Latin America's oldest and most traditional MTB marathon — since 1993, held every September in the historic iron-mining mountains around Mariana, Minas Gerais.
Build Your Personalized Race Fueling Plan — $19Iron Biker Brasil is Latin America's oldest and most traditional mountain bike marathon, held every year since 1993 in Mariana, Minas Gerais, in the historic Vale do Ouro (Gold Valley) iron-mining region. The 2026 edition runs September 11–13, offering a Friday warm-up ride, a Saturday XCO/short-course day, and the Sunday marathon that remains the event's centerpiece. Technical singletrack, iron-rich red dirt, steep climbs on old mule tracks and mine roads, and 30+ years of race culture make Iron Biker as much a rite of passage as a race. The organizer's slogans — 'NO FUN, NO WAY!' and 'Muito além de uma medalha' (much more than a medal) — capture the tone.
Distance
≈ 37–56 mi depending on category (main marathon on Sunday; shorter Sport / e-bike / duplas courses across the weekend)
Elevation
≈ 2,000–11,480 ft of climbing on the main marathon
Typical duration
4 – 8 hours for most amateur finishers on the marathon
Location
Mariana, Minas Gerais, Brazil (Vale do Ouro region, ~120 km southeast of Belo Horizonte)
Time of year
September 11 – 13, 2026 (Fri warm-up + Sat short course + Sun marathon)
Terrain
Technical singletrack, iron-rich red dirt, historic mule tracks and mine roads, rock gardens, steep climbs and fast rutted descents
A practical race-week checklist: carbs, hydration, sodium, caffeine and race-day supplies — print it or keep it on your phone.
Iron Biker spends hours in demanding singletrack — rock gardens, rooty descents, mine-road rubble — where safely opening a gel is impossible. Fueling windows must be planned around the terrain, not against it.
Short, steep climbs on loose iron-rich dirt push riders into repeated anaerobic efforts and burn glycogen faster than sustained tempo climbing does. Pacing the first hour is the single most predictive decision of the day.
September mornings in the Mariana mountains can drop below 54 °F, with afternoons routinely reaching 79–86 °F. Layering, sunscreen and hydration compliance all matter — one bad call on any of the three costs the second half.
Iron-rich dust in the second half of the day dries the mouth, worsens respiratory water loss and can amplify GI distress if intake is aggressive. Liquid-biased fueling is generally more tolerable than solid food from mid-race onward.
Aid stations are placed by terrain rather than by clock. Mid-pack riders can go 60–90 minutes between resupplies and need to plan bottle capacity for it — a single bottle empties in about 60 minutes at Mariana afternoon temperatures.
Historic mule tracks and mine roads deliver loose rock, exposed roots, rutted descents and the occasional hidden gully. Line choice and skill under fatigue matter more than raw power output — a crash in hour 4 ends day 5.
Course elevations range from 500 to over 4,270 ft. Not high enough to require altitude prep, but the Mariana high points make sustained tempo feel harder than sea-level equivalents, especially in the second half.
General, evidence-based guidance. Numbers should always be personalized to sweat rate, body mass, fitness and weather.
60–90 g/hr of mixed-source carbohydrate (glucose : fructose ~1 : 0.8) for most trained riders, weighted toward liquid and gel for the technical sections where chewing is unsafe. Trained guts can push toward 100 g/hr on longer marathon distances.
17–34 fl oz/hr adjusted for the day's temperature. Cool-morning riders systematically under-drink in the first two hours and pay for it in hour three or four. Drink to the clock, not to thirst — especially on the cold start.
500–1000 mg of sodium per liter of fluid as a default. Salty sweaters and warm afternoon-half riders should push toward 800–1200 mg/L. Under-salting is the most common cause of mid-race cramping on Iron Biker's steep climbs.
3–6 mg/kg body mass, split between pre-start (with breakfast) and a mid-race dose at the base of the biggest climb. A 154 lb rider targeting 5 mg/kg takes ~200 mg pre-race and 150 mg mid-race.
Every stop is a bottle swap first, calorie top-up second. Rehearse a one-minute stop in training so it stays one minute on race day. Pre-mixed bottles in a team box (or friend at aid 1 + aid 2) save 3–5 minutes across the day.
1–4 g/kg carbohydrate 2–4 hours before the gun, from familiar low-fiber, low-fat foods. A 154 lb rider targets 140–280 g CHO. Pão de queijo + banana + honey or arroz + mel are proven Brazilian options — no experiments on race morning.
