Carbon-Fiber Tent Pole Replacements

[Christopher V]

To save weight, I’m considering replacing my Easton Syclone poles in my MSR Hubba NX and Hubba Hubba NX tents with Easton’s 3.9 or 6.3 Custom Carbon Fiber tent pole sections. I saw some posts back in 2011 about the durability of carbon fiber poles (not good if they have to bend).  Has any of that changed in the past 9 years?  It would save me 5.5 oz. on my Hubba NX and 7 ounces on my Hubba Hubba NX.  Thanks!

[Roger Caffin]

CF poles can replace STRAIGHT Al poles without trouble.
But if the Al pole has a prebend, a curved section in the middle when not in use, it becomes a bit doubtful.

Cheers

[Eric Blumensaadt]

CF poles are very rigid and strong on compression. Side pressure – now so much.

I have had SWIX CF ski poles for XC racing since 1981 and they are SOoooo nice and weightless.

[Sam Farrington]

The latest heavier Easton carbon pole should work as a replacement for the Easton 340 alloy pole, but maybe not for the DAC poles used by MSR.  I would order from Quest one section without ferrule, and one ferrule separately for both the heavier and the lighter Easton carbon poles.  And see if they can be mated in any way to the hubs on the tents you have.  But I’d be careful of using a drill to bore any tubing projecting from the hubs.  The boring would weaken the temper, scar the alloy, and make the hub much weaker.

And there is another rub.  I haven’t met the new Hubbas, but the original Hubba that I modified used one hub on each side of the tent.  (hence the name, “Hubba”).   MSR may have modified the hubs, but the old ones overlapped the poles only a short distance.  Fibraplex sold hubs with the same issue.  Unfortunately, carbon poles need a lot of overlap so that that break pressures is spread over a longer portion of the pole tube.  The length of this portion is 1.5″ for the Easton ferrules, so the overlap on the hubs should be at least that, with the hub having projections that either stick at least 1.5″ into the pole tube, or over the pole tube.  All this is because carbon tube is at its weakest when break or crush pressure is applied to shorter lengths.  This is the reason that the original MSR carbon pole version of the Hubba did not use hubs for spreader poles, and the corners had to be staked individually; something you might do anyway, but some insist that at least the main portion of the tent be ‘freestanding.’

Note that the lighter Easton carbon poles have less spine, or more flex, than the heavier ones, and would not produce as rigid and stable a tent as the alloy or heavier carbon, the latter being a little over 30% heavier than the lighter carbon, but still well under the weight of the Easton alloy tubes.

If the carbon tube can be shimmed or otherwise made to fit over projections from the hubs on your tents, there are very light rings that fit over the end of the carbon tube called ‘nock collars’ that protect against arrow points from splitting carbon arrow shafts.  They come in a multitude of sizes from several manufacturers, so I was able to find one size that fits the carbon shafts I use tightly – no need for bonding.  Roger Caffin, bless his soul, turned his on a metal lathe; but the nock collars are lighter and less work.  Don’t think you need the collars at the end of each pole section, but where the tube goes into or onto the hub is an area of much greater stress for reasons I can see intuitively, but am not an engineer, so cannot explain scientifically.

The new Easton carbon poles are about the only ones I haven’t break tested.  It was costing money, and did not want to go with the heavier Easton carbons when there were arrow shafts that had almost as much spine, but were ~30% lighter.  Yes, confess that I’m a gram weenie, but hopefully recovering a bit.

[Roger Caffin]

I have seen two cases of CF poles broken at the end over an SS insert, but in case the break was due to someone standing on the pole at the joint by mistake. The 2D wrap stuff (many arrows) is remarkably strong.

Cheers

[Sam Farrington]

Roger,

I’m not sure that the alloy inserts, or ferrules, that Easton uses for carbon poles are the best idea.  The expansion and contraction characteristics of the two materials are different.  Standing on a carbon pole at a joint sounds like asking for trouble.

Fortunately, I found another carbon shaft from Easton, the Injexion, that is strong and comes in a size that fits snugly into multi-layer Gold Tip Expedition  Hunter 75/95 shafts used for poles.  So the Injexion shafts are cut up, and the ends buffed and sealed with Bondini glue to make into inserts, and I’ve had no breakages.  Other cyanoacrylic glues tried as a sealer did not work nearly as well, though.

[Roger Caffin]

The expansion and contraction characteristics of the two materials are different.
Absolutely! Easton did try with some hybrid poles: Al core with CF wrap. Great in the lab, OK in the summer, disaster in the winter. The Al shrank more than the CF in the cold, and the lot delaminated.

