Can a bar bag or frame bag ever get refused for the cables, a headlight bracket, or your knee?
One fit rule can never block; another just never has
Across the whole catalogue and all three reference frames — 39 frame-and-bag pairs — eight rules decide whether a bag fits. Five of them refused something somewhere in that sweep: inscribed-containment, seat-tube-length, exposed-post, tyre-droop and mount-requirements. Two did not refuse a single pair, and they did not for the same reason.
39frame-and-bag pairs checked across three reference frames and the full catalogue
The rule with no blocking branch at all
Three bags in the catalogue declare a measurement under declared-clearance: a 9000 ml handlebar bag, a 15000 ml handlebar bag, and a 3000 ml fork / cargo bag. Checked against every reference frame, each one reports the same clearance every time — nothing about the frame changes the number this rule produces.
| Category | Capacity | Clearance reported | Blocking |
|---|---|---|---|
| handlebar | 9000 ml | 22 mm | No |
| handlebar | 15000 ml | 2 mm | No |
| fork / cargo | 3000 ml | 6 mm | No |
Set one of those bags' declared clearance to -5 mm instead — a number that would mean it is already touching whatever it was measured against — and run the same rule again. It still reports clearanceMm: -5 and blocking: false. There is no branch in declared-clearance that a negative number reaches. It is not that nothing in this catalogue trips it; nothing could.
The rule that can block, and has never had to
Only one bag in the catalogue declares a thigh clearance. Checked against all three reference frames, it reports 4 mm every time — positive, and never blocking.
| Frame | Clearance reported | Blocking |
|---|---|---|
| Small · 47 cm | 4 mm | No |
| Medium · The Mule | 4 mm | No |
| Large · 58 cm, three-pack fork | 4 mm | No |
This rule is built differently from declared-clearance. Set the same bag’s declared thigh clearance negative and run it again: the finding comes back blocking: true, with no clearance to report. The branch is there. Nothing in this catalogue has ever reached it, because the one bag that declares the measurement clears by 4 mm on every frame it is checked against.
What this cannot tell you
This is one catalogue, not every bag that could exist. A bag that declared a thigh clearance at or below zero would trip thigh-strike the moment it entered the seed data; none has. That declared-clearance stays open under a negative number is a fact about this rule’s code, not a claim that a maker’s stated clearance can always be trusted — the rule does not check it against anything else, which is exactly what the test above shows.
Every claim above, and how it is known
- DERIVEDThe fit ruleset has 8 rules, checked across all three reference frames and the whole catalogue — 39 frame-and-bag pairs.
- DERIVED5 of those 8 rules produced at least one blocking finding somewhere in the 39 pairs: inscribed-containment, seat-tube-length, exposed-post, tyre-droop and mount-requirements.
- DERIVED3 bags in the catalogue declare a measurement under declared-clearance — a 9000 ml handlebar bag, a 15000 ml handlebar bag, and a 3000 ml fork / cargo bag.
- DERIVEDChecked against each reference frame, those three bags report clearances of 22 mm, 2 mm and 6 mm — the same figure on every frame, and never blocking.
- DERIVEDWith one of those bags' declared clearance set to -5 mm instead, declared-clearance still reports clearanceMm: -5 and blocking: false.
- DERIVEDOnly 1 bag in the catalogue declares a thigh clearance, and it reports 4 mm, non-blocking, on each of the three reference frames.
- DERIVEDWith that same bag's declared thigh clearance set negative, thigh-strike reports blocking: true with no clearance to give.
Other notes worked the same way
- Does wild camping actually need more than staying at campsites?
Wild camping adds one line over a campsite stay
- I think I am packing too much. What do I actually need?
Eight items, no matter what you answer
- The verdict blames one thing. If I fix it, does the bag fit?
Ten refusals rest on one objection; two have a second underneath
Every figure here came out of the same rules that answer the interview, so it moves when they do. Yours differ wherever your answers differ.