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7 minutes ago, Unventor said:

I knew the risk it posed, but when it happened, it surprised me as I never experienced the sensation before.

Riding through the winter is a great way to get used to riding on slippery surfaces. It's actually quite doable.

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8 hours ago, esaj said:

Hydroplaning comes up every now and then on the forums, the rough rule of thumb is something like 9 * sqrt(psi) = minimum speed in mph required for hydroplaning, but it doesn't take into account the tread pattern, shape or size of the tire, which (I think) further affect things. I ride usually with around 4 bar pressure (roughly 58 psi), that would be

9 * sqrt(58) = 68.54.. mph = around 110km/h

But if it was that simple, most passenger cars have pressures around 2 bar (29 psi), and would start hydroplaning around 48.47 mph = 78km/h. If that were always true, we'd have a lot more hydroplaning accidents with cars all the time. If anything, my (possibly wrong) logic would say that the car tire should hydroplane more easily, being more rectangular in shape, than more rounder bicycle/motorcycle/EUC tire. So the tread-pattern, size and shape of the tire must have some effect there, but to figure out exactly what would probably require very high level math and physics (fluid dynamics etc?), which goes way over my head... :P 

@esaj I thought that it was pounds to the ground per square inch.  I am 220 pounds and my wheel is 50 puonds for a total of 270 pounds.  When I stand on the wheel 2.5 square inches touch the ground. That means I am applying 108 psi to the ground.

 A family car in the US weighs 3,400 pounds with four tires at 9 square inches each.  That is 36 inches total.  That makes 94.4 psi to the ground. 

I don't know the rest of the math.  

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Posted (edited)
1 hour ago, RockyTop said:

@esaj I thought that it was pounds to the ground per square inch.  I am 220 pounds and my wheel is 50 puonds for a total of 270 pounds.  When I stand on the wheel 2.5 square inches touch the ground. That means I am applying 108 psi to the ground.

 A family car in the US weighs 3,400 pounds with four tires at 9 square inches each.  That is 36 inches total.  That makes 94.4 psi to the ground. 

I don't know the rest of the math.  

On a quick glance, the original formula comes from some aircraft stuff ("Source: Airbus "Getting to Grips with Aircraft Performance" Section 5.5.2.4, Page 82."), and only contains the tire pressure, not aircraft weight. But it's under otherwise specific criteria, and probably doesn't really apply directly with all types of vehicles...
Wikipedia says that 

Quote

Dynamic aquaplaning is generally related to tire inflation pressure. Tests have shown that for tires with significant loads and enough water depth for the amount of tread so that the dynamic head pressure from the speed is applied to the whole contact patch, the minimum speed for dynamic aquaplaning (Vp) in knots is about 9 times the square root of the tire pressure in pounds per square inch (PSI).[10] For an aircraft tire pressure of 64 PSI, the calculated aquaplaning speed would be approximately 72 knots. This speed is for a rolling, non-slipping wheel; a locked wheel reduces the Vp to 7.7 times the square root of the pressure. Therefore, once a locked tire starts aquaplaning it will continue until the speed reduces by other means (air drag or reverse thrust).[10]

So apparently the original "rule of thumb" has already been messed up in many sources by saying that the result is in mph, when it's in knots (1 knot = 1.15mph = 1.852kmh).

The original value I had for (my) 58 psi was

9 * sqrt(58) = 68.54

If that's knots, then the aquaplaning speed would be around 127km/h (a little under 79mph). Hardly something to worry with an EUC.

There's lots more information in the Wikipedia-article alone ( https://en.wikipedia.org/wiki/Aquaplaning ), if you're interested, I'd still think the chance of actually hydro/aquaplaning on an EUC with the speeds they can reach is near zero. Wet surface can be otherwise slippery, and you can faceplant for a gazillion different reasons, but I doubt hydroplaning is the actual cause in any case  ;) 

Edited by esaj
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5 minutes ago, esaj said:

aquaplaning speed would be around 127km/h (a little under 79mph). Hardly something to worry with an EUC.

Challenge excepted !! :w00t2:      I just need to more than double my speed........50 inch wheel .......... two 2,000 watt hubs side by side? ....... double everything ........ wind suite ....wind to my back ........down hill  ...................   

