Water displacement?
06-13-20, 06:55 AM
#1
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Water displacement?
What does that term mean in regard to bike riding ?
i heard that the tyre has to be fitted in the right direction for water displacement.
my back tyre is facing the wrong way according to the arrow so I’ll be getting it changed this week
i heard that the tyre has to be fitted in the right direction for water displacement.
my back tyre is facing the wrong way according to the arrow so I’ll be getting it changed this week
06-13-20, 07:23 AM
#2
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It has to do with the ability of a tire to move water from under the tread to avoid hydroplaning; at the speeds and tire pressures usually encountered in cycling hydroplaning is not a worry.
Approximately,
where 
is hydroplaning speed in mph and 
is pressure in psi; even at 25psi the hydroplaning speed is over 50mph.
Approximately,
where is hydroplaning speed in mph and is pressure in psi; even at 25psi the hydroplaning speed is over 50mph.
06-13-20, 07:30 AM
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If it bothered me, I'd wait until I had a flat that needed changing and flip the tire over then.
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06-13-20, 07:37 AM
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That directional arrow has to do with tread design and generally applies to MTB tires to get the best traction on loose surfaces. It has nothing to do with "water displacement". As dsbrantjr demonstrated, you will never hydroplane a bicycle.
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06-13-20, 07:54 AM
#5
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It has to do with the ability of a tire to move water from under the tread to avoid hydroplaning; at the speeds and tire pressures usually encountered in cycling hydroplaning is not a worry.
Approximately, where is hydroplaning speed in mph and is pressure in psi; even at 25psi the hydroplaning speed is over 50mph.
Approximately,
where is hydroplaning speed in mph and is pressure in psi; even at 25psi the hydroplaning speed is over 50mph.and tread design changes water displacement as well. So the equation should include many more variables.
06-13-20, 08:34 AM
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Interesting equation. But wouldn't tire width play a role as well? And system weight? I assume a 5 pound system would hydroplane before a 300 pound system with given tires and speed.
and tread design changes water displacement as well. So the equation should include many more variables.
and tread design changes water displacement as well. So the equation should include many more variables.
My point was to illustrate that hydroplaning is generally not an issue with cyclists.
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06-13-20, 09:24 AM
#7
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About the only way you can hydroplane with a bike is to drive it off a pier.
You have to keep pedaling until you hit the bottom though.
Bring scuba gear.
You have to keep pedaling until you hit the bottom though.
Bring scuba gear.
06-13-20, 09:37 AM
#9
Banned
the contact patch of a bicycle tire is too small to hydroplane.. and if its a slick surface, steel plates or paint, you will still need to be careful..
06-13-20, 04:03 PM
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The sipes on the tire tread are generally angled so that water, if encountered, will be directed towards the edge of the tread as the tire rolls over it, rather than towards the center of the tread where there is theoretically no place for it to escape. As noted above, this will not lead to hydroplaning under virtually any conceivable circumstances. Putting the tire on backwards is a "D'oh!" moment (I've done it), but as suggested above, it's perfectly OK to wait until the tire is removed for other reasons.
Heh... (afterthought!)... think of the arrows as a test to see if you're paying attention!
Heh... (afterthought!)... think of the arrows as a test to see if you're paying attention!
06-13-20, 05:55 PM
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06-13-20, 08:25 PM
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Bike tire marketing borrows from what many consumers already know, car tires. But the dynamics of car and bike tires are pretty different so what cars require is not completely transfered to bike tires. However the average consumer doesn't know this and as such can be manipulated by advertising (and labels are this to a large degree) claims.
I explain the hydroplaning possibilities as this. A car tire rolling along is a squeegee that builds up a wall of water in front of it. It needs channels to route that wall of water around it to prevent it from being lifted off the road by that wall of water. Much like a flat bottomed boat will plane on top of a lake. Now a bike tire is like a canoe on that lake. It's cigar like shape is very "hydrodynamic" and the water will readily flow around and past it's shape.
Having said that there's still the unmentioned issue of lessened friction/traction from the water acting like a lubricant. Much like oils on the road will increase a tire's ability to slip so to will water. Just not from hydroplaning. Andy
I explain the hydroplaning possibilities as this. A car tire rolling along is a squeegee that builds up a wall of water in front of it. It needs channels to route that wall of water around it to prevent it from being lifted off the road by that wall of water. Much like a flat bottomed boat will plane on top of a lake. Now a bike tire is like a canoe on that lake. It's cigar like shape is very "hydrodynamic" and the water will readily flow around and past it's shape.
Having said that there's still the unmentioned issue of lessened friction/traction from the water acting like a lubricant. Much like oils on the road will increase a tire's ability to slip so to will water. Just not from hydroplaning. Andy
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