does a light bike equal more speed for a heavy rider?



[email protected] wrote:
> On Sat, 14 Oct 2006 02:05:18 +0100, mblewett <[email protected]>
> wrote:
>> As a relative newbie, could you expand a bit on that please? When I hear
>> "smart and technically".. I think of my own personal definitions...
>> right gear, keeping the driving force as optimal as possible (no side to
>> side movement of the knees - just trying to keep power at right angles
>> to the pedals)

>
> There are places in any route where it's all too easy to slow down and not
> to flow, especially on the downhill immediately after a moderate rise.
> Since I know that I can go -much- faster on a slight downhill, if I top the
> rise and then back off to get my breath, I essentially miss out on the
> downhill acceleration the other side. In fact if you think about it, that
> might be just the place to stand up and sprint now and then.
>
> So I have to pay attention to opportunities to keep my speed up. If I have
> to slow going around a corner, I'll shift and up the cadence so that I'm
> efficiently back on pace right away. I'll look for places to cut corners
> and use the terrain most efficiently, though with caution, in traffic.
>
> Likewise if I'm in the wrong gear, I'll also lose speed and may end up
> slogging when I had plenty of energy and ability had I planned earlier,
> shifting and getting cadence up. (for example)


Thank you for explaining. On todays potter around, I've been trying to
ride "smart and technically" :)

It's taking a bit of thought, but have noticed a couple of things
already about my style of riding.

Normally I do change down as the cadence drops, but on todays experience
I think i've been changing down too late and/or perhaps by not enough.

Also i notice from experience that when I'm tired I'll try and get speed
up to try and reduce the effort needed for the next hill, so the physics
is in my head.. but hadn't really thought about using it in how I ride.

>>> then crank up the power on the
>>> second half, I can push up the number more easily. OTOH, going out and
>>> trying to maintain a certain speed, invariably I'll start to sag near the
>>> end, even though I usually get it back enough to finish strong.

>> I too sag at the end of a big push.. but working on the principle if I
>> sag a few yards further on than last time it's an improvement.

>
> That's why I say I try to relax on the first part and not make any
> mistakes, and then I frequently get a better average and can push harder
> (or actually sag less) on the second part.


Interesting. I have a suspicion why this might be so, but I'm going to
try it out to see what happens.

>>> Another little trick is to go ride the difficult parts of the course and
>>> get used to riding them at a higher than usual rate of speed. That way when
>>> ride the whole course, as I reach the 'sticky parts', I'm cued in to riding
>>> it at a brisk pace and I just click into that 'groove'; if that makes
>>> sense. ;-)

>> I hadn't thought of that.. but I'll give it a go.. it's not really a
>> course as such, more of a commute where I'm late for work ;o)
>>
>> Strange you mentioned 'click into that groove', I think I've experienced
>> my version a few times recently, where (for a few minutes on the open
>> road) cycling is zero effort and a real high.. soon as I realise it, it
>> seems to dissapear :(

>
> Yeah, that's cool.


It is a great feeling!

Being an engineer I've been thinking about the physics. If you draw a
gragh of effort against cadence (in a fixed gear on flat), you'll get a
u shaped graph... where you really want to cycle at the bottom on the u
(ie spend as little energy as possible)

Obviously it gets slightly more complex when you add in gears and gradients!

>>> So, do you have any particular bike in mind? I think Fuji has some nice
>>> light rides for a decent price.

>
> <snip>
>
>> As I mentioned, it's a similar goal... but its all relative!
>>
>> Currenty ride a Galaxy with everything fitted... so my reward will be a
>> road bike without a rack/mudguards et al.
>>
>> Although they look very nice, not sure I can afford some of the fuji's!
>> In the back of my mind there's this ****ling thought of doing a self
>> build.. if I can find a suitable secondhand frame.

>
> Save up your money. Many people think nothing of paying $1500US to get a
> computer, but think that's just too much to pay for a bike. IMO, right
> around $1500-2000 there's a price break point where you get huge bang for
> your buck, though for a starter bike (24lbs) $700 seems to be it. It's
> really exceptional equipment for the price.


