Avocet Touring Tires

[Trevor Jeffrey]

Peter wrote in message ...
>>
>> The rule developed for estimating when hydroplaning conditions exist for
>> landing planes which have smooth tires is that
>> V(mph) >= 10 * tire pressure (psi).

At what depth of standing water? Is this just for a film of water?
It must be taken into account that the usual standard for airstrip
construction is higher than that encountered on roads. So any tyre is
likely to perform better on a landing strip than on the road due to the
enhanced drainage of the landing strip.
TJ

 

[Peter]

Benjamin Lewis wrote:

> [email protected] wrote:

>>Not really interested in working out a derivation. If you are I'd
>>suggest starting by considering the force required to move the water out
>>of the way and what's available from the pressure of the tire.
>
>
> I was asking for a citation, not a theoretical derivation. Where did you
> get this formula from? Did they publish the data with which they derived
> it?

I don't have it at hand, but a place to look would be: Horne, Walter B.,
NASA Langley Research Center, "Skidding Accidents on Runways and
Highways Can be Reduced," Astronautics & Aeronautics, August 1967. Don't
know if this has the technical derivation, but one would probably be
included in the references provided in this paper. The formula is
commonly used in connection with pilot training.

 

[David Damerell]

Tim McNamara <[email protected]> wrote:
>John Forrest Tomlinson <[email protected]> writes:
>><[email protected]> wrote:
>>>A total loss of wheel traction on a single-track vehicle will
>>>result in an immediate sideways fall.
>>I've skidded both wheels momentarily without falling. Isn't that a
>>total loss of traction?

No, that's merely insufficient traction for everything you're trying to do,
and doesn't preclude there being sufficient to keep the wheels under the
bike.

>No, it's a partial loss. Try riding your bike on wet ice for a good
>sense of total loss of traction.

Even wet ice offers more grip than the macroscopic layer of water present
when a vehicle aquaplanes.
--
David Damerell <[email protected]> Distortion Field!

 

[David Damerell]

Robert <[email protected]> wrote:
>Loss of grip when cornering or braking is one thing. Increase of slip
>angle is what happens in the wet, when cornering. But you people must be
>a completely different class of riders to be able to go so quickly that
>you can cause genuine aquaplaning, and then live to tell the story.

Who are us people, plural? Only one person has claimed this.
--
David Damerell <[email protected]> Distortion Field!

 

[Robert]

David Damerell wrote:

> Robert <[email protected]> wrote:
.. . .
you people must be
>>a completely different class of riders to be able to go so quickly that
.. . .
>>you can cause genuine aquaplaning,
.. . .
> Who are us people, plural? Only one person has claimed this.

Quite right. I stand corrected. /Robert

 

[Trevor Jeffrey]

David Damerell wrote in message ...
>Even wet ice offers more grip than the macroscopic layer of water present
>when a vehicle aquaplanes.

And fails to understand what he wrote himself.
TJ

 

[Trevor Jeffrey]

foldedpath wrote in message ...
>
>And extraordinary claims require extraordinary proof. You're the one
>claiming you experienced hydroplaning on a bike.
>
>Maybe it would help advance the discussion if you went into more detail
>about that? You've mentioned what you think the water depth was, and
>your speed. What happened to the bike? Did your rear wheel suddenly
>start spinning faster? Did you brake and lock the front wheel while
>still moving forward in a straight line? Did you slide out of control?
>What led you to think you were hydroplaning?

I was freewheeling downhill, I locked the front wheel with only a light
touch of the brake, I maintained balance through steering whilst the front
wheel was still locked up without loss of speed. If it was a skid I'd have
pitched over the handlebars. the bike drifted towards the gutter, so I
released brake. There was no ****** at the steering it took maybe a second
for the wheel to get up speed. There where no leaves dirt or oil, and it
was sleeting. If you dont think it's aquaplaning because there was hail
mixed with the rain well that's your misunderstanding..


>
>One reason I'm skeptical is that loss of traction can be caused by many
>things, like dirt and other materials mixed with water. The streets in
>my neighborhood are extra slippery in the first half hour or so of
>rainfall after an extended dry spell. The accumulated dust, vehicle oil
>drops and water combine to make an emulsion film on the road. I notice
>this when driving a car as well as a bike, and I'm a extra careful when
>braking even at low speeds. It has nothing to do with hydroplaning.
>
>If I was riding down a hill and hit a flat spot with a thin film of
>water and lost traction, I'm not sure I'd automatically assume this was
>hydroplaning, unless all the other possibilities were definitely ruled
>out.
>
>--
>Mike Barrs

 

[Robert]

Trevor Jeffrey wrote:
---8<----cut
of the brake, I maintained balance through steering whilst the front
> wheel was still locked up without loss of speed. If it was a skid I'd have
> pitched over the handlebars.

