# aqua planning on 1.5 tyres?

Discussion in 'Cycling Equipment' started by Panda, Jun 10, 2003.

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1. ### Panda Guest

i have heard that you cannot aqua plan on bikes because of the size of contact area versus weight.
is this true for all widths of tyre inc 1.5inch? (assuming a pressure of 70psi or so)

thanks

panda

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2. ### Doug Huffman Guest

"panda" <[email protected]> wrote in message
news:[email protected]...
> i have heard that you cannot aqua plan on bikes because of the size of contact area versus weight.
> is this true for all widths of tyre inc
1.5inch?
> (assuming a pressure of 70psi or so)
>
>

Yes. Perhaps you could convince yourself by calculating the change in contact pressure with the
change in tire width.

3. ### Jim Price Guest

panda wrote:
> i have heard that you cannot aqua plan on bikes because of the size of contact area versus weight.
> is this true for all widths of tyre inc 1.5inch? (assuming a pressure of 70psi or so)

Speed is also a factor. To get an intuitive feel for what you would need to do to aquaplane on a
bike, imagine how fast you would have to run at a puddle of water such that when you reached it you
could aquaplane (not just slide) along the surface in your shoes. Then reduce the area of the bottom
of your shoes to the contact area of a set of bicycle tyres (even three inch tyres would have a
smaller contact patch than size 10 shoes). If you can reach that sort of speed on your bike, you
should be looking to set some world records, not worrying about aquaplaning .

Jim Price

4. ### Doug Milliken Guest

On Tue, 10 Jun 2003, Jim Price wrote:

> panda wrote:
> > i have heard that you cannot aqua plan on bikes because of the size of contact area versus
> > weight. is this true for all widths of tyre inc 1.5inch? (assuming a pressure of 70psi or so)
>
> Speed is also a factor. To get an intuitive feel for what you would need to do to aquaplane on a
> bike, imagine how fast you would have to run at a puddle of water such that when you reached it
> you could aquaplane (not

Surface is also a factor, a smooth steel plate (used around here during road repairs) is very
slippery when wet.

5. ### Jim Price Guest

Doug Milliken wrote:
> Surface is also a factor, a smooth steel plate (used around here during road repairs) is very
> slippery when wet.

I presume you are talking about partial aquaplaning. In full aquaplaning mode, I don't see the
surface having much of an effect. See:

http://www.centralflyingschool.org.uk/Winter/Aqua.htm

--
Jim Price

http://www.jimprice.dsl.pipex.com

Conscientious objection is hard work in an economic war.

6. ### Jobst Brandt Guest

Doug Milliken writes:

>>> I have heard that you cannot aqua plane on bikes because of the size of contact area versus
>>> weight. Is this true for all widths of tyre incl 1.5inch? (assuming a pressure of 70psi or so)

>> Speed is also a factor. To get an intuitive feel for what you would need to do to aquaplane on a
>> bike, imagine how fast you would have to run at a puddle of water such that when you reached it
>> you could aquaplane (not

> Surface is also a factor, a smooth steel plate (used around here during road repairs) is very
> slippery when wet.

Let's not confuse lubrication and flotation as in aqua/hydro-planing. In lubrication, mating
surfaces and the lubricant work together while in hydroplaning the surface, such as pavement
roughness, plays no role. As has been discussed often, a squeegee with a sharp rubber edge glides
effortlessly over glass on a few molecular layers of water. That is lubrication in contrast to tires
lifting off the road over water.

The round cross section of a slick bicycle tire produces a canoe-shaped contact patch with a leading
point that makes an excellent lateral water displacer. The shape is best seen by using an inked
stamp pad and pressing the inked wheel against a sheet of paper.

Lubrication is what makes a wet road slick, the smoother the surface the more slippery it is.

