Road tire life span



H

Hjalmar Duklæt

Guest
> Hutchinson Carbon Comp tires. They wear very well, but still have good
fast
> cornering characteristics (I use em in crits, but I'm only Cat 4, so we're
> not cornering at 30+) and pliable enough (even at 140PSI) that on long
> rides, I don't start cursing them out.


I also use Hutchinson Carbon Comp tires on my competition wheels. They have
been on for nearly three seasons now and probably run about 1500 miles. I've
not had any flats so far (knock on wood) besides the one I made when I put
them on for the first time (quite tight fit on Shimano wheels). These are
the only clinchers I've used so cannot say anything about other brands. By
the way I got a flat on my front tubular this morning. A real bang going at
35 mph. Luckily the glue kept it on.
Hjalmar
 
Rick Onanian writes:

>>> Your paved-drum/leaned-bike experiment sounds like a reasonable,
>>> if imperfect, test method for fictional roads made of perfectly
>>> clean and perfectly flat pavement. I rarely find roads like that,
>>> and when I do, the new-pavement fumes make riding somewhat
>>> unpleasant.


>> Maybe you can explain what is "imperfect about this test.


> The shape of the contact patch is different; the tire must conform
> to the drum's convex shape. Further, it sure sounds like a perfect
> surface, unlike a road surface, which is rarely so.


I think you'll find that a six foot diameter is adequate to
approximate a road for test purposes, considering the contact patch
length of a normally inflated tire. Besides, this is a comparative
test and the values it produced are repeatable and close enough from
road values for side slip that one cannot readily see a difference.

What is it that the drum diameter obscures?

>>>> I have experienced such slips often and even done so crossing
>>>> smooth paint stripes in the rain, but I don't attribute those
>>>> incidents to the tire but rather to sand on the road or a slick
>>>> wet spot. We ARE talking about handling ability of one tire over
>>>> another.


>>> Yes, but what good is it to know the handling ability on perfect
>>> pavement when we don't ride on such surfaces? We ride on roads
>>> with a bit of sand or a slick wet spot. Knowing the handling
>>> ability of a tire for such conditions is immensely more useful.


>> Let's not get into philosophy.


> What philosophy? I ride on real roads, with imperfect pavement,
> sometimes with sand or a slick wet spot. If a tire can't give a
> little and let me know before I suddenly find it airborne (and my
> body grounded), I want the BEST handling tire I can get.


Perfection is philosophical. Besides, if you cannot control the test
conditions you cannot perform the test. What you are suggesting is
that such tests cannot be performed because roads vary too much. Such
tests are performed on standardized conditions that give typical best
values. The user must estimate what degraded conditions he is
encountering that will give poorer results, such as loose gravel, oil,
slick spots and the like.

>> You claim to have slid tires on clean dry pavement and I said that
>> is not a recoverable condition so it


> I claim to have slid tires on real pavement. I doubt it was
> perfectly clean, and I doubt it was perfectly flat, although I
> didn't feel bumps.


Lets get away for your definition of "real pavement" and use pavement
like that in the picture I attached:

http://tinyurl.com/2gbsj

I think that is real enough and Pescadero Road has a few of these
curves with "real" pavement at about 40mph.

I'm sure you didn't slip in a curve when banked over at near 45
degrees because that is unrecoverable. What were the circumstances
and what was the speed.

>> cannot be the criterion for handling among different tires. We
>> generally don't ride beyond the limit of traction so the criterion
>> must be something else. I'm trying to get to the bottom of how you can
>> give comparative ratings to tires of similar size, inflation and
>> essentially smooth tread.


> I don't know how it can be done. IANAE. Something more realistic
> than a paved drum may be in order.


Again, what is it about a drum that you find deficient? It is the
common way tires are laboratory tested.

>>> Well, then we're not talking about a lot of precision here. Wheel
>>> imbalance can bounce a bike up and down in my hand at >20mph; that
>>> lifting/weighting force must affect the tire's load (and therefore,
>>> contact patch) each revolution.


>> I doubt that.


> Which part do you doubt? That the wheel can bounce the hand-held
> bike at >20mph, or that such a force must affect the tire's
> connection to the road?


Both. As I have explained at length.

