Does the sun make bikes go faster?

[Steve H]

I snuck out of work a bit early yesterday and got to ride home in glorious sunshine. Normally I've been cycling in the morning or evening before and after the sun is up or at weekends over the winter with cloudy skys.

Not sure whether it is purely psychological in me or whether it is the bike that is inspired by the sun, but the roads seemed smoother and my bike felt faster in the sunshine!

Anyone else experience this strange phenomenon?

 

[tradesecrets]

Well it's common for the heat of the sun to slighty melt the suface of roads again it depends on the Surface ..and it's easy to find tar used on roads becoming plyable .. especially if used to seal filled Holes by rds dept


but temps would have to exceed above normal


Air becomes thinner stagnated .. as well depending on location

 

[Sleeping Menace]

sun warmed the road.. also slightly warmed your tyres, increasing the pressure slightly, giving you a bit less rolling resistance..

and/or *more likely* .. it just felt bloody good to ride in the sun

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[Keith Oates]

I think that the warmer weather just makes your body feel and function better hence the ride seems easier and the speed increases accordingly. It's nice when it happens and you then return home with a large grin on the face!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Chrisz]

Warm air rises - so the air trapped in your tyres and the tubes of your frame becomes less dense in sunlight, tries to rise and thus makes your bike lighter - fact!

Added to that, everyone knows that sunglasses, as well as making you look cool, actually mean you drive/ride faster (just ask any BMW/Audi driver).

 

[potsy]

It's the solar powered electric motor he has that's doing it

It has been lovely riding into work last couple of days with the sun shining.

 

[Steve H]

It's the solar powered electric motor he has that's doing it

Curses - I'm rumbled

 

[youngoldbloke]

On the contrary I always find the bike feels freer, looser, more easy running in heavy rain. I put it down to the lubricating effect of all the moisture, and the reduction in friction.

 

[palinurus]

Yes it does.

Cold, dark: Feels slow, is slow
Cold, sunny: Feels slow, is a bit quicker
Warm, sunny: Feels faster, is faster
Warm, Dark: Feels really fast, is the same as warm, sunny

 

[mickle]

Warm air is less dense than cold air so there will be a reduction in aerodynamic drag.

Warm tyres are more plyable than cold tyres so there will be a reduction in rolling resistance.

Warm grease and lube has lower viscosity than cold so there will be a reduction in mechanical drag.

Warm weather clothing is less bulky than cold weather clothing and so will present a lower frontal area - reducing wind resistance.

The human body gets up to operating temperature faster in warmer weather.

 

[rattus]

I don,t know about the technical side of things but there,s nothing like getting out on a warm sunny early morning with just your short sleeved jersey and shorts on , a pair of shades and plenty of water to keep you going listening to the birds while you wind your way around quiet country lanes it just makes you feel better.Don,t get me wrong i cycle all year round but there,s nothing like the sun on your back, the summer can,t come quick enough for me.

 

[Globalti]

Don't want to make you jealous but I'm typing this from my hotel room in Johannesburg where I am on business. The bike is in its case at the end of my bed, tomorrow I shall assemble and test it and at 06:00 on Saturday I'll nip up the road to Cycle Lab and join one of their early Saturday morning road gangs, early to beat the heat and the traffic.

Temperatures are about 30 C during the day but the air is fresh thanks to the altitude, last time I rode here I had a feeling that the thinner air was helping me ride faster so I will let you know how it goes on Saturday.

Next Sunday 13th I'm in the Cape Argus, a 110km ride around The Cape with 35,000 riders. Did it last year and loved it.

 

[mickle]

Don't want to make you jealous but I'm typing this from my hotel room in Johannesburg where I am on business. The bike is in its case at the end of my bed, tomorrow I shall assemble and test it and at 06:00 on Saturday I'll nip up the road to Cycle Lab and join one of their early Saturday morning road gangs, early to beat the heat and the traffic.

Temperatures are about 30 C during the day but the air is fresh thanks to the altitude, last time I rode here I had a feeling that the thinner air was helping me ride faster so I will let you know how it goes on Saturday.

Next Sunday 13th I'm in the Cape Argus, a 110km ride around The Cape with 35,000 riders. Did it last year and loved it.

I think I speak for all of us when I say we hate you.

 

[Cardiac]

Warm air rises - so the air trapped in your tyres and the tubes of your frame becomes less dense in sunlight, tries to rise and thus makes your bike lighter - fact!

Sorry - science fail...

The mass of the air in the tyre remains the same (unless you have a puncture), and the volume remains the same (constrained by the tyre). So warming the air will not make the wheels lighter, but it will slightly increase the pressure. This may act to slightly lower the rolling resistance.

The air in the frame is generally open to the outside air anyway (via the seat tube, etc) and so does not contribute to the meaurable weight of the bike.

 

[Sheffield_Tiger]

it's not the bike, it's the leg muscles. I dismantled the bottom bracket and serviced it before I realised the clicks and creaks were coming from my legs in the winter