Great Divide Mountain Bike Route: the water carry, and what holds it
Everything else about this route is negotiable. Between Pinedale and Rawlins the body that maps it tells you to carry a specific volume of water, and that volume has to physically go somewhere on your bicycle. This page states the volume with its source, then subtracts it from three measured frames. On two of them it does not fit.
What the mapping body declares
Water to carry, Pinedale → Rawlins
DECLAREDThree to four US gallons per person, for a stretch the mapping body expects to take two days.
“Great Divide veterans recommend stocking up in Pinedale (or Rawlins for northbound riders) and carrying at least three to four gallons per person – at a weight of 25 to 33 pounds – for the long, typically two-day ride.”
Adventure Cycling Association · source · read
Why this stretch and not another
DECLAREDThe mapping body names this stretch as the one where water is hard to find.
“finding drinking water can be problematic between Pinedale and Rawlins”
Adventure Cycling Association · source · read
DERIVED The conversion below is ours, not theirs — the mapping body stated 3 US gallons to 4 US gallons and 25 lb to 33 lb, and nothing metric at all.
US liquid gallons, which is the gallon a US organisation writing for US riders means: 11,356 mL and 15,142 mL. Rounded once, here, and never again — every figure below is whole millilitres, so a verdict sitting on a boundary cannot flip because a float drifted.
Against three measured frames
Three reference frames — small, medium, large. They are the shapes the bag catalogue is checked against rather than measurements of anybody’s bicycle; yours comes from a photograph of your own. Every verdict below is the fit engine’s, run here rather than described, and the bag envelopes it reads are the only MEASURED thing on this page. Bottles are not subtracted, because nothing here has ever measured a bottle — so each figure is a ceiling on what the frame bag has to absorb rather than an estimate of it.
| Frame, and what it mounts | At 11.4 Lthe lower bound | At 15.1 Lthe upper bound |
|---|---|---|
| Small · 47 cmfork 0.0 L · frame bag 5.5 L | 5.9 L more than this frame has anywhere. | 9.6 L more than this frame has anywhere. |
| Medium · The Mulefork 0.0 L · frame bag 6.0 L | 5.4 L more than this frame has anywhere. | 9.1 L more than this frame has anywhere. |
| Large · 58 cm, three-pack forkfork 8.0 L · frame bag 9.0 L | 3.4 L of the frame bag · 5.6 L left | 7.1 L of the frame bag · 1.9 L left |
2 of the 3 frames cannot hold the water at the lower bound, let alone the upper, and the reason is not the frame bag. It is that neither has anywhere to bolt a fork cage: Salsa Anything Cage HD needs three-pack mounts, your frame has none. That is a categorical verdict rather than a tight one — there is no margin to argue about, and no amount of packing skill changes it.
On Large · 58 cm, three-pack fork the same ride is not a problem: 8.0 L of fork cages absorbs most of it before the triangle is opened at all. Same route, same declared requirement to the millilitre, opposite answers — and the only thing that differs is the bicycle, which is exactly why no page that does not know your bicycle can tell you.
A freezing night is not an edge case in any month of the season
What the freeze figures are
DECLAREDThe probability that at least one night in the month falls to 32 °F or below, per station, from the current 30-year normals. Not the fraction of nights that freeze — the chance that it happens at all while you are there.
“Probability of minimum temperature at least once monthly <= 32F”
NOAA publishes these in tenths of a percent, so a returned 354 is 35.4% and the ceiling of 1000 is 100%. Every value below carries NOAA’s completeness flag S — their best class, meaning 24 or more years of record.
NOAA NCEI, monthly normals documentation · source · read
| Station | Jun | Jul | Aug | Sep | Oct |
|---|---|---|---|---|---|
| Whitefish, MTUSC00248902 · 944.9 m | 21.8% | 1.3% | 4.5% | 82.9% | 100.0% |
| Butte Bert Mooney Airport, MTUSW00024135 · 1,678.2 m | 82.8% | 15.5% | 33.8% | 99.3% | 100.0% |
| Pinedale, WYUSC00487260 · 2,199.7 m | 98.6% | 35.4% | 80.5% | 100.0% | 100.0% |
| Rawlins Airport, WYUSW00024057 · 2,053.1 m | 63.6% | 3.3% | 4.0% | 93.9% | 100.0% |
| Steamboat Springs, COUSC00057936 · 2,092.8 m | 86.4% | 9.2% | 19.3% | 98.6% | 100.0% |
| Del Norte 2 E, COUSC00052184 · 2,391.2 m | 72.6% | 0.4% | 3.0% | 97.1% | 100.0% |
| Silverton, COUSC00057656 · 2,830.1 m · off-route | 100.0% | 68.3% | 55.2% | 100.0% | 100.0% |
Six of the seven stations sit on or beside the route. Silverton is roughly 60 km west of it and is included only because no on-route station sits near 2,800 m; it is the closest available analogue for what the high passes do. No station exists at Indiana Pass itself, so the route’s highest point has no data at all.
