Tires and railroad tracks

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Should you go fast or slow?

Would the best solution depend on whether the tracks were wet or dry?

Thanks
EJ in NJ

Unless you are being paid a fair amount to get from point A to point B
as fast as possible, common sense would say to stop, dismount the bike,
walk the bike across the tracks, remount the bike, and continue merrily
on your bike ride. I've seen more than a few wrecks at railroad track
crossings. Usually with groups when someone turns their bike so they
can cross 90 degrees to the tracks, and runs into someone else who
decided the tracks were not angled enough to turn 90 degrees. All of
your theoretical questions are meaningless because you don't have to
ride across dangerous tracks.

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Should you go fast or slow?

Fast, that way it'll be over with sooner.

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

What color is the bike?

"Ernie Willson" wrote: (clip)would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination? (clip)
^^^^^^^^^^^^^^^^^^
Obviously, wide, low pressure tires are less likely to drop into a track
slot. So, as you approach, switch to those tires. Then, don't switch back
unless you are pretty sure there are no more tracks for quite a while.

As to speed: At higher speed you are more likely to make it across without
falling in. But, if you don't make it, you will get hurt more. The
break-even point is mathematically derivable if you know all the variables.
Maybe someday the more advanced cyclometers will include this function. If
the cyclometer also has memory, you could play with this problem from your
hospital bed.

Ernie Willson said:

Should you go fast or slow?

Can you beat the train?

Donga

Ernie Willson wrote:
low?

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

Would depend on the height of the tracks above or below the surface
you're riding on. If they're high, dismount. If they're below or at
surface, makes no diff.

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

Quoted message said:

Should you go fast or slow?

First: determine whether they are wet or dry.

Dry rails are not slippery to rubber tires.

Second: If the angle is low enough for the tire to fall into the
flange groove or nearly so, zig-zag across the track to increase the
angle (your use of "steep angle" is reversed from common usage where a
steep angle is 90°.)

Speed has as good as no effect on this because the response between
wet steel and tire rubber occurs faster than than anything you do
regardless of tread pattern (that has no effect in such an interface.)

Jobst Brandt

Quoted message said:

Unless you are being paid a fair amount to get from point A to point B
as fast as possible, common sense would say to stop, dismount the bike,
walk the bike across the tracks, remount the bike, and continue merrily
on your bike ride. I've seen more than a few wrecks at railroad track
crossings. Usually with groups when someone turns their bike so they
can cross 90 degrees to the tracks, and runs into someone else who
decided the tracks were not angled enough to turn 90 degrees. All of
your theoretical questions are meaningless because you don't have to
ride across dangerous tracks.

I'm curious now. Do you dismount for curbs? How about curb cuts?
Speed bumps? Cattle guards?

I've just come out of a period of my life in which I regularly commuted
across dozens of railroad tracks (Port of Seattle area). The only
times I dismount to cross tracks is where there is no grade level
crossing-- where I have to climb the ballast, step over the rails, and
descend the ballast on the other side.

All the folks I rode with in those areas rolled over the tracks too,
but they were also quite familiar with conditions there. Perhaps
others would have been quicker to dismount. Only once every few years
have I crashed by crossing tracks, usually by hitting wet tracks at an
oblique angle in the dark and rain.

Chalo

On Wed, 03 Jan 2007 14:35:34 -0500, Ernie Willson

may have said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Should you go fast or slow?

Would the best solution depend on whether the tracks were wet or dry?

For all but a few stunt-capable riders, there is no safe way to
traverse such an obstacle which does not involve changing the angle of
approach so that the tire's contact patch never falls into the gap
along the rails. Essentially, this means that the rider must take
whatever action is needed in order to make the crossing angle
adequately large. I strive for between 90 and 60 degrees, but I will
accept 45 in ideal conditions.

A bike with a very wide tire can usually traverse a rail crossing at a
smaller angle than one with narrow tires, but the real-world railroads
generally have ruts next to the rails which are wide enough to reduce
the magnitude of the difference to a small amount.

All other considerations are secondary at best.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Chalo said:

Quoted message said:

Unless you are being paid a fair amount to get from point A to point B
as fast as possible, common sense would say to stop, dismount the bike,
walk the bike across the tracks, remount the bike, and continue merrily
on your bike ride. I've seen more than a few wrecks at railroad track
crossings. Usually with groups when someone turns their bike so they
can cross 90 degrees to the tracks, and runs into someone else who
decided the tracks were not angled enough to turn 90 degrees. All of
your theoretical questions are meaningless because you don't have to
ride across dangerous tracks.

I'm curious now. Do you dismount for curbs? How about curb cuts?
Speed bumps? Cattle guards?