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6 hours ago, yegwheel said:

Riding through the winter is a great way to get used to riding on slippery surfaces. It's actually quite doable.

I doubt I will risk that here in Sweden.

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Posted (edited)
4 hours ago, esaj said:

On a quick glance, the original formula comes from some aircraft stuff ("Source: Airbus "Getting to Grips with Aircraft Performance" Section 5.5.2.4, Page 82."), and only contains the tire pressure, not aircraft weight. But it's under otherwise specific criteria, and probably doesn't really apply directly with all types of vehicles...
Wikipedia says that 

So apparently the original "rule of thumb" has already been messed up in many sources by saying that the result is in mph, when it's in knots (1 knot = 1.15mph = 1.852kmh).

The original value I had for (my) 58 psi was

9 * sqrt(58) = 68.54

If that's knots, then the aquaplaning speed would be around 127km/h (a little under 79mph). Hardly something to worry with an EUC.

There's lots more information in the Wikipedia-article alone ( https://en.wikipedia.org/wiki/Aquaplaning ), if you're interested, I'd still think the chance of actually hydro/aquaplaning on an EUC with the speeds they can reach is near zero. Wet surface can be otherwise slippery, and you can faceplant for a gazillion different reasons, but I doubt hydroplaning is the actual cause in any case  ;) 

I was in a local bicycle shop discussing this subject and long story short, funny but he quoted 80 mph for a bicycle to hydroplane... @esaj you're freaking amazing... :blink:

Edited by Mark Lee
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34 minutes ago, esaj said:

 

A Tennessee-man was killed yesterday in a freak accident involving a home-made, monstrously-sized electric unicycle and a windsuit. According to eye witness reports, the man had been speeding down a cliff side with his 50" electric unicycle, powered by a flux capacitor providing over 4 jiggawatts of power. Soon after reaching a shallow pool of water he had made at the base of the hill, he got airborne thanks to the wind suite, and flew for a good quarter mile before hitting the ground face first, being killed immediately on impact. 

The accident investigation committee is still fighting over whether the vehicle began hydroplaning entering the pool of water or not. The only thing they agree on so far is that the speed must have still been below 88mph, because no time travel occurred.

 

:roflmao:

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On 8/28/2018 at 11:32 AM, esaj said:

9 * sqrt(psi) = minimum speed in mph required for hydroplaning

LOL that's very funny :)

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I agree with the MUD comments. That was my personal biggest learning issue. MUD (any wet dirt) around here is like ice. I now avoid going on hills when it may be muddy as well.

Also, not getting to confident once you DO learn to ride...and going too fast around blind spots.

Other than that, just ride safely (watching out for others)  and know your limits.

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While riding my EUC, I got a right leg cramp that hurts a lot.  The natural tendency is bend (forward and down) and lift the leg was a bad mistake.  The EUC speed up and turn causing a twisted fall, further hurting my left ankle.  Not sure if cramp can 100% be avoided.

Like any sports athlete, warm up the leg muscle, and hydrate well before a long hot ride.  If you sense discomfort in your leg, better slow down, and bring the EUC to a halt.  Rest and massage your leg before riding again. Never to bent forward in a surprise move.

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I learned a couple of more rules recently, the hard way:

- Don't be too confident in your riding skills, always check for obstacles in front of you

- Don't use your phone while riding, don't use messengers

 

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12 hours ago, maxkan said:

I learned a couple of more rules recently, the hard way:

- Don't be too confident in your riding skills, always check for obstacles in front of you

- Don't use your phone while riding, don't use messengers

I’ve got one to add:

- If the phone slips from your hand, DON’T try to reach out and catch it. Just let it fall, cheaper that way.

I actually didn’t crash, but it was a really close ”call”. Could’ve ended up having to replace body parts in addition to the phone display...

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I got one to add;

* Never trust pedestrians, especially "iZombies" (or people in general). As always in traffic, think for everybody else too!

The only real "accident" I had (luckily nobody hurt) was when somebody ahead of me took a step out in the bike lane because the person in front of us switched side from the bike lane to leave room for me. :efeee20b79: :facepalm:

Edited by sWiFt

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On 10/8/2018 at 5:33 PM, mrelwood said:

but it was a really close ”call”

Haha  :efefd8a002:

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