Monday, December 28, 2009

Long time between drinks

After a rather long enforced layoff after the last ITU worlds, today marks the start of training for this season. Yeah, kinda late, but better than never.

Been swimming a lot, but only running and riding infrequently. CTL 43.

It's time because Triathlon Australia, in their infinite wisdom (did you get the sarcasm there?) scrapped the Challenge Series, and moved all the National championship races from Mar 20, to OD in Canberra Jan 24, and Sprint Mar 20 to Feb 21. So instead of 90 days I now have 27 days to train for the OD champs and 55 for the Sprint champs. Nice one TA.

Might have to blow off the OD champs and concentrate on Sprint. Turns out after having chased this race all over the country for the last 10 years (Southport Qld, Forster NSW, Huskisson NSW), it's in my own backyard in Sandringham, Vic, on my local 2x20 course. So close I'd have to ride somewhere else first to get a decent warmup.

Saturday, December 12, 2009

Carbon Hydration system

Following up on the value of wind tunnel testing ... this little puppy helped refine my CdA down a tad more.







Carbon Hydration system by fishboy, with help from Raoul Luescher (my mold, his carbon work). That's an Oz 50 cent piece if you can't tell.

Xlab sticker to put people on the wrong trail

How it gets mounted... sorry ;-).

I will say this ... with a little patience, and some applied thought, you can produce stuff way better than a lot of the commercial crap floating around (and I do mean crap from an aero point of view). Bit more exxy... (like twice the price) but it works about 500% better, and a lot more satisfying.

The blue mold is shaping foam that can be bought commercially - about $50 for a 1.5 x 0.5 x 0.05 m slab.
Cardboard profiles sketched, then knife away the large chunks and 2 hrs of hand sanding to reach final shape.

Tuesday, November 24, 2009

Does no one believe tubulars are faster?

Maybe not a guru - just keen on testing stuff. No-one else I know of, including manufacturers, have this data available in an unbiased way.

On Google wattage there has been a lot of talk about poor performing tires and the wattage increases required to power the wheel:

* Group member Stuart Lynne reported 25-30 watts more power required to average 40kmh with Zipp 404 front/rear with Tufo S33's compared with clinchers on Bontrager aero rims
and 1-2 minutes slower in 3 TT performances than expected.
[url="http://groups.google.com/group/wattage/browse_thread/thread/6fb5493f2cfe9b0d/664eaa16273767d1"]http://groups.google.com/group/wattage/bro...64eaa16273767d1[/url]
* Mr. E reported Tufos slower than clinchers
[url="http://groups.google.com/group/wattage/browse_thread/thread/85173088b1fbbde/8e2dddb7f5c22984"]http://groups.google.com/group/wattage/bro...e2dddb7f5c22984[/url]
* Gary Zyriek reported similar findings
[url="http://groups.google.com/group/wattage/browse_thread/thread/3864131868d2a891"]http://groups.google.com/group/wattage/bro...864131868d2a891[/url]
* Opie OsCO reported similar findings (same thread above).
* Gene Fowler reported 225 watts to roll at 25 MPH @ 85 cadence on rollers with Tufos, 145 watts with clinchers, same speed/cadence
[url="http://groups.google.com/group/wattage/browse_thread/thread/c4cdef5f3d1683ed/242f0b0526b099b5"]http://groups.google.com/group/wattage/bro...42f0b0526b099b5[/url]

Some further information: [url="http://www.velonews.com/tech/report/articles/12493.0.html"]http://www.velonews.com/tech/report/articles/12493.0.html[/url]

Feel free to use whatever you like, but if there are ways to make things faster with relatively little effort, I'll take those gains thanks.

The value of Wind tunnel testing

After recently completing my second trip to the tunnel, I was inspired to see if I could have gotten a better result simply by throwing money at the problem. (Not that there is that much cash to outlay on bling in this neck of the woods.)

It's taken 2 years and a lot of trial and error to get to this point - while I'm not as aero as the Zabriskie's and Landis' of the world, for a non shrinking violet with swim specific shoulders it's getting there. My first round of tunnel testing over 12 months ago scored CdA values in excess of 0.285, with values around 0.275 being as good as it got at that point. Since then I'd done a lot of field testing to try and find ways of snipping off drag, and I was pretty keen to see how the tunnel stacked up with my field tests.

This round of tunnel testing was completed at Monash University, Melbourne, and I can't divulge the real data (such as what wheelsets resulted in what CdA) due to legal agreements, but here is a reduced summary of the data:




The results show a variety of positions and how many dollars it took to find that position (including the time in the tunnel). So closer to the left side of the graph is more aero, and closer to the bottom of the graph is less spent. Obviously we want the least drag for the least spent, which is the direction of the blue arrow. What's interesting here is that it challenges the notion that blinging up is the way to achieve faster speeds, in fact by running out and spending as much as possible you are pretty much guaranteed of achieving very little unless that spend includes some tunnel time.