Jobst Brandt [email protected] Palo Alto CA

7. ### Bluto Guest

"panda" <[email protected]> wrote:

> i have heard that you cannot aqua plan on bikes because of the size of contact area versus weight.
> is this true for all widths of tyre inc 1.5inch? (assuming a pressure of 70psi or so)

Maybe if you have the body weight of a squirrel and ride a bike like this
http://meditech.ch/ete.dragracing/velofusee.html , but I doubt
it.

I have ridden into standing water at 70mph on my motorcycle, which has much wider tires than a
bicycle, without any sign of hydroplaning.

Nobody has ever planed a bicycle, and nobody ever will. Wondering if 38mm tires will cause
hydroplaning is like wondering if wide fenders will cause you to take flight.

Chalo Colina

8. ### Doug Milliken Guest

On Tue, 10 Jun 2003 [email protected] wrote:

> Doug Milliken writes:
>
> >>> I have heard that you cannot aqua plane on bikes because of the size of contact area versus
> >>> weight. Is this true for all widths of tyre incl 1.5inch? (assuming a pressure of 70psi or so)
>
> >> Speed is also a factor. To get an intuitive feel for what you would need to do to aquaplane on
> >> a bike, imagine how fast you would have to run at a puddle of water such that when you reached
> >> it you could aquaplane (not
>
> > Surface is also a factor, a smooth steel plate (used around here during road repairs) is very
> > slippery when wet.
>
> Let's not confuse lubrication and flotation as in aqua/hydro-planing. In lubrication, mating
> surfaces and the lubricant work together while in hydroplaning the surface, such as pavement
> roughness, plays no role. As has been discussed often, a squeegee with a sharp rubber edge glides
> effortlessly over glass on a few molecular layers of water. That is lubrication in contrast to
> tires lifting off the road over water.

Thanks for the clarification. Just wanted to point out that even though bike tires don't hydroplane,
doesn't mean they will always grip on a wet surface. For another example, some places (ie, England)
use tar to patch, and this can leave a very smooth (almost glassy) surface.

9. ### Jobst Brandt Guest

Doug Milliken writes:

>>>>> I have heard that you cannot aqua plane on bikes because of the size of contact area versus
>>>>> weight. Is this true for all widths of tyre incl 1.5inch? (assuming a pressure of 70psi or so)

>>>> Speed is also a factor. To get an intuitive feel for what you would need to do to aquaplane on
>>>> a bike, imagine how fast you would have to run at a puddle of water such that when you reached
>>>> it you could aquaplane (not

>>> Surface is also a factor, a smooth steel plate (used around here during road repairs) is very
>>> slippery when wet.

>> Let's not confuse lubrication and flotation as in aqua/hydro-planing. In lubrication, mating
>> surfaces and the lubricant work together while in hydroplaning the surface, such as pavement
>> roughness, plays no role. As has been discussed often, a squeegee with a sharp rubber edge glides
>> effortlessly over glass on a few molecular layers of water. That is lubrication in contrast to
>> tires lifting off the road over water.

> Thanks for the clarification. Just wanted to point out that even though bike tires don't
> hydroplane, doesn't mean they will always grip on a wet surface. For another example, some places
> (ie, England) use tar to patch, and this can leave a very smooth (almost glassy) surface.

I think crack patching is done with smooth tar in most places. Enough riders have slipped on the
stuff around here, both up hill and down, the latter being more damaging. However, in France these
tar stripes are covered with a grey-green grit to improve traction. The problem with this material
is that it uses slow curing tar that presents a sliding problem itself as it can move laterally when
not yet cured.

Jobst Brandt [email protected] Palo Alto CA

10. ### Tim McNamara Guest

In article <[email protected]>, Doug Milliken <[email protected]> wrote:

> Thanks for the clarification. Just wanted to point out that even though bike tires don't
> hydroplane, doesn't mean they will always grip on a wet surface. For another example, some places
> (ie, England) use tar to patch, and this can leave a very smooth (almost glassy) surface.

