why are some roads faster regardless of topography??

wyadvd

the max speed of my 15 mile commute is normally a sprint up a hill to some lights (31mph) however there is one stretch where i cannot bring myself to go more than 16mph whatever i do! And its flat as a pancake! some flat stretches i easily cruiiise at 21mph.

Does anyone else recognise this phenomenon? or is it just me?.....either way why?

Chunkers1980

It's you. What a load of rubbish.

jim453

Chunkers1980 wrote:

It's you. What a load of rubbish.

Bit harsh.

Does sound a bit odd though.

Quicksand?

rick_chasey

Heavy roads.

wyadvd

well ive got to say, thats what it feels like...heavy road!

Maybe you get an optical illusion where a shretch looks flat but its actually uphill!

dodgy

Have you analysed the road on a mapping site? Perhaps it has a slight incline, it only takes a tiny inclination to make it seem slower.

rick_chasey

No heavy roads is a proper term.

It's the actual road surface.

For example - the UK has much slower roads than Italy. They provide more resistance.

The pyrenees back in the '70s used to be the same vs the alpes.

Ben6899

False flat?

"Positive" road surfaces?

jacob2910

had the road been freshly tarmaced

wyadvd

yes my alternative route is straight along a dual carriageway , exactly 10 miles i do it in 28 mins fairly easy...nice flat tarmac. i shall look anew at the quality of the tarmac on the slow sectionsof my longer route....

pbamf

To see if its a false flat just go in the opposite direction and see if you are faster on that stretch. Its that simple really

wyadvd

also reminds me of the real reasons why i hate cycling 'facilities' facilititate my ar$e!

antfly

Road surface definitely makes a difference and If you are on a dual carriageway you will also be getting sucked along by the passing traffic.

Pross

Rolling resistance of the surface combined with the fact that no road is as flat as a pancake. A long straight section of seemingly flat road will probably have a gradient of around 1% as a minimum for drainage reasons. Also, is the section of road more exposed so you could be riding with a barely noticeable cross / head wind? 31mph uphill sprint is impressive though :shock:

secretsqizz

wyadvd wrote:

yes my alternative route is straight along a dual carriageway , exactly 10 miles i do it in 28 mins fairly easy :shock: ...nice flat tarmac. i shall look anew at the quality of the tarmac on the slow sectionsof my longer route....

aye, I'm smoking a pipe at that pace as well as scratching my toes thru my sandles

wyadvd

ill post my endomondo workout next time i do it if you like.....

wyadvd

re : the hill up to lights, suspect adrenaline plays a part there , just want to go faster than the whiite van behind me would want to go. take it down a cog and crank the cadence to 150

wyadvd

trouble is if the lights go green im sh@gged...... Its more uphill after the lights. gets jeers from the van dohhhh

danowat

Do you race/TT wyadvd? if not, you should

wyadvd

been a 6 day a week 10/15 mile each way commuter on a sabbath september tiagra for the last 18 months. just push myself and interval train most day. never joined a club or competed. 44 yoa

wyadvd

danowat, are you on endo?

jonmack

I find the road between Keynsham and Bath to be really "slow", even on the declines feels like I should be able to push 35k but I find it hard to push 30... maybe I'm just a big pussy.

wyadvd

man after my own heart lol......

danowat

No, whats "endo"?, I use Garmin for my stats

wyadvd

endomondo, free download for any gps enabled phone. does most of what garmin does

ColinJ

I remember Robert Millar saying one year that the organisers of the Leeds Classic were "Taking the p*ss" with the severity of the route. It wasn't just the distance and the endless Yorkshire hills, it was also the 'heavy roads' which sapped the riders' strength. I think only about 20% of the peloton actually finished the race.

There's a lot more rolling resistance on a road surface coated with stone chippings than there is on smooth tarmac. It's very noticeable if you are riding on a stretch of 'heavy road' and then suddenly encounter a stretch of smooth tarmac, after road works, for example.

jim453

Pross wrote:

Rolling resistance of the surface combined with the fact that no road is as flat as a pancake. A long straight section of seemingly flat road will probably have a gradient of around 1% as a minimum for drainage reasons. Also, is the section of road more exposed so you could be riding with a barely noticeable cross / head wind? 31mph uphill sprint is impressive though :shock:

In which direction?

wyadvd

these slow stretches are on the commute ive done every day for the last 18 months. and sometimes it seems like the downhill direction is the slowest. but obviosuly if its only one way then its either a prevailing wind thing or its a slope (duh)

wyadvd

this is part of the route, and this mornings ride. I had a 4 minute fiddle with my helmet and a drink at the end which is included in the time and skewed the average speed im afraid (sorry about that):

http://www.endomondo.com/workouts/iP30fG4rahE

Buckled_Rims

It's the same phenomena that I see on hills and mountains, you sometimes cannot judge what is the highest point. I don't know the technical terms. But, without an instrument called an abney level to judge if you are standing higher or lower then what you are seeing.

Imagine 2 cairns on top of a mountain 50 metres apart, for a basic example. Sometimes no matter what cairn you stand at the other looks higher despite the fact one is 5 metres higher then the other.

This problem also happens on roads. See this road in Scotland for more explanation better then mine.

http://en.wikipedia.org/wiki/Electric_Brae

wyadvd

now THAT is interesting.....thanks for that. had a book called "phenomena" as a teenager full of strange stories of spontaneous human combustion and the like and i am sure this was mentioned somewhere........ next to the chapter on actual raining of live cats and dogs......