Wider tires, All-road bikes

On 1/26/2019 11:42 AM, AMuzi wrote:
On 1/26/2019 10:07 AM, Frank Krygowski wrote:
On 1/26/2019 2:04 AM, Sir Ridesalot wrote:
On Saturday, January 26, 2019 at 12:26:06 AM UTC-5, John
B. Slocomb wrote:
On Fri, 25 Jan 2019 21:47:45 -0500, Joy Beeson
wrote:

On Thu, 24 Jan 2019 00:50:28 -0000 (UTC), Duane

wrote:

I tried a couple of helmet mirrors and while they work
for seeing behind I
found that they presented a blind spot when coming to
intersections.

A few years ago I searched the Web for helmet mirrors,
and didn't find
one single mirror that didn't have four times the area a
mirror should
have.Â* If I didn't have a genuine Chuck Harris mirror,
I'd try
mounting one of the billboards in such fashion that only
one corner
was in my field of view.

A mirror should be the same size as the outside mirror
on your car. If
you get into the driver's seat wearing it and move your
head until the
helmet mirror covers the car's mirror, the corners of
the car mirror
should stick out.

I think that the distance the mirror is from your eye
also enters into
the equation, doesn't it?


Cheers,
John B.

I don't think you could have a mirror the same size as an
outside mirror on a car. The weight of it would cause it
to fall down and the size of it would definitely block
your vision. Frank likes the Take a Look mirror which is a
great mirror for eyeglasses. I like my round mirror that's
a little over and inch in diameter and is attached to my
helmet by a telescoping rod. What I most like about an
eyeglass or helmet mirror is the ability to scan behind me
with slight movements of my head. If I move my head more I
can even use the mirror to look over my right shoulder
instead of my normal left shoulder.

A couple minor points: I think Joy was talking about
_apparent_ size of the mirror being the same as a car's side
view mirror.

And I've never used a commercial mirror (although my wife
has). I don't really have an opinion on the Take-A-Look
model, unless that was the brand she used years and years
ago, that broke at some ball joint.



Take-A-Look is a simple bent wire with chromoplastic mirror:

https://www.amazon.com/Bike-Peddler-.../dp/B001VTQNVO

Chuck Harris:
http://www.palmbeachbiketours.com/lo...arview-mirror/


Both generally like yours I assume

Vaguely similar, yes. Mine is quite a bit simpler.


--
- Frank Krygowski

On Friday, January 25, 2019 at 5:28:11 PM UTC-8, Frank Krygowski wrote:
On 1/25/2019 2:44 PM, wrote:
On Thursday, January 24, 2019 at 6:05:05 PM UTC-8, John B. Slocomb wrote:
On Fri, 25 Jan 2019 11:48:28 +1100, James
wrote:

On 25/1/19 10:05 am, jbeattie wrote:
On Thursday, January 24, 2019 at 2:05:11 PM UTC-8, James wrote:
On 25/1/19 6:51 am, jbeattie wrote:


Some tires have pretty low RRs, but are heavy, which you can feel
climbing. https://www.bicyclerollingresistance.com/tour-reviews
Just going by a drum test doesn't tell you everything there is to
feel about a tire. This is not entirely imagined.


That pea under your mattress must be real uncomfortable.

The sluggishness of a 28mm versus 25mm Conti Grand Prix is noticeable
to me and yet the fatter tire has a claimed lower RR.
https://www.cyclist.co.uk/in-depth/7...-really-faster
Maybe it is princess and pea, but even in the fable, there was a pea,
and the princess could feel it. It was not a placebo pea. I do go
with the fatter tire in wet weather (and different model), regardless
of the somewhat slower feel.


I can't be bothered with changing tyres depending on the weather. The
bitumen roads are rough where I live. 90 psi enough in the front 23 mm
tyre otherwise my hands buzz. I go just as fast (or slow) with my back
tyre (25 mm Michelin measures 27 mm) at 80 or 90 psi. In fact it got
down to about 70 psi the other day before I pumped it back up. Didn't
notice any speed difference while I was riding - except the road seemed
slightly less rough.