No. No. No. Skidding does not mean that you were aquaplaning. That you
did not lose speed during the braking does not mean that you were
aquaplaning either. It just means that the coefficient of friction for
your tyre on that (wet) surface was pretty close to zero. The small
contact area of the tyre on the road will ensure that you will always
have contact with the road, assuming that the road is close to level,
i.e. does not fall away sharply.

What determines your not going end over end is that the coefficient of
friction of the tyre against road surface was not high enough for you to
lift the back wheel. But that will not be aquaplaning, since the front
tyre will still be in contact with the road, regardless of the water.
Bike tyres are that thin . . . (won't repeat here what 30 or so posters
have already tried to tell you).

Finally, your statement, "If it was a skid I'd have pitched over the
handlebars": It's when your front wheel does *not* skid, that you risk
going over the bars. Coefficient of friction reduces significantly
during a skid, due to the disintegration of the rubber. When you skid
the front, then you will either fall on your side, or, if you are quick
enough to release the brake (as you apparently did - well done),
recover, assuming that you weren't leaning too hard during the lockup.

HTH /Robert

 

[foldedpath]

"Trevor Jeffrey" <[email protected]> wrote in
news:[email protected]:

>
> foldedpath wrote in message ...
>>
>>And extraordinary claims require extraordinary proof. You're the one
>>claiming you experienced hydroplaning on a bike.
>>
>>Maybe it would help advance the discussion if you went into more
>>detail about that? You've mentioned what you think the water depth
>>was, and your speed. What happened to the bike? Did your rear wheel
>>suddenly start spinning faster? Did you brake and lock the front wheel
>>while still moving forward in a straight line? Did you slide out of
>>control? What led you to think you were hydroplaning?
>
> I was freewheeling downhill, I locked the front wheel with only a
> light
> touch of the brake, I maintained balance through steering whilst the
> front wheel was still locked up without loss of speed. If it was a
> skid I'd have pitched over the handlebars. the bike drifted towards
> the gutter, so I released brake. There was no ****** at the steering
> it took maybe a second for the wheel to get up speed. There where no
> leaves dirt or oil, and it was sleeting. If you dont think it's
> aquaplaning because there was hail mixed with the rain well that's
> your misunderstanding..

Okay, but here's what you wrote before, in describing the circumstances:

> Aquaplaning is the term, and certainly has happened to me riding a
> bicycle. Speed of about 40mph downhill, sheet of water over the road,
> bucketing it down. Apply brakes to slow to negotiate parked car,
> bike drifts towards gutter maintaining speed, look down, front wheel
> locked so release brakes. Balance was retained with slow response to
> steering efforts. Rare but possible.

So this event was initiated by you *braking to slow down* and not as a
result of gradually speeding up to the point where the tires started to
hydroplane.

As I wrote earlier, I've experienced true hydroplaning in a car, and it was
always a result of smooth acceleration to the point where further speed
started the tires planing. If it were possible on a bike (and as I
understand it, it's not), you might expect it to happen in a straight
downhill run where the bike continued to pick up speed. Not when braking.
When you brake, there is always a risk of skidding when the tire/pavement
contact can't support the deceleration force. This is not the same thing as
hydroplaning.

--
Mike Barrs

 

[Chris B.]

On Sat, 31 Jul 2004 08:41:49 -0700, Benjamin Lewis <[email protected]>
wrote:

>Chris B. wrote:
>
>> On Thu, 29 Jul 2004 18:46:54 -0400, Sheldon Brown
>> <[email protected]> wrote:
>>
<snip>
>>> It is very counterintuitive to ride on smooth tires. Most people, when
>>> they see slick tires, the first thing that goes through their head is
>>> the thought that they must be very slippery in wet conditions.
>>
>> People who comment on the slick tires I use usually seem to think that
>> the tires are worn to the point of total baldness.
>
>I have a pair of completely slick "Specialized Fatboys" on one of my
>bikes. The day after I bought them, someone remarked "wow, you must have
>ridden a long way on those!" If he'd looked closer, he would have seen the
>seam from the mold down the centre of the tire still visible.