Very true, and I think my parents thought I was mad that I spent more on
my bike than they sold their (secondhand, low mileage, good condition)
car! That probably says more about cars than bikes...
 
On Sun, 15 Oct 2006 23:52:02 +0100, mblewett <[email protected]>
wrote:

>[email protected] wrote:
>> On Sat, 14 Oct 2006 02:05:18 +0100, mblewett <[email protected]>
>> wrote:

<snip>
>Thank you for explaining. On todays potter around, I've been trying to
>ride "smart and technically" :)


Another thing I do to help with this concept is to do your ride with the
idea to 'smooth out or flatten out all the hills'. Ride up and over them,
smoothly standing to pedal and then getting back in the saddle efficiently
and anticipating the hills and bumps.

I try to ride with the absolute minimum of effort, rising out of the saddle
smoothly, keeping aero, knees in, light touch, kind of float on the bike.
Most of that is a mental illusion, but I find it helps

>It's taking a bit of thought, but have noticed a couple of things
>already about my style of riding.
>
>Normally I do change down as the cadence drops, but on todays experience
>I think i've been changing down too late and/or perhaps by not enough.
>
>Also i notice from experience that when I'm tired I'll try and get speed
>up to try and reduce the effort needed for the next hill, so the physics
> is in my head.. but hadn't really thought about using it in how I ride.
>
>>>> then crank up the power on the
>>>> second half, I can push up the number more easily. OTOH, going out and
>>>> trying to maintain a certain speed, invariably I'll start to sag near the
>>>> end, even though I usually get it back enough to finish strong.
>>> I too sag at the end of a big push.. but working on the principle if I
>>> sag a few yards further on than last time it's an improvement.

>>
>> That's why I say I try to relax on the first part and not make any
>> mistakes, and then I frequently get a better average and can push harder
>> (or actually sag less) on the second part.

>
>Interesting. I have a suspicion why this might be so, but I'm going to
>try it out to see what happens.


<snip>

>> Yeah, that's cool.

>
>It is a great feeling!
>
>Being an engineer I've been thinking about the physics. If you draw a
>gragh of effort against cadence (in a fixed gear on flat), you'll get a
>u shaped graph... where you really want to cycle at the bottom on the u
>(ie spend as little energy as possible)
>
>Obviously it gets slightly more complex when you add in gears and gradients!


I think there's also some areas where you can be working against yourself,
for instance if you're expending energy staying on the bike. It's strange.
Often you think you're well centered and balanced, but when you get
yourself fitted right, suddenly you're not pulling and pushing against the
bike and things feel easier. I noticed this when I put my rain bike on a
trainer. It was not adjusted right - I felt like I was falling forward off
the bike and my legs were not free to spin loosely. Took some adjusting of
the saddle and even putting the front wheel up on extra spacers (besides
the plastic cradle).

<snip>

>Very true, and I think my parents thought I was mad that I spent more on
>my bike than they sold their (secondhand, low mileage, good condition)
>car! That probably says more about cars than bikes...


Well it's a precision machine in which you're placing a lot of trust,
flying downhill at 60km/hr. Get the best you can afford.
 
Simon Brooke wrote:
> in message <[email protected]>, mblewett
> ('[email protected]') wrote:
>
>
>>I've along way to go to catch up! 25km/h is comfortable (on a
>>half-ladened tourer) but I find its stopping to look at the map the
>>kills my average speed on routes I don't know... and it seems to be
>>exponentially harder to go from 25 to 30 compared to 18 to 25km/h.

>
>
> That's because it strictly /is/ exponentially harder; the exponent being 2.
>
> Aerodynamic drag increases with the square of the speed.
>

Yes, and it gets worse, power = force X speed, so power is proportional
to speed^3

10% faster needs 33% more power!

--
Roger Thorpe

My email address is spamtrapped. You can work it out!
 
in message <[email protected]>,
[email protected] ('[email protected]') wrote:

> Simon Brooke wrote:
>> The anniversary of the crash is this Tuesday, and on Monday I and some
>> friends are repeating the same ride.