The same here. I went from 23mm to 25mm and then to 28mm tires and
while the ride certainly was better with the larger tires I couldn't
see any difference in average speed for a ride of say 10 miles (16
km). Although, at my age I'm certainly not the fastest thing on the
block :-)

Currently I'm presently running 28mm tires at 70 psi and other then
the noticeably softer ride I can't see any difference from the 23mm
tires I used to use. (well except I can't fit fenders to one of the
bike now )


Cheers,
John B.

The difference in average speed from these changes is only definable in TT terms. If you don't notice your speed decreasing and the ride is better why wouldn't you make the change?

The ride yesterday at the top of one of the climbs we started down the other side. It always seems to me that people are afraid to go fast because I can kick off and accelerate and then coast faster than most of the can pedal. What other thing could it be aside from lower rolling resistance. They all pass me going up hills.

Well, the ratio of weight to aerodynamic drag is a big answer to "what
else could it be." Those two factors are generally more important than
rolling resistance - not that rolling resistance doesn't matter.

Our club used to have a member whose nickname was "Downhill." He was
unbeatable at coasting. Nice guy. Waist size was about 50".

Notice, I'm not saying Tom is fat. I'm just explaining the main factors
in downhill speed.

In addition, I believe that downhill speed increases if the rider
suspends part of his weight on bent legs, instead of putting all his
weight on the saddle. Kinetic energy is lost by jostling the squishy
human body. With your body suspended, an upward jolt results in less
energy loss.

--
- Frank Krygowski

Remember - I'm 6'4" and 185 lbs. I have 7 sq ft of frontal area - that is 20% more than the normal rider.

On Saturday, January 26, 2019 at 12:39:45 AM UTC-8, wrote:
On Saturday, January 26, 2019 at 12:51:20 AM UTC+1, wrote:
On Friday, January 25, 2019 at 12:23:48 PM UTC-8, wrote:
On Friday, January 25, 2019 at 8:51:02 PM UTC+1, wrote:
On Friday, January 25, 2019 at 10:33:37 AM UTC-8, wrote:
On Friday, January 25, 2019 at 12:05:42 AM UTC+1, jbeattie wrote:
On Thursday, January 24, 2019 at 2:05:11 PM UTC-8, James wrote:
On 25/1/19 6:51 am, jbeattie wrote:
On Thursday, January 24, 2019 at 10:37:54 AM UTC-8, Frank Krygowski
wrote:
On 1/24/2019 12:35 PM, jbeattie wrote:
On Wednesday, January 23, 2019 at 8:17:00 PM UTC-8, Tim McNamara
wrote:


Well, that was what Jobst's tire testing reports presaged.
Lots of data on this, actually, and generally speaking it is
accepted that (all other things about the tires being equal)
the wider tire rolls with fewer losses. A good case in point is
the Continental 4000sII, which comes in three widths and the
widest has the best RR numbers. No doubt there is a point of
diminishing returns and I don't know where that is. I've got
the 4000sII Contis on my bike in 700 x 28 which measures at 31
and they are excellent tires, very pleased with them.

RR is an odd thing because it doesn't necessarily reflect how a
tire rides. Some low RR tires are sluggish and too balloon-tire
like for me.

I don't get it. How would a tire with low rolling resistance be
"sluggish"?

Yes, its counter-intuitive which means I'm correct in today's market.
https://janheine.wordpress.com/2018/...res-isnt-easy/
But actually, its usually weight and (maybe) casing related or
testing artifact.

I hated silks because they were squishy to me sprinting or climbing
out of the saddle and yet they had really low measured RR and were
light. I liked stiffer cotton tubulars. Fatter Contis have lower RR,
but the 28mm tires feel balloonish compared to the 23mms.
https://www.bicyclerollingresistance...0s-ii-23-25-28

Some tires have pretty low RRs, but are heavy, which you can feel
climbing. https://www.bicyclerollingresistance.com/tour-reviews Just
going by a drum test doesn't tell you everything there is to feel
about a tire. This is not entirely imagined.


That pea under your mattress must be real uncomfortable.