Fuel BEFORE entering technical sections and IMMEDIATELY after exiting them — never force intake with both hands on the bar. Set a 15-minute alarm on the head unit as a backstop. On climbs, sip constantly and take a gel every 20 min.
Within 30–60 minutes of the finish: 1.0–1.2 g/kg carbohydrate and 0.3 g/kg protein, plus 150% fluid replacement. Iron Biker's 3-day format means recovery nutrition on day 1 (Friday warm-up) shapes day 3 (Sunday marathon) — do not skip it.
Grams and millilitres per hour for each phase of the race. Personalize to your sweat rate, body mass and conditions.
Iron Biker Brasil Sunday marathon (37–56 mi, 4–8 hr) — targets for a mid-pack finisher
0 → first aid (~9–16 mi)·0:00 → ~1:00
Caffeine: 150–200 mg 20 min pre-start (with breakfast option)
Focus: Do NOT chase early moves — Iron Biker punishes riders who match early surges. Cap effort at high Zone 2 / low Zone 3 HR. Lock in a 15-min intake alarm from km 0.
First to second aid (~16–31 mi)·~1:00 → ~2:30
Focus: Force calories BEFORE entering rock gardens and IMMEDIATELY after exiting them. Watch how the gut is tolerating the intake in warm dust — pull back 10 g/hr if bloated.
Second to third aid (~31–43 mi)·~2:30 → ~4:00
Caffeine: 100–150 mg at the base of the biggest climb
Focus: Fixed HR / RPE ceiling. Force calories even at reduced appetite. Every aid stop: bottle swap first, calories second, do not linger.
Third aid to finish (~43–56 mi)·~4:00 → finish
Focus: Ride to power / HR, not to feel. Late-race under-fueling is where riders break — reset the 15-min alarm even if you 'know' the finish is close. Stay conservative on rutted descents.
Finish line to team box·T+0 → T+60
Focus: Recovery starts the moment you cross the line. Compress, shade, elevate. If riding Friday–Saturday too, this recovery window is what makes Sunday's marathon possible.
Aid station spacing and mid-race distances are provisional — confirm the exact 2026 marathon layout, cutoffs and category-specific distance in the current-year Manual do Ciclista on ironbiker.com.br. Individual sweat rate can shift fluid and sodium targets by ±30%; personalize with a pre-race sweat test.
A structured 48–72 hour carbohydrate-loading protocol tuned for a long day at altitude. Rehearse it before a training block, not for the first time on race week.
Target 6–8 g/kg body mass per day of carbohydrate while transitioning to lower-fiber, lower-fat foods that protect the gut for race day. Reduce raw vegetables, fried food and heavy sauces. Add 500–1,000 mg sodium per liter of fluid.
Target 8–10 g/kg body mass per day of carbohydrate from familiar low-fiber sources: rice, pasta, potato, bread, sports drinks, honey, pão de queijo. Keep protein moderate (1.2–1.6 g/kg/day). Reduce fat to ~0.5–0.8 g/kg/day. Hydrate to pale-yellow urine.
Same high-carb, low-fiber, low-fat pattern. Do not experiment with new foods, new restaurants, or a special 'pre-race' meal you have never eaten. Ride 30–45 min easy with 3–5 race-effort openers. Sleep 8+ hours.
1–4 g/kg carbohydrate 2–4 hours before the gun, from familiar low-fiber, low-fat foods. Add 30–50 g CHO 15–30 min before start via a gel and sports drink.
If riding Friday warm-up or Saturday short course before Sunday's marathon: within 30–60 min of each finish take 1.0–1.2 g/kg CHO + 0.3 g/kg protein, then a full meal 1–3 h later. Sunday's marathon depends on how well you refuel Friday and Saturday.
Iron Biker's opening kilometers often include a fast rollout followed by the first punchy climb. Riders who match early surges burn matches they will need on the long climbs of the middle third. Cap effort at high Zone 2 / low Zone 3 heart rate through the first 90 minutes.
Line choice in rocky singletrack decides GC time more than raw power. Ride your line even if the rider in front takes another — following bad lines to save 5 watts costs 30 seconds and a mechanical.
You cannot eat safely in Iron Biker's rock gardens. Force calories BEFORE entering each technical section and IMMEDIATELY after exiting. Losing one scheduled feed in a rock garden means chasing 30–40 g of missed carbs for the next 30 minutes.
Punchy Mariana climbs on loose iron-rich dirt reward steady spinning at threshold, not stomping. Standing efforts on loose surface tend to spin out — sit down, small gear, steady breathing.
