Author Topic: Exped Downbeat failure advice - replacement?  (Read 4222 times)

Jaded

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Exped Downbeat failure advice - replacement?
« on: 15 July, 2022, 01:10:52 pm »
So, after maybe 12 years of light use (occasional cycle camping and quite a few festival camps), my Exped burst a baffle.

What should I replace it with?
It is simpler than it looks.

ravenbait

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Re: Exped Downbeat failure advice - replacement?
« Reply #1 on: 15 July, 2022, 01:18:39 pm »
Can't answer you, but I am interested to find out what other people say.

Sam
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"Created something? Hah! But that would be irresponsible! And unethical! I would never, ever make... more than one."

Re: Exped Downbeat failure advice - replacement?
« Reply #2 on: 15 July, 2022, 01:22:15 pm »
Get the design that looks like buttoned furniture, it is apparently a lot better method of construction than the tube design.  So much so that the likes of Sea to Summit are offering lifetime guarantees.   I have one, it's as comfortable and warm as the three airbeds I've had fail (2 x Exped, i Big Agnes)

I have a little experience with HF welding, the type used on tube aribeds, though in a completely different context.  Welds that terminate without a hem, or fitting or T piece are prone to failure, won't always fail, just far more likely than if they did.  I don't know how the button/cell construction works.

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Exped Downbeat failure advice - replacement?
« Reply #3 on: 15 July, 2022, 01:44:29 pm »
I've heard the same about the designs with cells versus regular tubes, and about Sea to Summit, but no personal experience of either. I've been satisfied with my ME Helium, which has tubes and is nowhere near 12 years old. What sort of size and warmth are you looking for?

I'm also wondering if the thread title is a typo or an expression of your mood.
Riding a concrete path through the nebulous and chaotic future.

Jaded

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  • Formerly known as Jaded
Re: Exped Downbeat failure advice - replacement?
« Reply #4 on: 15 July, 2022, 02:06:03 pm »
 ;D ;D

It is quite appropriate! Luckily(!) it burst on my final morning. I’d not have been happy if it was earlier, walking 40 miles over the festival (and drinking some beer) required good sleeping!
It is simpler than it looks.

Re: Exped Downbeat failure advice - replacement?
« Reply #5 on: 15 July, 2022, 02:54:20 pm »
I personally have found it difficult to match Exped Downmats for comfort.   We've got through quite a number of Downmats but keep buying them.  🤔

Re: Exped Downbeat failure advice - replacement?
« Reply #6 on: 15 July, 2022, 03:06:44 pm »
My Exped syn UL has just failed also after very limited use (blown baffle). Reluctant to buy another. Have purchased a 7.5cm robust self inflator for car camping. I am not sure that paying £240 odd for a mat is worth it for me. I am currently therefore waiting for the Alpkit Cloudbase to come back into stock. The R. value is quite low however and it is quite narrow. Not sure how good the Exped Dura range is but that is also a possibility, as the higher R value and greater width option is preferable.
Get a bicycle. You will never regret it, if you live- Mark Twain

Re: Exped Downbeat failure advice - replacement?
« Reply #7 on: 15 July, 2022, 04:33:26 pm »
Thermarest have a lifetime warranty.

Kim

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Re: Exped Downbeat failure advice - replacement?
« Reply #8 on: 15 July, 2022, 11:01:35 pm »
I personally have found it difficult to match Exped Downmats for comfort.   We've got through quite a number of Downmats but keep buying them.  🤔

Pretty much this.  I'd consider a Synmat, but I'm not sure it's worth trading the lack of a relatively rare failure mode (blown baffles seems to be much more common than spitting feathers) for a lower R-value.  With a 5-year warranty, I treat it as a subscription.

I've been particularly careful about temperature changes since my last one went, making sure I let a bit of air out when I wake up and un-zip the  foot end of the sleeping bag or whatever.  Hopefully that'll reduce the stress on the baffles.

