Average power for 25 Mph

MarkAshton

I am interested to know what kind of power you guys need to hold 25 Mph (40 kph) on road bike setup?

I am assuming still conditions, average road surface and no aero clothing, helmets etc...

Its around the 330w mark for me on my current setup.

napoleond

Too many variables.

danowat

http://bikecalculator.com/index.html

willhub

330W on my current setup too.

I weigh 73kg and 5ft 10.

Can only do it for 10 miles tho.

paul2718

On the way in from yesterday's ride I happened to notice about 40kph at about 280W on a short level bit of the local bypass. Anyway I created a Strava Segment to see.

http://app.strava.com/segments/2224007

I'd hoped to flush out some more reliable power readings, but never mind.

Paul

bahzob

For me (70kg) on a road bike its around 325W. TT is 240W which just goes to show the difference a bike can make.

willhub

That's insane.

So say for example on a road bike if you did a 23:53, if you put out 325w on a full on TT bike what time do you do?

I do short 23's on a road frame, Shimano R550 wheel, Mavic Aksiums, but wear a skinsuit and do have proper TT bars on it, nothing else aero.

A guy I know on a proper fancy Specialized TT bike does 22:40s, but he's only needing to put out around 250w for that??

RoadMeridaBen

250 watts for 22:40 :O
My local course 300 watts at 63kg gets me a 22:48 on the TT bike lol
thats why its impossible to answer your question properly, all dependant on the course

Alex_Simmons/RST

One of my riders did 48.4km/h (30.1mph) for an hour solo at the track with an average of 300W.

RoadMeridaBen

Alex_Simmons/RST wrote:

One of my riders did 48.4km/h (30.1mph) for an hour solo at the track with an average of 300W.

How much does he weigh? I'd need to lose a stone to do that at my power :P

Alex_Simmons/RST

RoadMeridaBen wrote:

Alex_Simmons/RST wrote:

One of my riders did 48.4km/h (30.1mph) for an hour solo at the track with an average of 300W.

How much does he weigh? I'd need to lose a stone to do that at my power :P

It's not so much weight (~60kg) that matters, as aerodynamics. For that his CdA was circa 0.18m^2

Speed on flat terrain is all about power to aerodynamic drag ratio: power/CdA (W/m^2), and the relative wind vector.

furrag

I did 22:56 on a slower lumpy course (325ft climbing) on a road bike (skinsuit, 60mm deeps, + TT helmet) for 325w which is 26.1mph.

On the same course without aero gear, I did 24:13 for 318w (24.8mph). With the same set-up at Hillingdon (mainly flat with a little kick), I broke away and solo'd the last 20 minutes at 323w at 25mph.

Im 5'10" and was 71-72kg at the time, so ~4.51w/kg.

So:
Depends on your weight
Depends on your position (CdA)
Depends on your aero equipment
Depends on the weather & terrain

Not too many variables then.

I hate slippery bastards who record fantastic times for relatively little power. A CdA of 0.18 would be amazing to have!

SBezza

Furrag wrote:

I hate slippery bastards who record fantastic times for relatively little power. A CdA of 0.18 would be amazing to have!

With your height and weight, you should be able to get very slippery as well, it isn't as though you are built like a rigby player I suspect.

indjke

Furrag wrote:

On the same course without aero gear, I did 24:13 for 318w (24.8mph).

How do you think, could ~270W be realistic estimation for guy of the same height and a bit skinnier body (64 kg) for 24mph average? (Course with similar gain - about 500 ft for 18 miles, and no significant wind)

okgo

I'm 79/80kg and did 22.17 on the same course on the same day for only 5 watts more than Furrag and I didn't have a TT helmet, so he's obviously not as aero as he could be at his size (or my power meter is wrong).

amaferanga

24.5mph @ 324W on a road bike, 67kg, 5'9".

okgo

That seems slow for that power... Were you on a mountain bike?

JustBenonstrava

Watts demand rises with the square of the speed.

If you have power sensor(s), here's how to figure watts required for your TT attempt. Ride a fairly level out and back course. Start recording data. When finished, calculate this:
Avg watts ÷ avg speed ÷ avg speed.

Let's say your answer from this run is .44444
Take any speed, square it, multiply that by .44444 and it will take you (only you) that many watts to go that speed.

So with your kit, bike and weight you're looking at 178 watts to avg 20, and 278 to avg 25. It's incredibly accurate and incredibly specific. Go changing gear or weight and you'll need to retest.

imposter2.0

JustBenonstrava wrote:

If you have power sensor(s), here's how to figure watts required for your TT attempt. Ride a fairly level out and back course. Start recording data with a flying start. When finished, calculate this:
Avg nominal watts ÷ avg speed ÷ avg speed.

Let's say your answer from this run is .44444
Take any speed, square it, multiply that by .44444 and it will take you (only you) that many watts to go that speed.

So with your kit, bike and weight you're looking at 178 watts to avg 20, and 278 to avg 25. It's incredibly accurate and incredibly specific. Go changing gear or weight and you'll need to retest.

You know this thread is six years old..??

JustBenonstrava

You know how high it ranks on google after six years?

imposter2.0

JustBenonstrava wrote:

You know how high it ranks on google after six years?

How is that relevant to you digging up a six year old thread?

mamil314

Could necromancy be reclassified as Archaeology if the findings are, somewhat, interesting?

napoleond

Strava wasn’t even a thing back then!

joe2008

NapoleonD wrote:

Strava wasn’t even a thing back then!

Strava was fun back then

sloppyschleckonds

joe2008 wrote:

NapoleonD wrote:

Strava wasn’t even a thing back then!

Strava was fun back then

2011/12 were the bestest years on strava, only climbs and a couple of sprints were segments rather than every stretch of tarmac

haydenm

I used to have KOMs...

VamP

So you googled average power for 25mph, just to have a shot at answering someone's possible question on this subject? :-)

penski

JustBenonstrava said:

Watts demand rises with the square of the speed.


If you have power sensor(s), here's how to figure watts required for your TT attempt. Ride a fairly level out and back course. Start recording data. When finished, calculate this:

Avg watts ÷ avg speed ÷ avg speed.


Let's say your answer from this run is .44444

Take any speed, square it, multiply that by .44444 and it will take you (only you) that many watts to go that speed.


So with your kit, bike and weight you're looking at 178 watts to avg 20, and 278 to avg 25. It's incredibly accurate and incredibly specific. Go changing gear or weight and you'll need to retest.

Brilliant brilliant info, never come across this before.

mamil314 said:

Could necromancy be reclassified as Archaeology if the findings are, somewhat, interesting?

Haha! Should definitely be the case! We should be retaining, discussing knowledge that is useful/interesting.