Long rutted descents feel like rest but do not replace calories. Keep sipping, take a gel between technical sections, and ride within your skills — a crash in hour 4 costs more than the time you save on the descent.
Aid stops eat marathon time. Cap total stopped time to a written budget (60–90 sec per aid, 3–5 min total across the marathon). Pre-mixed bottles + a written stop plan cut stopped time in half.
A modern XC hardtail (fast, light, efficient on climbs) or a 100–120 mm short-travel trail bike both win Iron Biker. Hardtails favor climbing efficiency; a short-travel full-suspension protects the back on rocky descents and preserves late-race power. Race the platform you have trained on.
Most riders run 2.2–2.4" tubeless XC tires with reinforced casings. Iron-ore rock chips are famously unforgiving — avoid ultralight casings. Semi-aggressive tread with strong cornering knobs handles the rocky-to-loose-dirt range. Fit fresh tires 2–3 weeks pre-race and confirm sealant is topped up.
Starting point for a 154–176 lb rider on 30 mm internal rims: 20–24 psi front, 22–26 psi rear. Add 2–3 psi for heavier riders or rockier route years. Test on Ouro Preto / Mariana-style terrain if possible — rocky red dirt feels different than smooth home loops.
A 32–34t front chainring paired with a 10–52t (SRAM) or 10–51t (Shimano) 12-speed cassette gives most amateurs a bailout for the steepest Mariana pitches. Elite riders often go 34–36t front.
Four-piston brakes with 180 mm rotors front and 160–180 mm rear handle the rutted descents. Fresh pads race week, bed them in on a short descent. Carry a spare set in the team box — dry-season dust wears pads faster than mud.
A 100–150 mm dropper is worth the small weight penalty on Iron Biker's rutted descents for most amateurs. Front-of-pack racers weigh the trade-off individually.
Two large bottle cages plus a 51–68 fl oz hydration pack is the common setup — bottles alone leave you exposed between aid stations in Mariana afternoon heat. Some elite riders skip the pack on the shortest categories.
Minimum: 2× CO₂ + inflator, tire plug kit, mini pump, tubeless spare tube, tire lever, chain quick link, multi-tool with chain breaker, spare derailleur hanger. Zip-tie a valve core tool to the frame. Iron-ore dust chews drivetrains — carry chain lube for nightly cleaning across the 3-day weekend.
| T-4 h | Wake, coffee, first breakfast (1–2 g/kg CHO) from familiar low-fiber, low-fat foods: pão de queijo + banana + honey, arroz + mel, or oatmeal + fruit. Hydrate 17 fl oz with sodium. |
|---|---|
| T-2 h | Second small feed (~50 g CHO) — fruit + sports drink. Chamois cream, sunscreen SPF 50+, kit on with morning layer. |
| T-90 min | Bike check — tire pressure, brakes, chain lube, dropper, computer, bottles loaded (pre-mixed), top-tube bag stocked. Layer for 50–59 °F start. |
| T-45 min | Ride or drive to the start venue. Sip 7–10 fl oz sports drink. Restroom. |
| T-20 min | First caffeine dose (100–200 mg if used). Final sunscreen check. Confirm HR / power start plan with yourself. Warm layer over kit until 5 min out. |
| T-5 min | Half a gel. Breathe. Commit to a conservative first hour (do not chase early surges). |
| Gun | Rollout. Cap effort in the first hour — the deciding sections come at hours 3–5, not in the opening rush. |
Every entry route into the Iron Biker, from the annual lottery to qualifier races, coaching-program slots and charity entries.
Register online at ironbiker.com.br/inscricoes. First-lot pricing is discounted; pricing tiers up as the event fills through the year. Confirm current-year pricing, category eligibility, installment options and deadlines on the official site.
Iron Biker typically runs Pro Elite (M/F), age-group solo categories, Duplas (teams of two), Sport / short-course entries and one of Brazil's largest e-bike brackets. Choose based on your fitness, technical skill and finish-time goal — the marathon is the flagship but not the entry point.
Team-of-two categories require your partner to finish each stage within a maximum time gap. Pick a partner whose fitness, technical skill and mechanical ability match yours — a mismatched duo loses 10–20 minutes per stage waiting or pulling.
Refund and transfer windows are set year-by-year. Historically a partial refund window closes 30–60 days pre-event; category changes and transfers may be possible before published deadlines, subject to fees. Always confirm the current-year policy.
Airports, lodging, packet pickup, parking and crew access for the Iron Biker.
Fly into Confins / Belo Horizonte (CNF) and drive ~75 mi / 2 – 2.5 hours to Mariana via BR-262 and BR-356. Rio de Janeiro (GIG) is ~280 mi / 6 hours. Rental car is the practical option — no reliable shuttle to Mariana.