Indeed. In addition to road surface variations (asphalt, concrete, pure tar, painted stripes, etc)
all rubber is not created equal in terms of wet traction. Silica-based rubber seems to have much
less wet traction than carbon black-based rubber.

11. ### x Guest

RE/
>Just wanted to point out that even though bike tires don't hydroplane, doesn't mean they will
>always grip on a wet surface. For another example, some places (ie, England) use tar to patch, and
>this can leave a very smooth (almost glassy) surface.

Another variable seems to be the rubber used in the the tire. I usually ride a set of WTB's and have
done a fair number of 2-3 hour rides in the rain on them - so I'm pretty much dialed in to their
behavior in the wet.

The other day, I tried my other bike with a set of Heng Shin 120 tpi kevlar bead semislicks and
almost ate it just pulling out of my driveway. Those suckers are *really* slippery. Strangly enough,
I had a set of the same pattern, but in a coarser thread and seemingly-different compound and don't
recall them being unusually slippery...
-----------------------
PeteCresswell

12. ### Doug Huffman Guest

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
>
> Indeed. In addition to road surface variations (asphalt, concrete, pure tar, painted stripes, etc)
> all rubber is not created equal in terms of wet traction. Silica-based rubber seems to have much
> less wet traction than carbon black-based rubber.

WOW! The holy grail of bike tires. Low traction should mean low RR.

13. ### Tim McNamara Guest

In article <[email protected]>, "Doug Huffman"
<[email protected]> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...
> >
> > Indeed. In addition to road surface variations (asphalt, concrete, pure tar, painted stripes,
> > etc) all rubber is not created equal in terms of wet traction. Silica-based rubber seems to have
> > much less wet traction than carbon black-based rubber.
>
> WOW! The holy grail of bike tires. Low traction should mean low RR.

And landing on your ass in corners in the rain. With the added benefits of wearing out about twice
as fast *and* costing more. Silica rubber colored tires really should be marketed by infomercial.

14. ### Mark Hickey Guest

"(Pete Cresswell)" <[email protected]> wrote:

>The other day, I tried my other bike with a set of Heng Shin 120 tpi kevlar bead semislicks and
>almost ate it just pulling out of my driveway. Those suckers are *really* slippery. Strangly
>enough, I had a set of the same pattern, but in a coarser thread and seemingly-different compound
>and don't recall them being unusually slippery...

Some tires come coated with a protectant that is VERY slick. I discovered this the hard way on
the first corner after mounting a new set of tubulars (I hit the ground before I even knew it
was coming).

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the \$695 ti frame

15. ### Sheldon Brown Guest

Mark Hickey wrote:

> Some tires come coated with a protectant that is VERY slick. I discovered this the hard way on the
> first corner after mounting a new set of tubulars (I hit the ground before I even knew it was
> coming).

A friend of mine washed his motorcycle a few years ago, and used Armorall on the tires. Looked
really great for a few minutes.

He just barely survived the crash, doesn't use two-wheeled vehicles any more, doesn't walk all that
well either...

Sheldon "Shiny Isn't Always Good" Brown +--------------------------------------------------+
| My son George has written a Trombone Concerto | You can hear it at http://sheldonbrown.com/mp3 |
+--------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

16. ### Mark Hickey Guest

Sheldon Brown <[email protected]> wrote:

>Mark Hickey wrote:
>
>> Some tires come coated with a protectant that is VERY slick. I discovered this the hard way on
>> the first corner after mounting a new set of tubulars (I hit the ground before I even knew it was
>> coming).
>
>A friend of mine washed his motorcycle a few years ago, and used Armorall on the tires. Looked
>really great for a few minutes.
>
>He just barely survived the crash, doesn't use two-wheeled vehicles any more, doesn't walk all that
>well either...

I once made the same mistake on my motorcycle saddle. I hit the gas and it was a good thing I was
wearing shorts, because that allowed me to grab the gas tank with my knees before I shot off the
back (or the motorcycles shot out from under me).

>Sheldon "Shiny Isn't Always Good" Brown

I'm straining not to make a shaved head joke here...