> The first part can be tested by holding the rear of the bike a foot
> off the ground, and using the other hand to pedal it up as fast as
> you can. Mine provides a definite up-and-down motion, which I
> experimentally corrected by balancing the wheel.


THAT is an unrealistic test.

>> Having descended at more than 50mph often without having balanced
>> wheels, I have not felt so much as a hint of imbalance from my
>> conventional wheels that are not balanced. Besides that, as I


> I've never passed 45mph, but even at that speed, I either did not
> feel imbalance or wouldn't know it from road vibration.


>>> A rider can tell if he got through his favorite curve (which has
>>> real-world pavement) at a higher speed without any traction
>>> reduction.


>> Yes? How do you determine "traction reduction". This is what is
>> at the root of this subject and I propose that you cannot sense
>> this without exceeding the limit and crashing. Therefore, claiming
>> that one tire handles better than another is an undefined
>> subjective claim.


> I don't know how you determine it. I agree that such a claim would
> be subjective.


I know what it is and have crashed as well as having measured it the
test equipment I have described. I don't think you have the
information to make the suppositions you do.

>> I repeat, you didn't slip on clean dry pavement. I don't claim that
>> you didn't slip but it was for some reason other than traction
>> limitation of the tire. It was more likely some foreign object on the
>> road or a spot of some lubricant.


> Like I said, real world road. Not a testing machine in a lab. I
> can't imagine how it could be tested.


Are you implying that the scene in the attached URL is not real world.
I ride around that curve in that manner often as I do with many other
curves. I also have piles of tires I have worn to the cords as well
as rims on which they served. There are a lot of test miles
accumulated.

I think you need to get out of your "real world" pavement and get to
reality.

Jobst Brandt
[email protected]
 
T

Tim McNamara

Guest
Benjamin Lewis <[email protected]> writes:

> Selling tires is important to tire manufacturers. Why would
> improving traction be important to them if consumers don't demand
> it, or believe their claims without examining any data? The
> goodness of their hearts?


Preventing expensive lawsuits? What the tire manufacturers are
banking on is that the vast majority of bike riders just want to look
like they could go fast, rather than actually going fast and operating
the equipment at the limits of functionality. These people never
remotely approach the margins of safety.

People like Jobst- and perhaps you- who live near and frequently ride
in mountains push the equipment much closer to the limits than I do,
living as I do in flat to rolling terrain and no longer racing. To
those folks, whose health and possibly survival is dependent on the
equipment functioning properly, traction is a rather important feature
in a bike tire. I was much more aware of traction as an issue two
summers ago when I rode in the Alps, riding tight corners with long
drops to the outside; in the Minneapolis-St. Paul area there is just
nothing at all like that. Stopping traction is more important for
avoiding getting mashed by some latte-swilling SUV driver yakking on
their damned cell phone.
 
T

Tom Nakashima

Guest
<[email protected]> wrote in message
news:MI%[email protected]
> I know what it is and have crashed as well as having measured it the
> test equipment I have described.


Jobst,
I have yet to see a cyclist crash or go down on DRY payment when leaning too
far into a turn.
I have a crash on wet payment as in the case of Jan Ulrich in last year's
Tour de France.

Is there a warning when you lean too far over in a turn that would be
unrecoverable and result in a crash.
Is it possible to recover if you have leaned too far over in a turn?

I'll have to say, you have a lot of guts to even attempt this test. I could
probably attempt this with full leathers and a full face motorcycle helmet.
-tom
 
R

Rick Onanian

Guest
On Tue, 22 Jun 2004 19:25:32 GMT, [email protected]
wrote:
>> The first part can be tested by holding the rear of the bike a foot
>> off the ground, and using the other hand to pedal it up as fast as
>> you can. Mine provides a definite up-and-down motion, which I
>> experimentally corrected by balancing the wheel.

>
>THAT is an unrealistic test.


What do you find unrealistic about it? Are you not strong enough to
hold the rear of your bike up with one hand, and pedal it in a high
gear with the other?

That is a REAL, not just realistic, demonstration of a force found
in a moving bicycle. It is a force that we choose to ignore, because
it seems inconsequential; but if we're talking about high-precision
rating of tire handling ability, it could make a difference, just as
a bumpy road makes a difference in traction. The casing of the tire
would affect how well it deals with the constant high frequency
load-unload cycle.
--
Rick Onanian
 
T

Tom Sherman

Guest
Helmut Springer wrote:

> [email protected] wrote:
>
>>That depends on whether you think traction is an important parameter.

