General Cycling Discussion - can a bike hydroplane?

at reasonable speeds that an average cyclist would travel, would it be possible to hydroplane on a bicycle?

i've never had it happen to me, the road tires are too narrow and mtb tires have too much bite.

According to Saint Brown, the answer is no. I think I remember his calculation that it would require speeds of 70+mph.

According to Saint Brown, the answer is no. I think I remember his calculation that it would require speeds of 70+mph.

Here is the link (http://www.sheldonbrown.com/tires.html#hydroplaning) for you...but the basic answer is no. FWIW I have never hydroplaned and have never seen anyone hydroplane a bicycle. You are more likely to slip, slide and lose traction due to oil on the pavement more than anything else.

Aaron:)

It could probably be done, but would take a LOT of work to make it happen.

Get a 90 pound rider on a 14 pound bike that has a light front end and is shod with a pair of custom made 4 inch wide muscle bike slicks that look like this, but without the grooves:
http://i3.ebayimg.com/06/i/000/f1/79/e548_1.JPG

Some motorpacing might help, as well...

Still, even though it's nigh on impossible to hydroplane on a bike, it's not a good idea to change direction in a puddle. Keep the bars straight 'til you exit said puddle.

No way. I've seen some calculations on it, too, and I think the figure was WAY above 70--something like 150mph. The tire contact patch of a high pressure road tire isn't much more than a square inch, so the loading is pretty high. That squeezes the water out.
That doesn't mean you can't skid in the rain, though. The water lubricates things pretty well, especially if you hit something like a paint stripe.

I've ridden through water on 26x2.125" tires and no hydroplaning.

http://www.sheldonbrown.com/tires.html#hydroplaning

Reference: FAA-H-8083-3A, Ch 8
Gives a formula of: knots = 8.6 * sqrt(psi)

although unlikely i thought it may have been possible, i was with a buddy and his car hydroplaned at sub 30 mph

another mystery is solved

thank you

although unlikely i thought it may have been possible, i was with a buddy and his car hydroplaned at sub 30 mph

Really? How? Were the tires bald? Did he overdo the steering? Did he stomp the gas (if it was a FWD car -- especially if it was mid-turn)? Did he hit a patch of oily pavement?

I can make my Civic wash out into understeering on wet pavement if I want, but hydroplaning means I'm either running my Azenis or going way too fast for road conditions.

Really? How? Were the tires bald? Did he overdo the steering? Did he stomp the gas (if it was a FWD car -- especially if it was mid-turn)? Did he hit a patch of oily pavement?

I can make my Civic wash out into understeering on wet pavement if I want, but hydroplaning means I'm either running my Azenis or going way too fast for road conditions.

yeah you pretty much hit the nail on the head. it was an old sh***y ram cargo van it was raining and he did hit the gas pretty hard into a turn. dunno about the tires though, if they were anything like the rest of the van they probably had cords showing haha

Well I guess yer all too slow, I've always had problems with hydroplaning when it's wet out.
HTFU and ride like the wind! :roflmao2:

Just wondering...how much of an issue is hydroplaning on a motorcycle? Seems like just having 2 wheels instead of 4 would greater reduce the hyroplaning potential.

Just wondering...how much of an issue is hydroplaning on a motorcycle? Seems like just having 2 wheels instead of 4 would greater reduce the hyroplaning potential.

It's possible, but I highly recommend against it. :innocent:

Just wondering...how much of an issue is hydroplaning on a motorcycle? Seems like just having 2 wheels instead of 4 would greater reduce the hyroplaning potential.

I once saw a BMR K1200LT hydroplane at 65MPH. He said it was like riding on ice......... right before he high sided!

Keep in mind the shape of the tires. In a cross section view, a car tire (and maybe some motorcycle tires) is flat on the bottom. A bicycle tire is oval or round in cross section. There's no surface to get up on plane. Well, maybe some of the big cruiser tires really are flat on the bottom - I'm not sure.

Keep in mind the shape of the tires. In a cross section view, a car tire (and maybe some motorcycle tires) is flat on the bottom. A bicycle tire is oval or round in cross section. There's no surface to get up on plane. Well, maybe some of the big cruiser tires really are flat on the bottom - I'm not sure.


All motorcycle tires I am aware of are round. And, I've changed a lot of them.