Mr. Chalo, if you had read the original post, you likely would not have
asked the questions above. Below is what the original person wrote:

"Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel),"

Given that the original question was about tracks that were nearly
parallel to your direction of travel, I assumed these were dangerous
tracks to ride across. So I suggested walking across them. If the
person had asked about tracks merely crossing the road at 45 degrees,
then I would have responded to just ride across them. But if the
tracks are nearly parallel, and you are wondering if you need special
tires or pressure in your tires, then I think you are into the category
where you just eliminate the entire problem by not riding across
railroad tracks that are nearly parallel to the road. Why subject
yourself to considerable risk for no material benefit?

I do not ride my road bikes into or over curbs. I tend to not mistreat
my equipment by intentionally abusing it. Many on this forum seem to
have a different philosophy in life and try to destroy and abuse
everything. Curb cuts are solid, there is no gap, crack to catch the
front wheel. Speed bumps and cattle crossings are 90 degrees to the
road. Just ride across them. If you were ever to attend Hell Week you
would get considerable experience in riding across cattle guards. And
stream crossings across the road. In that part of the world the
streams are dry most of the time, exxcept when they are overflowing, so
they just route the streams across the roads. No culverts or bridges.
The Hell Week promoters specifically say to walk across the stream
crossings that have water in them due to the likelihood that there will
be slick mud under the water. They understand its not a risk worth
taking. Unfortunately in 2006 one very experienced person took the
risk on about the only crossing with water, drought in the area for
many years. And he broke his leg when he went down on the slick mud at
a very slow speed.

Quoted message said:

I've just come out of a period of my life in which I regularly commuted
across dozens of railroad tracks (Port of Seattle area). The only
times I dismount to cross tracks is where there is no grade level
crossing-- where I have to climb the ballast, step over the rails, and
descend the ballast on the other side.

All the folks I rode with in those areas rolled over the tracks too,
but they were also quite familiar with conditions there. Perhaps
others would have been quicker to dismount. Only once every few years
have I crashed by crossing tracks, usually by hitting wet tracks at an
oblique angle in the dark and rain.

Chalo

In article <[email hidden]>,

Paul Cassel said:

Would depend on the height of the tracks above or below the surface
you're riding on. If they're high, dismount. If they're below or at
surface, makes no diff.

I agree. Train tracks aren't any worse than ice, and I've ridden on
enough of *that* to know that it's mostly about keeping your center of
gravity balanced over the wheels. Stand up and try to ride as straight
as possible over as short a distance on the bad surface as possible.

--
My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
heapnode.com, localhost, x-privat.org

I prefer doing a MTB-style bunny hop over any track whenever possible
to eliminate any tire/angle/traction questions when it comes to RRs.
Every set of tracks is different and some can be very nasty, esp. when
wet.

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Should you go fast or slow?

Would the best solution depend on whether the tracks were wet or dry?

Thanks
EJ in NJ

I lift my front wheel over each rail no matter what the angle, wet or
dry. I don't worry about the rear.

dkl

Doug Landau said:

Quoted message said:

Assuming that you had to ride a bike across a set of railroad
tracks which were at a steep angle to you (i.e. nearly parallel to
your direction of travel), would you be less likely to slip and
fall with wide low pressure tires, narrow high pressure tires, or
some other combination?

Quoted message said:

Quoted message said:

Should you go fast or slow?

Quoted message said:

Quoted message said:

Would the best solution depend on whether the tracks were wet or

dry?

Quoted message said:

I lift my front wheel over each rail no matter what the angle, wet
or dry. I don't worry about the rear.

You're fooling yourself about traction. If the front wheel will slide
sideways the rear will do the same. You may not have seen an
involuntary rear wheel slide "u-turn" with subsequent landing flat on
the road, but it happens with your method. The lower the angle the
easier it is on a wet crossing.

Jobst Brandt

In article <[email hidden]>,

Quoted message said:

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

Quoted message said:

Should you go fast or slow?

First: determine whether they are wet or dry.

Dry rails are not slippery to rubber tires.

Second: If the angle is low enough for the tire to fall into the
flange groove or nearly so, zig-zag across the track to increase the
angle (your use of "steep angle" is reversed from common usage where a
steep angle is 90°.)

Speed has as good as no effect on this because the response between
wet steel and tire rubber occurs faster than than anything you do
regardless of tread pattern (that has no effect in such an interface.)

Jobst, regarding the speed: wouldn't higher speeds improve your chances
of staying upright as your momentum would favour continuing across the
tracks?

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

Ryan Cousineau said:

Quoted message said:

Quoted message said:

Assuming that you had to ride a bike across a set of railroad
tracks which were at a steep angle to you (i.e. nearly parallel to
your direction of travel), would you be less likely to slip and
fall with wide low pressure tires, narrow high pressure tires, or
some other combination?

Quoted message said:

Quoted message said:

Quoted message said:

Would the best solution depend on whether the tracks were wet or

dry?

Quoted message said:

Quoted message said:

Quoted message said:

Should you go fast or slow?

Quoted message said:

Quoted message said:

First: determine whether they are wet or dry.

