Hub & spoke Vs single hoop?

[Moondog55]

I'm wondering if it is being used so much because it is stronger or if it is just that the use of hub & spoke increases usable floor space or is simply a little lighter?
Anybody here used one of these new frame systems in weather hard enough to really test them?
If they are lighter does anybody know by how much?
Are they cheaper to make because they seem to use a little less aluminium

[Franco]

I would think they are used for several reasons.
For example at Tarptent we don't use "hubs" but we have the spreader pole in the Rainbow/Double Rainbow and that was done simply to overcome the pointed roof of the Microlite and other similar tents and also give a somewhat rain protected entry.

Yes you do get less stability but also less weight, smaller packed size and of course allows for a narrower (smaller footprint) and different shaped shelter too.

[RonK]

I'm suspicious about the reliability of hubs, and have avoided them even though it may mean a little extra weight to carry.
My preference is for a three pole tent design where the vestibules are supported by a pole rather than pegged out with or without a spreader.

[Hermione]

I doubt hub poles are stronger, though someone with a greater understanding of physics might provide a better explanation. I have an MSR tent with this sort of pole configuration and it's fine in my home state, but doesn't stand up at all well to even a small amount of snow. For any walking where I'm anticipating crummy weather (e.g Tassie, NZ etc) I prefer the three pole configuration that RonK mentioned. Part of the issue with strength might just be that hub poles are generally found on lighter weight 2 -3 season inner pitch first tents, I like outer pitch as I think the pole sleeves distribute the load more evenly. I also think that the hub itself might be tricky to repair in the field if that was necessary. Having said that, my MSR is very quick and easy to pitch and great for most conditions I experience at home, it all depends what you're using the tent for I guess.

[Moondog55]

Bringing this one back to the top
I've been playing with the hubbed pole set I got at the Rays shutdown sale
This is the pole I experimnted with for my winter basecmp tent.
Would anybody be willing to hazrd a guess as to the optimum distance part for the 2 "feet" of the hub triangulated bse?
The legs are each 1120mm long
I am guessing that the same rules as apply to lifting and climbing belays apply and that the best angle is between ~45 and 30 degrees or less
If somebody has one of these tents with the hubbed frames could they measure the length and distance apart for me next time they put the tent up i'd appreciate it

[Mark F]

I have an REI 1/4 dome but the pole hubs serve a different purpose. As the distance along the base increases any downward forces on the hub create greater sideways flex on the base poles. Without doing the maths I expect that the base poles should form two sides of an equilateral triangle - ie the base distance should be close to the pole length in your case 1120mm. This I suspect is the optimum for stress vs. area enclosed. I must do the maths on this.

Maths added. Assumes flat structure and angle is the angle between the vertical and the pole - double to get the angle between the poles, base is the distance between the pole bottoms.

Area enclosed is greatest at 45deg. At 30deg it is 87% so not a lot of loss.
20 deg - vertical height = 1052mm, base = 766mm,
30 deg - vertical height = 970mm, base = 1120mm,
40 deg - vertical height = 858mm, base = 1440mm,
45 deg - vertical height = 792mm, base = 1584mm,

[Moondog55]

Thanx Mark
Maximum strength would be more my interest in this case but for a large group tarp height is also important.
This is me assuming the strength in compression is similar to strength in tension as per rigging or climbing slings but if it is sronger in compression at 45 deg then I'll put the spacing at around 1000/1200mm.
Have you seen the huge shelter tarp from 3F UL?
https://www.aliexpress.com/item/3F-UL-G ... 2139191c6a

I was thinking what I have just assmbled would work as an extra in the middle as I won't be using it for the winter tent

[Mark F]

There are no issues with most poles in tension or compression. The real problem is the bending moment which will be dependent on the design of the hubs and other factors. What will be true is that the bending moment will increase as the angle increases. Way beyond my pay grade to calculate.

[Franco]

Walrus was the first brand of tents (tha I kow of...) to use the hub.
This is their reason why :
RAPID HUB
A number of our tent designs center around the use of our "Rapid Hub." Our hub tents are related to the widely-known structures called Geodesics.

Why the Rapid Hub? Here are the principal reasons - Triangulation: Look around at constructions that require stability, strength and stiffness, from a tripod to a bridge girder, you will see triangulation at work. Less material needed to achieve rigidity: our hub-style tents can use less pole footage. Rapid set-up and take-down: since the hub allows the pole system to be inter-connected, the poles easily fold up with the tent skin. No poles to be lost. No poles to insert and remove. Set-up is simple and swift.

Most systems use pole crossings, because that is where a semi-triangulation takes place. The problem is that there is much slack at that point, as poles can slide over one another; some tent makers try to correct this problem by tying the poles together with a fastening device. The Rapid Hub is like a pole crossing, but it is much more rigid, as the poles are fixed at the point of intersection. A hub is somewhat like a triple pole crossing, without the pole crossing through the intersection. You accomplish more with less.

Rapid Hub provides stiffness and lightweight strength with economy and elegance.
One of those tents , the Arc 4 :

Jim Giblin, the MSR Hubba designer, used to be at Walrus. (now MSR tent category manager)
Note that the MSR mountaineering/expedition tents don't use hubs.

MSR Stormking, all season,non hubbed Easton Syclone poles
Hubba Hubba ,3 season, hubbed DAC Featherlite poles.

[slparker]

Is there evidence that hubs are a weak point in tents?

In a strong wind will the hub fail or the pole?

[Moondog55]

given the difference in size/thickness between a wand section and the the hub section it will be the wands/poles that fail The hubs I have here are 10mm thick with an 8mm hole and the wand joiner is 0.8mm thick, what may happen is the wand jumping out of the hub if not tied down I think

[andrewa]

Interestingly theoretically, but bottom line comes down to practical use.

I snow camp mostly on Bogong for weekends. Over 25-30 hrs, none of my tents have failed. To me, it mostly comes down to weight. My 10lb plus Kathmandu 4 pole geodesic 3"person tent with extra pole in vestibule in great. My Hilleberg Nallo's also work fine, but weigh less. I have a 700g single tent to try out this winter. As I'm not up there for a protracted period of time, most shelter will do the job for me.

A

[Moondog55]

Practical use often comes down to the best compromise between strength, weight, stability and ease of erection.
With good tent design all of these factors should be taken into consideration
If splitting the load to the gound using a hub divides the forces equally between 2 pole sections rather than one then doesn't the central joining pole part become the weak point?
Looking at it from a design point of view isn't Eurekas Timberline tent frame system also a hub?

[Franco]

Yes the Timberline have a hub of sorts but the poles go into it much deeper than the standard hubs. (note the triangulation)


still on rough weather , this can happen :

the poles were not damaged.

[Moondog55]

Jeez they are cost cutting there aren't they!
That plastic is not even fibre reinforced
Original hub was 6061 thick walled tube