>
> [...]
>
>>That for me falls into the definition "is important". How can this
>>not be important to a tire manufacturer?

>
>
> That is where engineering and marketing divide, and many will
> prioritize the latter as the market tends to reward it 8-/


This is true of human life in general: talking the talk almost
invariably is more rewarding than walking the walk.

--
Tom Sherman – Quad City Area
 
Tom Nakashima writes:

>> I know what it is and have crashed as well as having measured it
>> the test equipment I have described.


> I have yet to see a cyclist crash or go down on DRY payment when
> leaning too far into a turn.


I have and did so myself in years past. That's called low-siding when
the bicycle goes out from under the rider. Low side because the
distance to the ground is relatively small. High-siding is worse
because the rider goes up and over the bicycle and hits harder. My
friend did that on Mt. Hamilton recently on the day of the bicycle
race... Collar bone + two ribs.

> I have a crash on wet payment as in the case of Jan Ulrich in last
> year's Tour de France.


I've done that too, also low-side but broke a hip on one of these.
That was all years ago when I was "young and beautiful" as ladies
often say.

> Is there a warning when you lean too far over in a turn that would
> be unrecoverable and result in a crash.


None at all, and when it starts going it is obvious. Judging from
riders I pass down hills, few people ever get close to that point on
dry pavement. On wet roads it occurs more often because the limit is
so variable and is hard to assess.

> Is it possible to recover if you have leaned too far over in a turn?


Not on dry pavement because there is nothing approaching that will
increase traction at that lean angle... that is increasing rapidly as
the slide progresses.

> I'll have to say, you have a lot of guts to even attempt this test.
> I could probably attempt this with full leathers and a full face
> motorcycle helmet.


I don't do such tests at speed. I ride below the limit, that is more
than most riders are willing to approach because they haven't
experienced the angle that is possible. It is also good to have seen
tires on a testing machine exceed 45 degrees to have a feel for what
is reasonable.

Jobst Brandt
[email protected]
 
T

Tim McNamara

Guest
"Tom Nakashima" <[email protected]> writes:

> <[email protected]> wrote in message
> news:MI%[email protected]
>> I know what it is and have crashed as well as having measured it
>> the test equipment I have described.

>
> Jobst, I have yet to see a cyclist crash or go down on DRY payment
> when leaning too far into a turn.


I've seen it in crits. Is there a warning? No- it's pretty much
instantaneous. Is it recoverable? Only by sheer luck. My personal
experience was with being leaned way over in a crit and then striking
a pedal, which lifted the rear tire. I didn't crash, but that had
everything to do with luck and nothing to do with riding skills.
Scared the hell out of the guy on my wheel.
 
T

Tim McNamara

Guest
Rick Onanian <[email protected]> writes:

> On Tue, 22 Jun 2004 19:25:32 GMT, [email protected]
> wrote:
>>> The first part can be tested by holding the rear of the bike a
>>> foot off the ground, and using the other hand to pedal it up as
>>> fast as you can. Mine provides a definite up-and-down motion,
>>> which I experimentally corrected by balancing the wheel.

>>
>>THAT is an unrealistic test.

>
> What do you find unrealistic about it? Are you not strong enough to
> hold the rear of your bike up with one hand, and pedal it in a high
> gear with the other?
>
> That is a REAL, not just realistic, demonstration of a force found
> in a moving bicycle. It is a force that we choose to ignore, because
> it seems inconsequential; but if we're talking about high-precision
> rating of tire handling ability, it could make a difference, just as
> a bumpy road makes a difference in traction. The casing of the tire
> would affect how well it deals with the constant high frequency
> load-unload cycle.


It seems inconsequential precisely because it is. Have you calculated
the forces involved in this imbalance relative to the vertical loading
from your body weight? It'd be an interesting mathematical problem-
with the force resulting from the imbalance being a tiny fraction of
the mass of the rider and bike.