The sluggishness of a 28mm versus 25mm Conti Grand Prix is noticeable to me and yet the fatter tire has a claimed lower RR. https://www.cyclist.co.uk/in-depth/7...-really-faster Maybe it is princess and pea, but even in the fable, there was a pea, and the princess could feel it. It was not a placebo pea. I do go with the fatter tire in wet weather (and different model), regardless of the somewhat slower feel.

-- Jay Beattie.

In this month edition of TOUR magazine they tested the new Continental GP5000 tyres 25, 28 mm, clincher and tubeless (TL) smooth and rough asphalt 7 and 5,5 bar. At 35 km/hr an 85 kg:


https://photos.app.goo.gl/CHzQASm7YEqbVc4M7

Lou

Lou, can you give us the gist of that? I don't read German (well, not much) and the magazine article can't be copied and shoved through a translator.

It appears that there is a typo with the initial 7 bar reading not for a 25 but rather a 28. And it also appears that the rolling resistance was tested on a smooth surface.

There is a typo. The 5.5 bar reading for the TL version (tubeless) was for a 28 mm wide tyre. For each tyre there was a measurement on rough surface (rau, top bar)) and on a smooth surface (glatt, bottom bar). They tested at a speed of 35 km/hr at a total weight of 85 kg.

Translated summary (fazit) ahum:

'among the top allround tires the Conti GP5000 regained the top position. Despite their solid construction and best puncture resistance they have an incredible low RR and very good traction. The performance jump has its price though. The price for the foldable clincher is euro 62.90 and for the tubeless version euro 74.90 a piece.'

I just ordered a set 25 mm for euro 45.75 a piece at my preferred online supplier for my Canyon Aeroad replacing the Conti GP4000 S II 25 mm which lasted more than 4500 km. For the last 5-10 years you can't go wrong with Continental GP 4000S, GP 4000S II and I expect the same from these GP 5000. We will see the coming season.


Lou

Well, 5.5 watts isn't much but remember that most of the people here would have trouble maintaining 200 watts so an almost three percent improvement while not the sort of thing you could feel would make a difference in the way you feel after a long ride.


I agree with you onthat. 5.5 watt is significant for me. I did a sport medical test 2 weeks ago. Part of is measuring your ECG and blood preesure while riding a stationary bike with an increasing resistance until you pass out ;-). The doctor challenged the intern what protocol to use and not telling me. I challenged the doctor that I could predict the maximum power I could manage and we covered the power display of the bike. I wrote down 325 W on a paper and ended up with 335 W. How is that possible she asked. That is what feeling you get training with a power meter ;-) The protocol used increased the power by 10 Watt steps. I definitely could feel that at the end.

Lou

That's pretty damn strong. At the end of last season I did a ride in which I did 10K at 300 watts. I didn't feel it until sometime later on the return trip.

On 1/26/2019 8:07 AM, Frank Krygowski wrote:
On 1/26/2019 2:04 AM, Sir Ridesalot wrote:
On Saturday, January 26, 2019 at 12:26:06 AM UTC-5, John B. Slocomb
wrote:
On Fri, 25 Jan 2019 21:47:45 -0500, Joy Beeson
wrote:

On Thu, 24 Jan 2019 00:50:28 -0000 (UTC), Duane
wrote:

I tried a couple of helmet mirrors and while they work for seeing
behind I
found that they presented a blind spot when coming to intersections.

A few years ago I searched the Web for helmet mirrors, and didn't find
one single mirror that didn't have four times the area a mirror should
have.Â* If I didn't have a genuine Chuck Harris mirror, I'd try
mounting one of the billboards in such fashion that only one corner
was in my field of view.

A mirror should be the same size as the outside mirror on your car. If
you get into the driver's seat wearing it and move your head until the
helmet mirror covers the car's mirror, the corners of the car mirror
should stick out.

I think that the distance the mirror is from your eye also enters into
the equation, doesn't it?


Cheers,
John B.

