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Anyone should be able to get 0.25 without too much difficulty, as long as you've got an aero helmet/skinsuit etc.
I was stuck at 0.250m^2 for a while back in 2008, you really do have to keep plugging away at it and it'll reap dividends. I'm down to ~0.191m^2 now.
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What does this plugging away involve, specifically?
Genuine question.
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What does this plugging away involve, specifically?
Toblerones down his socks :-)
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0.27 was estimated from a TT using Aerolab. Cervelo P2, disc, PX 50mm, giro advantage, skinsuit, overshoes... Obvious inaccuracies include traffic (although it was a quiet race) and the fact speed was recorded via the GPS and not a wheel magnet. Hence my intention to do some proper field testing this year. If I can get down to 0.22 by September with a position I can sustain for an IM then I'll be overjoyed. :-)
Looking at photos I actually think that my position was worse in 2014 than in 2013 and previously. Previously I usually wore a pair of Oakleys for races, whereas photos seem to reveal that for most of 2014 I unintentionally wore my regular specs. Obviosly the Oakleys covered a wider area of my vision and I think that this means that I had to hold my head much higher in order to see through the lenses on my normal specs, as opposed to keeping my head down and peeping our of the very top of the oakleys. Will try to arrange a visor for next season and will make an effort to race without glasses since I can still see fine and I don't get on with contacts.
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Getting field testing done, mostly. If you can't/don't field test outside of races, then it makes it a bit more difficult as you have to use other riders as benchmarks, and they're often not consistent (both in power output and also aerodynamics if they're changing stuff too).
Of course I'm obliged to advertise the work I do (currently no open slots for testing though), but you can do it yourself. The simplest thing is just to ride on an out and back stretch of road 1km in length at either constant power or constant speed and see the effect on either power or speed through changes.
If you really want to get faster you find the time to do it - some years back I was going to Birmingham airport at 3am for testing because there was a quiet loop nearby, little wind at that time in the morning and the atmospheric data from the airport was really good.
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Visors are good for holding your head in a better position, for sure. That 0.270 might be a result of you setting the Crr too low, so could be closer to 0.250.
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Toblerones down his socks :-)
lol.
@fizzy.bleach At the most basic level it involves a power meter and field testing your aerodynamics using a program like aerolab in golden cheetah. At a more advanced level it either involves going to a wind tunnel or paying Xav to strap a weathervane to your bike.
I have this link bookmarked for home-spun aero testing.
EDIT: or what Xav said
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@xavierdisley possibly... I hadn't really given much thought to Crr and just used a 'typical' value I saw on TTF. For this year I was sort of working on the premise that consistency in the data was marginally more important than outright accuracy as my main goal will be to improve my position. I'm not really in a position where I can do detailed testing of different wheel combos etc.
This weekend I was planning on trying 3x 20 minutes using my TTbike with training wheels (with magnet) to get some updated baseline numbers. Runs 1 and 3 I was going to use my normal position and then use run 2 to try something different. My first thought was simply to ride run 2 sat up on the base bars in an attempt to see weather my testing protocol was sufficiently sensitive to detect a big difference, but maybe I'll just try keeping my head down more instead.
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Keep your head down for the second (obviously with aero helmet on for all of it). It's good to know whether tucking in makes you quicker and you don't have to wrench on the bike in between intervals to test it.
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Is that a Shimano CN-NX01 chain? Why don't Shimano make an actual track chain?
Chainring is an "interesting" choice too, Cycling Weakly says composite, @MagnusBackstedt says PEEK. Raw PEEK doesn't seem like it could be stiff enough for a chainring without being either about an inch thick or reinforced with some stiff fibres, so it could be both. My thinking on reducing drivetrain losses tends towards more stiffness and hardness than the standard aluminium, i.e. steel teeth, maybe with an aluminium or carbon fibre carrier to keep the weight down.
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Dunno what it's made of, but it's got more chainring bolts than is traditional.
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Hmsorry for newbie question but how do people calculate CDa?
Also @ Ewan - have you looked at my bike leg from wales? My ftp was about 220 at the time and plans were ruined by the brutality of the swim but it should give you an idea of what you need for a decent bike leg.... That said there always seems to be one horrific element of the course in wales!
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Dunno what it's made of, but it's got more chainring bolts than is traditional.
It's a chainline adapter, like the one Fibrelyte made for Cliff Voller, which you posted in the Fixed TT bikes thread
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Ya know I did wonder if it was something like that, but I thought the BCDs weren't different enough.
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You can build a chainline adapter without there being a difference between the PCD of the spider and that of the chainring, you just have to offset the holes by enough for the cutaways in the ring to clear the spider tabs.
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You've always been allowed to slope the top tube whichever way you want, the UCI ban on Lo-Pros related to different-sized wheels.
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Ed, look at this thread on TTF, plus there are a load of other threads too. Basically as Xav says, ride a short loop at a known power and then use the aero-lab feature in golden cheetah to estimate CdA. As I understand it the real important bits are a good bit of traffic free road with a good surface and a sensibly designed testing protocol.
Re. Wales, I did have a cheeky look and I'll reply in the Tri thread so as not to get too SLVLSS in here.
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About
The Hour Record
Posted by
@hippy
Indeed... unfortunately I'm not even close to being ~95kg #sadface:
A key objective for this season is to improve my aeros, and if the weather holds then I'll hopefully go out and try to gat some baseline data on Sunday morning.