Standing on a carbon pole at a joint sounds like asking for trouble.
It did ask.

The owner was very apologetic when he asked for replacements.

Cheers

[Douglas S]

Sam,

How would you compare the weight and strength of your multi-layer Gold Tip Expedition  Hunter 75/95 with Injexion inserts poles to the .346″ carbon fiber and .365  Syclone carbon/aluminum poles that Quest sells?

I’m pondering making a new set of carbon poles for a Hilleberg Niak. The Niak comes with 9mm DAC Featherlight NSL poles, but, they have a two pre-bends in each pole, about a quarter of the length up from each end. Does the pre-bend pre-empt me from succeeding here, or might the flex on the Expedition Hunter arrow shafts work out?

Doug Stephens

[Roger Caffin]

Be warned that the hybrid carbon fibre / aluminium poles have a very poor record in cold weather. The aluminium shrinks a lot more than the CF, and eventually they delaminate. Could be embarrassing.

Cheers

[Douglas S]

Thanks for pointing that out Roger. I’m up in Anchorage, AK and cold weather performance is essential.

 

[Sam Farrington]

Hi Douglas,

I did carbon tube break tests some years ago, and used arrow shafts, kite shop shafts, Fibra-plex tent tubes and about every carbon tube I could get my hands on, plus an Easton .344 diameter tent pole for comparison.  The Gold Tips I mentioned were superior to all of the others tested, including the Easton .344  (I think they call them ‘nanolites’).

Finding the Easton carbon arrow shafts that fit snugly inside the Gold Tips to use for ferrules, or inserts, came from a Cabella’s catalog that noted the Outer Diameter of the Easton Injexion 330 carbon shafts – which just happened to fit snugly into the the Gold Tips.  They are a little heavier (thicker tubing walls) than the Gold Tips, but certainly better than alloy, for all the reasons Roger Caffin mentioned.   If you are going to use alloy tubing for ferrules, make them external ferrules, as this will deter the carbon tubing from distorting into an oval and becoming more subject to breakage.  The Easton .340 tent pole tube fits snugly over the Gold Tips.

Later, Fibraplex beefed up their ferrules, and Pierre Descoteaux, who was posting threads about his Cuben Fiber tunnel tents, agreed to buy me some ferrules as part of a larger order of his own, in return for my producing a Gold Tip pole to try on one of his tunnels.  The Fibraplex ferrules also work snugly with the Gold Tips.  I did not hear from Pierre, but fear the pole I made may not have been stiff enough for the larger tents he was making.  Stayed with the Easton shafts for ferrules because the place where pole sections join can be more subject to breakage and might benefit from the beefier Eastons.  I’ve gone on many 2-3 week treks with the Gold-Tips w/ Easton Ferrules, and have never had a break.  So no longer carry a spare pole section, as was done initially with carbon; rather just a couple short alloy tubes to tape over any breaks, should they occur.

When buying carbon arrow shafts, you also get some alloy tips, that fit inside the shafts, and can be drilled to accept shock cord, and make good end tips for the ground end of the pole.  You also get plastic nocks that fit into the shafts -The nock parts can also be sawn off and buffed to make end tips, but it is a little more dicey to drill a depression to hold a knotted end of shock cord.  Goodwinds kites also sell some plastic end tips that fit into the Gold Tips and can be adapted for shock cord connections.

As regards the weights, the Gold Tips are 8.9 grains per running inch (gpi).  Just use google to convert grains to the unit of measure you want and vice-versa.  Generally, the Easton .346 carbon poles run about 30% heavier than the Gold Tips, and the alloys add quite a bit more.

Please note that the Syclone poles from Quest are not carbon, but rather a composite.  With a little research, I think you will find they are not on a par with filament wound carbon or carbon wrapped tubes with the grain running in different directions.  With the break tests, I found that most of the carbon tubes available are not fit for use as tent poles.

The prebent DAC poles are a stickler.  Carbon simply does not prebend.  You would need to make and install alloy elbows and bond them to the poles.  But I’ve no experience with Hilleberg tents, so can’t give you particulars.  Can say that I’ve made large and small Ti elbows to sew into tent peaks, and fittings that connect the carbon poles to the peaks.  Although Sierra Designs, and evidently Hilleberg, use prebent poles, even if they were elbowed together, there might be too much stress on the carbon tubes.  That is why I bought a One Planet Goondie to modify, because it is basically a two pole single cross wedge dome with a transverse strut across the top to keep the peaks over the doors.  Keeping it simple is best for both MYOG and for carbon.