Re: Exped Downbeat failure advice - replacement?
« Reply #9 on: 16 July, 2022, 08:45:19 am »
I have done similar to Kim but also realised that I might have been over inflating in the past.  I find that even when it looks not quite inflated, once you lay upon it the displacement firms it up and is enough to keep you off the ground thus doing it's job.

We do have a humongous Exped Megamat which is absolutely awesome but way too big for anything but car camping.

Kim

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Re: Exped Downbeat failure advice - replacement?
« Reply #10 on: 16 July, 2022, 12:40:14 pm »
I have done similar to Kim but also realised that I might have been over inflating in the past.  I find that even when it looks not quite inflated, once you lay upon it the displacement firms it up and is enough to keep you off the ground thus doing it's job.

I believe the destructions say something to the effect that if you're kneeling on the mat, the right pressure is just when your knees stop bottoming out.

But that doesn't account for temperature changes.  If you inflate to a reasonable pressure at night when it's 12C, it'll be much higher when you're finally accepting that it's no longer fun being in the tent at 26C in the morning.

Re: Exped Downbeat failure advice - replacement?
« Reply #11 on: 16 July, 2022, 01:21:05 pm »
At last mat purchase, having decided that the Neoair original that I'd been using wasn't up to all season use, I took the view that the difference in failure reports on assorted fora between Exped and Thermarest was enough to choose a Neoair XTherm, which was much the same in insulation value to a Downmat 7.
An added advantage is that inflation by mouth isn't really a problem if the pumpsack gets forgotten, and that down-spitting isn't going to happen.
At the time there were insufficient reports from SeaToSummit or Big Agnes mat users to form a view on them.

When looking at insulation, I'd take the view that about R=2.5 would risk being inadequate during the October-April period when a frost may happen, and I sleep relatively warm.
Note that R-values come in ISO units as well as the more common US units (BTU/hour/Sq. foot, deg F). The difference is such that 1 ISO = 6 US, so check if the number is in the 1 to 1.5 range.

As for inflation pressure, is "knees just stop bottoming out" when kneeling on the mat? If so, I'd call that too hard.
I generally aim to compress the mat to about half thickness when in a side-sleeping position.

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Exped Downbeat failure advice - replacement?
« Reply #12 on: 17 July, 2022, 04:29:14 pm »
R values are supposed to be standardised now using an ASTM test.
https://ultralightoutdoorgear.co.uk/r-value-explained-i206
Riding a concrete path through the nebulous and chaotic future.

ravenbait

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Re: Exped Downbeat failure advice - replacement?
« Reply #13 on: 22 July, 2022, 02:31:11 pm »
I ended up getting a Sea to Summit Women's Etherlite (R3.5) to replace my decades old, mouldy, super uncomfortable, now-binned thermarest.

I haven't used it in anger, yet, but it is whole worlds away from my last mat. I think I should be very comfy indeed.

Now I just need to sort out a new tent.

Sam
https://ravenbait.com
"Created something? Hah! But that would be irresponsible! And unethical! I would never, ever make... more than one."

Jaded

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  • Formerly known as Jaded
Re: Exped Downbeat failure advice - replacement?
« Reply #14 on: 22 July, 2022, 02:34:04 pm »
Well, I ended up with Sea to Summit too, and I've blown it up, seems comfortable. An Etherlite.

Will be used in anger at Womad, shortly...
It is simpler than it looks.

hellymedic

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Re: Exped Downbeat failure advice - replacement?
« Reply #15 on: 26 July, 2022, 03:23:10 pm »
I have done similar to Kim but also realised that I might have been over inflating in the past.  I find that even when it looks not quite inflated, once you lay upon it the displacement firms it up and is enough to keep you off the ground thus doing it's job.

I believe the destructions say something to the effect that if you're kneeling on the mat, the right pressure is just when your knees stop bottoming out.

But that doesn't account for temperature changes.  If you inflate to a reasonable pressure at night when it's 12C, it'll be much higher when you're finally accepting that it's no longer fun being in the tent at 26C in the morning.

