Potential good news for Mt. Washington access. - Page 4 - Cycling Mob: Road Cycling, Mountain Biking and More

01-07-2005, 01:47 PM

Mike Kruger wrote:

> 1. Wouldn't mountain bike tires take more heat, just because
> of their greater mass and volume?

Rim mass and area makes more difference in dissipating heat than rubber and air
(which are not good conductors). However, most mountain bike rims are not too
different from road bike rims in this respect. The important factors are a
mountain bike tire's lower pressure, and maybe a fatter, more robust bead hook.

> 2. On a mountain bike on a fire road, wouldn't one still be
> going more slowly than on a road bike on a paved road?

The potential energy to be dissipated is the same either way. Though it's
counterintuitive, higher speeds actually produce lower rim temperatures, because
of increased airflow. The hottest my rims ever got was creeping down very steep
(>20%) grades.

Matt O.

01-07-2005, 01:47 PM

Mike Kruger wrote:

> 1. Wouldn't mountain bike tires take more heat, just because
> of their greater mass and volume?

Rim mass and area makes more difference in dissipating heat than rubber and air
(which are not good conductors). However, most mountain bike rims are not too
different from road bike rims in this respect. The important factors are a
mountain bike tire's lower pressure, and maybe a fatter, more robust bead hook.

> 2. On a mountain bike on a fire road, wouldn't one still be
> going more slowly than on a road bike on a paved road?

The potential energy to be dissipated is the same either way. Though it's
counterintuitive, higher speeds actually produce lower rim temperatures, because
of increased airflow. The hottest my rims ever got was creeping down very steep
(>20%) grades.

Matt O.

01-07-2005, 01:47 PM

Mike Kruger wrote:

> 1. Wouldn't mountain bike tires take more heat, just because
> of their greater mass and volume?

Rim mass and area makes more difference in dissipating heat than rubber and air
(which are not good conductors). However, most mountain bike rims are not too
different from road bike rims in this respect. The important factors are a
mountain bike tire's lower pressure, and maybe a fatter, more robust bead hook.

> 2. On a mountain bike on a fire road, wouldn't one still be
> going more slowly than on a road bike on a paved road?

The potential energy to be dissipated is the same either way. Though it's
counterintuitive, higher speeds actually produce lower rim temperatures, because
of increased airflow. The hottest my rims ever got was creeping down very steep
(>20%) grades.

Matt O.

01-07-2005, 03:51 PM

Matt O'Toole writes:

> Mountain bikers ride fire roads like that all the time. The
> mountains of the western US are riddled with them -- 4000' climbs at
> over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> tires. So I don't see what the big deal is. There are a bunch of
> roads around here with sustained grades like that, but nothing that
> long -- 2-3 miles at most.

I'm unclear on what you are proposing. Do you mean that tires do not
blow off rims from brake heating? As a counterpoint, I have had two
of these occurrences and have witnessed many more. Beyond that, most
tandems use hub brakes because tire bow-off is such a problem for
them, having more mass and less wind drag than single bicycles and
only two rims for two people.

> However, when you have such a road that's a magnet for cyclists, you
> have a management problem. As mentioned, that particular road is
> privately owned, so there may be liability concerns too. I say
> people ought to be free to crash if they want to, but unfortunately
> US law and insurance doesn't work that way.

I think the management doesn't want the contention for road space
between bicycles and cars. I am aware of these problems locally
because there are a great many drivers who will not pass a bicyclist
climbing a grade on a curvy road even if the bicyclists rides outside
of the edge stripe on a paves highway. On an unpaved road this could
case traffic jams even with light auto traffic.

Jobst Brandt
[Only registered and activated users can see links. ]

01-07-2005, 03:51 PM

Matt O'Toole writes:

> Mountain bikers ride fire roads like that all the time. The
> mountains of the western US are riddled with them -- 4000' climbs at
> over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> tires. So I don't see what the big deal is. There are a bunch of
> roads around here with sustained grades like that, but nothing that
> long -- 2-3 miles at most.

