Single bikes are scary!

[Clive George]

Normally when I'm riding alone, I tend to do relatively flat stuff - no more
than 1:8 on my regular rides. Most hillier riding is done on a tandem.

This afternoon I decided to see what one of the hillier rides is like on my
own. Sort and vicious - Settle -> Kirkby Malham -> Malham, then back via
Langcliffe. 675m ascent and back in 17.5 miles or so (I'm just under a mile
out of Settle).

First thing I'm reminded of is I've got the wrong gears (or the wrong legs -
but I can't change those). The first hill was a bit hard with the headwind
blasting in my face to help it.

And on the way down to KM I'm reminded of the subject of this post - eek,
it's scary on one of these small bikes! Normally I just point the bike down
the hill, pedal like buggery, and slam the brakes on when I need to stop.
The tandems are really good at this - dead stable at speed, and no skill
required with the brakes at all - just squeeze as hard as you can. Now I'm
on this light little thing, can feel all the surface imperfections and am
rather less confident about doing an emergency stop.

Still, got to 55 on the way down the nice straight hill into Cowside, which
is a new record for me on my own

cheers,
clive

 

[[email protected]]

Clive George wrote:
>
> Still, got to 55 on the way down the nice straight hill into Cowside, which
> is a new record for me on my own
>
I'm always impressed by the people who can break 50mph. Do you just
coast or are you pedalling like mad?

I've managed 49.9mph on a bike with a 48/13 ratio which works out as a
cadence of about 177 which was absolutely flat out (for me) and
stopping pedalling meant the bike slowed down.

If we assume a 52/12 ratio and a 206cm circumference, 55mph needs a
cadence of 166 which is still pretty extreme.

What sort of gearing do people have on their bikes?

Tim.

 

[Paul Boyd]

[email protected] said the following on 26/06/2006 09:13:

> I'm always impressed by the people who can break 50mph. Do you just
> coast or are you pedalling like mad?

I've only ever done it twice, both times when I was a darn sight younger
and scaring myself sh*tless in the process, and that was coasting down
hills. Pedal? I didn't dare do anything except close my eyes!!!!

And this was steel rims with those ever-so-wonderful leather brake
blocks. Braking at the bottom took a long time for anything to happen...

--
Paul Boyd
http://www.paul-boyd.co.uk/

 

[Clive George]

<[email protected]> wrote in message
news:[email protected]...
>
> Clive George wrote:
>>
>> Still, got to 55 on the way down the nice straight hill into Cowside,
>> which
>> is a new record for me on my own
>>
> I'm always impressed by the people who can break 50mph. Do you just
> coast or are you pedalling like mad?

In this case, pedalled a 52/13 gear on 210cm circ. wheels to somewhere in
the high 40s then got in a tuck - there was a pretty good tailwind. I've not
managed over 44 or 45 on that bike before - but then I tend to do the
steepest hill on my normal rides with a headwind.
When I was younger I got to 49 with a 46x12 in the same situation as you
with 48x13.

The road tandem has 50x11 on 195cm circ. wheels, which is a bit easier - I
think we've pedalled at 55, possibly more.

cheers,
clive

 

[dkahn400]

[email protected] wrote:

> I'm always impressed by the people who can break 50mph. Do you just
> coast or are you pedalling like mad?
>
> I've managed 49.9mph on a bike with a 48/13 ratio which works out as a
> cadence of about 177 which was absolutely flat out (for me) and
> stopping pedalling meant the bike slowed down.
>
> If we assume a 52/12 ratio and a 206cm circumference, 55mph needs a
> cadence of 166 which is still pretty extreme.
>
> What sort of gearing do people have on their bikes?

Once you're up to about 35mph (conventional bicycle) pedalling downhill
is futile or even counter-productive as the pedalling action induces
more and more drag as the speed increases. At some point well below
50mph this extra drag is enough to overcome the extra power generated
at the wheel. A really good aerodynamic tuck is the secret. Bum behind
the saddle, body as flat as possible, head low, feet at
quarter-to-three, knees and elbows in, hands on the tops close to the
stem or, if you're brave enough, flat against either side of the stem.
Put the imaginative faculties on hold.

