taras0000

Well in that case, I'll have a Kraken and Ginger Ale.

carleton

Comin' right up!

taras0000

I'm wondering, if a PM was designed with track use in mind first, would it not be a more bombproof PM? Make it track worthy and back-adapt for road use. Essentially all you would be doing is dumbing it down.

carleton

I'm not sure what you mean. What would make it bombproof?

I think the fundamental differences start with the duration of the efforts being recorded.

A road ride can reasonably be 3 or 4 hours. And it's reasonable for a rider to have weeks worth of rides before (s)he downloads them.
Memory cards are (were) expensive.
Measuring the readings and writing to the memory card takes power.
The batteries in the cranks should last for at least a season before replacing or recharging.

These are major constraints that dictate what's going on. So, based on that, here is what the engineers cane up with:

- Use as little power as possible.
- Read data once per pedal stroke.
- Write 1 record per pedal stroke to the memory card in the head unit.
- Automatically turn off when the rider hasn't pedaled in 120s. (ever wonder why your PM doesn't get the first few pedal strokes of your pursuit or kilo? That's why.)


In my humble opinion, the ideal track power meter would operate like a high-speed video camera:

- It wouldn't record any power until you turned it on. It would record speed, cadence, HR, etc... as you do your warmups and cool downs. Who needs power data from when they are riding in circles in the infield??
- There are separate speed, cadence, HR, and power meter sensors (this is important)
- When a rider is ready to start an effort (i.e. in the starting gate or pushing off for a flying 200), they would turn on the High Speed Power Meter ™©. A red "RECORDING" light will come on to let the rider know that's it's pulling more juice than normal.
- The PM cranks will then record at something like 10Hz (10x/second) then report that data to the head unit every pedal stroke.
- The rider rides the effort.
- Then when they are done, the rider turns off the High Speed Power Meter ™© and no more power data is being sent to the head unit (which is still recording speed, cadence, and HR...). This way they can still record ride time and workout time.
- Oh, ride time and workout time should be separated in the head unit. Workout time is the time since you first got on the bike for the day. Ride time is time actually moving.


That would be close to perfect.

Other features:

- Use MEMORY CARDS instead of in-device memory. This way an athlete can do some efforts then hand the card to coach for on-site analysis instead of removing the head-unit and having the coach download it.
- Maybe use memory cards on the cranks, too and sync the data when you upload it to the software. This would solve the cranks needing persistent storage issue.
- User replaceable batteries using standard batteries that one can find in a store. Screw a charger. If the user uses rechargeable store batteries fine. But, it's easier for me to carry packs of new batteries in my track bag than it is for me to find a wall socket so I can recharge my head unit in the infield!

You are wondering, "Why would you turn off the power meter???" Well, if you've ever spent time analyzing track PM files, you'll realize that we are only interested in the power when we are doing efforts or races. Nobody cares about the power you expended during warmups or cool downs between efforts or riding rollers. So, why bother recording it?

"But how will the file look with no power data?"
Just fine. It will look like a normal file with lines for speed, cadence, and HR being charted constantly and power being charted intermittently no different than if you were having sensor issues and the power signal was cutting in and out. But, with this, you are manually controlling the ON/OFF switch for power data

PS:

If someone really does implement this, please send me one for free. You know this is a good idea

carleton

Also, I really don't think having Left and Right power data is of any real value. Yeah, it's interesting data to have and say, "Geez, I press 5% harder with my right leg than I do my left." but, are you going to do anything different now that you have that information? Probably not.

That's like your car giving you a report that states that you make 5% more right turns than you do left turns. "OK...thanks?"

SprintzNKiloz

+1. I have a quarq on my track bike that shows L/R balance and guess what? I have imbalances when I jump and do starts. Shocker

MrMinty

I like the idea of a track based PM. If you have the headunit constantly running, shouldn't it measure power whatever?

Surely a 5% difference is only natural and nothing to worry about?

Dalai

Pedaling asymmetry is well studied. Power fluctuations and different efforts is well documented too. 5% is a big deal if power is measured using one leg and just doubled.

queerpunk

I recently had a thing that involved some serious knee pain and misalignment that, when I was riding, would cause me to lose a lot of power in my left leg. I wondered how much power I was losing. A PM that shows L/R distribution would tell me how much. But that's like the only use I can think of for L/R data.

carleton

Reread my post about it and you'll see why power during anything other than doing your efforts is generally useless.

You probably have GPS on your smart phone...is it recording now?...or do you only record during rides or runs? See my point?

Same with track efforts. When analyzing files, we are only interested in stuff that happens during races or efforts. My proposal is to turn on "high fidelity" monitoring only during those times. That addresses the concern about higher frequency recording using up more battery or more memory.

Poppit

I use a garmin 520 for everything on my track bike but don't monitor power, tend to use the Wattbike in the gym for that which I sync to the 520 to record all the info. Even then the power info is used to establish my MMP (max minute power) which then sets all the training zones.

