Poor Penetration

BridlingtonBiker

I've only been road biking for about 3 months. Two of which I wasn't due to snow. I went out with my local cycling club on Sunday as usual. It was a really windy day and when heading into wind no matter how hard i tried I just couldn't keep up as the wind seemed to stop me dead.

I think this may be due to my weight (sub 60kg) and the other chaps are just heavier so the wind has less of an effect due to their inertia. The bonus seemed to be going downwind I could almost drop them with ease even though they are much fitter than I am.

Anyone else notice this or have an alternative theory?

Schobiedoo

You already said it in your post.

"they are much fitter than I am"

They will have better leg strength and technique than you if you've only been road biking for a month.

floosy

Im now sub 54kgs and it was windy (15 +mph) on the club run yesterday...and i took my turn on the front just like everyone else...
but ive now got a years worth of power in the legs from specific training at the gym.

keep at it.... you will get there...

pilot_pete

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

dodgy

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

He said downwind, not downhill 8)

thecrofter

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

desweller

thecrofter wrote:

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

No he wouldn't.

bianchimoon

DesWeller wrote:

thecrofter wrote:

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

No he wouldn't.

+1 the mass of a heavier rider will make him descend quicker

BridlingtonBiker

I best get a lot more miles in these legs of mine then. Do you think it's unrealistic for me to aim to do 100 miles by the end of summer. I've currently done a 45 mile ride but it near killed me

bianchimoon

BridlingtonBiker wrote:

I best get a lot more miles in these legs of mine then. Do you think it's unrealistic for me to aim to do 100 miles by the end of summer. I've currently done a 45 mile ride but it near killed me

Nah, you should have no problem keep training, choose the right day and the right route, along with company you enjoy, plan your cafe stops, it'll fly by

markos1963

bianchimoon wrote:

DesWeller wrote:

thecrofter wrote:

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

No he wouldn't.

+1 the mass of a heavier rider will make him descend quicker

I suggest you all look up Newton
Btw unless you have discovered a new human subspecies all humans have the same mass.

desweller

markos1963 wrote:

bianchimoon wrote:

DesWeller wrote:

thecrofter wrote:

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

No he wouldn't.

+1 the mass of a heavier rider will make him descend quicker

I suggest you all look up Newton
Btw unless you have discovered a new human subspecies all humans have the same mass.

All....humans....have...the...same...mass? Eh?

I'm afraid you're going to have to explain that unconventional statement.

Bobbinogs

I have a slightly different mass to that of Adam Raynor, and now it will be posted on tinternet so it must be true.

bianchimoon

markos1963 wrote:

bianchimoon wrote:

DesWeller wrote:

thecrofter wrote:

Pilot Pete wrote:

Anyone else notice this or have an alternative theory?

Surely if they are heavier they would overtake you going downhill, unless they weren't peddling and you were!

PP

Gallileo would disagree with you

No he wouldn't.

+1 the mass of a heavier rider will make him descend quicker

I suggest you all look up Newton
Btw unless you have discovered a new human subspecies all humans have the same mass.

Not quiet sure how you're defining mass, But body weight in the context of biological and medical science is used to describe the body's mass, hence we all have different BMI's (Body MASS index) my mass is not the same as a 60kg person. Hence on a downhill slope all things being equal except weight/mass in a freewheel (passive) descent a heavier rider will reach terminal velocity quicker than a lighter rider.

bianchimoon

All....humans....have...the...same...mass? Eh?

I'm afraid you're going to have to explain that unconventional statement.[/quote] + 1 to that

meanredspider

Very simply Force = Mass x Acceleration

Force on the bike = Mass (rider+bike) x 9.8m/s2 (acceleration due to gravity)

The steeper the hill the more this force acts to pull the rider+bike down the hill. The heavier the rider, the higher the force.

badly_dubbed

BridlingtonBiker wrote:

I've only been road biking for about 3 months. Two of which I wasn't due to snow

this is your problem. pure and simple.

the more you do something....the better you get

waynej

OK let's get this straight. Heavier things do not fall faster (accelerate quicker) than lighter things. This was proven by Galileo and Newton in the 17th century.

A heavier thing will have more energy not more speed.

The work of Hungarian nobleman Baron Roland Eotvos proved this. It's due to the difference in inertias between the 2 objects.

If 2 items of the same dimensions but different materials (eg one lead, one wood) are dropped from the same height they will accelerate at the same rate and have the same velocity at the end. They will however impact with different energies (heavy thing hit harder).

Cheers.

meanredspider

waynej wrote:

OK let's get this straight. Heavier things do not fall faster (accelerate quicker) than lighter things. This was proven by Galileo and Newton in the 17th century.

A heavier thing will have more energy not more speed.

The work of Hungarian nobleman Baron Roland Eotvos proved this. It's due to the difference in inertias between the 2 objects.

If 2 items of the same dimensions but different materials (eg one lead, one wood) are dropped from the same height they will accelerate at the same rate and have the same velocity at the end. They will however impact with different energies (heavy thing hit harder).

Cheers.

Try that experiment with a sheet of expanded polystyrene and a sheet (same shape and size) of lead. The missing piece is the air. In a vacuum they will fall at the same rate but introduce air and the "weight" of the object (mass x g) becomes important in the balance of forces.

markos1963

bianchimoon wrote:

All....humans....have...the...same...mass? Eh?

I'm afraid you're going to have to explain that unconventional statement.

+ 1 to that[/quote]

Don't confuse weight with mass, 99% have the same mass(density) because we are mostly made up from water(70% approx)

meanredspider

markos1963 wrote:

bianchimoon wrote:

All....humans....have...the...same...mass? Eh?