I've been over 50mph a number of times, but not quite as high as 55.
Maximum respect!

--
Dave...

 

[Clive George]

"dkahn400" <[email protected]> wrote in message
news:[email protected]...

> Once you're up to about 35mph (conventional bicycle) pedalling downhill
> is futile or even counter-productive as the pedalling action induces
> more and more drag as the speed increases. At some point well below
> 50mph this extra drag is enough to overcome the extra power generated
> at the wheel.

Um - that's not actually true. I've got a hill where I regularly do about
40mph. If I pedal, I go faster than if I coast. If I stop pedalling, I slow
down.

My aero crouch isn't that extreme (hands are still next to the brakes for
example) and I've got a pannier and bar bag - this might make the increased
drag from pedalling less relevant, but not that much.

cheers,
clive

 

[soup]

Clive George wrote:
> Still, got to 55 on the way down the nice straight hill into Cowside,
> which is a new record for me on my own

55 is mega, once got 37 mph down a hill and I was scared ****less.
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[Helen Deborah Vecht]

"soup" <[email protected]>typed


> Clive George wrote:
> > Still, got to 55 on the way down the nice straight hill into Cowside,
> > which is a new record for me on my own

> 55 is mega, once got 37 mph down a hill and I was scared ****less.

Even I've done 38mph down East Heath Road (now humped :-() NW3 and over
40mph in teh countryside.

--
Helen D. Vecht: [email protected]
Edgware.

 

[elyob]

<[email protected]> wrote in message
news:[email protected]...
>
> Clive George wrote:
>>
>> Still, got to 55 on the way down the nice straight hill into Cowside,
>> which
>> is a new record for me on my own
>>
> I'm always impressed by the people who can break 50mph. Do you just
> coast or are you pedalling like mad?
>

53.3 mph on my mountain bike, hacking down the Brighton side of Ditchling
Beacon. Had gone well past the gearing of my bike, but had tucked in behind
two racers who gave me a big tow. They were very surprised to see me still
with them at the bottom!

 

[soup]

Helen Deborah Vecht wrote:
> "soup"
> > 55 is mega, once got 37 mph down a hill and I was scared ****less.
> Even I've done 38mph down East Heath Road (now humped :-() NW3 and
> over 40mph in teh countryside.

May have gone faster when I was younger and uncomputerised but that is
the fastest I have gone recently and it was plenty fast for me.
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[soup]

soup wrote:
> May have gone faster when I was younger and uncomputerised but that is
> the fastest I have gone recently and it was plenty fast for me.

ADDITION :- This was on a "Y" frame with knobbly tyres on.
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[Tony Raven]

soup wrote on 26/06/2006 16:31 +0100:
> Clive George wrote:
>> Still, got to 55 on the way down the nice straight hill into Cowside,
>> which is a new record for me on my own
>
> 55 is mega, once got 37 mph down a hill and I was scared ****less.

I've had over 50 on my mountain bike in the Peak District and regularly
over 40 on the tandem and my road bike. Whether I get over 40 on the
local hill depends not on my pedalling down the hill but how much speed
I carry at the start of the hill. A bit of welly up to 30mph near the
top makes sure I get well over 40 at the bottom, where there is a stop
sign and T-junction to test the anchors, without pedalling.

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

 

[dkahn400]

Clive George wrote:
> "dkahn400" <[email protected]> wrote in message
> news:[email protected]...
>
> > Once you're up to about 35mph (conventional bicycle) pedalling downhill
> > is futile or even counter-productive as the pedalling action induces
> > more and more drag as the speed increases. At some point well below
> > 50mph this extra drag is enough to overcome the extra power generated
> > at the wheel.
>
> Um - that's not actually true. I've got a hill where I regularly do about
> 40mph. If I pedal, I go faster than if I coast. If I stop pedalling, I slow
> down.
>
> My aero crouch isn't that extreme (hands are still next to the brakes for
> example) and I've got a pannier and bar bag - this might make the increased
> drag from pedalling less relevant, but not that much.