I don't think you could have a mirror the same size as an outside
mirror on a car. The weight of it would cause it to fall down and the
size of it would definitely block your vision. Frank likes the Take a
Look mirror which is a great mirror for eyeglasses. I like my round
mirror that's a little over and inch in diameter and is attached to my
helmet by a telescoping rod. What I most like about an eyeglass or
helmet mirror is the ability to scan behind me with slight movements
of my head. If I move my head more I can even use the mirror to look
over my right shoulder instead of my normal left shoulder.

A couple minor points: I think Joy was talking about _apparent_ size of
the mirror being the same as a car's side view mirror.

And I've never used a commercial mirror (although my wife has). I don't
really have an opinion on the Take-A-Look model, unless that was the
brand she used years and years ago, that broke at some ball joint.

Breaking at a ball joint sounds a lot like a "Third Eye" brand mirror.
They work great when new, then the joints wear out and they sag, sag, sag.

As an alternative, a few years ago I tried a "Efficient Velo Tools"
"Safe Zone Helmet Mirror," and after an adjustment, found I liked it.
EVT is a local (Portland) company. The mirror is huge, helmet mounted,
and a bit farther from the eye (hence the need for hugeness). Looks
kinda dorky (a bit Dalek-esque), but it works well and doesn't sag like
the Third Eye brand.

https://www.efficientvelo.com/safe-zone-helmet-mirror/

BTW, EVT makes some really nice shop-grade repair equipment.

Mark J.

On 26/1/19 12:28 pm, Frank Krygowski wrote:
On 1/25/2019 2:44 PM, wrote:


The difference in average speed from these changes is only definable
in TT terms. If you don't notice your speed decreasing and the ride is
better why wouldn't you make the change?

The ride yesterday at the top of one of the climbs we started down the
other side. It always seems to me that people are afraid to go fast
because I can kick off and accelerate and then coast faster than most
of the can pedal. What other thing could it be aside from lower
rolling resistance. They all pass me going up hills.

Well, the ratio of weight to aerodynamic drag is a big answer to "what
else could it be." Those two factors are generally more important than
rolling resistance - not that rolling resistance doesn't matter.

Our club used to have a member whose nickname was "Downhill." He was
unbeatable at coasting. Nice guy. Waist size was about 50".

Notice, I'm not saying Tom is fat. I'm just explaining the main factors
in downhill speed.

In addition, I believe that downhill speed increases if the rider
suspends part of his weight on bent legs, instead of putting all his
weight on the saddle. Kinetic energy is lost by jostling the squishy
human body. With your body suspended, an upward jolt results in less
energy loss.


We used to have rolling races several times a week when I lived in
Melbourne. Some guys had more aero wheels. Some had tighter fitting
clothes. The most important factor though, was how aero the position
you could maintain on the bike, and then how well you could judge a
slipstream and timing to accelerate behind someone and pass them before
the line.

Sitting on the top tube with your bum under the nose of the saddle, and
hands near the middle of the bars with elbows held low, etc., and head
down seemed best.

I think we were more aero than Sagan, but we couldn't get to the brakes
easily.

http://cycling.today/peter-sagans-de...w-study-finds/

--
JS

On Sunday, January 27, 2019 at 1:56:42 AM UTC+1, wrote:
On Saturday, January 26, 2019 at 12:39:45 AM UTC-8, wrote:
On Saturday, January 26, 2019 at 12:51:20 AM UTC+1, wrote:
On Friday, January 25, 2019 at 12:23:48 PM UTC-8, wrote:
On Friday, January 25, 2019 at 8:51:02 PM UTC+1, wrote:
On Friday, January 25, 2019 at 10:33:37 AM UTC-8, wrote:
On Friday, January 25, 2019 at 12:05:42 AM UTC+1, jbeattie wrote:
On Thursday, January 24, 2019 at 2:05:11 PM UTC-8, James wrote:
On 25/1/19 6:51 am, jbeattie wrote:
On Thursday, January 24, 2019 at 10:37:54 AM UTC-8, Frank Krygowski
wrote:
On 1/24/2019 12:35 PM, jbeattie wrote:
On Wednesday, January 23, 2019 at 8:17:00 PM UTC-8, Tim McNamara
wrote:


Well, that was what Jobst's tire testing reports presaged.
Lots of data on this, actually, and generally speaking it is
accepted that (all other things about the tires being equal)
the wider tire rolls with fewer losses. A good case in point is
the Continental 4000sII, which comes in three widths and the
widest has the best RR numbers. No doubt there is a point of
diminishing returns and I don't know where that is. I've got
the 4000sII Contis on my bike in 700 x 28 which measures at 31
and they are excellent tires, very pleased with them.