>
> That was quite a chilling story, go careful tomorrow.
>
> On a more humble note, whilst out riding today I noticed that whilst
> freewheeling downhills I was pulling a considerable distance in front
> of the person I was riding with. He is some 6 stone lighter than me.
> We swapped bikes and again I went ahead on the downhill stretches, each
> time reaching a terminal velocity some 5 mph faster than the other
> rider.


We're back; we had a great ride, and no problems apart from one puncture.
Pictures were taken at Ye Olde Crashe Syte, and will be on a website near
you shortly. I have to say I have been descending today somewhat more
circumspectly than last year!

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Madness takes its toll. Please have exact change.
 
raisethe wrote:
> Simon Brooke wrote:
>> I'm pretty confident you're wrong. My good friend Dougie, who, as
>> mentioned earlier in this thread, is twenty stone plus, rides a
>> Specialized Tarmac with Mavic Ksyrium Elite wheels, comme ca:
>> http://www.roadcyclinguk.com/news/article/mps/UAN/946/v/1/sp/
>> http://www.specialized.com/bc/SBCBkModel.jsp?spid=17943



> So do you know any carbon fibre frames or complete bikes that come in
> a touring spec (eg clearance for 35mm tyres and mudguards, provision
> for racks) ?


Koga Miyata do something (BikeFix in London being one dealer). It was
reviewed in the CTC magazine a few issues ago, and I recall the conclusion
was "OK, but hardly anything special in weight or performance at the price".
I think there were a few specific negatives which would have worried me were
I considering one (no I cannot recall the details, and can't put my hand on
that issue of Cycle).

For a touring spec bike (racks, medium-fat tyres, mudguards, etc), I cannot
see a carbon frame making such a massive weight saving over a well designed
steel one. At the price (over £2,000), you're well into the quality custom
built market. Builders such as Mercian, Roberts, etc. will do superb bikes
at that price (and very very good ones for considerably less).

So the choice of a carbon frame over steel comes down to ride comfort (does
carbon vs quality steel frame make much difference?? I know the forks will),
fit, price, and not forgetting the all important uk.r.c.
kitchen-photo-blingness.



- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
 
in message <[email protected]>, Nigel Cliffe
('[email protected]') wrote:

> raisethe wrote:
>
>> So do you know any carbon fibre frames or complete bikes that come in
>> a touring spec (eg clearance for 35mm tyres and mudguards, provision
>> for racks) ?

>
> Koga Miyata do something (BikeFix in London being one dealer). It was
> reviewed in the CTC magazine a few issues ago, and I recall the
> conclusion was "OK, but hardly anything special in weight or performance
> at the price". I think there were a few specific negatives which would
> have worried me were I considering one (no I cannot recall the details,
> and can't put my hand on that issue of Cycle).
>
> For a touring spec bike (racks, medium-fat tyres, mudguards, etc), I
> cannot see a carbon frame making such a massive weight saving over a well
> designed
> steel one. At the price (over £2,000), you're well into the quality
> custom built market. Builders such as Mercian, Roberts, etc. will do
> superb bikes at that price (and very very good ones for considerably
> less).


The frame makes up a low proportion of the weight of any bike, and of a
tourer much more so.

> So the choice of a carbon frame over steel comes down to ride comfort
> (does carbon vs quality steel frame make much difference?? I know the
> forks will), fit, price, and not forgetting the all important uk.r.c.
> kitchen-photo-blingness.


It makes a /huge/ difference to comfort: other things being equal carbon
fibre bikes are the most comfortable you can get. Against that is the fact
that accident damage cannot be assessed except by specialists, and that if
structurally damaged the frame is unlikely to be repairable. In practice,
at least with the current generation of carbon fibre frames, I would
expect a steel frame to have a longer life expectancy, particularly under
touring conditions; but I'd still personally choose carbon.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

Morning had broken, and there was nothing left for us to do
but pick up the pieces.