Author Topic: Wattage Required to do 40k for one hour.  (Read 5366 times)

Re: Wattage Required to do 40k for one hour.
« Reply #25 on: January 29, 2018, 10:01:16 pm »
and which way was the wind blowing, and how strong was it?

3kph and from the North according to my Garmin Connect activity (which was probably what the weather was at the start of the activity). The first 40km were due East for about 7km (quite sheltered), then S/SES for the remainder.

I can't remember any noticeable wind during any of it.
"Yes please" said Squirrel "biscuits are our favourite things."

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Wattage Required to do 40k for one hour.
« Reply #26 on: January 29, 2018, 10:35:50 pm »
My last two 25 mile TTs were 233W for 57:06 and 234W for 57:04.  Both were last spring, neither were ideal weather wind-wise, both were on a TT bike with full pointy hat get-up and both were on the A168/A19 north of Topcliffe.

Re: Wattage Required to do 40k for one hour.
« Reply #27 on: January 31, 2018, 08:15:55 pm »
That's very similar to my last 25, 230w for 57:28.
I would have guessed that you would have put out more power than that!

Re: Wattage Required to do 40k for one hour.
« Reply #28 on: January 31, 2018, 09:34:48 pm »
Interesting.   Did a long 53 last year but it was a fast day on the E2.

At some point I’ll find out what my power numbers are.

LMT

Re: Wattage Required to do 40k for one hour.
« Reply #29 on: February 03, 2018, 10:10:56 pm »
Depends on the bike, for me on my recumbent it's a little under 200 watts - Z2. ;D

Having just checked a ride, pre LEL training I done a 80.52km ride with 541m of elevation in 2:17.31. AP was 180w and NP was 193w.

Re: Wattage Required to do 40k for one hour.
« Reply #30 on: February 04, 2018, 10:06:02 am »
These all sound like very low figures, which surprises me because I'd have thought watt-measuring components would be calibrated on the generous side.  However, you can get artificially low figures depending on the way it's done, e.g. a hub will give lower power measurements because of drivetrain losses, and the meters that only measure from the left crank will give spuriously low results if you're very right-legged.  Personally, at my age, I just don't want to know.  If I can get up hills with the first few in the group, that's fine by me  :)
Never tell me the odds.

Re: Wattage Required to do 40k for one hour.
« Reply #31 on: February 04, 2018, 02:30:24 pm »
I’ve seen the 250w estimate a few times on the TT forum so it sounds about right.

Aero tech has moved on so much that there’s riders cracking the hour at much lower wattages.  I also don’t measure my power on the bike and I haven’t done a ramp test for a few years.   I know I was faster last year and that’s all that really bothers me.

LEE

  • "Shut Up Jens" - Legs.
Re: Wattage Required to do 40k for one hour.
« Reply #32 on: February 04, 2018, 07:48:10 pm »
I'd guess at 250-280 Watts, if you are aero.

My FTP is about 280.  I never rode a TT bike but I know it would most likely reduce my ability to produce 280W.

I can do 30k in an hour on a "normal" bike.  I have no idea what difference to my speed a full aero setup would make.  I don't want to try because I would seem forever slow afterwards.
Some people say I'm self-obsessed but that's enough about them.

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Wattage Required to do 40k for one hour.
« Reply #33 on: February 04, 2018, 08:14:05 pm »
FYI my figures come from a spider-based unit.

simonp

  • Omnomnomnipotent.
Re: Wattage Required to do 40k for one hour.
« Reply #34 on: February 04, 2018, 08:25:57 pm »
That sounds cruel.

IanDG

  • The p*** artist formerly known as 'Windy'
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Re: Wattage Required to do 40k for one hour.
« Reply #35 on: February 05, 2018, 07:15:48 am »
Just 'did it' back in the day no idea what wattage. But then I'm an old fart! It's great how the science of sport has developed. Something I was very interested in back in the 70s/80s ;)

Re: Wattage Required to do 40k for one hour.
« Reply #36 on: February 05, 2018, 02:07:04 pm »
This topic made me think about the Watts I can produce (FTP 222 at the moment, but going up) and how fast it will get me.
For those who are/have been actively time trialling - how did you go about "getting aero"? I want to try TTing this year (only 10s and maybe a 25 if it goes well), but I'll be restricted to riding my road bike https://www.cube.eu/uk/2017/road-triathlon/attain/cube-attain-gtc-pro-disc-greynflashgreen-2017/. Is it worth getting some cheapass aero bars, or just focusing on riding in the drops (or aero laid out on the hoods) - how much difference will it make?

LittleWheelsandBig

  • Whimsy Rider
Re: Wattage Required to do 40k for one hour.
« Reply #37 on: February 05, 2018, 02:20:12 pm »
Aerobars are worth getting. I stopped racing seriously nearly a quarter century ago but when aerobars came in, they were noticeably quicker than when on the drops (with all other equipment the same).
Wheel meet again, don't know where, don't know when...

sib

Re: Wattage Required to do 40k for one hour.
« Reply #38 on: February 05, 2018, 02:26:21 pm »
Aero bars definitely worth it - also skinsuit and aero helmet if you want maximum advantage.
As to how to find the best position either pay for it e.g. aerocoach or use your powermeter to do some diy testing.

Re: Wattage Required to do 40k for one hour.
« Reply #39 on: February 05, 2018, 02:42:01 pm »
I don't think it's worth paying to find my "best position" on what is a flawed TT bike (seat angle laid back, long head tube, disc brakes). I don't have a budget for a TT bike though (not even a cheap secondhand one).

sib

Re: Wattage Required to do 40k for one hour.
« Reply #40 on: February 05, 2018, 02:44:23 pm »
I don't think it's worth paying to find my "best position" on what is a flawed TT bike (seat angle laid back, long head tube, disc brakes). I don't have a budget for a TT bike though (not even a cheap secondhand one).

