Commuting Aerodynamics

iainmoss

I've just been reading about the new SRAM bar-end shifters designed for time trials etc. They claim to save 36 seconds on an Iron Man course just by returning to their original position. I have been informed that an Iron Man cycle course is 112 miles or thereabouts.

I'm not suggesting swapping my straight bars for some time-trial Superman affair but what about pointing my wheel's quick-release levers backwards? I ride 150 miles per week. I reckon I would save about 50 seconds.

I'm ignoring the other crap adorning my bike, such as air horn, dynamo, dynamo wires, saddle bag, mudguards, lights.......

What d'ya think?

Kieran_Burns

I think you should take emery cloth to your quick release levers and reshape them into small wings. This would increase lift on the bike so you would lose weight as you cycled more quickly.

It would save you....oooooo..... 30 minutes at least!

Gavin Gilbert

Your assumptions on time saved are strangely, almost correct.

Most testers don't use QR's and fit allen key skewers, and the consensus is it saves about 10 seconds on a 25..

If you want to get serious with the aggregation of small gains you'll need to trim your cable ends to a gnats whisker of their securing bolts, put electrical tape over your chainring bolts and mount your front brake on the frame side of the fork.....

always_tyred

Get 20c tyres and bladed spokes.

Wear a skinsuit and a pointy helmet.

Never ride on the hoods, only the drops.

Ride in the middle of the lane where there are better drafting opportunities and the tarmac is smoother.

Greg T

iainmoss wrote:

I'm ignoring the other crap adorning my bike, such as air horn, dynamo, dynamo wires, saddle bag, mudguards, lights.......

What d'ya think?

I'd think that you have got wolves closer to the sledge (do you like that?) than the direction of your QR levers......

always_tyred

Gavin Gilbert wrote:

the consensus is it saves about 10 seconds on a 25..

Mmm.

If you tell 100 tt-ers that you have put magic air in the tyres, about 75 of them will thank you at the end for saving them "10 seconds".

Indeed, as I recall, about 10 years or so ago, there was a myth that using helium made your bike lighter and so faster.

My conclusion is that if you took the brain out of most time triallists, they would all go quite a lot faster.

Gussio

Always Tyred wrote:

Indeed, as I recall, about 10 years or so ago, there was a myth that using helium made your bike lighter and so faster.

Helium molecules are teeny and tires might well be deflated halfway through a TT if inflated with said gas.

I'll get my coat.....

always_tyred

Gussio wrote:

Always Tyred wrote:

Indeed, as I recall, about 10 years or so ago, there was a myth that using helium made your bike lighter and so faster.

Helium molecules a teeny and tires might well be deflated halfway through a TT if inflated with said gas.

I'll get my coat.....

Indeed. Best to use hydrogen instead. Although autoignition can be slightly irritating in the event of a puncture.

ansbaradigeidfran

Erm, why is hydrogen going to be any better?

Helium (He2) has four protons, neutrons, and electrons, whereas Hydrogen (H2) has two protons and two electrons. Isn't that smaller?

iainmoss

Best to use Nitrogen- I'm already using it and is saves me 5 seconds on my daily commute. It may not be as light as helium or hydrogen but is inert and keeps my PSI nice and constant whatever the weather.

Some really nice suggestions above for time saving. What was all that about wolves? Over my head, for sure.

Keep those suggestions coming.
I'm going to ride home without tyres tonight to see if the lower rolling resistance of aluminium will be of benefit.

gtvlusso

Cover yourself in lard, you will slip through the air quicker and be able to slip through the tightest gaps in traffic with ease...

always_tyred

ansbaradigeidfran wrote:

Erm, why is hydrogen going to be any better?

Helium (He2) has four protons, neutrons, and electrons, whereas Hydrogen (H2) has two protons and two electrons. Isn't that smaller?

Two atoms vs. one atom.

He

H-H

Littigator

I'm going to saw one leg and one arm off before heading home to experiment hnot just with the weight savibng but also as to the effect had due to unbalanced aerodynamics.

After that I shall be taking up ATs suggestion of removing my brain!

ansbaradigeidfran

Move to Escherville, and make sure that there's a downhill route to work, and back home again!

cougie

Anyone remember the L shaped cranks - for greater leverage ?

ansbaradigeidfran

Always Tyred wrote:

ansbaradigeidfran wrote:

Erm, why is hydrogen going to be any better?

Helium (He2) has four protons, neutrons, and electrons, whereas Hydrogen (H2) has two protons and two electrons. Isn't that smaller?

Two atoms vs. one atom.

He

H-H

I yield to the poster with a chemically-oriented avatar!

always_tyred

ansbaradigeidfran wrote:

Always Tyred wrote:

ansbaradigeidfran wrote:

Erm, why is hydrogen going to be any better?

Helium (He2) has four protons, neutrons, and electrons, whereas Hydrogen (H2) has two protons and two electrons. Isn't that smaller?

Two atoms vs. one atom.

He

H-H

I yield to the poster with a chemically-oriented avatar!

Oh, the wasted years.

coffeecup

you could of course mount a couple of mini jet engines to the back like this guy:

http://www.coolest-gadgets.com/20060617 ... d-bicycle/

ansbaradigeidfran

Drafting strictly forbidden!

Tailend Charlie

cougie wrote:

Anyone remember the L shaped cranks - for greater leverage ?

or bio-pace oval chainset??

cougie

I had one of those ! (only cos that was what was on the bike when I bought it cheap)

Didnt notice any difference.

unclemalc

gtvlusso wrote:

Cover yourself in lard, you will slip through the air quicker and be able to slip through the tightest gaps in traffic with ease...

Mmmm...lard. Works for me....

http://www.ratemyeverything.net/image/8 ... _LARD.ashx

2tired2ride

gtvlusso wrote:

Cover yourself in lard, you will slip through the air quicker and be able to slip through the tightest gaps in traffic with ease...

You could just pedal faster?

gtvlusso

The most aerodynamically in-efficient part of a bike is the human pedalling it - get rid of that and it will go like stink......oh, hang on...

woodyonthebeach

if you are going down to the root of different gas. Try nitrogen the gas its self is less suseptable to air tempreture and i believe is lighter again than helium. This it may have been talked about already

biondino

I don't think nitrogen is lighter than helium...

neiltb

i know n2 isn't lighter than helium.

I have been cycling home into a nasty cold north wind this week, uphill too (well as much of a hill that we have here in toronto), have been tucked as low and as narrow as i can get and it's still murder. Wearing jeans, riding mtb with fenders seems as aerodynamic as a wardrobe.
Getting to work has been a joy though.

woodyonthebeach

hydrogen is the lightest gas. But as you all should know it is ever so slightly explosive.

You could fill your tyres up with it. Wouldn't recommend it as you could have a little bit of an issue it you were ever to be close to a naked flame that would burn through your tyre.

ansbaradigeidfran

neiltb wrote:

I have been cycling home into a nasty cold north wind this week, uphill too (well as much of a hill that we have here in toronto)

Hills? Toronto? :shock:
Where did you find a hill? Richomnd Hill perhaps, or is it a river valley?