RR is an odd thing because it doesn't necessarily reflect how a
tire rides. Some low RR tires are sluggish and too balloon-tire
like for me.

I don't get it. How would a tire with low rolling resistance be
"sluggish"?

Yes, its counter-intuitive which means I'm correct in today's market.
https://janheine.wordpress.com/2018/...res-isnt-easy/
But actually, its usually weight and (maybe) casing related or
testing artifact.

I hated silks because they were squishy to me sprinting or climbing
out of the saddle and yet they had really low measured RR and were
light. I liked stiffer cotton tubulars. Fatter Contis have lower RR,
but the 28mm tires feel balloonish compared to the 23mms.
https://www.bicyclerollingresistance...0s-ii-23-25-28

Some tires have pretty low RRs, but are heavy, which you can feel
climbing. https://www.bicyclerollingresistance.com/tour-reviews Just
going by a drum test doesn't tell you everything there is to feel
about a tire. This is not entirely imagined.


That pea under your mattress must be real uncomfortable.

The sluggishness of a 28mm versus 25mm Conti Grand Prix is noticeable to me and yet the fatter tire has a claimed lower RR. https://www..cyclist.co.uk/in-depth/...-really-faster Maybe it is princess and pea, but even in the fable, there was a pea, and the princess could feel it. It was not a placebo pea. I do go with the fatter tire in wet weather (and different model), regardless of the somewhat slower feel.

-- Jay Beattie.

In this month edition of TOUR magazine they tested the new Continental GP5000 tyres 25, 28 mm, clincher and tubeless (TL) smooth and rough asphalt 7 and 5,5 bar. At 35 km/hr an 85 kg:


https://photos.app.goo.gl/CHzQASm7YEqbVc4M7

Lou

Lou, can you give us the gist of that? I don't read German (well, not much) and the magazine article can't be copied and shoved through a translator.

It appears that there is a typo with the initial 7 bar reading not for a 25 but rather a 28. And it also appears that the rolling resistance was tested on a smooth surface.

There is a typo. The 5.5 bar reading for the TL version (tubeless) was for a 28 mm wide tyre. For each tyre there was a measurement on rough surface (rau, top bar)) and on a smooth surface (glatt, bottom bar). They tested at a speed of 35 km/hr at a total weight of 85 kg.

Translated summary (fazit) ahum:

'among the top allround tires the Conti GP5000 regained the top position. Despite their solid construction and best puncture resistance they have an incredible low RR and very good traction. The performance jump has its price though. The price for the foldable clincher is euro 62.90 and for the tubeless version euro 74.90 a piece.'

I just ordered a set 25 mm for euro 45.75 a piece at my preferred online supplier for my Canyon Aeroad replacing the Conti GP4000 S II 25 mm which lasted more than 4500 km. For the last 5-10 years you can't go wrong with Continental GP 4000S, GP 4000S II and I expect the same from these GP 5000. We will see the coming season.


Lou

Well, 5.5 watts isn't much but remember that most of the people here would have trouble maintaining 200 watts so an almost three percent improvement while not the sort of thing you could feel would make a difference in the way you feel after a long ride.


I agree with you onthat. 5.5 watt is significant for me. I did a sport medical test 2 weeks ago. Part of is measuring your ECG and blood preesure while riding a stationary bike with an increasing resistance until you pass out ;-). The doctor challenged the intern what protocol to use and not telling me. I challenged the doctor that I could predict the maximum power I could manage and we covered the power display of the bike. I wrote down 325 W on a paper and ended up with 335 W. How is that possible she asked. That is what feeling you get training with a power meter ;-) The protocol used increased the power by 10 Watt steps. I definitely could feel that at the end.

