Potential good news for Mt. Washington access. - Page 21 - Cycling Mob: Road Cycling, Mountain Biking and More

01-11-2005, 12:29 AM

>> Alfred Ryder wrote:
>> I would be interested in knowing whether the blow-off point is
>> affected by
>> whether someone is sitting on the bike or not. The only blow-off I
>> have had
>> was a few seconds after coming to a complete stop.

Frank Krygowski wrote:
> When our tandem was brand new (long, long ago) it suffered two blowouts
> as it sat alone in a bedroom, at least an hour after mounting and
> inflating the tires. I never did figure that out.

Most likely an installation issue.

--
Andrew Muzi
[Only registered and activated users can see links. ]
Open every day since 1 April, 1971

01-11-2005, 12:29 AM

>> Alfred Ryder wrote:
>> I would be interested in knowing whether the blow-off point is
>> affected by
>> whether someone is sitting on the bike or not. The only blow-off I
>> have had
>> was a few seconds after coming to a complete stop.

Frank Krygowski wrote:
> When our tandem was brand new (long, long ago) it suffered two blowouts
> as it sat alone in a bedroom, at least an hour after mounting and
> inflating the tires. I never did figure that out.

Most likely an installation issue.

--
Andrew Muzi
[Only registered and activated users can see links. ]
Open every day since 1 April, 1971

01-11-2005, 09:32 PM

>I think Jobst nailed it on the head. While it might be interesting to
>explore all the nuances of this phenomenon, all that really matters is
>what the tire does when actually rolling down a steep hill with a
>rider on board.
>
>But to add my voice to the chorus of armchair testers, I'd suggest
>that it might be interesting to see the effects of using a deep rim on
>the rear wheel to see how effective the extra mass is at getting rid
>of the heat.

Rim heating gets a lot of discussion on the tandem list, for obvious
reasons.

Several posters anecdotally believe that deep dish rims are helpful because
of the extra mass and the area which can be cooled.

I've put forward the theory that rims with ceramic braking surfaces *may*
offer additional resistance to heating as the ceramic *may* serve as an
insulating layer reducing heat induction into the aluminum rim. I found at
least one technical source which appeared to support this idea, but no "real
world" testing has been performed to develop real data on bikes.

Chris Neary
[Only registered and activated users can see links. ]

Chris & Tracey
1999 Co-Motion Speedster

01-11-2005, 09:32 PM

>I think Jobst nailed it on the head. While it might be interesting to
>explore all the nuances of this phenomenon, all that really matters is
>what the tire does when actually rolling down a steep hill with a
>rider on board.
>
>But to add my voice to the chorus of armchair testers, I'd suggest
>that it might be interesting to see the effects of using a deep rim on
>the rear wheel to see how effective the extra mass is at getting rid
>of the heat.

Rim heating gets a lot of discussion on the tandem list, for obvious
reasons.

Several posters anecdotally believe that deep dish rims are helpful because
of the extra mass and the area which can be cooled.

I've put forward the theory that rims with ceramic braking surfaces *may*
offer additional resistance to heating as the ceramic *may* serve as an
insulating layer reducing heat induction into the aluminum rim. I found at
least one technical source which appeared to support this idea, but no "real
world" testing has been performed to develop real data on bikes.

Chris Neary
[Only registered and activated users can see links. ]

Chris & Tracey
1999 Co-Motion Speedster

01-11-2005, 09:32 PM

>I think Jobst nailed it on the head. While it might be interesting to
>explore all the nuances of this phenomenon, all that really matters is
>what the tire does when actually rolling down a steep hill with a
>rider on board.
>
>But to add my voice to the chorus of armchair testers, I'd suggest
>that it might be interesting to see the effects of using a deep rim on
>the rear wheel to see how effective the extra mass is at getting rid
>of the heat.

Rim heating gets a lot of discussion on the tandem list, for obvious
reasons.

Several posters anecdotally believe that deep dish rims are helpful because
of the extra mass and the area which can be cooled.