I'm afraid you're going to have to explain that unconventional statement

Don't confuse weight with mass, 99% have the same mass(density) because we are mostly made up from water(70% approx)

I think you're confused. To all intents and purposes, mass and weight are the same on the scales (the difference is that weight = mass x acc due to gravity (an effective constant)). Density is something else again - that's mass per unit volume - which will be broadly similar but that leads to the point that, if I'm twice the volume of you, I'll have twice the mass (and twice the weight too) - assuming we have the same density.

balthazar

markos1963 wrote:

bianchimoon wrote:

All....humans....have...the...same...mass? Eh?

I'm afraid you're going to have to explain that unconventional statement.

+ 1 to that

Don't confuse weight with mass, 99% have the same mass(density) because we are mostly made up from water(70% approx)[/quote]

I think you're confusing mass with specific weight. People have different masses because they're different sizes, despite all having the same specific weight (density). Big ones fall faster, as explained by others. Newton isolated air drag from the problem and exposed important proofs about gravity. Galileo wasn't involved that I can think, unless it's a different Galileo of course. The lesser-known one.

orbeaorca

Someones post has turned into a physics lesson :?

meanredspider

orbeaorca wrote:

Someones post has turned into a physics lesson :?

I think it was necessary. Some folk need some physics refreshers.

balthazar

orbeaorca wrote:

Someones post has turned into a physics lesson :?

The question was answered perfectly in the first reply. The discussion then just drifted off, as they do: nothing wrong with that.

bexley5200

whos eat all the jaffa cakes

P_Tucker

waynej wrote:

OK let's get this straight. Heavier things do not fall faster (accelerate quicker) than lighter things. This was proven by Galileo and Newton in the 17th century.

A heavier thing will have more energy not more speed.

The work of Hungarian nobleman Baron Roland Eotvos proved this. It's due to the difference in inertias between the 2 objects.

If 2 items of the same dimensions but different materials (eg one lead, one wood) are dropped from the same height they will accelerate at the same rate and have the same velocity at the end. They will however impact with different energies (heavy thing hit harder).

Cheers.

Utterly wrong. For an eye-opening demonstration of how air resistance affects velocity, jump out of a plane with a parachute, and deploy it. Record the speed you hit the ground. Now do it again, but don't open your parachute.

waynej

At no point did I mention air resistance. If you look at the post you will see the following:

"... 2 items of the same dimensions but different materials..." eg a 6" ball of wood and a 6" ball of lead.

If we neglect the effect of air, mass is unimportant - the acceleration is the same.

Old experiment (we did this at school):

Take a vacuum tube, a penny and a feather.

Put penny and feather in tube.

Invert tube.

Penny falls faster than feather.

Evacuate tube and re-invert.

They fall at the same rate.

Air is important if the shape, material finish, etc are different not if they are the same. When the shapes, etc are the same or air is removed the accelerations of the items are the same.

neeb

This is one of these subjects that a lot of people get confused about (because of partial explanations and because it's slightly counter-intuitive), but it's actually quite simple:

- The force of gravity is what makes objects accelerate when they are falling / going down hill.

- Gravity is proportional to mass, so heavier objects will have a greater force of gravity operating on them.

- However (this is the important point), heavier objects also NEED a greater force acting on them to make them accelerate - Force = mass x acceleration. What this means is that if there was no air resistance, all objects would accelerate at the same rate. The mass of heavier objects means they need more force to accelerate, but that same mass also gives them this extra force. So heavier objects fall at the same rate, but they have more energy, and thus it requires more energy to slow them down again.

- In an atmosphere, air-resistance is the main decelerative force on a falling object. But the air resistance of a heavy object is often not much different from the air-resistance of a light object (as objects get bigger, the surface area goes up by the power of 2 while the volume goes up by the power of 3). So the force of air resistance will tend to slow down lighter objects more (F= m a again). So heaver cyclists will end up going faster downhill, all other things being equal.

bianchimoon

neeb wrote:

This is one of these subjects that a lot of people get confused about (because of partial explanations and because it's slightly counter-intuitive), but it's actually quite simple:

- The force of gravity is what makes objects accelerate when they are falling / going down hill.

- Gravity is proportional to mass, so heavier objects will have a greater force of gravity operating on them.

- However (this is the important point), heavier objects also NEED a greater force acting on them to make them accelerate - Force = mass x acceleration. What this means is that if there was no air resistance, all objects would accelerate at the same rate. The mass of heavier objects means they need more force to accelerate, but that same mass also gives them this extra force. So heavier objects fall at the same rate, but they have more energy, and thus it requires more energy to slow them down again.

- In an atmosphere, air-resistance is the main decelerative force on a falling object. But the air resistance of a heavy object is often not much different from the air-resistance of a light object (as objects get bigger, the surface area goes up by the power of 2 while the volume goes up by the power of 3). So the force of air resistance will tend to slow down lighter objects more (F= m a again). So heaver cyclists will end up going faster downhill, all other things being equal.

thanks for common sense and reason, well articulated meanredspider and neeb

waynej

Basically, when we neglect outside influences, the accelerations are the same.

When we include the outside influences and look at items such as bearing friction, air resistance, rolling resistance, etc the system is more complicated. The energy available to overcome these items will be greater with the heavier rider as the kinetic energy they have at any given time is greater.

So yes, a heavier rider may end up being quicker due to having more energy to overcome the outside influences but, and this is where I was coming from initially, the general case is that acceleration due to gravity (when all other factors are omitted) is the same for all bodies irrespective of mass.