Stupid gearing (or an encounter with Succombs Hill)

On resuming cycling after an enforced six week break, I
decided that it would be a good idea to steer clear of
any difficult routes in order to maximise the enjoyment
of the ride. This of course included steep hills. But
those of you who have followed my occasional posts to
the group may know I have thing for climbing hills, and
yesterday the siren song proved too strong, so I decided
I would go for broke and tackle the hardest hill in my
area - Succombs Hill.

This hill is rather short - about just over a quarter of
a mile. However, it is *steep* - a 'single arrow' slope to
begin with, followed by a 25% slope conveniently located
near the top. However, I have done it in the past so I
figured I shouldn't have any problems this time around.

Well, I rode from my home in South London till I got to
Wapses Lodge roundabout from which the hill begins. I
instantly engaged into a 32 inch gear and started to
climb. I was able to make it up the single arrow slope
without too much difficulty by not exerting myself too
much, and I actually believed I would be able to make
it all the way up.

Then I started up the 25% section, and it instantly
became hard going - it was looking like I was going
to be defeated by this hill. But I had a joker in
the pack - a 23 inch gear which I thought should be
more than enough to see me up this hill. So I changed
down again, and I was doing OK for all of three seconds,
when all of a sudden I did a 'wheelie'! "Hey, that's
not in the script!" I thought, and brought the bike
under control again, whereupon I did another wheelie!
Faced with the choice of the wrath of motorists annoyed
at my playing silly buggers on a very steep road and
accepting defeat at the hands of the hill, I chose the
latter option and pushed my bike over to the pavement,
where I continued pushing it up the hill.

So here are the inevitable questions:

1. Why the spontaneous wheelies in the low gear? Would
staying in a higher gear have prevented this?

2. When I got off, I was experiencing back and abdominal
pains, as though those muscles had been hard at work
on the hill. What work would these muscles have had
to do on the climb?

Cheers,

--
Akin

aknak at aksoto dot idps dot co dot uk

"Sky Fly" wrote in message
...

1. Why the spontaneous wheelies in the low gear?

Coz you're not on a tandem. It's just the opposite of applying your front
brake too hard - your pedalling force will tend to lift the front wheel, and
in a jolly low gear and on a steep hill the effect is strongest.

You just need to redistribute your bodyweight. Getting out of the saddle
works very well for this.

Would staying in a higher gear have prevented this?

Sort of, but at the expense of actually giving you enough force on the wheel
to get you up that hill!

cheers,
clive

"Clive George" typed


"Sky Fly" wrote in message
...

1. Why the spontaneous wheelies in the low gear?

Coz you're not on a tandem. It's just the opposite of applying your front
brake too hard - your pedalling force will tend to lift the front wheel, and
in a jolly low gear and on a steep hill the effect is strongest.

You just need to redistribute your bodyweight. Getting out of the saddle
works very well for this.

Would staying in a higher gear have prevented this?

Sort of, but at the expense of actually giving you enough force on the wheel
to get you up that hill!

cheers,
clive


Front panniers can prevent wheelies.

--
Helen D. Vecht:
Edgware.

Sky Fly wrote:

1. Why the spontaneous wheelies in the low gear? Would
staying in a higher gear have prevented this?

Don't use higher gears purely for that reason if you can help it. Smooth
moderate pedalling with good weight distribution and not pulling suddenly
on the bars strongly should prevent the wheelies once on the move. In
fact you might be better off with even lower gears if you can't climb
smoothly with what you have - although there does come a point where it's
hard to balance because you're going so slowly (and 23" is a wall-climbing
gear already). Strengthening the legs will then help you to use higher
gears properly instead. Might be necessary for 25%. That's a mad
gradient!

Also try starting in a higher gear (then changing down) if to avoid the
take-off wheelies ...or just enjoy them! :-)

~PB

"Sky Fly" writes:

So here are the inevitable questions:

1. Why the spontaneous wheelies in the low gear? Would
staying in a higher gear have prevented this?

When you get out of the saddle and stomp, the drive to the rear wheel
is very unsmooth: it comes in great pulses as your feet go down. Each
of these pulses causes considerable (temporary) acceleration. On a
steep hill, particularly if your bike has a short wheelbase, the
centre of gravity is not far forward of the rear contact patch in any
case, so it doesn't take much acceleration to lift the front wheel.