That's a little spooky; those are the tires I use and I also had the
comment made to me soon after I bought them.

I can't help but wonder, are you also good looking? <g>

 

[Don DeMair]

"Don DeMair" <[email protected]> wrote in message
news:[email protected]...
> I'm looking for a good touring tire. One that will be puncture resistant,
> especially in the rain. I've tried the Specialized Armadillo and was
pretty
> happy with it, I may buy it again. The other tire I tried was the
> Continental Top Touring. I found this tire to ride a bit harsh.
>
> I would prefer a slick tire (without a tread pattern) because I think the
> inverted tread actually catches debris and may lead to more flats. I also
> don't believe that tread pattern does anything to improve wet or dry grip
on
> the road. And I don't use my touring bike off-road.
>
> Right now, I'm considering the Avocet FasGrip Duro Plus. Probably in a
> 700x32. Anyone have experience with this tire?
>
> -Don
>

As the original poster, I thought I'd report that I just received the Avocet
FasGrip Duro Plus tires (from Harris Cyclery). They're exactly the tire I
was looking for. They feel pretty good just going around the block. If
this thread has any life left in it, I'll report back after getting a few
miles on them.

-Don

 

[James Scott]

Don DeMair wrote:
> Right now, I'm considering the Avocet FasGrip Duro Plus. Probably in a
> 700x32. Anyone have experience with this tire?

I have a set with about 150 miles on them. Since they went on a new bike
I can't comment about relative handling, comfort, or perceived rolling
resistance. I can say that they mounted easily on Sun CR-18s and are
providing a satisfactorily comfortable ride at 90psi (along with
everything else I changed, including saddle). They're also quite large
in diameter; it seems like the difference between 23mm and 28mm
(comparing Contis to Roly-Polys) isn't as great as the difference
between the Roly-Polys and the Avocet Duro Pluses.

Honestly the 32mm is probably overkill for an unloaded bike on paved
roads, assuming you're not on the far right tail of the body weight bell
curve. All other things being equal you might look at the 28s.

JLS
--
James "And 0 instances of aquahydroplaning so far" Scott
www.jls.cx

 

[Phil Brown]

>Honestly the 32mm is probably overkill for an unloaded bike on paved
>roads, assuming you're not on the far right tail of the body weight bell
>
>curve. All other things being equal you might look at the 28s.

I have 32s on my rendoneusse and it rides like a Cadillac limosine.
Phil Brown

 

[Booker C. Bense]

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In article <[email protected]>,
James Scott <[email protected]> wrote:
>Don DeMair wrote:
>> Right now, I'm considering the Avocet FasGrip Duro Plus. Probably in a
>> 700x32. Anyone have experience with this tire?
>
>I have a set with about 150 miles on them. Since they went on a new bike
>I can't comment about relative handling, comfort, or perceived rolling
>resistance. I can say that they mounted easily on Sun CR-18s and are
>providing a satisfactorily comfortable ride at 90psi (along with
>everything else I changed, including saddle). They're also quite large
>in diameter; it seems like the difference between 23mm and 28mm
>(comparing Contis to Roly-Polys) isn't as great as the difference
>between the Roly-Polys and the Avocet Duro Pluses.
>
>Honestly the 32mm is probably overkill for an unloaded bike on paved
>roads, assuming you're not on the far right tail of the body weight bell
>curve. All other things being equal you might look at the 28s.
>

_ Overkill maybe, but it sure is nice to finish a century without
your neck, back and arms screaming. I say if your bike can fit
32's and your not a slave to the cyclocomputer, you should try
a pair. Then you can through away all that useless gel stuff.

_ Booker C. Bense

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[Piaw Na]

> Right now, I'm considering the Avocet FasGrip Duro Plus. Probably in a
> 700x32. Anyone have experience with this tire?

Yeah. We went to Europe on our tandem last year with the K version of
this tire in the 700x32 size.
(http://www.geocities.com/piawandlisa/trip2003.html) The rear tire
wore out about 6 months after we came back, at around 3200 miles. I
moved the front to the rear and it's still going strong, after a 700
mile Colorado tour, about half of which was with a load.

Interestingly enough, for local rides we use the 700x28 size of the
same tire, and that wears out a lot faster (especially considering
that we don't usually carry a heavy load on our local rides) at around
1600 miles.

Team weight is 230 pounds, 270 pounds with bike. If you weigh less
than this and don't carry excessive load you should get more mileage
out of this tire. We've been very happy with the tires and will
proceed to buy more as we wear out our supply.