All of these tests where conducted on the same TT frame, by the same person (TT frame not included in cost). Point 4 is the default starting point, having spent nothing.

By adding just a time trial helmet drag drops from 0.265 to 0.253 (Point 3) which pretty much confirms that the most effective thing you can do for time trialling or triathlon is add an aero lid, if you don't already have one. Not only that, you may spend more than $6000 on aero wheels and still not derive as much advantage as using the aero lid (Point 6). Despite this, I regularly speak to people who remain convinced that blinging up with wheels is their next big thing, while in fact they are still using a road helmet.

By adding some tunnel test time to our aero helmet we managed to drop drag from 0.253 to 0.243 (Point 2) which was better than almost all the expensive aero wheels we tried, at roughly 1/7th the cost.

Finally the three best price for drag positions (adjacent to point 1) were all achieved with the same wheelset, at roughly 2/3 the cost of the more expensive wheels. Kinda lucky really since these are my default race wheels.

Best position achieved (point 1) was using a custom hydration system, designed/shaped by lil ol me, and brought into its full carbon glory by Raoul Luescher from http://www.luescherteknik.com.au/ - a top bloke and there is nothing that he can't do with carbon. (Raoul is also the bloke responsible for organising the tunnel testing - thanks mate).

So just how significant is going from 0.265 to 0.230 ish? Well if you use a modest 200w of power over a 40 km TT, a CdA of 0.265 will net 1:05:37, while 0.230 will be almost 3 min quicker (2:51) stopping the clock at 1:02:46. If the power rises to 270w, the difference drops to 2:35, but this is still a very significant time saving. (These figures assume a flat, straight line course with no turn arounds).

So the moral of this story is if you're competitive enough to care about going fast, then less than a grand invested in tunnel time might be a very wise investment, and probably much better than four to six times as much thrown into aero wheels.

In terms of which positions you'd choose, they're numbered 1 through to 6, 1 being the most desireable, and 5-6 the least desireable. Doing nothing (point 4) is probably better than spending $6+k and getting a marginal improvement (point 6 blue dots) - you need tunnel time to refine a position to extract more drag saving. There are a lot of things you can do with 6k!

As a final aside, how did my field tests compare with the tunnel? Best estimate from repeated field tests for my number 1 position (point 1) were 0.233 compared with the tunnel measured value of 0.233 - can't be too upset about that, and it means I'm pretty confident that when I see something in field testing that is repeatable, I need to pay attention to it.

I could tell you which of these would be faster, but then I'd have to kill you ...





Big thanks to:

Cyclespeed, TCR, Raoul Luescher, and David Burton and the folks at the Monash Wind tunnel.

Monday, March 30, 2009

3 hrs runnin

Urg. 2 hrs running easy this morning, including quite a bit of walking - old body takes a bit to get going after stiffening up overnight. Another 1:15 running later in the day easy - you have to love the Botanical gardens scenery at the tan. 28km total.

Saturday, March 28, 2009

New SRM maiden voyage

Managed to get the new SRM on the bike and head out today for a ride this arvo.
Nice, fine calm day, but a bit of traffic around (Grand prix weekend). SRM and Garmin behaved nicely, but think I set the offset incorrectly in the Calibrate power section, was 449, and should have been set to 719 - maybe. The offset process works like this:

On the Garmin 705 to set the offset:
Menu button: select Settings: Ant+Sport:Accessories
Spin the SRM crank backwards 5 or 6 revolutions (or maybe a few more) to activate the power meter.
Finish with the crank horizontally, and put no pressure on the crank.
The power meter should be detected, and the Calibrate Power screen should activate.
The offset number should stabilise.
At this point, press Enter (by clicking the joystick down in the central position) to save the offset value.
Press Enter again to leave the config screen.
For best results, you should leave the bike at the same ambient temperature for 30 mins or so before doing the offset. The offset shouldn't vary more than a few points generally.

Note: This is with firmware 2.60 - at least Garmin has an easy way to update the firmware on the Edge, as with all their devices. Check Web updater on the garmin website.

The other thing to have calibrated is the slope of the power meter. Each SRM has a slope value in Hz, which varies as a result of the manufacturing process... over time the resins used for the strain gauges can settle in a little more, leading to changes in slope. SRM recommend checking slope every month or so when new - problem is that you can set the slope in the Edge 705, but not read the calibration values - you need a Powercontrol SRM head unit for that.

To set the slope in the Garmin Edge 705:

Have look on the back plate of the SRM. The slope value will be listed in Hz (mine is 21.3).
Menu button: select Settings: Ant+Sport:Accessories
Now use the joystick and press left-right-left (intuitive eh?)
A new screen appears with the SRM serial number (mine is #14999, missed by 1)
and the slope field.
Use the joystick to enter your slope value.
Select mode to exit these screens.