I'm pretty sure it is true, and I don't think you've shown otherwise.
It may well be possible to gain speed at 40mph by pedalling,
particularly with an inefficient tuck, but you would gain more by
improving your position. Don't forget that when coasting at 30mph,
pedalling up to 35mph takes as much power as riding at 25mph on the
flat in nil wind. At 50mph that same amount of power would only
accelerate you up to 52mph, and you will certainly lose more than 2mph
by coming out of an efficient tuck to pedal.

--
Dave...

 

[dkahn400]

soup wrote:
> soup wrote:
> > May have gone faster when I was younger and uncomputerised but that is
> > the fastest I have gone recently and it was plenty fast for me.
>
> ADDITION :- This was on a "Y" frame with knobbly tyres on.

The hum from the tyres must have been deafening.

--
Dave...

 

[soup]

dkahn400 wrote:
> soup wrote:
> > ADDITION :- This was on a "Y" frame with knobbly tyres on.
> The hum from the tyres must have been deafening.

Not so much a hum as a R O A R )
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[Chris Eilbeck]

Helen Deborah Vecht <[email protected]> writes:

>> 55 is mega, once got 37 mph down a hill and I was scared ****less.
>
> Even I've done 38mph down East Heath Road (now humped :-() NW3 and
> over 40mph in teh countryside.

I've managed 44mph on my tourer on the road to Monmouth from Hereford.
I've not had a huge amount of speed from my new-to-me road bike
though. It's too high geared for me and I'm not fit enough to ride it
up any of the decent hills around here, just out across the valley.

Chris
--
Chris Eilbeck

 

[Clive George]

"dkahn400" <[email protected]> wrote in message
news:[email protected]...
> Clive George wrote:
>> "dkahn400" <[email protected]> wrote in message
>> news:[email protected]...
>>
>> > Once you're up to about 35mph (conventional bicycle) pedalling downhill
>> > is futile or even counter-productive as the pedalling action induces
>> > more and more drag as the speed increases. At some point well below
>> > 50mph this extra drag is enough to overcome the extra power generated
>> > at the wheel.
>>
>> Um - that's not actually true. I've got a hill where I regularly do about
>> 40mph. If I pedal, I go faster than if I coast. If I stop pedalling, I
>> slow
>> down.
>>
>> My aero crouch isn't that extreme (hands are still next to the brakes for
>> example) and I've got a pannier and bar bag - this might make the
>> increased
>> drag from pedalling less relevant, but not that much.
>
> I'm pretty sure it is true, and I don't think you've shown otherwise.
> It may well be possible to gain speed at 40mph by pedalling,
> particularly with an inefficient tuck, but you would gain more by
> improving your position. Don't forget that when coasting at 30mph,
> pedalling up to 35mph takes as much power as riding at 25mph on the
> flat in nil wind. At 50mph that same amount of power would only
> accelerate you up to 52mph, and you will certainly lose more than 2mph
> by coming out of an efficient tuck to pedal.

Still not convinced. I did just try it again

I wonder if it would help if I mentioned that the hills I'm doing this on
aren't that big - eg the one today is only 50m drop in about 800m. (steepest
at the top). This means you don't actually get time to coast up to speed in
a tuck - you need to put in the extra by pedalling. And this is pedalling
quite hard - definitely not at a sustainable pace.

cheers,
clive

 

[Geoff. Hayward]

Bearing in mind all those good people who were scared "****less" at speed,
are you sure the hum was only from the tyres?
Geoff.
"soup" <[email protected]> wrote in message
news:[email protected]...
> dkahn400 wrote:
>> soup wrote:
>> > ADDITION :- This was on a "Y" frame with knobbly tyres on.
>> The hum from the tyres must have been deafening.
>
> Not so much a hum as a R O A R )
> --
> This space intentionally left blank.
>
>

 

[soup]

Tony Raven wrote:
> I've had over 50 on my mountain bike

Much Kudos for that.

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[soup]

Tony Raven wrote:
> I've had over 50 on my mountain bike in the Peak District

Wasn't it a bit crowded. )
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