I've put forward the theory that rims with ceramic braking surfaces *may*
offer additional resistance to heating as the ceramic *may* serve as an
insulating layer reducing heat induction into the aluminum rim. I found at
least one technical source which appeared to support this idea, but no "real
world" testing has been performed to develop real data on bikes.

Chris Neary
[Only registered and activated users can see links. ]

Chris & Tracey
1999 Co-Motion Speedster

01-12-2005, 10:12 AM

On Tue, 11 Jan 2005 06:37:07 GMT, Joe Riel <[Only registered and activated users can see links. ]> wrote:

[snip maths re: spoke tension vs. rim temp]

Following on from your (Joel) and Carl's brief dialogue,
ISTR that at least two people who frequent this group
have constructed FE models of the bicycle wheel
hub-spokes-rim, primarily to investigate the validity
of the "stands on its spokes" statement.

Maybe, if asked nicely, they could be persuaded to
superpose a thermal or equivalent initial strain loadcase
on the rim elements and report their findings thereafter?

01-12-2005, 10:12 AM

On Tue, 11 Jan 2005 06:37:07 GMT, Joe Riel <[Only registered and activated users can see links. ]> wrote:

[snip maths re: spoke tension vs. rim temp]

Following on from your (Joel) and Carl's brief dialogue,
ISTR that at least two people who frequent this group
have constructed FE models of the bicycle wheel
hub-spokes-rim, primarily to investigate the validity
of the "stands on its spokes" statement.

Maybe, if asked nicely, they could be persuaded to
superpose a thermal or equivalent initial strain loadcase
on the rim elements and report their findings thereafter?

01-12-2005, 10:12 AM

On Tue, 11 Jan 2005 06:37:07 GMT, Joe Riel <[Only registered and activated users can see links. ]> wrote:

[snip maths re: spoke tension vs. rim temp]

Following on from your (Joel) and Carl's brief dialogue,
ISTR that at least two people who frequent this group
have constructed FE models of the bicycle wheel
hub-spokes-rim, primarily to investigate the validity
of the "stands on its spokes" statement.

Maybe, if asked nicely, they could be persuaded to
superpose a thermal or equivalent initial strain loadcase
on the rim elements and report their findings thereafter?

01-12-2005, 10:50 AM

nobody <[Only registered and activated users can see links. ]> writes:

> On Tue, 11 Jan 2005 06:37:07 GMT, Joe Riel <[Only registered and activated users can see links. ]> wrote:
>
>
> [snip maths re: spoke tension vs. rim temp]
>
> Following on from your (Joel) and Carl's brief dialogue,
> ISTR that at least two people who frequent this group
> have constructed FE models of the bicycle wheel
> hub-spokes-rim, primarily to investigate the validity
> of the "stands on its spokes" statement.
>
> Maybe, if asked nicely, they could be persuaded to
> superpose a thermal or equivalent initial strain loadcase
> on the rim elements and report their findings thereafter?

Do you recall who they were? I don't. I also don't recall
seeing any followup to that, that is, whether they actually
built the models.

Joe

01-12-2005, 10:50 AM

nobody <[Only registered and activated users can see links. ]> writes:

> On Tue, 11 Jan 2005 06:37:07 GMT, Joe Riel <[Only registered and activated users can see links. ]> wrote:
>
>
> [snip maths re: spoke tension vs. rim temp]
>
> Following on from your (Joel) and Carl's brief dialogue,
> ISTR that at least two people who frequent this group
> have constructed FE models of the bicycle wheel
> hub-spokes-rim, primarily to investigate the validity
> of the "stands on its spokes" statement.
>
> Maybe, if asked nicely, they could be persuaded to
> superpose a thermal or equivalent initial strain loadcase
> on the rim elements and report their findings thereafter?

Do you recall who they were? I don't. I also don't recall
seeing any followup to that, that is, whether they actually
built the models.

Joe