This notion of imbalance as a "significant" issue comes from cars,
where the wheel is free to have a vertical excursion thanks to the
suspension and then only if the shock absorber is worn to the point
that it doesn't damp the wheel movement correctly. A bicycle wheel
cannot move freely in this manner even in a fully suspended bike,
because the forces probably aren't high enough to overcome stiction.
The forces are much higher with a car wheel, which is turning several
times faster than a bicycle wheel and weighs 10 to 20 times more, so
there is much more inertial energy involved. When you hold the bike
up in the air and spin the wheel, you are providing no damping.
 
R

Rick Onanian

Guest
On Tue, 22 Jun 2004 23:42:56 -0500, Tim McNamara
<[email protected]> wrote:
>Rick Onanian <[email protected]> writes:
>> it seems inconsequential; but if we're talking about high-precision
>> rating of tire handling ability, it could make a difference, just as

>
>It seems inconsequential precisely because it is. Have you calculated
>the forces involved in this imbalance relative to the vertical loading
>from your body weight? It'd be an interesting mathematical problem-
>with the force resulting from the imbalance being a tiny fraction of
>the mass of the rider and bike.


I suspect the force in question is only a few pounds. It's
inconsequential for real-world riding, but not for
_high-precision_measurements_. We can either talk about real-world
handling, on roads whose imperceptibly imperfect surface probably
provides more reciprocating force than wheel imbalance...or we can
talk about measuring tire ability very precisely. Or we can quit
because, well, this discussion is pointless... <G>
--
Rick Onanian
 
Tim McNamara writes:

>>> I know what it is and have crashed as well as having measured it
>>> the test equipment I have described.


>> Jobst, I have yet to see a cyclist crash or go down on DRY payment
>> when leaning too far into a turn.


> I've seen it in crits. Is there a warning? No- it's pretty much
> instantaneous. Is it recoverable? Only by sheer luck. My personal
> experience was with being leaned way over in a crit and then
> striking a pedal, which lifted the rear tire. I didn't crash, but
> that had everything to do with luck and nothing to do with riding
> skills. Scared the hell out of the guy on my wheel.


Ah yes, but that does not rate as a break out from leaning too far.
That fits the description of a temporary loss of traction below the
limit. It is similar to slipping across a slick spot or a spot of
sand on the road. Once the lean angle exceeds the traction there is
no return to stability.

Jobst Brandt
[email protected]
 
B

Benjamin Weiner

Guest
[email protected] wrote:
> Tom Nakashima writes:


> > I have yet to see a cyclist crash or go down on DRY payment when
> > leaning too far into a turn.


> I have and did so myself in years past. That's called low-siding when
> the bicycle goes out from under the rider. Low side because the
> distance to the ground is relatively small. High-siding is worse
> because the rider goes up and over the bicycle and hits harder. My
> friend did that on Mt. Hamilton recently on the day of the bicycle
> race... Collar bone + two ribs.


> > Is there a warning when you lean too far over in a turn that would
> > be unrecoverable and result in a crash.


> None at all, and when it starts going it is obvious. Judging from
> riders I pass down hills, few people ever get close to that point on
> dry pavement. On wet roads it occurs more often because the limit is
> so variable and is hard to assess.


> > Is it possible to recover if you have leaned too far over in a turn?


> Not on dry pavement because there is nothing approaching that will
> increase traction at that lean angle... that is increasing rapidly as
> the slide progresses.


> > I'll have to say, you have a lot of guts to even attempt this test.
> > I could probably attempt this with full leathers and a full face
> > motorcycle helmet.


> I don't do such tests at speed. I ride below the limit, that is more
> than most riders are willing to approach because they haven't
> experienced the angle that is possible. It is also good to have seen
> tires on a testing machine exceed 45 degrees to have a feel for what
> is reasonable.


I think most riders are chary of approaching the limit of lean
angle, since it is difficult to judge when you are approaching
the limit and the penalty is obvious. As a corollary, when people
go into a turn too hot, I think they usually instinctively take it
too wide and cross the centerline or go off the road, rather than
increase lean and low-side it. Ullrich went into the bushes that way
in the Tour a few years ago. That may be why one rarely sees
people low-siding on dry pavement.

A couple of my friends say they can take that first left hand
turn on Pescadero Road without any braking, but I'm too chicken;
it is a long way to ride home with road rash.
 
