Can Too High Gears be Lowered on SRAM Dualdrive?

Roger Merriman

Peter Clinch <p.j.clinch@dundee.ac.uk> wrote:

> Artemisia wrote:
> > Dave Larrington wrote:
> >
> >> Though you /may/ run out of traction, as I discovered to my cost 2/3
> >> of the way up the Koppenberg a few years ago :-(
> >
> > How's that - wheels spinning around in place? Would this be because of
> > slippery or muddy roads, or is it a mechanical problem? Could you regain
> > traction by gearing up and then down again?
>
> While it's worse on muddy roads, make any road steep enough and the
> wheel will slip, simply a matter of not enough friction. You could
> change up, but then it might be simply too hard to move the pedals!
>
the lane nr my folks house as it gets steeper gets worse, more holes and
during winter/spring covered with shale,and well what ever washes off
the hills. so bit of balancing act getting enought traction and so one
can still turn the cranks, still it's not a hill one uses to get from A
to B more for the i'll beat it. heh some of the folk in the village
woun't drive their cars up it. it averages 20% with peaks well into the
30% mark along with nice slippy bits, its great fun attually in a hot
sweaty, why am i doing this? kind of way

> It's worth noting that this is only a problem on /seriously/ steep hills
> (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks
> it's quite easy to run out of traction. At which point you get off and
> push...
>
looks fun in a jiggly sort of way.


> Pete.

roger
--
www.rogermerriman.com

Artemisia

Peter Clinch wrote:

> It's worth noting that this is only a problem on /seriously/ steep hills
> (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks
> it's quite easy to run out of traction. At which point you get off and
> push...

My hill is seriously steep. And it's not practical to get out and pull
because on that kind of incline the SPD shoes just slip and slip, and
the bike is so heavy that it pulls me over.

I have had the trike lose traction on the dirt path that immediately
follows or precedes the killer hill. But here it was just a case of too
deep muddy goo.

EFR
Ile de France

Peter Clinch

Artemisia wrote:
> Peter Clinch wrote:
>
>> It's worth noting that this is only a problem on /seriously/ steep hills
>> (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks
>> it's quite easy to run out of traction. At which point you get off and
>> push...
>
> My hill is seriously steep.

How seriously? Koppenberg is famously difficult for
/professionals/. What's the actual gradient? There should be no
trouble with traction on a typically surfaced 20% hill, and those
are very unusual.

> And it's not practical to get out and pull
> because on that kind of incline the SPD shoes just slip and slip

There shouldn't be any particular trouble walking up a 20% hill in
a pair of recessed-cleat shoes as long as it isn't an expecially
slippy road.

> the bike is so heavy that it pulls me over.

It's a tricycle, it can't fall over, and if it can't fall over
it'll have trouble pulling you with it!

> I have had the trike lose traction on the dirt path that immediately
> follows or precedes the killer hill. But here it was just a case of too
> deep muddy goo.

Mud, ice, diesel, wet leaves, drain covers can have you lose
traction on level ground. You're never going to resolve all
traction problems, but that doesn't make bikes/trikes unusable.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/

Dave Larrington

In news:68rrd2F2u162aU1@mid.individual.net,
Peter Clinch <p.j.clinch@dundee.ac.uk> tweaked the Babbage-Engine to tell
us:
> Artemisia wrote:
>> Peter Clinch wrote:
>>
>>> It's worth noting that this is only a problem on /seriously/ steep
>>> hills (see http://en.wikipedia.org/wiki/Koppenberg). But with
>>> muddy tracks it's quite easy to run out of traction. At which
>>> point you get off and push...
>>
>> My hill is seriously steep.
>
> How seriously? Koppenberg is famously difficult for
> /professionals/. What's the actual gradient? There should be no
> trouble with traction on a typically surfaced 20% hill, and those
> are very unusual.

Koppenberg is about 20%; the problem is that there is sand between the
cobblestones, so if the rear wheel gets into a longitudinal gap, you are
stuffed. I've done 25% a few times, most notably Bushcombe Lane:

http://preview.tinyurl.com/5mp5hu
(redirects to streetmap.co.uk)

at the start of the Cotswold Corker. I only had traction issues where it
starts to level out, due to the mud, grit, water and skog(tm) which are
frequently to be found strewn about the minor roads of the BRITONS' England
in the month of February. On the steeper bits lower down I was OK, except
for having to avoid those unable to remain upright and who were thus
toppling gracelessly into the hedge, or the front gardens of householders
unfortunate enough to live on the route.

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
I am Wan, for I am pursued by the Army of Plums.

bugbear

Dave Larrington wrote:
> In news:68rrd2F2u162aU1@mid.individual.net,
> Peter Clinch <p.j.clinch@dundee.ac.uk> tweaked the Babbage-Engine to tell
> us:
>> Artemisia wrote:
>>> Peter Clinch wrote:
>>>
>>>> It's worth noting that this is only a problem on /seriously/ steep
>>>> hills (see http://en.wikipedia.org/wiki/Koppenberg). But with
>>>> muddy tracks it's quite easy to run out of traction. At which
>>>> point you get off and push...
>>> My hill is seriously steep.
>> How seriously? Koppenberg is famously difficult for
>> /professionals/. What's the actual gradient? There should be no
>> trouble with traction on a typically surfaced 20% hill, and those
>> are very unusual.
>
> Koppenberg is about 20%; the problem is that there is sand between the
> cobblestones, so if the rear wheel gets into a longitudinal gap, you are
> stuffed. I've done 25% a few times, most notably Bushcombe Lane:

Longstaff "double drive" sounds helpful here.

BugBear

Dave Larrington

In news:7tSdnaOhuoJY6bTVRVnytQA@posted.plusnet,
bugbear <bugbear@trim_papermule.co.uk_trim> tweaked the Babbage-Engine to
tell us:
> Dave Larrington wrote:
>> In news:68rrd2F2u162aU1@mid.individual.net,
>> Peter Clinch <p.j.clinch@dundee.ac.uk> tweaked the Babbage-Engine to
>> tell us:
>>> Artemisia wrote:
>>>> Peter Clinch wrote:
>>>>
>>>>> It's worth noting that this is only a problem on /seriously/ steep
>>>>> hills (see http://en.wikipedia.org/wiki/Koppenberg). But with
>>>>> muddy tracks it's quite easy to run out of traction. At which
>>>>> point you get off and push...
>>>> My hill is seriously steep.
>>> How seriously? Koppenberg is famously difficult for
>>> /professionals/. What's the actual gradient? There should be no
>>> trouble with traction on a typically surfaced 20% hill, and those
>>> are very unusual.
>>
>> Koppenberg is about 20%; the problem is that there is sand between
>> the cobblestones, so if the rear wheel gets into a longitudinal gap,
>> you are stuffed. I've done 25% a few times, most notably Bushcombe
>> Lane:
>
> Longstaff "double drive" sounds helpful here.

Not if the trike in question is a recumbent with a single rear wheel, thobut
:-)

I've got a Ken Rogers upright trike with 2WD, but have yet to use it in
anger, on account of it having no brakes.


--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
External Transparent Wall Inspection Operative.