sep 2026

    27 mile loop from our campsite through area mountains. Windy! Elevation gain of 2,041 feet. Scenic.

    Saturday, September 12 ride
    Posted 16 days ago

My Sponsors

  • Kick Cancer's Butt Day matched donation
    “Here's your matched donation from a group of wonderful Children's Cancer Research Fund supporters. THANK YOU so much for your awesome efforts to kick cancer's butt!”
    $450.02
    Received this donation 20 days ago
    John 'Zac' Brennan
    John
    “Thank you.”
  • Matched Day Matching Donation
    “Here's your matched donation from a group of wonderful Children's Cancer Research Fund supporters. THANK YOU so much for your awesome efforts to fight kids' cancer!”
    $254.81
    Received this donation 6 days ago
    John 'Zac' Brennan
    John
    “Thank you for your support! Every dollar for research is vital.”
  • Mike and Sharon Kinsella
    $207
    Received this donation 4 days ago
    John 'Zac' Brennan
    John
    “Mike and Sharon, Thank you very much for your donation and support. I had oral surgery down in Grand Junction yesterday. I’m going to ramp up my riding to hit my goal of at least, 500 miles.☮️❤️Zac”
  • Pat O’Leary
    “Cancer Sucks! Thanks for riding to support the Children’s Cancer Research Fund. ♥️”
    $207
    Received this donation 15 days ago
    John 'Zac' Brennan
    John
    “Thank you Little Dear☮️❤️”
  • Christopher Flanagan
    $103.50
    Received this donation 49 days ago
    John 'Zac' Brennan
    John
    “Chris, Thank you for your support. I’m gearing up for next month’s Ride. Been riding when the heat relents. A few mornings and evenings. My legs are good ,it’s the smoke that’s reduced my normal ride levels this Spring/Summer. I’m coming to Junction Monday afternoon, August 24th. Oral surgeon follow up visit Tuesday am. I would like to get together. Dinner Monday? Brunch Tuesday? Lemme know Please share my link with friends and family!”
  • Donald Carluccio
    $103.50
    Received this donation 20 days ago
    John 'Zac' Brennan
    John
    “Thank you Judy and Don☮️❤️”
  • Anonymous
    $103.50
    Received this donation 20 days ago
    John 'Zac' Brennan
    John
    “Thank you ☮️❤️”
  • Greg Krallman
    “Go gettem Zac , I think it’s awesome that you do this every fall .”
    $103.50
    Received this donation 37 days ago
    John 'Zac' Brennan
    John
    “Thank you, Greg! You know the value of support that we can give each other. Whether you’re on the giving or the receiving end of it, it’s vital that we continue to help each other out. These little children fighting their cancers need all the support, help and love that we can give them. Research is critical. Please share my ride at https://greatcyclechallenge.com/Riders/JohnBrennan”
  • Jeff and Gloria Halliday
    “Thank you, Zac, for taking on such a critical problem. Your annual commitment to fight cancer goes a long way to putting an end to a terrible threat. Bravo!”
    $103.50
    Received this donation 13 days ago
    John 'Zac' Brennan
    John
    “Thank you Jeff & Gloria for your support. The kids and their families thank you as well. Also the researchers whose funding has been cut by politicians. Zac ☮️❤️”
  • Joe Huselton
    “Come out of your driveway slower”
    $103.50
    Received this donation 19 days ago
    John 'Zac' Brennan
    John
    “I’m making up for lost time. Thank you Joe for your generous support!! Zac”
  • Lura Briscoe
    “Way to go Zach! Thank you for being there for Jeff! Lots of love and big hearts! Lura”
    $103.50
    Received this donation 39 days ago
    John 'Zac' Brennan
    John
    “Lura, Thank you so very much! This Cycle Challenge is fun for me, except when it’s hot!! The small amount of suffering I feel from the heat is nothing compared to what these little children go through with their cancer treatments. Please share my ride with your family and friends. ☮️❤️❤️ I miss Jeff.”
  • Mark Lobstein
    “Thanks for your dedication Zac! Doug is peddling right there with you….”
    $103.50
    Received this donation 13 days ago
    John 'Zac' Brennan
    John
    “Hey Mark! Thank you for your support! We are finally getting rain here. Of course we are camping. Our drier than dry Western environment really needs it. I can ride in the rain, it’s nothing compared to what these kids endure. Treatment requires breakthroughs by researchers. Please share my link.Zac☮️❤️”
  • Mike & Cindy Ruzicka
    “Thanks for doing this, Zac!”
    $103.50
    Received this donation 40 days ago
    John 'Zac' Brennan
    John
    “Mike&Cindy, thank you for your support. The kids and their families also thank you. The monies we raise support children’s cancer research. We need to keep the scientists working. We need to eliminate all cancers, especially children’s cancers! Please share my link with friends and family! ☮️❤️”
  • Rob Dilldine
    “Zac, I'm very proud of you. Peddle on my Friend!”
    $103.50
    Received this donation 39 days ago
    John 'Zac' Brennan
    John
    “Hey Rob, thanks for your kind support. These children need all the help we can give them to fight these terrible cancers. The researchers need funding, and this is where we come in. I’m gonna go for a ride shortly. Take care buddy.☮️❤️ Please share my link with friends and family!”
  • Rob Wilmoth
    “Atta Boy Zac! Thanks for your efforts. Rob”
    $103.50
    Received this donation 20 days ago
    John 'Zac' Brennan
    John
    “Thank you Rob☮️❤️”
  • Susan Teuton
    $103.50
    Received this donation 6 days ago
    John 'Zac' Brennan
    John
    “Thank you Susan❤️ These kids deserve a healthy shot at life. Research funding has been interrupted down here. Trouble is these terrible childhood cancers keep keeping on.☮️❤️Zac”
  • TBH Plumbing & Heating
    “How about delivering some material while you're out on your rides? That burn some miles! 😂😂”
    $103.50
    Received this donation 19 days ago
    John 'Zac' Brennan
    John
    “Thank you Tucker for your generous donation. AND the job offer. Unfortunately you can’t afford me😎”
  • TIMOTHY ANDERSON
    “Keep peddling you beast. Thx for fighting kids cancer.”
    $103.50
    Received this donation 13 days ago
    John 'Zac' Brennan
    John
    “Tim and Laura, thank you for your help. The boundary waters are forming up at Pearl Lake. But you know, we need the rain. It makes it difficult to get motivated to go ride. But I shall endeavor to persevere.”
  • Tom Raushenbush
    “Make it happen Zac. Enjoyed fishing with you!”
    $103.50
    Received this donation 19 days ago
    John 'Zac' Brennan
    John
    “Thank you Tom. I’m out on a ride now. It’s a beautiful day in the neighborhood.☮️❤️”
  • Wayne and Lisa Adamo
    $103.50
    Received this donation 20 days ago
    John 'Zac' Brennan
    John
    “Thank you Wayne and Lisa☮️❤️”
Donate Now