Quoted message said:

Quoted message said:

Dry rails are not slippery to rubber tires.

Quoted message said:

Quoted message said:

Second: If the angle is low enough for the tire to fall into the
flange groove or nearly so, zig-zag across the track to increase
the angle (your use of "steep angle" is reversed from common usage
where a steep angle is 90??.)

Quoted message said:

Quoted message said:

Speed has as good as no effect on this because the response between
wet steel and tire rubber occurs faster than than anything you do
regardless of tread pattern (that has no effect in such an
interface.)

Quoted message said:

Jobst, regarding the speed: wouldn't higher speeds improve your
chances of staying upright as your momentum would favour continuing
across the tracks?

It would do that but the bicycle having little mass will still deflect
out from under the speeding mass. In fact the unintended U-turn is a
great example of that. Sure there is a reasonable speed where upright
stability on a bicycle improves but it will not keep the tire from
being deflected there being little mass at the road surface.

I think if you re-read what I said about wet and dry, and the approach
angle, it holds true for the circumstances the OP mentioned.

My best encounter with this was riding over the frozen Bodensee that
had essentially invisible 10-15cm wide cracks at various angles.
Speed mad no difference. The bicycle went to the side and I went
straight ahead. Jumping was not an option because landing on slick
ice is just as hazardous as trying to ride over the crack.

http://www.trentobike.org/Countries/Switzerland/Tour_Reports/Ice_Princess_1963/

The picture ought to best give the conditions.

Jobst Brandt

Ryan Cousineau said:

In article <[email hidden]>,

Quoted message said:

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

Quoted message said:

Should you go fast or slow?

First: determine whether they are wet or dry.

Dry rails are not slippery to rubber tires.

Second: If the angle is low enough for the tire to fall into the
flange groove or nearly so, zig-zag across the track to increase the
angle (your use of "steep angle" is reversed from common usage where a
steep angle is 90°.)

Speed has as good as no effect on this because the response between
wet steel and tire rubber occurs faster than than anything you do
regardless of tread pattern (that has no effect in such an interface.)

Jobst, regarding the speed: wouldn't higher speeds improve your chances
of staying upright as your momentum would favour continuing across the
tracks?

Yes. However, it would not improve the bicycle's chances of staying upright.

Ron

Quoted message said:

Unless you are being paid a fair amount to get from point A to point B
as fast as possible, common sense would say to stop, dismount the bike,
walk the bike across the tracks, remount the bike, and continue merrily
on your bike ride.

I cross street-car tracks on a daily basis, and several of them are
curving from perpendicular to parallel to me where I have to cross (ie,
grand unions.) Your suggestion to get off the bike is a bit insane
considering I would be in the middle of a busy intersection.

Brian Huntley said:

Quoted message said:

Unless you are being paid a fair amount to get from point A to point B
as fast as possible, common sense would say to stop, dismount the bike,
walk the bike across the tracks, remount the bike, and continue merrily
on your bike ride.

I cross street-car tracks on a daily basis, and several of them are
curving from perpendicular to parallel to me where I have to cross (ie,
grand unions.) Your suggestion to get off the bike is a bit insane
considering I would be in the middle of a busy intersection.

They're installing light rail tracks in the Phoenix east valley now,
and one place is going to (no doubt) cause some nasty accidents, at
least until they change something.

The tracks are just north of the ASU campus, and the tracks are
curving beside a fairly popular road, used by lots of cyclists. The
worst part of this is the T intersection that meets the rails, since
the road forming the base of the T is the one that leads to most of
the parking for the campus. This means that there are lots of bikes
making a right or left at the T.

Thing is, making a right requires you to very carefully navigate the
margin between the first rail and the road (a couple feet between the
curb and rail). Misjudging the turn, or simply not seeing the rail
(most college kids don't bother with lights) will drop your front tire
into the deep seam next to the rail.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Quoted message said:

Ernie Willson said:

Assuming that you had to ride a bike across a set of railroad tracks
which were at a steep angle to you (i.e. nearly parallel to your
direction of travel), would you be less likely to slip and fall with
wide low pressure tires, narrow high pressure tires, or some other
combination?

Quoted message said:

Would the best solution depend on whether the tracks were wet or dry?

Quoted message said:

Should you go fast or slow?

First: determine whether they are wet or dry.

This is also my second and third. No way I will engage a wet rail any more,
once was enough. The family on the caravan that was behind me when I went
down on the way to Spiez (Simmenthal, CH) looked pretty scared.

Ciao,
--
Roberto Divia` Love at first sight is one of the greatest
Dep:PH Bat:53 Mailbox:C02110 labour-saving devices the world has ever seen
Route de Meyrin 385 ---------------------------------------------
Case Postale Phone: +41-22-767-4994
CH-1211 Geneve 23 CERN Fax: +41-22-767-9585
Switzerland E-Mail: [email hidden]