Options in Mariana (colonial center, closest to start) and Ouro Preto (7 mi away, more restaurant density). Book 3–6 months in advance for race weekend — the event fills both towns. Confirm any official host-hotel partnership on ironbiker.com.br before booking independently.
Held in Mariana on the days before Sunday's marathon per the current-year Manual do Ciclista. Attend any pre-race briefing — course changes, cutoffs and safety notices are announced there. Bring photo ID and registration confirmation.
Ship your bike ahead via a specialized courier or fly with a bike case (Brazilian domestic airlines charge R$ 200–500 per segment). If flying with the bike, arrive at least 48 hours before Sunday's marathon to allow reassembly and any post-transport mechanical issues.
Familiar low-fiber, low-fat foods are non-negotiable in race week. Mariana and Ouro Preto have quality restaurants but portions and timing may not match your rehearsed routine — negotiate early breakfast service with your hotel and bring familiar staples if traveling long distances.
The 3-day format (Fri warm-up + Sat short course + Sun marathon) means logistics span three days. Riders entering only the marathon should still plan for Friday packet pickup and Saturday pre-ride if the course allows.
You cannot safely open a gel in a rock garden. Riders who skip a scheduled feed 'because the trail is technical' arrive at the next open section already 15 g behind — front-load instead.
Cold-start hours suppress thirst even as sweat losses build in the first climbs. Structured intake matters MORE in the cold, not less. Force one full bottle before you feel warm.
Technical MTB burns glycogen faster than steady road tempo at the same average power. Iron Biker intake targets should sit at the top of the recommended range, not the bottom.
Iron-rich dust plus long time-on-course amplifies GI risk. Race only what you have trained on 4+ hour rides — even a familiar-looking new gel is a bad bet.
Thirst under-reports fluid deficit by 1–2%. On a 6+ hour Iron Biker day, that gap compounds into cramping and cognitive fog by hour 5.
The 3-day format tempts riders to celebrate Friday and Saturday and 'save' the discipline for Sunday. Under-fueled recovery on Friday shows up on Sunday's queen climb, not before.
Rutted iron-ore descents reward committed line choice more than heavy braking. Practice descending fatigued in training — Iron Biker descents come after 3+ hours of climbing.
Iron Biker updates its route regularly. Do not plan aid mileage, climb sequence or checkpoint spacing off prior years — confirm from the current-year Manual do Ciclista published on ironbiker.com.br.
Iron Biker Brasil has been held every year since 1993, making it the oldest continuously-run mountain bike marathon in Latin America. Over 30+ editions the event has hosted more than 35,000 participants and riders from 25+ countries, cementing its place as a rite of passage in Brazilian MTB culture.
The event is based in Mariana, a UNESCO-recognized colonial town founded in 1696 in the heart of Minas Gerais' historic iron and gold mining region. Iron Biker's course runs through the surrounding Vale do Ouro (Gold Valley) on old mule tracks, mine roads and singletrack — terrain that literally shaped Brazil's colonial economy.
The organizer's slogans — 'NO FUN, NO WAY!' and 'Muito além de uma medalha' (much more than a medal) — capture the event's tone. Iron Biker is not the fastest, flattest or biggest race in Brazil, but its combination of tradition, terrain and finish-line culture keeps it the one every serious Brazilian mountain biker wants on their palmarès.
The 2025 edition was won by Diogo Nascimento (Elite Men) and Gabriela Ferolla (Elite Women), continuing a long tradition of top Brazilian MTB athletes shaping their careers at Iron Biker.
Two riders on the same start line can need very different fueling. FTP, target finish time, body mass, sweat rate, temperature, altitude adaptation, nutrition products and race goals all change the answer. A generic 60 g/hr recommendation is a starting point, not a plan.
Free calculators, checklists and articles to help you personalize your Iron Biker plan.
A practical race-week checklist: carbs, hydration, sodium, caffeine and race-day supplies — print it or keep it on your phone.
Every athlete is different. FTP, finish time, body weight, sweat rate, weather, nutrition preferences and race goals all change what you should eat and drink.
FuelQ Pro builds a personalized race fueling strategy tuned to your ride — carbohydrate, hydration, sodium, caffeine and recovery, mapped to the course.
A Race Fueling Plan gives you a personalized strategy for this event. The free checklist helps you prepare the basics first: race-week setup, 48-hour prep, race morning, hydration, sodium, caffeine, aid stations, and backup calories.
