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Duotone kite pumping.. Is it just me or is 6 psi weird?
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Matt V

Since 26 Oct 2014
461 Posts
Summer- OR Coast, Winter - My van near good snow
Explosive Diarrhea



PostTue Sep 01, 20 9:04 am     Reply with quote

Old North - Duotone, had the scam going for years and apparently is still doing it! 6 PSI is printed on there to avoid any warranty issues with a blown-out Leading Edge. Not even their team Riders pump up to only 6 PSI.
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runaway

Since 31 Aug 2010
59 Posts
Anchorage
 



PostFri Aug 26, 22 1:18 pm    Pump till pings Reply with quote

I have been North and Duotone forever. Have always pumped tight. No Blow outs and no stretching seams. My old OR 5m razor is starting to blow out from tight pumping, but gonna sew it. YUP I'm poor and I like that little kite!

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dobermankby

Since 07 Jul 2021
22 Posts

 



PostFri Aug 26, 22 4:16 pm     Reply with quote

Not an expert by any means, but I test it by holding the kite upright and trying to fold onto itself. If you cannot fold, it's good to go.

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Justsmile

Since 20 Jul 2009
1521 Posts
Not Portland
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PostFri Aug 26, 22 8:08 pm     Reply with quote

North or Twotone should be embarrassed for even printing 6psi is adequate. No one wants a limp leading edge or limp strut!!!!
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windpig

Since 28 Aug 2008
233 Posts

Stoked



PostSat Aug 27, 22 6:49 am     Reply with quote

Maybe it’s supposed to have been a 9 all this time?!
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Marcus O

Since 30 May 2018
97 Posts

 



PostSat Aug 27, 22 7:43 am     Reply with quote

Not sure if this is true or not, but a Duotone rep told me the 7 psi is due to the flex strut. Apparently the kite won't perform as well if over pumped. I've tried around 7-10 psi and really haven't noticed any difference in performance on my Neos so who knows Confused

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dan.at.duotone

Since 15 Apr 2010
31 Posts
Gorge
 



PostMon Aug 29, 22 11:23 am     Reply with quote

Our (Duotone's) designer Ken had some thoughts on overpumping which I find surprisingly interesting... I've seen how he studies elongation and pressure and how inflated tubes of different material deform differently under different loads at different inflation pressures. It seems esoteric but it becomes very important when designing kites/wings. It's also of interest to the end user because it actually has significant impacts on performance and longevity of the kites...

- Over inflation can cause extra elongation of the LE which stretches the entry of the canopy in the spanwise direction and flattens the entry curvature of the canopy, thus hurting kite performance.

- Over inflation stretches the LE circumferentially, which increases LE diameter, which pushes the struts toward the trailing edge of the kite and flattens the canopy entry.

- This happens the most with standard Dacron and Aluula, as both materials stretch fairly easily.

- Over inflation of Aluula can stretch the cloth past its elastic limit, thus flattening the canopy entry permanently and ruining the kite even if the user tries to use it at recommended pressure thereafter.

- LE stretch is less of a risk with the Penta TX cloth in the LEs of our SLS kites because Penta is very robust against stretching in the spanwise direction. However, even Penta can be overinflated.

- Over inflation increases the torsional stiffness of the LE and can reduce a kite's ability to turn as designed

- Over inflation can also make tip struts too stiff, which can also hurt the ability of a kite to turn as designed.


I have this little note to add also: Our recommendation has nothing to do with warranties/fear of blowing the LE. If you blow a seam on your LE within a year I warranty the kite, I have never asked how hard the kite was pumped nor have I ever accused someone of overpumping their kite. I never even noticed the 6psi recommendation (I think we've changed it to 7 now? Could be wrong, I still never look) because I always just pump it till it's hard. Plus as noted earlier here the pump gauges are pretty worthless...

Also: anyone know how to change my username on here? I should probably get on that at some point. For the record I'm with Duotone, not North...

-Dan

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Windian

Since 28 Apr 2008
869 Posts
Newport, OR
NEWPORT OG



PostMon Aug 29, 22 1:21 pm     Reply with quote

Quote:
I never even noticed the 6psi recommendation (I think we've changed it to 7 now? Could be wrong, I still never look) because I always just pump it till it's hard. Plus as noted earlier here the pump gauges are pretty worthless...


Okay, so how hard is hard?

I respect the research that Ken Winner and the Duotone team put into the optimum kite inflation. You guys are at the fore-front of kite design and materials used. Since the pump gauges vary widely and cannot be used unless the user calibrates their own pump gauge against the hardness of the bladders after pumping, what is the best determination of enough pressure for ideal kite performance?

I own a quiver of Duotone SLS Neos and absolutely love everything about how the kites perform especially for kitesurfing in ocean waves where I live. Maybe since I really like how my kites are working when riding, then I have the correct pressure dialed. I use a WMFG pump and pretty much pump till it is difficult, but not impossible to continue pumping. I would think it is easily 7 psi, but not yet 10 psi. If I squeeze the leading edge right at the largest diameter near the inflation valve with one hand I can depress the bladder no more than 1/8" of an inch. Stoked to hear that Penta TX provides the best performance against stretching of the different materials out there.

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Matt V

Since 26 Oct 2014
461 Posts
Summer- OR Coast, Winter - My van near good snow
Explosive Diarrhea



PostMon Aug 29, 22 5:46 pm     Reply with quote

Matt V wrote:
Old North - Duotone, had the scam going for years and apparently is still doing it! 6 PSI is printed on there to avoid any warranty issues with a blown-out Leading Edge. Not even their team Riders pump up to only 6 PSI.


C'mon man!

Everybody knows this story. Why we gotta re has dis one? Same old scam still going? Gotta give tommy-twotone props for keeping the scam alive.

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