I Raced the 2025 Tour Divide. Here’s What Nobody Tells You.
A preparation guide for ultra-endurance athletes — from someone who rode 1,000+ miles of it relatively fast and learned the hard way.
@ClaireJencks on YouTube
I have to start with a great confession: I now understand that the Great Divide Mountain Bike Route is not, primarily, a mountain bike race.
I know. Sacrilege. You would think that the word is right there in the name. And yet.
The GDMBR is a 2,745-mile gravel and road race from Banff, Canada to Antelope Wells, New Mexico. It’s 90% unpaved, but technical MTB terrain is maybe five percent of it. The rest is long, exposed, stunning, relentless gravel double-track and good old American highway. The racer’s job is to cover 130 to 150 miles per day (or in the case of 2025 men’s winner, Robin Gemperle, 230 miles on average).
Every. Single. Day. Until you’re done.
I raced the 2025 edition on a Specialized Epic hardtail 29er. I stayed between 5th and 10th place for women while on course and targeted 120–140 miles per day at 125–150 watts. I rode 11 to 13 hours daily through 95–105°F Montana heat, into 40+ mph headwinds, on a course that featured fire reroutes and sporadic downpours.
What I found is that the race is won and lost (in this order) on how well you sleep, how consistently you eat, how well you packed, how fast you move through towns, and whether you can keep your head on straight through hour eleven of a fourteen-hour day.
I came in prepared — months of structured training, a dialed kit, a solid strategy. And even then, I pulled out on the border of Wyoming, 1000+ miles in, due to an injury requiring surgery.
This is the info I wish I’d had before I started.
1. Reset Your Mental Model of the Race
I’m a mountain biker at heart, so be kind when you read the next sentence. Despite the immense prep work and months of training involved in this race, somewhere in the back of my head I still thought it was going to be mountain biking forward. I was so wrong.
The moment it crystallized for me was on the first day, coming out of one of the only strictly single-track sections for hundreds of miles. I was flying up and down, zooming around berms, enjoying myself immensely, only to be unceremoniously dumped right back onto the same gravel road we’d been paralleling the entire time. It would be hundreds of miles before I saw any more single-track.
The truth is, the scenery on this route is staggeringly beautiful and often incredibly remote. The riding is mostly gravel roads. Both things are completely true, so if you’re a MTBer used to adrenaline-filled downhill, you need to go in clear-eyed about the vast amount of roadways you’re going to pedal.
It’s worth it either way.
If you’re a gravel racer scoffing at my silly assumptions, well, mountain bike skills will also serve you well. Headed down ~6,000 ft. Koko Pass on the first evening, I started flying past people who had passed me on the uphill. Now they had dismounted and were picking their way down on foot.
Yes, walking down an entire mountain. On gloriously downhill-slanted double track.
In their defense, many people were on rigid gravel bikes, while I had 110mm of travel and knobby tires, which helped enormously on the chunky descents. But that moment clarified something else helpful about the route:
This race requires you to be comfortable and efficient in all conditions, including descending fast on a heavily loaded bike at speed while mentally drained. If that’s not something you’re training for specifically, start now.
Choosing the right bike for the route is key. While there’s a s*&^load of climbing, what goes up must also come down. Plan accordingly.
The GDMBR is not the race you pictured when you first heard the name. It’s harder in different ways, and more beautiful than you can imagine.
My Strategy: Think in Resupplies, Then Think in Sleep
My 2025 approach was to mentally segment the route between resupply points, targeting daily distances that would land me in a town at the end of each day. This worked well as a first-time framework — clear targets, no food anxiety.
If I raced it a second time, I’d flip the variable: organizing days around sleep rather than fuel. Specifically: how far can I go today so that I end up somewhere with a hotel? The 2025 winner never camped once. At 250+ miles per day he had his pick of towns every night. While that’s not realistic for most of us - both from pedaling and cost perspective — the logic holds at any pace. On the nights I slept in a hotel (1/3rd of the time) my recovery was noticeably better. When the choice is between 16-20 nights on a squirrely camping mattress or in a hotel, I’d take the hotel every time, no contest.
Side note: for the love of Pete, do not go off route for food or hotels. There are a few spots that are really tempting, I’m looking at you Seeley Lake, but I promise, the people who did lost hours and hours.