I'm unclear on what you are proposing. Do you mean that tires do not
blow off rims from brake heating? As a counterpoint, I have had two
of these occurrences and have witnessed many more. Beyond that, most
tandems use hub brakes because tire bow-off is such a problem for
them, having more mass and less wind drag than single bicycles and
only two rims for two people.

> However, when you have such a road that's a magnet for cyclists, you
> have a management problem. As mentioned, that particular road is
> privately owned, so there may be liability concerns too. I say
> people ought to be free to crash if they want to, but unfortunately
> US law and insurance doesn't work that way.

I think the management doesn't want the contention for road space
between bicycles and cars. I am aware of these problems locally
because there are a great many drivers who will not pass a bicyclist
climbing a grade on a curvy road even if the bicyclists rides outside
of the edge stripe on a paves highway. On an unpaved road this could
case traffic jams even with light auto traffic.

Jobst Brandt
[Only registered and activated users can see links. ]

01-07-2005, 03:51 PM

Matt O'Toole writes:

> Mountain bikers ride fire roads like that all the time. The
> mountains of the western US are riddled with them -- 4000' climbs at
> over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> tires. So I don't see what the big deal is. There are a bunch of
> roads around here with sustained grades like that, but nothing that
> long -- 2-3 miles at most.

I'm unclear on what you are proposing. Do you mean that tires do not
blow off rims from brake heating? As a counterpoint, I have had two
of these occurrences and have witnessed many more. Beyond that, most
tandems use hub brakes because tire bow-off is such a problem for
them, having more mass and less wind drag than single bicycles and
only two rims for two people.

> However, when you have such a road that's a magnet for cyclists, you
> have a management problem. As mentioned, that particular road is
> privately owned, so there may be liability concerns too. I say
> people ought to be free to crash if they want to, but unfortunately
> US law and insurance doesn't work that way.

I think the management doesn't want the contention for road space
between bicycles and cars. I am aware of these problems locally
because there are a great many drivers who will not pass a bicyclist
climbing a grade on a curvy road even if the bicyclists rides outside
of the edge stripe on a paves highway. On an unpaved road this could
case traffic jams even with light auto traffic.

Jobst Brandt
[Only registered and activated users can see links. ]

01-07-2005, 03:51 PM

Matt O'Toole writes:

> Mountain bikers ride fire roads like that all the time. The
> mountains of the western US are riddled with them -- 4000' climbs at
> over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> tires. So I don't see what the big deal is. There are a bunch of
> roads around here with sustained grades like that, but nothing that
> long -- 2-3 miles at most.

I'm unclear on what you are proposing. Do you mean that tires do not
blow off rims from brake heating? As a counterpoint, I have had two
of these occurrences and have witnessed many more. Beyond that, most
tandems use hub brakes because tire bow-off is such a problem for
them, having more mass and less wind drag than single bicycles and
only two rims for two people.

> However, when you have such a road that's a magnet for cyclists, you
> have a management problem. As mentioned, that particular road is
> privately owned, so there may be liability concerns too. I say
> people ought to be free to crash if they want to, but unfortunately
> US law and insurance doesn't work that way.

I think the management doesn't want the contention for road space
between bicycles and cars. I am aware of these problems locally
because there are a great many drivers who will not pass a bicyclist
climbing a grade on a curvy road even if the bicyclists rides outside
of the edge stripe on a paves highway. On an unpaved road this could
case traffic jams even with light auto traffic.