Lou

That's pretty damn strong. At the end of last season I did a ride in which I did 10K at 300 watts. I didn't feel it until sometime later on the return trip.

You cannot compare the two values Tom. It depends on the used protocol. They started at 55 W and increased it within a little more than 10 minutes to 335 Watt. So on average I managed only 195 Watts for 10 minutes but of those ten minutes I was a couple of minutes way over my treshold power which would be at this time of the season between 200-220 Watt. So beforehand I had some calculation to do. They said they start at 55 W and the test would last about 10 minutes. Afterwards they said they expected me to manage around 300 Watts, so my test took a little longer. If they had followed a different protocol I would ended up at a different power level. Anyone can manage 800 Watt for a couple of seconds.

Lou

Tom Evans wrote:
On 25/01/2019 00:19, Mark J. wrote:

I've been tempted to buy a cheap fat bike for the novelty; I expect it
would handle like a tank.


I got a cheap adventure (like a cross) bike, 40mm tyre, as a stopgap
when my normal road bike was out of action for a few weeks.

The results were very surprising. The geometries were the same, the tyre
rolling resistance didn't appear to be much different and the extra 4kg
didn't appear to make much difference to my speed.

On the plus size it was a more comfortable to ride, it felt slightly
more solid on the road.

I now ride it all the time in preference to my road bike.




Few years back I bought a cheap but relaxed CX bike pre adventure bikes
etc, it had its issues mainly it’s brakes which where canti and couldn’t
cope with being used like a MTB lite, it’s weight I generally didn’t
notice, I even took it up Mt Teide

I replaced it last year with a adventure bike, which main advantages are
better brakes cable disk vs canti and 2/9 vs 3/7 gearing.

It is my road bike, I do tend to run CX sized tyres as generally is more
choice and to give mud clearance. But I do notice how it rides bumps and
frankly is much more grip, some will be the type of tyres, some the size.

I don’t appear to be any slower, checking my times. Any differences are
marginal.

Roger Merriman

On 1/26/2019 8:25 PM, Mark J. wrote:
On 1/26/2019 8:07 AM, Frank Krygowski wrote:
On 1/26/2019 2:04 AM, Sir Ridesalot wrote:
On Saturday, January 26, 2019 at 12:26:06 AM UTC-5, John B. Slocomb
wrote:
On Fri, 25 Jan 2019 21:47:45 -0500, Joy Beeson
wrote:

On Thu, 24 Jan 2019 00:50:28 -0000 (UTC), Duane
wrote:

I tried a couple of helmet mirrors and while they work for seeing
behind I
found that they presented a blind spot when coming to intersections.

A few years ago I searched the Web for helmet mirrors, and didn't find
one single mirror that didn't have four times the area a mirror should
have.Â* If I didn't have a genuine Chuck Harris mirror, I'd try
mounting one of the billboards in such fashion that only one corner
was in my field of view.

A mirror should be the same size as the outside mirror on your car. If
you get into the driver's seat wearing it and move your head until the
helmet mirror covers the car's mirror, the corners of the car mirror
should stick out.

I think that the distance the mirror is from your eye also enters into
the equation, doesn't it?


Cheers,
John B.

I don't think you could have a mirror the same size as an outside
mirror on a car. The weight of it would cause it to fall down and the
size of it would definitely block your vision. Frank likes the Take a
Look mirror which is a great mirror for eyeglasses. I like my round
mirror that's a little over and inch in diameter and is attached to
my helmet by a telescoping rod. What I most like about an eyeglass or
helmet mirror is the ability to scan behind me with slight movements
of my head. If I move my head more I can even use the mirror to look
over my right shoulder instead of my normal left shoulder.

A couple minor points: I think Joy was talking about _apparent_ size
of the mirror being the same as a car's side view mirror.

And I've never used a commercial mirror (although my wife has). I
don't really have an opinion on the Take-A-Look model, unless that was
the brand she used years and years ago, that broke at some ball joint.

Breaking at a ball joint sounds a lot like a "Third Eye" brand mirror.
They work great when new, then the joints wear out and they sag, sag, sag.