Do you have a power meter or is your wattage derived from the turbo ?

LittleWheelsandBig

  • Whimsy Rider
Re: Wattage Required to do 40k for one hour.
« Reply #41 on: February 05, 2018, 02:46:12 pm »
Do roll-down tests. If you ensure no wind, constant temperature and consistent road surfaces, they are quite repeatable.
Wheel meet again, don't know where, don't know when...

Re: Wattage Required to do 40k for one hour.
« Reply #42 on: February 05, 2018, 03:10:11 pm »
I don't think it's worth paying to find my "best position" on what is a flawed TT bike (seat angle laid back, long head tube, disc brakes). I don't have a budget for a TT bike though (not even a cheap secondhand one).

Do you have a power meter or is your wattage derived from the turbo ?
I have P1 pedals. I guess for aero tests I would need to find a flat bit of road where I ride at a given wattage for a mile or something and see what the speed is. And then repeat and repeat. Rolldowns would be an alternative if I can find the right sort of hill...

sib

Re: Wattage Required to do 40k for one hour.
« Reply #43 on: February 05, 2018, 03:14:56 pm »
Yes. Those are the simplest ways to test although you have to be wary of the impact of wind or traffic.

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #44 on: February 05, 2018, 04:51:56 pm »
I have P1 pedals. I guess for aero tests I would need to find a flat bit of road where I ride at a given wattage for a mile or something and see what the speed is. And then repeat and repeat. Rolldowns would be an alternative if I can find the right sort of hill...

You could do a lot better than that with Robert Chung’s virtual-elevation method, described here (PDF). Tiny differences in drag can be reliably detected with this imaginative technique. And since many cyclists and coaches use it, there are plenty of helpful descriptions of the process online. I think some training software packages automate many of the steps.

zigzag

  • unfuckwithable
Re: Wattage Required to do 40k for one hour.
« Reply #45 on: February 05, 2018, 04:53:41 pm »
few simple modifications (inline seatpost with the saddle in forward position, -17deg stem with no spacers underneath and clip-on tribars) can make a road bike reasonably faster. going further - aero kit and wheels, although it gets more expensive, and if tt's get you hooked i'm certain you'll be able to justify a dedicated tt bike.

when i entered my only tt (the 24hr one) i thought i'd need a suitable bike for the task (got it second hand, but pristine), it was a rushed purchase and served me well so far. i took it out on several other rides, but i use it mainly for training indoors now.

Re: Wattage Required to do 40k for one hour.
« Reply #46 on: February 05, 2018, 05:01:54 pm »
That pdf is ace, thanks Sam D. As an ex aerodynamics student it's right up my street. :)
I'll have to get some aerobars and see what that does to my position. Stem and seatpost (maybe I can just spin this around) are attainable within budget too, if necessary, but I'll try one step at a time.  :)
Thanks everyone, and sorry for the thread hijack!

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Wattage Required to do 40k for one hour.
« Reply #47 on: February 05, 2018, 05:09:09 pm »
Good general rules of thumb
- Tribars, skinsuit and aero helmet are all good investments. 
- For the helmet, get a proper one, not one of these 'aero road helmets' - they're no better than a backwards cycling cap and for the likelihood you'll actually fall off in a TT, you might as well go bareheaded.  The Bell Javelin and Giro Selector can be picked up pretty cheap these days, but are good solid all-round bets. 
- Set the tribars up so your hands are basically touching in the middle. 
-If you're worried about the length of the headtube, get tribars that place the bars under or in front of the handlebars rather than on top, so the arm pads can lie directly on the bars. These Ritchey ones would do the job, as would some similar ones made by 3T or the low mount ones made by Zipp. 
- To get your bars even lower, fit a steeper stem.  Planet X tend too be a good source of these. 
- Ride around in your TT position a lot to adapt yourself to it.  If you set up a super-aggressive position straight away and race in nit without practice, you'll be down on power.   
- Don't worry about your laid back position.  Massively forward tri positions have gone out of favour in the TT world: the thinking these days is that getting your saddle low is really important aerodynamically, and pushing it back will allow you to do that without losing too much power - you'll have to adapt to the tighter hip angle but to an extent that's trainable.  Also, excessively high and forward saddles are bad for bike handling. 

Testing
Since you've got a power meter, a Chung test is the best way to estimate your drag coefficient.  Basically you ride round in circles, the algorithm shunts all the unknown variables into 'virtual elevation' and then you alter your CdA until VE = Zero.  There's free software available that allows you to do this: see Golden Cheetah.

Ideally you want somewhere with zero wind and traffic, and a constant surface so your rolling resistance stays the same - i.e. a velodrome.  Outside, it can be quite hard to control those so you won't be able to fine tune, only to get a rough idea, but the circular nature of the course means that you can gauge the accuracy of the test by how well all the VE values line up at the end of each lap.

The quick way to do this is to pay someone to do this for you in a velodrome, but if you don't have a TT bike yet, don't spend £500 on doing that, put it towards any of the things above which are all low hanging fruit.

[SD beat me to it on the Chung testing link]

Re: Wattage Required to do 40k for one hour.
« Reply #48 on: February 07, 2018, 06:08:36 pm »
You could do a lot better than that with Robert Chung’s virtual-elevation method, described here (PDF).

Oh, I've met him! (Wasn't anything to do with cycling; related to boyfriend's work...)

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #49 on: February 07, 2018, 08:53:24 pm »
You sure it wasn’t another Robert Chung? If so, what does he do for a living?