2. Sleep Is Your Most Important Input
I targeted seven hours a night, lights out by 11pm. I hit this most nights, but had to be ruthless about it. When rolling into a town after dark, everything takes longer than expected — sorting the bike, finding food, handling the sleep setup. The prep time eats into recovery time fast, and five hours of sleep at this output level is a slow-motion disaster that compounds daily. I’ve done it for shorter efforts, but two weeks of sleep deprivation is no joke.
I used a bivy. It works, it’s light, and on cold years I wouldn’t choose it again. It’s a tight, claustrophobic space and sleep quality suffers for it. A lot of 2025 racers were using the Z Lite ultralight — similar weight, meaningfully better sleep. I’d go that direction. I’d also size up the sleeping bag: I carried a 30-degree bag and was genuinely cold on a couple of nights, even in a down jacket and down pants. A 20-degree bag is the move.
But honestly? The bigger upgrade is strategic. Planning days around hotel towns or mid-day heat naps and executing that 80% of the time — my sense is that changes everything about how the race feels.
3. Fueling: I Became a Calorie Consumption Machine
At some point in the first week, my relationship with food changed completely. Taste became irrelevant. Quality became a distant memory. The only thing that mattered was calories, constantly, in any form available.
I found this out conclusively at my post-race dentist appointment.
She looked at my teeth, looked at me, and raised her eyebrows. But, “I’ve been brushing AND flossing every morning and night” I told her. “The issue, was, see, that I’d been biking a lot!” She failed to grasp the connection until I explained the 10,000 calories a day of mostly high-fructose sugar. She was not particularly pleased.
There’s a real irony to this race. You’re out in some of the most spectacular wilderness in North America, and the fuel getting you through all of it is the trashiest food imaginable. It’s like running an F1 car on corn-oil.
And yet — it somehow works.
I ate 300–400 calories per hour for 11–13 hours daily and set a repeating 20-minute alarm on my phone as a prompt to eat something and drink water. I’d use this system from Day 1 again without hesitation.
A representative day:
morning burrito
three bags of Pop-Tarts (one per hour)
two Snickers
two Mars bars
a king-size Twix
a pastry
a Coke
a burger and fries
two bags of jelly beans and Haribo
chocolate milk
abundant maple syrup
a burrito before bed.
I ate as aggressively as I could, had zero digestive issues after Day 1, and still lost six pounds over eight days.
By Day 5 or 6 my metabolism had fully recalibrated. No alarm needed — I could feel hunger arriving every 20 minutes like clockwork and estimate the timer to within about 20 seconds. The body adapts. I found it helped to start eating before I felt like I needed to, not after.
The Quality Window: Days 1 and 2
Helena — around mile 300–400 — is the first point with a proper bike shop and quality nutrition options. Before that, it’s whatever’s available. So I’d front-load the good stuff on a second attempt: as much high-grade sport nutrition (Gnarly, Skratch, Green mix, whatever I train with) as I could carry for the first two days. The fuel-to-weight ratio is excellent, and those early miles matter more than they feel like they do. The gas station food is coming regardless — might as well start the engine on premium.
4. The Mental Game
I’ll admit something. On the evening of Day 1, climbing Koko Pass while carrying my bike, I was quietly smug about the people cursing out loud at how hard it was. Full-volume complaints: “This pass is terrible. This is so awful, I hate this.” And I remember thinking — we signed up for this. We chose this. How could anyone in this mental state right out of the gate?
Then Day 6 arrived.
I was deep in Idaho. Flat. Straight. Roads extending to the horizon in every direction. Had battled through 40 mile per headwinds for 100 miles. No one around. Hadn’t seen another rider in hours, a men’s group leaving together and carrying on past where I’d expected them to stop.
I hit my own wall — the exact same wall I’d watched other people hit on Koko. The same “for what?” moment. The same creeping spiral: I’m definitely not going to win this, I can go hard every day and it won’t matter, what is the actual point of this, this suffering in the middle of nowhere.
The fence post game started somewhere around there. Can I make it to that fence post? Okay. What about the next one? The turn after that? I had to break the infinite flat into pieces small enough to survive. It worked, and it was also slightly absurd — here I was, someone who had voluntarily signed up for a 2,745-mile race, negotiating with myself to make it to a single fence post. And then the one beyond that.