As an alternative, a few years ago I tried a "Efficient Velo Tools"
"Safe Zone Helmet Mirror," and after an adjustment, found I liked it.
EVT is a local (Portland) company.Â* The mirror is huge, helmet mounted,
and a bit farther from the eye (hence the need for hugeness).Â* Looks
kinda dorky (a bit Dalek-esque), but it works well and doesn't sag like
the Third Eye brand.

https://www.efficientvelo.com/safe-zone-helmet-mirror/

Yow, that IS huge!

The first eyeglass mirror I made, in the mid-1970s, was probably about
1" square with a stem extending maybe 4" out from my glasses frame. But
I soon realized that smaller was better. A shorter extension allowed a
smaller mirror for the same field of view. The smaller mirror had less
mass and the shorter wire was stiffer, so there was less vibration. and
a shorter mirror suffered fewer bumps and snags. And it doesn't obstruct
forward vision as much, if at all.

So I experimented over the years to get the length as short as possible
while still giving a clear view past my shoulder. I also moved from
square or round mirrors to rectangular ones, because horizontal field of
view is much more valuable than vertical field of view. And I changed
the construction method, using plastic mirror instead of glass, with no
metal backing. As I mentioned, these things now weigh only about 2 grams.

Maybe the only disadvantage is that if I happen to drop one of my
mirrors, it becomes almost invisible. I recall one stop at a grocery
store when I was parking my bike inside their big entryway. As I took
the mirror off, I dropped it. It took several minutes for me to spot it
lying there on their patterned flooring.


--
- Frank Krygowski

On 1/26/2019 9:42 PM, James wrote:
On 26/1/19 12:28 pm, Frank Krygowski wrote:
On 1/25/2019 2:44 PM, wrote:


The difference in average speed from these changes is only definable
in TT terms. If you don't notice your speed decreasing and the ride
is better why wouldn't you make the change?

The ride yesterday at the top of one of the climbs we started down
the other side. It always seems to me that people are afraid to go
fast because I can kick off and accelerate and then coast faster than
most of the can pedal. What other thing could it be aside from lower
rolling resistance. They all pass me going up hills.

Well, the ratio of weight to aerodynamic drag is a big answer to "what
else could it be." Those two factors are generally more important than
rolling resistance - not that rolling resistance doesn't matter.

Our club used to have a member whose nickname was "Downhill." He was
unbeatable at coasting. Nice guy. Waist size was about 50".

Notice, I'm not saying Tom is fat. I'm just explaining the main
factors in downhill speed.

In addition, I believe that downhill speed increases if the rider
suspends part of his weight on bent legs, instead of putting all his
weight on the saddle. Kinetic energy is lost by jostling the squishy
human body. With your body suspended, an upward jolt results in less
energy loss.


We used to have rolling races several times a week when I lived in
Melbourne.Â* Some guys had more aero wheels.Â* Some had tighter fitting
clothes.Â* The most important factor though, was how aero the position
you could maintain on the bike, and then how well you could judge a
slipstream and timing to accelerate behind someone and pass them before
the line.

Sitting on the top tube with your bum under the nose of the saddle, and
hands near the middle of the bars with elbows held low, etc., and head
down seemed best.

I think we were more aero than Sagan, but we couldn't get to the brakes
easily.

http://cycling.today/peter-sagans-de...w-study-finds/

I've used that article's "Pantani" position from time to time. I think
I'd be nervous about trying the "Sagan" position. And the "Froome" looks
even scarier - too reminiscent of coasting fast on a high wheeler or
"Ordinary" bike.

These days, I generally stay on the saddle and use the aero bar built
into the curved handlebar bag I built. The bag may even act as a partial
fairing. I coast at least as fast as anyone I ride with, so it's good
enough for me.

Then, of course, there's this:
https://www.youtube.com/watch?v=3Iz7ZMALaCY

I once had a friend who did that on his motorcycle. I _think_ he's still
alive...

--
- Frank Krygowski

On 1/27/2019 6:43 AM, Roger Merriman wrote:
...

... checking my times... Any differences are
marginal.

These days, that applies to almost every "improvement" regarding bicycling.


--
- Frank Krygowski