The other interesting issue is the refresh rate - there must be a 3 sec or so averaging of power, so when you eyeball the current power output it isn't actually showing what your effort is (unless you've been constant power for 3 sec). In reality not really an issue for steady state riding, but might make some difference if you want to see what you are actually produding right now. Doesn't appear to be a setting for this either in the Garmin 705.

Sunday, March 22, 2009

SRM arrived.

Yay! It arrived. Will hopefully have some time to get on bike.

Friday, March 13, 2009

SRM arriving Monday or Tuesday

Hmmn. SRM is in the country and has local taxes paid, should arrive at work on Tuesday or Wed next week... only 4 or 5 more sleeps! Might have to do the grand unboxing video on YouTube ... stay tuned.

It has been a bit of a tough first week - around 10 hrs of running including 3 hrs of hard stuff. Luckily, last Monday was a holiday and swimming wasn't on, so one less session to try to have to fit in (and one less morning up at 4:45 am).

Running in the hills tomorrow... inc 40 mins hard.

And officiating on Sunday at a local race - hope I get to get draftbusting duty - might take the video camera out on the motor bike to get some (hopefully cool) footage.

Tuesday, March 10, 2009

Urk. No rest for the wikid.

Well after last weeks end-of-season rest week (wow a whole 7 days off) (facebook status: Mmmn. Beer.) back on the wagon.
2 days in 2.5 hours of running done, including 50 minutes of threshold this morning.

Amazing how a week off can make you feel crap when you start again ... or maybe it was the beer.

Tuesday, March 3, 2009

New toy: status update

SRM has been manufactured and is awaiting export clearance from Deutschland... should be here towards end of next week.

Sunday, March 1, 2009

New toy ordered: SRM wireless and Garmin 705

Well after the demise of the ol Ergomo, ponied up today for a new SRM wireless with a Garmin head unit. The Garmin 705 is the only head unit of all the power meters (besides now defunct Ergomo) that actually has a backlight so you can see what is going on in the depths of Melbourne winter. As an added bonus, its $350USD cheaper than the SRM PCVI head unit... seems like there are a lot of SRMs getting out there with a G head now!

Can't wait to get it installed on the TT machine and finally get some accurate readings on power output. Interesting fact about calibration: it is possible to use a series of known weights to check the slope at various forces and arrive at a better estimate. Most calibration attempts I've seen only work off a single weight, good for calibrating that amount of force only, but not so good for checking the slope over a range of forces. Have enlisted the help of an AIS specialist to check this out.

Should also mean I can resume aero testing, which has taken a back seat while power readings have been less than repeatable.

Thursday, February 26, 2009

Season over - early but over

Tri season is over. We'll at least for me. Rest-ish week this week and into Wk 1 of Worlds campaign next week.

So managed 7th National Sprint, 8th Canberra (ACT Sprint) and 2nd Vic Sprint, 100 selection points and a spot in M40-44 looking comfortable.

Still have the racing bug though ... might have to squeeze in a few more races to practice transitions and tactics ...

Tuesday, February 17, 2009

Should I carry a spare tube/CO2 in a race?

The age old question, should you carry spares racing?

You can, and often it saves a long walk back to transition if you do flat, but there are some other alternatives. It is possible to pre-inject puncture repair fluid into the tube, and if - heaven forbid - you puncture in a race, and your sealant of choice works, you'll hear a short pssscht, followed by the tire magically healing itself. Usually you'll only lose a couple of PSI, not even enough to worry about stopping for.

There are a couple of products on the market that purport to do this:

Vittoria Pitstop, which is a pressurised latex foam in a can, which cost me 3rd at the 2008 worlds (got 9th instead.) Don't bother with it - it is inferior in a lot of ways, and is also not recommended by a number of people I know!
I think the main issue is that the foam is too light inside the tube to actually stem the airflow through a cut, and so the tyre ends up deflating anyway. I've attempted to fix 3 other punctures under non race conditions, with every one failing.
I should add that most of the Vittoria tyres are actually a good product, it is just this particular product that is not worth purchasing.

HOWEVER:

Get some Doc Blue or Stans liquid sealants from your LBS.
Insert the goo BEFORE you race
Follow directions on the bottle (Unscrew your valve core, insert recommended dose of fluid, rescrew valve core, pump up and ride for 5km)

I've fixed 3 tiny sized glass flats on a very expensive front tubular glued on a race wheel this way. The tube is overglued (better rolling resistance, and that is a whole nuther article) so not that keen on having to take it off and either put a new tubbie on or get the old one fixed.

Sure you still have the dilemma, should I carry spares, but now you have some added race insurance!