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the \$695 ti frame

17. ### H. M. Leary Guest

In article <[email protected]>, Mark Hickey <[email protected]> wrote:

> Sheldon Brown <[email protected]> wrote:
>
> >Mark Hickey wrote:
> >
> >> Some tires come coated with a protectant that is VERY slick. I discovered this the hard way on
> >> the first corner after mounting a new set of tubulars (I hit the ground before I even knew it
> >> was coming).
> >
> >A friend of mine washed his motorcycle a few years ago, and used Armorall on the tires. Looked
> >really great for a few minutes.
> >
> >He just barely survived the crash, doesn't use two-wheeled vehicles any more, doesn't walk all
> >that well either...
>
> I once made the same mistake on my motorcycle saddle. I hit the gas and it was a good thing I was
> wearing shorts, because that allowed me to grab the gas tank with my knees before I shot off the
> back (or the motorcycles shot out from under me).
>
> >Sheldon "Shiny Isn't Always Good" Brown
>
> I'm straining not to make a shaved head joke here...
>
> Mark Hickey Habanero Cycles http://www.habcycles.com Home of the \$695 ti frame

Jeese! Was THAT your motorcycle that we Armoraled over at Garcia's ( Scottsdale ) one night???

--
"Freedom Is a Light for Which Many Have Died in Darkness"

- Tomb of the unknown - American Revolution

18. ### Mark Hickey Guest

"H. M. Leary" <[email protected]> wrote:

> Mark Hickey <[email protected]> wrote:

>> I once made the same mistake on my motorcycle saddle. I hit the gas and it was a good thing I was
>> wearing shorts, because that allowed me to grab the gas tank with my knees before I shot off the
>> back (or the motorcycles shot out from under me).
>
>Jeese! Was THAT your motorcycle that we Armoraled over at Garcia's ( Scottsdale ) one night???
>

Heh heh heh... far from it.

If someone lives in the Phoenix east valley and is reduced to getting their Mexican food fix from
Garcia's, they DESERVE to have their saddle slicked up. You could drive by my favorite Mexican place
in Scottsdale a dozen times and never see it (strangely, it's directly across from a Taco Bell that
gets about 4x the business - which doesn't speak too highly of taste among Scottsdale residents).

Besides, the new Corbin saddle I got on my BMW has a nice lip behind my butt that would probably
keep me on the bike no matter how slick the saddle (not that I'm planning to test that premise).

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the \$695 ti frame

19. ### Jobst Brandt Guest

Doug Huffman writes:

>> Indeed. In addition to road surface variations (asphalt, concrete, pure tar, painted stripes,
>> etc) all rubber is not created equal in terms of wet traction. Silica-based rubber seems to have
>> much less wet traction than carbon black-based rubber.

> WOW! The holy grail of bike tires. Low traction should mean low RR.

Oh? What, in your perception causes rolling resistance? Why should low traction result in low RR?

http://draco.acs.uci.edu/rbfaq/FAQ/8b.14.html

Jobst Brandt [email protected] Palo Alto CA

20. ### Mark Hickey Guest

[email protected] (Chris Zacho "The Wheelman") wrote:

>Bicycles tires are round, they don't trap water like car tires do, instead, they plow through
>it, like the hull on a ship. Granted, if a bicycle were to travel fast enough, it could
>theoretically hydroplane, but the speed that would be required must be way up there. I doubt you
>ever ride that fast.

I once did a duathlon (run-bike-run) in Florida where the first run was dry, but then it rained like
crazy during the bike leg. It was funny watching those who didn't ride in the rain deal (or try
to...) with it. They'd soft pedal down the one hill since water was collecting in the road, and I
was flying just to see how much of a rooster tail I could kick up. I also made up a lot of ground on
other racers in the corners (tires and roads aren't all that slick once the top layer of accumulated
oil has been rinsed off by heavy rain).

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the \$695 ti frame