Have no idea how the Hilleberg prebent poles fold up for packing, but would suggest an alloy external prebent ferrule over the carbon, and glueing it in place.  But do not use epoxy glue near carbon, as it will weaken it.   It has destroyed airplane rudders.  Most super glues are OK, and Roger uses one that cures flexible:  [email protected].   I have tentpole tube in my scrap buckets that will fit nicely over the Gold Tip; but the big challenge is the bending.   The Easton .344 tubes are probably too highly tempered for cold bending.   Tent pole tube is normally tempered, so heating it to bend can destroy the temper and weaken it.  Roger Caffin has invented a device that will cold bend the highest tempered Easton .340 tent tube, but not with a sharper bend that I suspect may be what is on the Hilleberg poles.  I could try to put a three inch radius on a 4″ piece(s) without heat using a Rigid ratchet bender.  And a photo of the bent section with the degree of bend noted would be very helpful.   Note that the Quest elbows for .344 tubing only fit will with the .340.

You must be freezing to death in Anchorage.  We are at the bottom of Mount Chocorua in NH, and the cold air just sits in the basin.  The two sheepdogs, one sheltie and one aussie, went for a mile walk this evening on town roads.  They are young, but me not so much, and it was a more than a little numbing.

Hope this is helpful.

[Roger Caffin]

I have been using Loctite Black Max superglue: the ‘black’ refer to micro particles of rubber (I think) which makes the superglue a shade more compliant. (= less brittle)

I have two ‘benders’. One puts a curve, not a bend, into Easton aluminium arrow shafts. I use that for my frame packs. The other puts a controlled bend into SS tubing for the elbows. Yes, even thin-wall SS tube is heavier than CF, but they have never failed me.

Cheers

[Douglas S]

Thanks for all of the information. The pre-bend on my Niak aluminum poles is guesstimated to be a 15 to 20 degree arc over 2 x 17″ pole sections. The photo shows 4 sections with the first and last being straight and the middle pre-bent. I haven’t studied it carefully yet but it looks to me like the pre-bend approximates the finished arc of the pole when the tent is set up. In other words, the final poles arc is uniform and not visibly impacted by the pre-bend. Therefore, the pre-bend might be intended to maintain the pole strength vs intended to impact the shape of the pole arc.

I’ve got a set of of the Easton carbon 6.3/.346″ sections sufficient to make up a set for the Niak and I’m just going to have see how it sets up. I’m hoping the carbon poles will be able to flex to the same radius as the aluminum pre-bend. They do have the aluminum ferrules so I’ll be cautious about using them when it is frigid.

If things work out with the Easton 6.3’s maybe I will then try again using the Gold Tips with carbon ferrules and Black Max superglue..

I’ll have to look at the One Planet Goondie for when I need a new project!

FYI, Climate is not so different here as in the Whites. We probably get a bit more prolonged cold spells down to -20F, but, we just had a 4 day Chinook blow through with temps in the 50’s that melted a perfectly fine base of snow. The real challenge here is the length of the winters and the really short day lengths. It is dark here for a long time.

Still, we make up for it in the summer when I might head out for an 8 mile hike up a 4000′ peak, starting at 8pm …..

Thanks again for all the DYI beta.

Doug Stephens

[Sam Farrington]

Doug,

A couple comments that might be helpful, and a puzzle.

First, the link to the Goondie modification:  https://backpackinglight.com/forums/topic/81307

Second, the modified Goondie was a much older model, and even its ‘solid’ inner had a fair amount of mesh on top that would admit water during pitching.  But the current model seems to have a full solid inner, not waterproof but with a DWR treatment that will block water for the short time it takes to pitch.  A dry pitch is a big deal for me.  So here’s a link to the new Goondies:  https://www.oneplanet.com.au/product/goondie-1-nylon/

Now to the puzzle.  Can’t see anything in your photo that looks like a sharp bend, like the ones Sierra Designs and some others put on their poles.  The four sections in your photo remind me of what some poles looked like on an old tent with less tempered alloy poles.  After being bent into hoops for a long time, they adopted a permanent prebend that looked like the one in your photo, with a slight bend over a long distance.  I’m mystified.  Could it be that your Hilleberg pole just adopted a slight permanent bend after much use?  Anyway, it’s nothing you would need an elbow for in order to duplicate.  Am probably missing something.

[Douglas S]

Sam,

I’ve had a couple Hilleberg tents and am 100% certain those poles come pre-bent from the factory. Since the pre-bend matches the final arch, it prevents some work hardening from repeated flexing and actually provides more strength (or so I’m told) I’ll report back on how the Easton carbon poles work on the Niak.