The GDMBR is an extraordinary crucible for mental fortitude. The crucible does not care how prepared you thought you were going in. Every day is the longest day you’ll have on a bike. What matters is how you keep picking up the pieces.
The Wall 👆
A few things that helped: keeping headphones in my frame bag by default — not in my ears — added just enough friction that I didn’t burn through the audiobook library in the first three days. I saved audio for the hard, lonely stretches, and those books were invaluable. I never thought I’d read Churchills biography, but 42,000 listening pages later, here we are.
I also found that narrating out loud — calling out cool sights “pretty view!”, commenting on terrain, talking to my own body parts with friendly concern— “come on legs, we got this!” — while strange and works surprisingly well. And knowing the “for what?” moment is coming, that it’s normal — and that it can be overcome — that knowledge alone is half the battle.
Something I didn't fully anticipate was how much mental energy it's possible to burn on other people's races. Who's ahead, who just passed me, why that person seems to be moving faster on the climbs — none of it is relevant information, and yet the brain serves it up constantly. What I found actually helped was treating each day as its own isolated event: my watts, my sleep, my fueling, my forward progress. The race is too long and too individual to spend any of it running someone else's math.
One more thing I noticed: towns are psychologically destabilizing deep in a race. Out on route with nothing around for 100+ miles, there’s nowhere to stop — “forward” is the only option. The moment you hit a town, the exit is right there. That pull gets stronger as the days accumulate. I found it helped to have a plan for moving through towns with clear intention, rather than letting them become a slow emotional negotiation.
5. Gear: What Worked, What Didn’t, and One Catastrophic Mistake
If you’re looking for yet another GDMBR gear list, I’ve got you covered here.
This list is a easier on the eyes and more interactive but doesn’t include the full repair kit.
The Bike
I rode a Specialized Epic hardtail 29er — 110mm travel, 34T chainring, SRAM 10–52T cassette, 23 lbs without gear. The gearing was right for the climbing, and the suspension earned its keep on the chunky gravel descents off mountain passes. A gravel bike is doable — people do it — but the vibration on the descents would be significant. Some people use handlebar suspension, some people put forks on their gravel bikes - the Salsa Cutthroat (essentially spec’d for this race) is a very popular alternative.
For suspension, I’d prioritize the fork over a seatpost or stem option — that’s where it pays dividends on the descents. And based on what happened with my hands over the course of the race and training, I’d go drop bars next time. The variety of hand positions is genuinely protective over thousands of miles in a way flat bars aren’t. Cockpit fit is something I’d want sorted — and tested under real load — months before the start date.
One thing I couldn’t have done without: the Peak Designs phone mount on the cockpit. Setting 20-minute alarms, calling ahead to hotels, checking the route — having the phone immediately accessible and secure saved real time and mental energy every single day. Yes, irony of ironies even miles from civilization, having the phone truly handy is clutch.
Bags
My setup:
Small backpack for overflow food and rain gear
Two Revelate Mountain Feedbags for water bottles
Oveja Negra Seat Jammer L for clothing
Revelate Pitchfork Aero bag for sleep kit
Revelate Mag Tank 2000 for quick-grab food
Revelate Rifter Frame Bag for everything else.
This worked well — I’d replicate it, swapping only the backpack for a USWE-Rush vest for better fit.
The Bear Spray Situation
In Banff, I picked up bear spray and used a strap to attach it to my front fork. Seemed reasonable. Sometime on Day 3, I started hearing a faint rattling — the kind of sound that briefly registers as potentially important, but not quite enough to stop for when the legs feel good and the pace is right. I heard it for a while.
And then the rattling stopped.
I was relieved.
About an hour later I realized: the rattling had stopped because my bear spray had vibrated off the fork somewhere on the road behind me. Gone. Into the Montana wilderness. The best solution I saw on the entire route was a racer who’d mounted theirs on a fidlock attached to the aerobars — bombproof and immediately accessible. That’s what I’d do next time.
Clothing: The Only Rule That Actually Matters
What I brought:
50+ UPF arm sleeves
Fingered mtb gloves
A lightweight jersey
MTB Shorts
Bibs - Would remove
Fisherman gloves for cold and wet conditions
Down jacket
Down pants
Rain jacket
Rain pants
I’d add knee/leg warmers on a second attempt.