[science pedant]

Does this really make a significant difference? Pressure is proportional to absolute temperature so a rise from 10C to 37C will increase pressure by less than 10%...

Kim

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Re: Exped Downbeat failure advice - replacement?
« Reply #16 on: 26 July, 2022, 09:25:22 pm »
Well, temperature changes of the type typically experienced on a clear night certainly makes a real difference to how inflated the mat is from a comfort perspective.  A mat blown up hard during the day will be soft at bedtime, and a mat blown up hard at bedtime will be harder than you can reasonably achieve with the usual inflation method in the morning.  I suppose that's a volume change at a constant pressure determined by the size and weight of the person lying on it, up to the point where the mat can't expand any more.

Whether the stress on the baffles due to the additional pressure in that scenario is significant is left as an exercise for the reader.  If the mat's properly engineered, it shouldn't be possible to over-inflate it by lungs / integrated pump / schnozzel alone, but a large temperature change might exceed that.

It stands to reason that a duff weld will fail at the moment of greatest stress, the important question is whether it was going to fail anyway...

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Exped Downbeat failure advice - replacement?
« Reply #17 on: 26 July, 2022, 09:35:18 pm »
A mat blown up hard during the day will be soft at bedtime, and a mat blown up hard at bedtime will be harder than you can reasonably achieve with the usual inflation method in the morning. 
What do you consider "bedtime" and "morning"? Because this seems back to front to me. If you inflate the mat in the morning, by bedtime it's had all day to heat up and the air inside to expand. And if you inflate it at bedtime, it then has a night of falling temperatures, so should be at lower pressure. Unless the warmth of the person lying on top is sufficient to heat it up? I suppose it also depends on the weather, and I'm perhaps being unduly influenced by the fortnight of gloriously hot sunny weather I had in June (excepting the weekend actually at York... ).
Riding a concrete path through the nebulous and chaotic future.

Kim

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Re: Exped Downbeat failure advice - replacement?
« Reply #18 on: 26 July, 2022, 10:02:13 pm »
Bedtime is some time after sunset, when the air temperature has reached the point where you feel cold enough to think being in a sleeping bag would be a significant improvement over whatever you're currently wearing.  Say 10pm-midnight.  If you pumped your mat up at, say, 6pm, it will have become significantly more floppy as the air inside it cooled.

Morning is when the sun rises over the trees and heats the air in your tent from 10C to 30C over the course of about half an hour, and you reluctantly decide that you're not going to get any more sleep.  You don't really notice the mat getting firmer, because you're preoccupied with brightness and cockerels and shedding layers in the least awakening way possible.  Unless a baffle goes per-POP!

Obviously winter or cloudy weather moderates this effect, and things work differently in un-BRITISH climates.

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Exped Downbeat failure advice - replacement?
« Reply #19 on: 27 July, 2022, 07:35:51 am »
Yokay, it all depends on habits and of course weather on the day. Most relevantly though, I've rarely-to-never heard of this failure mode except with Exped.
Riding a concrete path through the nebulous and chaotic future.

Re: Exped Downbeat failure advice - replacement?
« Reply #20 on: 27 July, 2022, 10:33:47 am »
Most relevantly though, I've rarely-to-never heard of this failure mode except with Exped.
Exped are the market leaders so it's hardly surprising you'll hear about more of them, but just try Google images to see plenty of examples from other manufacturers. My first one, same issue, was a Big Agnes.
If anyone could work out a way to terminate an internal weld without it becoming vulnerable to lifting, there'd be a queue of people interested for all sorts of applications.  Instead the mat designers have gone down a different path with the cell type construction, even though I have one, I can't work out how it's made, but the manufacturers seem confident it'll be more reliable.


Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Exped Downbeat failure advice - replacement?
« Reply #21 on: 27 July, 2022, 01:43:16 pm »
Instead the mat designers have gone down a different path with the cell type construction, even though I have one, I can't work out how it's made, but the manufacturers seem confident it'll be more reliable.
Baffles me too!
Riding a concrete path through the nebulous and chaotic future.