Quinn8it

Just got off the phone with SRM.
Looks like next week I'll have a new wired/wireless Track SRM, my old PC5 for wired, and a refurbished PC7 for running wireless..
Excellent customer service as always by SRM.. Excited for the new PM!

taras0000

By bombproof, I just mean that it's going to work no matter what, and do it well, and properly.

If you design the PM with a track specific bent, then you can "de-tune" it for road use.

If you can make it sample at 10Hz (or more) for track use in HI-FI mode, then it would be easy enough to make a "Road" setting that only samples at 1Hz. Things like that when it comes to PM attributes.

Essentially, a track PM needs the programming and hardware to work at redline, something that road PMs don't do very well, or at all. The performance we're wanting from a track PM put a lot of strain on it's components and programming, and any PM designed with these attributes could easily be back adapted for road use.

Basically, if you can sprint, you can also walk all day. Most PMs can walk all day, but few can sprint, nevermind even jog.

carleton

Good points and good analogy.

Dalai

Great news. Can concur - have also had great support from SRM.

- Fixed the sending coil on my SRM Pro wired cranks for free when damaged by baggage handlers on the flight back from the States.
- Offered a wireless FSA spider for a very reduced rate when I discovered a chain ring bolt hole on the spider of my wired FSA unit had cracked. Never asked if I was the original owner.
-PCV Keyboard, electronic board and battery replaced free of charge by SRM Oceania. I'd just bought it second hand on ebay; again no questions about original ownership asked.

carleton

I missed this post.

Yeah, SRM has great customer service. I've been to their US headquarters. They are really nice.

Voodoo76

I still think you can't beat Power for pacing and targeting aerobic efforts. I returned to old school for shorter intervals (1m or less), using target gear and cadence. For me the efforts feel much more effective this way. For some reason it's easier for me to battle and hang onto a cadence than a power number. I am finding the measured power useful though, verifying that my workload is the same on the trainer as outdoors. I need to adjust target gear a little inside to get the same power output at target rpm.

carleton

This brings me to another point/question:

Power is a mathematical combination of Torque and Cadence. I wonder, would it be more useful if we trained (and paced) using the raw Torque values? And effectively separate the Cadence component when riding the effort.


The head unit might display:
Speed: X kph
Torque: Y n-m
Cadence: Z rpm

That would probably be more useful than showing the calculated Power value.

So, instead of a pursuiter thinking, "I need to maintain X watts for the next 4 laps..." maybe "I need to average Y Newton-meters of torque for the next 4 laps..."

The reason I say torque over Power is that for a given average speed, the cadence will change if you adjust the gearing, and therefore the product that is Power.

I'm not saying we should. I'm just thinking out loud and wondering if that would be of use.

The power meters can do this right now. They transmit the raw torque values and the power is calculated in the head units. PowerTap's PowerAgent software actually shows you the torque in the chart of your efforts, but not on the head unit.

Thoughts?

SprintzNKiloz

Post calibration in my garmin it will actually show you the torque value on the head unit until you back out of the calibration screen. That, in turn has sort of planted a seed in my brain of basically saying, "well, I know about where my optimal cadence is for a given event, so now I should really just focus on what gear gives me the ability to maximize toque at a that cadence." If that made sense. I'm suffering from pre-caffeinated sprinters brain at the moment. So short answer is: yes, I think there's value in sending torque values (or reading them post training) off power meters.

SprintzNKiloz

Functional Threshold Torque :-D

carleton

Exactly!

I think that, when pacing, we are more aware of the torque that we are applying (and holding back) than we are of the cadence. In fact, when we "blow up", that's a function of applying too much torque rather than cadence.

Power is the product of torque and cadence. Show the torque.

SprintzNKiloz

When I do kilos I am living proof of blowing up after applying too much torque. My weekend project now will be to see if I can get the torque values out of my Garmin. Now I'm curious...

Voodoo76

Interesting thought about pushing too hard on the pedals. So are you talking about looking at the minimum torque needed to maintain a given rpm?

carleton

Figure out how to import it into PowerAgent or Golden Cheetah.

PowerAgent is more refined. Golden Cheetah is open source software so it's not as polished.

More so, the "Functional Threshold Torque" (as Sprintz put it). Basically, what's the maximum torque you can sustain without going anaerobic and "burning a match" or "popping". So, it's less about cadence and more about force.

Cadence is a factor, though. It determines how much of a micro-rest you get between pedal strokes.

Big gears give longer micro-rests, but require more torque to move.

queerpunk

I use Golden Cheetah. It definitely takes a little while to figure out the software - how to make it look the way you want it, removing useless charts and adding ones that you do like, and how to navigate preferences and options and whatnot. But once you figure it out and get comfortable with it, it is a very high powered software. definitely not too tough to create charts and summary data of torque data.