Robens tents,anyone had/got one?

[hamster]

I wonder if wrapping the ends with fibreglass around the stress raisers is enough to control the tension that causes fatigue.

[bretonbikes]

I wonder if wrapping the ends with fibreglass around the stress raisers is enough to control the tension that causes fatigue.

Actually when on tour - if I see a crack starting to appear I wrap the end with a bit of gaffa-tape (one of my touring triumverate of gaffa-tape, zip-ties and superglue) and it seems to made a big difference. Might be worth putting a couple of turns round every joint before it cracks. But a ring of fibreglass would be immensely strong.

[foxyrider]

I think the likelihood of pole breakage increases dependent on section length. My PowerLizard has short (30cm) straight sections allowing a fairly tight bend just from joint movement.

OTOH my Taurus has fewer, longer sections for a similar arch some of which are pre shaped. The slight bends are no real issue when strapping to a rack but I can't help thinking the fewer sections are at least partly responsible for the couple of pole breakages incurred.

I can sort of see what you're getting at but in practice it doesn't work like that - in fact if the joints are that loose you risk the joint becoming a 'knee' where there is a stress point. I've actually replaced the poles in some Decathlon tents with poles of much longer sections and the rate of failure dropped considerable. It's the joints that fail - especially in tents that use the common 'press-fit' of ferrul inside the tube held with four little pressed dimples. These dimples often show cracks when new.

Personally I would avoid a design like the powerlizard for our use unless the poles were pre-bent - it's possible someone somewhere will get 20 weeks out of it without a pole snapping, but the average would be much less. If you want something with a similar form then the Robens is much the same but completely avoids the tight radius (crazy price here too! - http://www.outdoorworlddirect.co.uk/rob ... -tent.html).

With all these designs the killer is fatigue - how many times you bent the pole back and forth to pitch it (and ours obviously get pitched every day) and how long they are under stress. Just like aluminium used in aircraft they all have a 'stress-life' measured in hours after which they are unreliable - it's just some designs 'stress-life' is woefully short.

Just to be clear I wouldn't suggest the PowerLizard for your business either - you need idiot proof and as indestructible as possible. You've found something that works for your business and i'm not going to argue over that!

Re the poles - it's my opinion based on my experience - the failed pole sections had gone over ten years without any issue but several suffered failure on one trip. These were all the pre shaped sections not the shorter straight ones in the same string. Not a great issue - sections replaced for little outlay and set up back to good as new - maybe!

The joints aren't 'loose', quite tight actually but there is still some movement - i've only ever seen a failure as you describe on much bigger frame tent poles! But I'm guessing operator error will have you seeing more interesting damage/failures than most! When i've spent £400 on a tent i'm gonna take good care of it, personally i'd be even more careful with hired stuff but others I know, don't have that philosophy.

[hamster]

I wonder if wrapping the ends with fibreglass around the stress raisers is enough to control the tension that causes fatigue.

Actually when on tour - if I see a crack starting to appear I wrap the end with a bit of gaffa-tape (one of my touring triumverate of gaffa-tape, zip-ties and superglue) and it seems to made a big difference. Might be worth putting a couple of turns round every joint before it cracks. But a ring of fibreglass would be immensely strong.

I did it to make bivvy poles out of kite poles using woven glass tape and epoxy...Seemed to work. The self adhesive parcel tape with glass weave reinforcement is probably just as good and far less messy.

[bretonbikes]

I think the likelihood of pole breakage increases dependent on section length. My PowerLizard has short (30cm) straight sections allowing a fairly tight bend just from joint movement.

OTOH my Taurus has fewer, longer sections for a similar arch some of which are pre shaped. The slight bends are no real issue when strapping to a rack but I can't help thinking the fewer sections are at least partly responsible for the couple of pole breakages incurred.

I can sort of see what you're getting at but in practice it doesn't work like that - in fact if the joints are that loose you risk the joint becoming a 'knee' where there is a stress point. I've actually replaced the poles in some Decathlon tents with poles of much longer sections and the rate of failure dropped considerable. It's the joints that fail - especially in tents that use the common 'press-fit' of ferrul inside the tube held with four little pressed dimples. These dimples often show cracks when new.

Personally I would avoid a design like the powerlizard for our use unless the poles were pre-bent - it's possible someone somewhere will get 20 weeks out of it without a pole snapping, but the average would be much less. If you want something with a similar form then the Robens is much the same but completely avoids the tight radius (crazy price here too! - http://www.outdoorworlddirect.co.uk/rob ... -tent.html).

With all these designs the killer is fatigue - how many times you bent the pole back and forth to pitch it (and ours obviously get pitched every day) and how long they are under stress. Just like aluminium used in aircraft they all have a 'stress-life' measured in hours after which they are unreliable - it's just some designs 'stress-life' is woefully short.

Just to be clear I wouldn't suggest the PowerLizard for your business either - you need idiot proof and as indestructible as possible. You've found something that works for your business and i'm not going to argue over that!

Re the poles - it's my opinion based on my experience - the failed pole sections had gone over ten years without any issue but several suffered failure on one trip. These were all the pre shaped sections not the shorter straight ones in the same string. Not a great issue - sections replaced for little outlay and set up back to good as new - maybe!

The joints aren't 'loose', quite tight actually but there is still some movement - i've only ever seen a failure as you describe on much bigger frame tent poles! But I'm guessing operator error will have you seeing more interesting damage/failures than most! When i've spent £400 on a tent i'm gonna take good care of it, personally i'd be even more careful with hired stuff but others I know, don't have that philosophy.

Yes operator error is a big part, and often the straining may have occurred long before the actual failure (which can often happen in the middle of the night). But then my own tent is on it's 3 rd pole set and I'm dead careful;-) Though saying that it is now 15 years old and has probably a years use overall!