J

jobst.b[email protected]

Guest
Benjamin Weiner writes:

> I think most riders are wary of approaching the limit of lean
> angle, since it is difficult to judge when you are approaching the
> limit and the penalty is obvious. As a corollary, when people go
> into a turn too hot, I think they usually instinctively take it too
> wide and cross the centerline or go off the road, rather than
> increase lean and low-side it. Ullrich went into the bushes that
> way in the Tour a few years ago. That may be why one rarely sees
> people low-siding on dry pavement.


Some of that is because the idea that one should not brake in a turn
has been pounded into their heads. This is untrue as I have explained
and it is evident from anyone who is cornering near the limit. They
always are on the brakes in the apex of the turn. The details of
this are outlined in:

http://draco.acs.uci.edu/rbfaq/FAQ/9.15.html

and shown in:

http://tinyurl.com/2gbsj

> A couple of my friends say they can take that first left hand
> turn on Pescadero Road without any braking, but I'm too chicken;
> it is a long way to ride home with road rash.


That is the turn in the picture above and I do not take it without
braking. If they are doing that then they are not going fast enough
as they enter the curve. Of course that also depends on how
streamlined they are with respect to their weight. I suspect I could
take that corner without braking if I was wearing a floppy jacket and
didn't pedal on the approach to the curve.

The second left hand curve also requires braking if you are going
fast, even though it has a larger radius. At that point you should be
going faster than in the previous left hander.

Jobst Brandt
[email protected]
 
T

Tim McNamara

Guest
[email protected] writes:

> Tim McNamara writes:
>
>>>> I know what it is and have crashed as well as having measured it
>>>> the test equipment I have described.

>
>>> Jobst, I have yet to see a cyclist crash or go down on DRY payment
>>> when leaning too far into a turn.

>
>> I've seen it in crits. Is there a warning? No- it's pretty much
>> instantaneous. Is it recoverable? Only by sheer luck. My
>> personal experience was with being leaned way over in a crit and
>> then striking a pedal, which lifted the rear tire. I didn't crash,
>> but that had everything to do with luck and nothing to do with
>> riding skills. Scared the hell out of the guy on my wheel.

>
> Ah yes, but that does not rate as a break out from leaning too far.


Yes, that's true. I was a little OT there.

> That fits the description of a temporary loss of traction below the
> limit. It is similar to slipping across a slick spot or a spot of
> sand on the road. Once the lean angle exceeds the traction there is
> no return to stability.


I've had slight slippages like that occur in races crossing the lane
striping; slipping on these is much more pronounced when it is wet, of
course. But the width of the excursion, if that's the correct term,
is only a couple of inches and then once you're off the stripe you're
back on pavement with a high coefficient of friction. Front wheel
slippage seems to be less recoverable than rear wheel slippage.

If one wishes to see lots of crashes due to such slippage, watch the
1993 men's road race championships in Oslo Norway- a nasty wet day
with lots of crashes resulting from the wheels slipping out on lane
stripes. Some of them looked quite painful. IIRC Ekimov actually
went over a "Jersey wall" type barrier and landed on commuter railroad
tracks.
 
Tim McNamara writes:

>> That fits the description of a temporary loss of traction below the
>> limit. It is similar to slipping across a slick spot or a spot of
>> sand on the road. Once the lean angle exceeds the traction there
>> is no return to stability.


> I've had slight slippages like that occur in races crossing the lane
> striping; slipping on these is much more pronounced when it is wet,
> of course. But the width of the excursion, if that's the correct
> term, is only a couple of inches and then once you're off the stripe
> you're back on pavement with a high coefficient of friction. Front
> wheel slippage seems to be less recoverable than rear wheel
> slippage.


> If one wishes to see lots of crashes due to such slippage, watch the
> 1993 men's road race championships in Oslo Norway- a nasty wet day
> with lots of crashes resulting from the wheels slipping out on lane
> stripes. Some of them looked quite painful. IIRC Ekimov actually
> went over a "Jersey wall" type barrier and landed on commuter
> railroad tracks.


