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.