NOAA NCEI, 1991–2020 U.S. Climate Normals · source · read
October freezes at every station including the lowest, at 100%. September runs 82.9% to 100%. Even July — the middle of the season — is 35.4% at Pinedale and 15.5% at Butte, and the high-altitude analogue is 68.3%.
What this page will not do is turn that into a sleeping-bag rating. The figure everyone repeats for this route rests on two riders’ memory of one trip; the numbers above are a national agency’s 30-year record at named stations. Converting the second into the first would throw away the only thing that makes it better than the first.
When it opens, and what actually closes it
When the route is rideable
DECLAREDEarly summer to mid-autumn, typically June to October, with a start no earlier than late June or early July and an exit by mid-October at the latest.
“Because June is typically a wet month in the northern Rockies, and often a cold one at the higher elevations, we recommend that you do not attempt to ride prior to late June or early July. High-country snowpack may prevent certain portions from being passable until then, anyway.”
Adventure Cycling Association · source · read
Colorado opens later, and the reason is physical
DECLAREDThe Colorado sections are not passable in a typical year until early July, because of snowpack rather than a calendar.
“Due to high-country snowpack, some portions are not even passable in a typical year until that time.”
Adventure Cycling Association · source · read
What the mapping body says the nights do
DECLAREDCold nights and early evening thunderstorms — wet and cold together, which is not the same problem as thin air.
“Expect early evening thunderstorms and cold nighttime temperatures.”
Adventure Cycling Association · source · read
So the constraint is snowpack on the high passes rather than a date, which is why the Colorado opening is later than the Montana one. And at the top the problem the mapping body describes is wet andcold together, not thin air — a page that reduces this route to “it is high” is wrong about it.
Three thousand miles, or two thousand seven hundred
Two sources describe this route and give materially different numbers, and one of them disagrees with itself. We state both, name both, and do not average them: 3,097.3 and 2,696 average to 2,896.65, a figure describing no route anybody has ridden.
Total distance
- 3,097.3 milesDECLARED
Adventure Cycling Association · source · read
- 2,696 miles (4,339 km)REPORTED
bikepacking.com · source · read
A gap of 401.3 miles, and the two are not describing the same line on the ground: the first runs Jasper, Alberta to Antelope Wells, New Mexico and puts 585.1 miles of that in Canada; the second runs Banff to Antelope Wells. Jasper is well north of Banff. Neither page states its measurement method, and neither publishes a Banff-to-Roosville figure, so the terminus difference plausibly accounts for most of the gap and demonstrably not all of it.
Total ascent
- 207,535 ft southbound, 206,075 ft northboundDECLARED
Adventure Cycling Association · source · read
- 149,664 ft (45,618 m) in the stat blockREPORTED
bikepacking.com · source · read
A gap of about 57,871 ft, which the different northern termini do not account for on their own. Neither source states an ascent methodology, and that is precisely why this cannot be resolved rather than a thing we have not tried hard enough at.
Total ascent, within one page
- 149,664 ft in the stat blockREPORTED
bikepacking.com · source · read
- “over 200,000 feet … of elevation gain and loss” in the proseREPORTED
bikepacking.com · source · read
The same page, two figures, and they cannot both describe the same quantity. Gain plus loss is the obvious candidate and it does not close: doubling 149,664 ft gives roughly 299,000 ft, not 200,000. Recorded unresolved.
Which we used: The mapping body’s figures, and the reason is stateable rather than a preference: they map and maintain this route and publish a per-section data table with directional ascent, so their number has a defined referent. That is a reason to prefer it, not proof it is right.
The high point disagrees too, and in two directions at once: the third party says 11,913 ft, and the mapping body’s own prose and its own data table say two different things.
Highest named pass
DECLARED11,910 ftIndiana Pass, southern Colorado.
Adventure Cycling Association · source · read
Route maximum elevation
DECLARED11,950 ftThe maximum in the route data table, for the whole route and for section 5.
The source does not reconcile this with the 11,910 ft it gives for Indiana Pass, which its prose calls the route’s highest pass. A pass is not necessarily the high point of the road over it, but the source does not say so, so both are recorded and neither is corrected against the other.