I am curious about the tires these riders used on that course. From
what I have seen, many racers ride on colored tires, some of which
make all sorts of claims to have more traction on the side than the
middle depending on color stripes. This is so much BS because a rider
needs maximum traction when braking before a curve while upright as
well as needing it to get around the corner. There is no excuse
except fashion to have any less traction than the best on the entire
tread and that is presently still gotten only with carbon black tread.

People who say otherwise are either lying or are as uneducated in the
matter as the public on whom they pass this sort of hype is. The
former is probably true, there not being an excess of tribological
expertise in the bicycle business, judging from the faux pas we see
regularly. I recall when Umma-Gumma, non black, tires were foisted on
the 7-Eleven team for their lower RR but were so bad in the wet that
crashes rapidly got them back to the supplier.

Jobst Brandt
[email protected]
 
D

Dave Lehnen

Guest
[email protected] wrote:

>
> I am curious about the tires these riders used on that course. From
> what I have seen, many racers ride on colored tires, some of which
> make all sorts of claims to have more traction on the side than the
> middle depending on color stripes. This is so much BS because a rider
> needs maximum traction when braking before a curve while upright as
> well as needing it to get around the corner. There is no excuse
> except fashion to have any less traction than the best on the entire
> tread and that is presently still gotten only with carbon black tread.
>


Since maximum braking when upright is limited by the angle from the
front contact patch to the center of gravity, as often discussed on
this newsgroup, traction greater than required to raise the rear
wheel does not provide better deceleration. Even the hardest-
compound touring tires seem capable of lifting the rear wheel, at
least in dry conditions.

When cornering, acceleration is limited only by traction. It would
make sense to trade off some tread life, or rolling resistance, or
cut resistance, if it would help traction, on the side tread.

Since bicycles can't brake at much more than about 0.6g, it would
make sense to optimize the center tread for other desirable
properties, as long as traction was more than could be used anyway.

> People who say otherwise are either lying or are as uneducated in the
> matter as the public on whom they pass this sort of hype is. The
> former is probably true, there not being an excess of tribological
> expertise in the bicycle business, judging from the faux pas we see
> regularly. I recall when Umma-Gumma, non black, tires were foisted on
> the 7-Eleven team for their lower RR but were so bad in the wet that
> crashes rapidly got them back to the supplier.
>
> Jobst Brandt
> [email protected]


Dave Lehnen
 
T

Tim McNamara

Guest
[email protected] writes:

> Tim McNamara writes:
>
>> If one wishes to see lots of crashes due to such slippage, watch
>> the 1993 men's road race championships in Oslo Norway- a nasty wet
>> day with lots of crashes resulting from the wheels slipping out on
>> lane stripes. Some of them looked quite painful. IIRC Ekimov
>> actually went over a "Jersey wall" type barrier and landed on
>> commuter railroad tracks.

>
> I am curious about the tires these riders used on that course.


Boy, I have no idea and I don't have a copy of the video. I do
remember quite clearly seeing riders slip out in turns as they crossed
the heavy white painted stripes, the wheels going out almost
instantaneously. There were some very painful looking crashes.
 
T

Tom Nakashima

Guest
<[email protected]> wrote in message
news:[email protected]
>
> > I have yet to see a cyclist crash or go down on DRY payment when
> > leaning too far into a turn.

>
> I have and did so myself in years past. That's called low-siding when
> the bicycle goes out from under the rider. Low side because the
> distance to the ground is relatively small. High-siding is worse
> because the rider goes up and over the bicycle and hits harder. My
> friend did that on Mt. Hamilton recently on the day of the bicycle
> race... Collar bone + two ribs.
>

I didn't think "High-siding" was possible on a bicycle until I saw Joseba
Beloki do it in last years Tour de France. I believe that was due to melted
tar at high speeds through a turn. I'm thinking he might have hit the rear
brake.

I'm don't worry much about my cornering ability , but more concerned about
the road condition on high speed descents. My hardest fall was when someone
put sand on the road during the winter to help melt the ice. The roads were
dry, but I lost traction on the sand. I also slipped and almost lost it on
the back side of Mt. Hamilton due to some gravel on the road.
-tom
 
G

g.daniels

Guest
tire loss is directly related to:
lack of $$
lack of tire availability
necessity to use cycle NOW
answer-stock tires
 
G

g.daniels

Guest
the ones with sand embedded cost more?
what happened to walnut shells?
 

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