Ygduf

I just ride up 20+ minute hills.

waterrockets 

I've done a few tests of terrain vs. 5' power. I'm consistent, within a Watt or two, between an 8% climb or a rolling course (5' around a 7' loop). In the heat of summer, I've started swapping hill repeats for open road for VO2Max intervals too. This keeps me cooler, and I can hit the same power numbers even with 45mph descents during the interval.

revchuck 

What is this "uphill" of which you speak?

shovelhd

That works. The steadier the grade, the better.

I don't know anyone who does 60 minute tests.

Wylde06

If I had a 20+ minute hill I wouldn't know what to do with myself. I don't even have a 2 minute hill. What are hills?

veloboy971

For me it depends on what kind of intervals I am doing. Being able to crack out a max 5 minute number in the first 1/3 of the race probably won't do anything but waste energy. However being able to do 92% of your max 5 minute power at the end of a race, if executed in the right spot likely will do some damage. That's the value I see in doing intervals at the end

waterrockets 

It's good to vary it. There are advantages to simulating the situation, but there are also advantages to nailing yourself squarely in your training zones when you're fresh, to efficiently generate the training stress.

Voodoo76

Along these lines a new trick for this old dog has been realizing the impact even 200W can have on speed down a modest hill. I'm using gearing much more aggressively over rollers than I did pre-PM.

globecanvas

I've been setting power PRs practically every ride the past couple of weeks. It's awesome, but what's got me worried is that they are not always correlated with hill climb PRs (though sometimes they are). I'm going to borrow a powertap tomorrow and run it along with my crank PM to make sure it's not lying to me.

Creatre

The past couple of times I made a bump up to the next level I kept questioning my power meter over and over. But eventually realized that fitness had just gone to a new level. There are actually posts in the quarq thread on SC where I thought my Quarq was broken.

But then again I dunno about the stages still, but it seems like it's been reliable for you for the most part.

shovelhd

The failure mode of my Quarqs were always the other way around.

Creatre

My Riken is still really solid at the moment. I'm thinking of maybe switching to a powertap over the winter though just because I only use one set of wheels anyway and don't like all the bad stuff I've seen on Quarq's still. But not sure yet.

shovelhd

If you're Riken is solid, it's solid. I'd ride it until you suspect it's gone bad.

globecanvas

I did this experiment today, running a borrowed (old silver PT Pro) Powertap along with my (Cannondale) Stages.


AP: Stages 166w, PT 157w (diff 9w, 5.4%)
Z4 interval: Stages 286w, PT 272w (diff 14w, 4.9%)
Z5 interval: Stages 341w, PT 325w (diff 16w, 4.7%)
Max: Stages 853w, PT 814w (diff 39w, 4.6%)


According to Home page Friction Facts, drive train losses should be about 3% of total power. In my case, the chain and crank are practically new, but the cassette on the Powertap was very bad, slipping frequently (every 15-30 seconds) when power was anywhere above Z4.

Based only on this information, it appears the Stages is reading a few percent high. I'll send the data to Stages and see what they say.

bbbean 

Or maybe the PT is a little low. As long as the unit is consistent on the bike you train/race with, does it matter?

Ygduf

only in that if it's reading high he won't, for the next couple of years, know if he's actually seeing improvement or just drift. Won't matter in a race, but would be pretty irritating each upload.

globecanvas

I have another Stages on a different bike, so it matters if one of them is reading high compared to the other. Unfortunately I can't compare them directly to each other, but the reason I started looking at this in the first place was that I noticed higher power with the Cannondale Stages, compared to the Rival Stages, was not as correlated with faster hill climb times as it should have been.

globecanvas

Stages support acknowledged that the PM appears to be reading high, and offered to take it back for recalibration. They said they have had some calibration problems with their Cannondale units, because the aluminum is so much thinner on SISL crankarms compared to Rival or Dura-Ace.

I have nothing but good things to say about Stages support, they were never defensive about the problem or trying to find fault with my claims.

I didn't want to send the unit back before this weekend's race (which I didn't end up racing anyway), and in the meantime there was an annoying BB-area creak I wanted to deal with, so I took the crank arms and pedals off and greased everything. Once reinstalled, the unit now seems to be reading accurately! I did a 13-minute climb yesterday and the power was very consistent with the time.

mike868y

how useful is a powermeter if the readings can be thrown off (or i guess in this case...on) by greasing the bb?

Ygduf

globecanvas

Charitably, the installation was tweaked in some way that created some tension in the crankarm, throwing off the power readings and causing a creak. Uncharitably, the unit is oversensitive to conditions. Time will tell.

waterrockets 

I wouldn't be surprised if the vibrations sent through the crankarms from the creak could cause some noise in the sensor readings. Not the end of the world to keep your BB from creaking.

Creatre

Quarq firmware got released this week, with this functionality:

- Activates accelerometer cadence in all power meters with an LED and CR2032 battery. Accelerometer cadence will switch on automatically when a magnet is not present.

Could be interesting. Wondering the accuracy and if it's worth having a magnet now.

Wylde06

Ive had the wahoo key for a few weeks now and still havent updated. I think I will now. I wonder if its a fail safe so if you lose your magnet you will still have power? Would be interesting to see if things are the same with and without.

slynkie

I believe someone from Quarq mentioned on the Wattage list that the feature is intended as a backup for when the magnet is not available - perhaps it's not perfected for very low or high cadences. Worth updating for imo, just in case..