Adventure Cycling Association · source · read
Bear-resistant food storage: an open question, and we could not close it
Food storage rules exist on this route’s Montana national forest land and are administered by the Forest Service. What they require, which containers qualify, and which order binds which land are all things this page does not state, because the host that publishes them refused us.
- www.fs.usda.gov
- Every URL we tried returned 403, including /robots.txt itself. So the legal bear-resistant food storage requirement on this route’s Montana national forest land is unverified and is not stated here as a requirement. We did not work around it: a search engine’s summary of a page that refused us is that page’s content arriving by another door.A 403 to our user agent — the fourth register, and it wins over robots.txt · their page
- adventurecycling.org/…/map-updates
- The route addenda — current-year closures, detours and corrections. Link only, so this page carries no current conditions at all.A 403 to our user agent, on a path robots.txt permits · their page
Food storage — what the mapping body advises
DECLAREDAdvice from the body that maps the route, and advice is all it is.
“Store all food, garbage, and other attractants in a bear-resistant manner, well away from your tent. This can include hanging them in a stuff sack from rope slung over a high, isolated tree branch, or storing them in a bear-proof container provided at some campgrounds.”
The mapping body saying riders should store food in a bear-resistant manner is not the same claim as a Forest Service order making it mandatory on named land. We have the first. We could not get the second — see below.
Adventure Cycling Association · source · read
Two documents, and the border they are for
Crossing into Canada, and back
DECLAREDThe route crosses the US–Canada border in Montana and British Columbia. US citizens need one of four documents; everyone else needs a visa as well.
“all U.S. citizens crossing the U.S.-Canadian border in either direction need one of the following: a passport, a U.S. Passport Card, an Enhanced Driver’s License (EDL), or a NEXUS card. Visitors who are not U.S. or Canadian citizens will also need a visa.”
Adventure Cycling Association · source · read
Riders under 18, unaccompanied
DECLAREDA parental permission letter is advisable — the mapping body’s own word, and not "required".
“Those younger than 18: For entering Canada or the U.S., if you are not traveling with your parents, it is advisable to carry a letter stating that they have granted you permission to visit.”
Adventure Cycling Association · source · read
What we could not source
8 things a page about this route would normally state, that we could not source. They are listed rather than filled in.
- A sleeping-bag temperature rating
- Not on any source we consulted. The widely repeated 20 °F figure for this route rests on two riders’ memory and is unsourced; the freeze probabilities above are what we have instead, and they are a different and better claim. We will not convert one into the other.
- An overnight low in °C or °F, anywhere on the route
- We fetched freeze probability rather than the normal minimum temperature. At the route’s highest point there is nothing to fetch: the nearest station is 800 m lower and 60 km off-route, so any temperature quoted at the pass would be extrapolated.
- Which food-storage order binds, and what it requires
- The Forest Service host returns 403 to us on every path. Search result metadata suggests the current order may be R1-2023-02 covering 2023–2028, and that R1-22-31 is a Flathead visitor guide rather than the order — but that rests on URL slugs, not on documents we could open, so neither is published here as the order that binds.
- Where the water sources are between Pinedale and Rawlins
- The mapping body refers riders to its narrative, which is part of a purchased map product rather than the public page.
- Ascent methodology, for either source
- Neither states one. This is the reason the 57,871 ft disagreement cannot be resolved.
- Crossing requirements at the southern terminus
- The route ends at the US–Mexico border rather than crossing it, and the mapping body’s page states no Mexico requirement. Not assumed.
- Current-year closures, detours and conditions
- The addenda path 403s to us. Link only — check it yourself before you go.
- A numeric snowpack threshold for "passable"
- Snowpack is given as the mechanism that closes the early season, with no depth, date or station threshold behind it.
What is measured here, and what is not
- Measured
- Bag envelopes and mount requirements, hand-digitised from what each maker publishes, and the three reference frames they are checked against. Nothing else on this page, and only this may reach a fit verdict.
- Declared
- Every route fact above, each carrying the URL it came off and the day we read it. The mapping body on its own route; a national weather agency on its own stations.
- Reported
- The second set of distance and ascent figures, from a third party describing somebody else’s route. Quoted and linked, never merged into ours.
- Derived
- The gallon-to-millilitre conversion, and every subtraction in the table. Each is a function of the three above and names what produced it.
The other two routes, and why their answers differ
Both halves, for your own bike
The join needs a figure and a frame. The interview produces the first from ten questions and no account; a photograph of the drive side produces the second. This page borrowed three frames to make its point, and none of them is yours.