Thanks for the link to the Goondie, might seriously consider one next time. One can never have too many tents.

I like the Niak because it is a relatively light 2-person freestanding tent and has only one entrance and no rear vestibule. I’ll be using it solo, mostly on river trips, as I’ve come to appreciate a bit more space. I haven’t weighed it myself but Hilleberg lists it at 53 ounces packed weight which includes 10 stakes. About the same as your solo Goondie’s initial weight. If it is raining hard I can pitch it fly first and keep the inner tent bone dry. I’m just trying to lose some weight with carbon poles, and, projects keep me occupied in the winter.

I’d like to turn one of these into a single wall tent by ditching the inner tent entirely and connecting the bathtub floor to the fly with a band of bug netting, quite similar to a Tarptent Protrail. Sounds like another project and maybe a Goondie will work well for that one.

Best regards,

Doug Stephens

[Sam Farrington]

Doug,

First, a few comments about the old Goondie, not the new ones I linked above.  The old one came with a bathtub floor that was beyond bomber, so replaced it with a best quality (6.6) 30 denier silnylon floor with the same dimensions.  The old floor fabric was saved because it would work great for a super light pack.  After the mods, the old Goondie weighed just below 2.5 lbs, including 6 shepherd hook Ti stakes.  Either the four corners and 2 vestibules could be staked, or in high winds, 4 guylines rolled up in pockets in the fly could be unrolled and substituted for the 4 corner stakes.  The guylines hold the tent solidly on the ground, so no additional stakes are needed.  Very creative on the part of One Planet.

Solo wedge tents need something to stabilize the poles part way up, else they have a tendency to scissor closer to each other.  One Planet used velcro loops connecting the fly to the inner which are a bear to install.  So instead, 2 short carbon struts were installed  part way up the poles to hold them apart on each side of the tent.  The old Goondie’s inner tent was clipped to the poles at intervals and the clips were attached to the inner with twill tape.  So arrow nocks were added to each end of short carbon struts and inserted around the twill tape.  This kept the poles apart, and made pitching a lot easier, and the carbon struts weighed a lot less than the many velcro loops that were removed.  Enough about that, and back to your latest post:

I see now that the Hilleberg poles are prebent as you said, and the bends are slight, but appear to run the length of the poles.  If not the whole length, then the arc of the poles when pitched would be less where unbent pole sections are used.  However, you cannot prebend with carbon because unless you are manufacturing the carbon layup, the carbon poles cannot be prebent.  This would be so for both the Easton and Gold Tip carbon poles.  So the question is whether the Hilleberg tent can be pitched with unbent carbon poles.  Possibly, because good carbon poles will bend more than some think without being stressed.  Here are some photos of Gold Tip and the stiffest Victory carbon poles easily flexed into hoops:

When hooped as above, the poles will naturally assume the shape of a parabola, which arcs a little more tightly at the top of the hoop than would a partial circle.  However, alloy pole sections can be substituted for the carbon ones to make the arc tighter at other points on the hoop.

Looked at the Niak tent on their site, and my guess is that the Easton poles will flex to fit that tent.  But if not, slightly prebent alloy pole sections would have to be substituted for some of the carbon ones, which might be a daunting task.  So I hope the Easton carbons work as is.  Please let us know.  Agree that the carbon poles should provide good weight reduction.

Won’t comment on single walls because in northern New England and Colorado, I find an inner wall greatly reduces condensation, up with which I will not put.  With a tent that is bone dry inside, and spacious, I can prepare food, dine and do whatever in rainstorms without getting wet.  The weight penalty for the tent I’m working on with a solid inner ceiling is only about 2 ounces, not counting the bug netting I’d install anyway.  For the ceiling, I found some great sub one oz ripstop poly camo at RBTR which is the color of clouds and should make the tent feel light and airy.  Agree with you that making what would otherwise be a rear vestibule on a solo tent into a rear extension of the floor is a great way to add space without adding weight.

From reading the BPL forums, my sense is that the new normal weight goal for a non DCF spacious double wall solo tent is around 20 oz, down from 32 oz, and 20 oz is what I’m shooting for.

[Pierre Descoteaux]

Sam and all, the poles for my cuben tunnel have fared well but I shamefully have to admit it has seen little use. I’ve also been lucky with the weather on the few outings.  Therefore I can’t draw a useful conclusion.

I did make a pole mixing pre curved aluminum sections at the middle with carbon fiber arrow shafts on each sides to good results. This could solve the issue.

[Sam Farrington]

Pierre,

Thanks for the update and your experience with combo alloy/carbon poles.

[Author]

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