Will my bike hold the water I need?

2 nights · wild camping · cold but not freezing (8 °C) · gravel and tracks · towns daily

Answer “What is the longest stretch without water?” with “Over 100 km” on that ride and the planner asks for 7.5 L. On Small · 47 cm there is nowhere to put 2.0 L of it: no fork mounts, and the largest frame bag that clears its triangle cleanly is 5.5 L, which would have to hold your food and your tools as well. On Large · 58 cm, three-pack fork the same ride is not a problem at all: 2 fork positions at 4.0 L each is 8.0 L before the triangle is opened.

Same ride. Same 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.

Each row is the ride above with one answer changed, and the figure that answer produces. Each cell is what that much water does to that frame once every cage it can actually mount is full. Bottles are not subtracted, because we hold no bottle volume — so every cell is a ceiling on what the triangle has to absorb rather than an estimate of it.

The interview asks 10 questions and 4 of them reach this figure. The other 6 leave it exactly where it was, which is why they have no row: a table of answers that change nothing is a table pretending to reason.

Three reference frames — small, medium, large. They are the shapes the catalogue is checked against, not 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.

• Small · 47 cm

  Fits a 3–5 L frame bag · 2 bottle positions · no rear rack mounts · no fork cage mounts · max 7.2 L in-frame

  Water in the triangle

  The largest frame bag in our catalogue that clears this triangle cleanly is 5.5 L — Rockgeist Mr Fusion 5.5 L, nothing on this frame limits it. A bladder cannot hold more than the bag it goes in, and everything else you pack is in there with it.

  Water on the fork

  Nothing bolts on here. Salsa Anything Cage HD needs three-pack mounts, your frame has none. That is a categorical verdict, not a tight one: there is no margin to argue about.

  Bottle positions

  2 — counted off the frame, and left as a count. We have never measured a bottle, so turning positions into litres would mean inventing the number this page exists to derive.

• Medium · The Mule

  Fits a 4–7 L frame bag · 2 bottle positions · rear rack mounts · no fork cage mounts · max 10.6 L in-frame

  Water in the triangle

  The largest frame bag in our catalogue that clears this triangle cleanly is 6.0 L — Apidura Expedition Frame Pack 6 L, 18 mm clearance at the down-tube boss. A bladder cannot hold more than the bag it goes in, and everything else you pack is in there with it. Reported Tight on this frame and so not counted above — the clearance is inside the margin the measurement itself carries: Restrap Frame Bag L at 7.0 L, limited by thigh line at 4 mm; Tailfin Frame Bag L at 6.5 L, limited by clearance at the down-tube boss at 3 mm.

  Water on the fork

  Nothing bolts on here. Salsa Anything Cage HD needs three-pack mounts, your frame has none. That is a categorical verdict, not a tight one: there is no margin to argue about.

  Bottle positions

  2 — counted off the frame, and left as a count. We have never measured a bottle, so turning positions into litres would mean inventing the number this page exists to derive.

• Large · 58 cm, three-pack fork

  Fits a 6–9 L frame bag · 3 bottle positions · rear rack mounts · fork cage mounts · max 13.5 L in-frame

  Water in the triangle

  The largest frame bag in our catalogue that clears this triangle cleanly is 9.0 L — Revelate Ranger 9 L, 80 mm spare along the top tube. A bladder cannot hold more than the bag it goes in, and everything else you pack is in there with it. Reported Tight on this frame and so not counted above — the clearance is inside the margin the measurement itself carries: Restrap Frame Bag L at 7.0 L, limited by thigh line at 4 mm; Tailfin Frame Bag L at 6.5 L, limited by clearance at the down-tube boss at 3 mm.

  Water on the fork

  2 positions for Salsa Anything Cage HD at 4.0 L declared each — 8.0 L. The mount count is what bounds this, and a mount count is something you can only get by looking at the frame.

  Bottle positions

  3 — counted off the frame, and left as a count. We have never measured a bottle, so turning positions into litres would mean inventing the number this page exists to derive.

One thing straps on rather than bolting, so no frame rules it out: Voile Strap cargo mount, 3.0 L — and the engine reports it Tight on all three, on 6 mm of strap purchase on a rigid fork leg. Read its own note before filling it with water: “Strap-only fitting on a rigid fork, rated to 2.5 kg.” — water is the one load whose volume and its mass are the same number, so a capacity and a load rating are the same sentence said twice.

The bottle-cage-versus-frame-bag argument is the one every guide has, and every guide settles it with “depending on the size of your bike”. It is a clearance, and a clearance is a number: Tailfin Frame Bag L passes 3 mm from the down-tube boss.

That is inside the margin a photograph-measured frame carries, so the engine reports it Tight rather than Fits — we know the frame to about a centimetre and this clearance is smaller than what we know. A verdict sitting on a tolerance boundary must not be called a fit. The maker says what to do about it, and we print it rather than paraphrasing: “May contact the bottle cage — use a side-entry cage or remove it.”

On Small · 47 cm there is no such number, because no bag with a recorded boss clearance clears that triangle in the first place. An absent number is reported as absent here; it is not rounded up into reassurance.

Measured

A frame triangle: its edges in millimetres and its in-frame volume, scaled off the wheel in a photograph of your own bike. On this page three reference frames stand in for it, and every figure that comes from one says so.

Declared

Every bag capacity, envelope and clearance above. They are hand-digitised from what each maker publishes — we did not cut one open — and where a maker adds a note, it is printed in the maker’s words.

Derived

The water figure, the fit verdicts, and every subtraction on this page. Each is a function of the two above, and each names the answer or the dimension that produced it.

Reported

Nothing. No sentence here is quoted from a person, so there is no interview and no anecdote to source. If that changes, the quote arrives verbatim with a URL and a date or it does not arrive.

What is deliberately absent: a bottle volume, a weight for anything, and a recommendation. The first two were never measured; the third depends on a ride and a frame, and this page has borrowed both.

The join needs a figure and a frame. The interview produces the first from 10 questions and no account; a photograph of the drive side produces the second. Neither is worth much without the other, which is the whole argument of this page.

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