The solution is two fold

(i) Sit and spin as long as you can. So long as you're spinning and
not mashing the power delivery is relatively smooth, so you don't get
as severe pulses of acceleration.

(ii) Keep your centre of gravity as far forward as possible. When
seated, lean your torso far forward. When standing, try to keep your
body weight vertically over the pedals. On very steep hills you'll
find there comes a point where your seated body puts your CofG aft of
the rear contact patch, so you _have_ to get up to prevent going over
backwards, and then keeping the bike going gets _very_
tricky. Fortunately, roads are very rarely that steep.

2. When I got off, I was experiencing back and abdominal
pains, as though those muscles had been hard at work
on the hill. What work would these muscles have had
to do on the climb?

Standing or sitting? If standing, they're doing a lot of holding the
bike upright, which is normally done by your but on the saddle.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

There are no messages. The above is just a random stream of
bytes. Any opinion or meaning you find in it is your own creation.

"Sky Fly" wrote in message
...

Then I started up the 25% section, and it instantly
became hard going - it was looking like I was going
to be defeated by this hill. But I had a joker in
the pack - a 23 inch gear which I thought should be
more than enough to see me up this hill.

I came across this hill, totally out of the blue when riding home from
Sussex one day, with a lowest ratio of about 46 inches and already
knackered, I didn't even attempt it (

Also the bend and the cars make it a bit too unpleasant for me to want to
play on it.

"Simon Brooke" wrote in message
. uk...
"Sky Fly" writes:

So here are the inevitable questions:

1. Why the spontaneous wheelies in the low gear? Would
staying in a higher gear have prevented this?

When you get out of the saddle and stomp, the drive to
the rear wheel is very unsmooth: it comes in great pulses
as your feet go down. Each of these pulses causes
considerable (temporary) acceleration. On a steep hill,
particularly if your bike has a short wheelbase, the
centre of gravity is not far forward of the rear contact
patch in any case, so it doesn't take much acceleration
to lift the front wheel.

The solution is two fold

(i) Sit and spin as long as you can. So long as you're
spinning and not mashing the power delivery is
relatively smooth, so you don't get as severe pulses of
acceleration.

Actually Simon, I *was* sitting - I'm not a fan of 'la
danseuse', especially on a steep hill where I need
as much control over the bike as possible.

(ii) Keep your centre of gravity as far forward as
possible. When seated, lean your torso far forward. When
standing, try to keep your body weight vertically over
the pedals. On very steep hills you'll find there comes
a point where your seated body puts your CofG aft of
the rear contact patch, so you _have_ to get up to
prevent going over backwards, and then keeping the bike
going gets _very_ tricky. Fortunately, roads are very
rarely that steep.

Yeah, I might try that if the mad thought enters my head
to do a hill that steep again. Personally, I doubt I will
try again, unless someone starts paying good money for
doing 25% gradients.

2. When I got off, I was experiencing back and abdominal
pains, as though those muscles had been hard at work
on the hill. What work would these muscles have had
to do on the climb?

Standing or sitting? If standing, they're doing a lot
of holding the bike upright, which is normally done by
your but on the saddle.

As I mentioned earlier, I was sitting all the way. Any
explanation in this case?

--
Akin

aknak at aksoto dot idps dot co dot uk

Sky Fly wrote:
As I mentioned earlier, I was sitting all the way. Any
explanation in this case?

The same explanation (and my reply too) still applies. Pulses of hard
acceleration cause the wheelies - which can be reduced by smoothing out
the power delivery (and improving weight distribution if necessary).

~PB

On Fri, 7 Nov 2003 18:45:50 GMT, Helen Deborah Vecht
wrote:

Front panniers can prevent wheelies.

But only if they're wheelie heavy.

--
Dave...

Sky Fly wrote:

Actually Simon, I *was* sitting - I'm not a fan of 'la
danseuse', especially on a steep hill where I need
as much control over the bike as possible.


If you are sitting lean forward and bend you elbows so you are pulling back
on the bars with each pedal stroke, not upwards which is the more natural
position. Helps keep the front wheel on the ground a lot more.

Tony