My buddy who hydroplaned on his Beemer, is very experienced, and we have 100s of thousands of miles together. He has ridden on ice and snow his whole life, so if he says something, I believe him. He is my Iron Butt Association buddy, and all of our certifications are together.

It just happened on I-40 in Oklahoma one rainy afternoon. I went thru the same area, seconds before he did, and had no problem.

there are some really fat rear tires for choppers that are close to the width of some passenger tires on cars

The hydroplaning formula is the square root of tire pressure times 9. So if you are running 60 psi in your mountain bike it works out to just under 70 MPH, if you are running 36 psi in car tires it works out to 54 MPH. If in your car you are running 30 psi it works out to just under 50 MPH. Weight actually has nothing to do with it. You stop hydroplaning at 7.95 times the square root of tire pressure. I'm sure it is not exactly correct in ALL circumstances , but is rather close.

Weight actually has nothing to do with it.

I find this difficult to believe. I'd almost bet money we could get a vehicle at GVW of 120 lbs. to plane at a lower speed than I could with same vehicle with weight added to make a GVW of 360 lbs.

I believe that formula requires an "All other variables being equal, " as a preface.

The point of the formula is that the same tire on the same vehicle at the same weight will plane at a lower speed if it has lower pressure.

Hmm, no mention of tread, either. I found the formula you speak of, with a dead link to a NASA study. I'm intrigued...

I know it doesn't seem it should be the case, but actually it applies to a B747 at 390 metric tons and tricycles, what I'd like to know is what if a tire is made of solid rubber <smile> but to answer the thread, it does look like hydoplaning on a bicycle would be difficult.

I find this difficult to believe. I'd almost bet money we could get a vehicle at GVW of 120 lbs. to plane at a lower speed than I could with same vehicle with weight added to make a GVW of 360 lbs.

I believe that formula requires an "All other variables being equal, " as a preface.

The point of the formula is that the same tire on the same vehicle at the same weight will plane at a lower speed if it has lower pressure.

Hmm, no mention of tread, either. I found the formula you speak of, with a dead link to a NASA study. I'm intrigued...

Did some research on tires in college for auto and truck accidents in college, 30 years ago. As I recall the equation for hydroplaning in MPH was 10.6 x air pressure in PSI squared...which is very close to Shelton's posted equation. Lower air pressure increases the contact patch, which is like having two water skis instead of one....you can ski at slower speeds with 2 skis....same with car tires. We even tested it on a section of road that would have a 1/4 of water during mild rains....and it was spot on

Did some research on tires in college for auto and truck accidents in college, 30 years ago. As I recall the equation for hydroplaning in MPH was 10.6 x air pressure in PSI squared...which is very close to Shelton's posted equation. Lower air pressure increases the contact patch, which is like having two water skis instead of one....you can ski at slower speeds with 2 skis....same with car tires. We even tested it on a section of road that would have a 1/4 of water during mild rains....and it was spot on

I meant to say the square root of the air pressure, i.e. 6 times 10.6, for tires with 36 psi.

I'd imagine a proper experiment would require a tow vehicle with deep tread tires pulling a non-suspended trailer with, say, 1/8" tread tires through a 1/4" of water.

Take some runs with the trailer unloaded, then take some runs with 1000 lbs of weight on the trailer, making sure the tongue weight is equal in both situations. I'm thinking something like my boat trailer, but without leaf springs. It's maybe 400 lbs.

I'm not sure what the best telemetry would be to determine when the trailer begins to plane...

Of course bikes can hydroplane!
Just ride it off the end of a dock-

I'd imagine a proper experiment would require a tow vehicle with deep tread tires pulling a non-suspended trailer with, say, 1/8" tread tires through a 1/4" of water.

Take some runs with the trailer unloaded, then take some runs with 1000 lbs of weight on the trailer, making sure the tongue weight is equal in both situations. I'm thinking something like my boat trailer, but without leaf springs. It's maybe 400 lbs.

I'm not sure what the best telemetry would be to determine when the trailer begins to plane...

Adding weight to the vehicle won't change the hydroplane speed, for a given tire pressure. More weight will give a larger tire foot print, but the loading on each square inch of the tire foot print will still be equal to the inflation pressure, i.e. 30 pounds, if 30 psi inflation. For 30 psi, at about 58 mph the surface tension of water is strong enough for the tire to hydroplane.