And now the most important gear lesson in this entire guide, delivered as plainly as I can:
Race what you trained. No last minute swaps, upgrades or additions. Whatever the body has adapted to over months of training — that is what goes in the bag.
I trained for months in unpadded Patagonia shorts. They were perfect. On race day, I added padded bibs. Don’t ask me why. Saddle sores developed almost immediately. Once they developed, switching back wasn’t an option. By Day 5 I was standing exclusively on the pedals, which put 130 miles of torque per day through my knees. The entire cascade traced back to a single last-minute decision that contradicted months of adaptation.
Don’t do this. I was dumb and second-guessed myself. Stick to the plan, Stan.
6. Race Logistics
Communication and Registration
There’s almost no official communication until four or five days before the start. After sending a letter of intent (an email to tourdivide@gmail.com stating the intention to race), a pre-race email arrives the week prior to the race with a Google Form for your information and Spot tracking details.
At that point: confirm your tracker is set up for 10-minute tracking intervals, set up the public tracking link, add it to the shared doc, and then test it. Actually, test it twice.
Arriving in Banff / Canmore
Book accommodation months in advance — this is peak tourist season in a major tourist corridor and things fill up fast. Book refundable to retain flexibility, and arrive at least a day early (two is better). Bear spray needs to be sourced on arrival if flying in, a final gear check is worth doing, and there’s something genuinely enjoyable about walking around looking at everyone else’s bike setups and quietly second-guessing your own.
There’s a loosely organized pre-race gathering the evening before — informal, word-of-mouth, more social than tactical. Worth it if you want to meet people before the start but nothing will be missed with non-attendance.
GPX Files and Navigation
The official GPX files are…HUGE. They can and might be updated even after the official versions go out — worth monitoring email through race day.
I used gpx.studio to chop the full route into six sections, but you could chop these into daily sections, or whatever your heart desires. Even chopped, those sections stalled my Wahoo, and I ended up having to clear all previously loaded routes and reinstalling the Wahoo ELEMNT app entirely.
I’d budget real time for this — not 11pm the night before departure.
I ALSO downloaded the full route via RideWithGPS onto my phone and kept it accessible throughout the race. Visual map backup on the phone, independent of the Wahoo, was extremely useful — I’d treat it as non-negotiable.
Wahoo settings worth getting right:
Turn off GPS re-routing (follow the track, don’t let it autocorrect)
Set to ‘Track Up’ mode for better orientation
Strip the main screen down to map, watts, and heart rate. Nothing else.
7. Training
Find a friend. I have an incredible friend enabled me to take this one - without her knowledge and help I wouldn’t even have made it to day one. She put together my training plan, coached me through hours and hours of learning and stuck with me as I geared up to the take this on. It takes a team to get through challenges like this and I highly recommend finding likeminded souls to do this with.
The approach that we settled on for me was progressive Zone 2 with an increasingly loaded bike — progressively heavier gear, progressively longer days, using the actual equipment I’d race with. On long training days, point-to-point routes felt more motivating than loops and better replicated the mental texture of the race itself.
I also found it was worth keeping hard efforts off the loaded bike during training — saving loaded riding for Zone 2. Better for morale, better for the knees, and arriving at race day having built capacity without accumulating unnecessary wear.
One thing I’d sort out earlier on a second attempt: the device charging ecosystem. Head unit, Spot tracker, phone, pedals, headphones, they all suck up battery juice. Even with a dynamo hub and a charging brick — knowing how each one charges (ie where it is on the bike), how long it lasts, and what to do if something goes wrong is invaluable. Getting this dialed far before race day eliminates an entire category of stress that compounds when you’re already tired.
The Bottom Line
The GDMBR demands more than any training block can fully prepare you for. The heat, the isolation, the fence-post negotiations somewhere in Idaho, the “for what?” moment that arrives on it’s own schedule whether you’re ready for it or not — those are things you meet in the moment.
But from what I saw, the athletes who struggled most almost never struggled because they lacked fitness. They struggled because they underestimated the logistics, made a last-minute gear change that undid months of adaptation (me, yeah that was me), didn’t have a sleep strategy, or went way off-route looking for a hamburger.
Every small decision on this race compounds. Do the preparation genuinely right and it shows.
P.S. Maybe get a dental checkup after the race. You know, just in case.
Claire Jencks likes to do hard bike related stuff and share it on YouTube. Subscribe at youtube.com/@ClaireJencks