Jobst Brandt
[Only registered and activated users can see links. ]

01-07-2005, 05:18 PM

<[Only registered and activated users can see links. ]> wrote in message
news:tgFDd.662$[Only registered and activated users can see links. ]...
> Matt O'Toole writes:
>
> > Mountain bikers ride fire roads like that all the time. The
> > mountains of the western US are riddled with them -- 4000' climbs at
> > over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> > tires. So I don't see what the big deal is. There are a bunch of
> > roads around here with sustained grades like that, but nothing that
> > long -- 2-3 miles at most.
>
> I'm unclear on what you are proposing. Do you mean that tires do not
> blow off rims from brake heating? As a counterpoint, I have had two
> of these occurrences and have witnessed many more. Beyond that, most
> tandems use hub brakes because tire bow-off is such a problem for
> them, having more mass and less wind drag than single bicycles and
> only two rims for two people.
>
> > However, when you have such a road that's a magnet for cyclists, you
> > have a management problem. As mentioned, that particular road is
> > privately owned, so there may be liability concerns too. I say
> > people ought to be free to crash if they want to, but unfortunately
> > US law and insurance doesn't work that way.
>
> I think the management doesn't want the contention for road space
> between bicycles and cars. I am aware of these problems locally
> because there are a great many drivers who will not pass a bicyclist
> climbing a grade on a curvy road even if the bicyclists rides outside
> of the edge stripe on a paves highway. On an unpaved road this could
> case traffic jams even with light auto traffic.
>
> Jobst Brandt
> [Only registered and activated users can see links. ]

01-07-2005, 05:18 PM

<[Only registered and activated users can see links. ]> wrote in message
news:tgFDd.662$[Only registered and activated users can see links. ]...
> Matt O'Toole writes:
>
> > Mountain bikers ride fire roads like that all the time. The
> > mountains of the western US are riddled with them -- 4000' climbs at
> > over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> > tires. So I don't see what the big deal is. There are a bunch of
> > roads around here with sustained grades like that, but nothing that
> > long -- 2-3 miles at most.
>
> I'm unclear on what you are proposing. Do you mean that tires do not
> blow off rims from brake heating? As a counterpoint, I have had two
> of these occurrences and have witnessed many more. Beyond that, most
> tandems use hub brakes because tire bow-off is such a problem for
> them, having more mass and less wind drag than single bicycles and
> only two rims for two people.
>
> > However, when you have such a road that's a magnet for cyclists, you
> > have a management problem. As mentioned, that particular road is
> > privately owned, so there may be liability concerns too. I say
> > people ought to be free to crash if they want to, but unfortunately
> > US law and insurance doesn't work that way.
>
> I think the management doesn't want the contention for road space
> between bicycles and cars. I am aware of these problems locally
> because there are a great many drivers who will not pass a bicyclist
> climbing a grade on a curvy road even if the bicyclists rides outside
> of the edge stripe on a paves highway. On an unpaved road this could
> case traffic jams even with light auto traffic.
>
> Jobst Brandt
> [Only registered and activated users can see links. ]

01-07-2005, 05:18 PM

<[Only registered and activated users can see links. ]> wrote in message
news:tgFDd.662$[Only registered and activated users can see links. ]...
> Matt O'Toole writes:
>
> > Mountain bikers ride fire roads like that all the time. The
> > mountains of the western US are riddled with them -- 4000' climbs at
> > over 10%, sometimes over 15%. Rims get hot, but not enough to blow
> > tires. So I don't see what the big deal is. There are a bunch of
> > roads around here with sustained grades like that, but nothing that
> > long -- 2-3 miles at most.
>
> I'm unclear on what you are proposing. Do you mean that tires do not
> blow off rims from brake heating? As a counterpoint, I have had two
> of these occurrences and have witnessed many more. Beyond that, most
> tandems use hub brakes because tire bow-off is such a problem for
> them, having more mass and less wind drag than single bicycles and
> only two rims for two people.
>
> > However, when you have such a road that's a magnet for cyclists, you
> > have a management problem. As mentioned, that particular road is
> > privately owned, so there may be liability concerns too. I say
> > people ought to be free to crash if they want to, but unfortunately
> > US law and insurance doesn't work that way.
>
> I think the management doesn't want the contention for road space
> between bicycles and cars. I am aware of these problems locally
> because there are a great many drivers who will not pass a bicyclist
> climbing a grade on a curvy road even if the bicyclists rides outside
> of the edge stripe on a paves highway. On an unpaved road this could
> case traffic jams even with light auto traffic.
>
> Jobst Brandt
> [Only registered and activated users can see links. ]