Measure the tube, not the joint, and match the outer diameter exactly — the common sizes are 7.9, 8.5, 9.0, 9.5 and 11 mm, and nothing bridges between them. A pole a half millimetre out will not connect, because the ferrule that joins two sections is machined to one size.
Why the ferrule catches people out
The ferrule is the short metal sleeve at the end of a section that the next section slides into. It is deliberately wider than the pole it joins, so a diameter read off a ferrule is always too big — usually by enough to buy you the wrong pole set entirely.
Put the callipers across the plain tube, halfway along a section, away from any joint. If the pole is bent at that point, measure a straight section instead; a crushed tube reads under.
Three numbers, in order
Outer diameter first, because it is the one with no tolerance. Then section length, usually somewhere between 40 and 65 cm, which sets both the folded size and how many sections you need to make up the run. Then total assembled length, which is what actually has to match the sleeve or clip run on your tent.
Getting the first two right and the third wrong gives you a pole that connects and does not reach. Getting the first one wrong gives you a pole that does nothing at all.
Material changes how it fails, not whether it fits
7075 aluminium bends before it breaks and can often be straightened enough to finish a trip. Fibreglass is cheaper and splinters, which is why it is the giveaway at the low end of the shelf. Carbon is lightest and least forgiving.
None of this affects fit. A 9.0 mm carbon section and a 9.0 mm alloy section will join, though mixing them in one pole is not something to plan around.
The shock cord is the other half
A pole that will not stand up is more often a slack shock cord than a broken section. Check the cord diameter and whether a replacement length is supplied with the pole set, because rethreading a pole with cord that is too thin leaves the sections loose at the ferrules and too thick makes it impossible to fold.
And the repair kit you carry
The same measurement decides a pole splint — the short sleeve in a tent repair kit that has to slide over your pole’s outer diameter. A kit built around 8.5 mm does nothing for an 11 mm pole. Measure the pole before you buy the kit, not after the pole snaps on a windy pitch.
What to write down before you order
Outer diameter measured across the tube with callipers, section length, section count, total assembled length, material, and shock cord diameter. Listings publish those in different orders and some publish only two of them; a set that does not state its outer diameter is a set you cannot match, whatever else it says.
What people ask before buying
Can I measure the diameter with a ruler?
Not reliably. The sizes sit close enough together that a ruler laid across a curved tube rounds to the wrong one. Callipers across the tube are the only way to separate 8.5 mm from 9.0 mm with any confidence.
What if the maker does not publish the pole diameter?
Then it has to be measured off the pole itself, on the tube. Many tent listings state the pole material and section count but not the diameter, and that is a specification the page simply does not give you.
Last reviewed 6 September 2026