Best affordable power meters
06-21-19, 04:34 PM
#26
Senior Member
Join Date: Aug 2014
Posts: 2,433
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 741 Post(s)
Liked 412 Times
in
230 Posts
If you have multiple bikes, haven't heavily invested in a specific non-PM pedal and cleat type, and are willing to spend a few minutes swapping pedals, then it's hard to beat the price of a single set of dual-sided pedals.
I went dual-sided and find L/R balance info to be quite illuminating. Changing my saddle height alters my balance, as does spinning vs. grinding. I've also noticed that imbalance is often due to not unweighting on the upstroke efficiently, rather than having a weaker downstroke.
I went dual-sided and find L/R balance info to be quite illuminating. Changing my saddle height alters my balance, as does spinning vs. grinding. I've also noticed that imbalance is often due to not unweighting on the upstroke efficiently, rather than having a weaker downstroke.
06-21-19, 04:50 PM
#27
Senior Member
Join Date: Nov 2017
Location: Seattle
Posts: 1,957
Bikes: Specialized Roubaix, Canyon Inflite AL SLX, Ibis Ripley AF, Priority Continuum Onyx, Santana Vision, Kent Dual-Drive Tandem
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 878 Post(s)
Liked 726 Times
in
436 Posts
Same happens when "sprinting." My measly power increases when I make a note to unweight. I don't look at power or L/R balance to remind me during those efforts outdoors, but I noticed it was affecting my sprinting when doing out of saddle efforts indoors so started paying more attention to how I pedal outdoors. I realized that, just like with climbing, not unweighting (which is a bit unnatural to do indoors with a bike that can't be thrown side to side) was sapping my power while standing.
06-21-19, 09:02 PM
#28
Senior Member
Join Date: May 2019
Posts: 520
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 229 Post(s)
Liked 327 Times
in
179 Posts
It's difficult (at least for me) without a power meter to ride slow enough to actually be in recovery. I will ride faster than that if I'm not paying attention.
06-21-19, 09:08 PM
#29
Senior Member
At the start of last season I had a 4iiii installed on my left crank. Having PM data is absolutely invaluable for measuring you against yourself!. This season I've created a Garmin screen that doesn't show power or heart rate... I think that it is very easy to get into the habit of riding to a number (i.e. I "know" that I can hold 200watt for 100km...so I do exactly that.) By turning off the power and heart ( as well as average everything,etc (I only show slope, cadence, speed and temperature), I'm back to riding the road and not to the numbers. It might sound stupid, but I'm actually finding that my end power and heart rate are rate where I would have been had I known them. But I'm back to not caring as long as I ride the road as best as I can. I still want the power, but it only seems to matter AFTER the ride.
06-21-19, 10:59 PM
#30
Senior Member
I think when he said "get better" he meant on the bike. Your weight is important to your health, but I don't think that's what we're talking about here.
Also, my Garmin thinks I burned 4,100 calories earlier this week on a steep 11 mile hike. Based on the alignment of the planets or something. When you ride, it's even worse, at least hiking involves a mass over distance calculation but a freewheel nullifies that on a bike. It really has no idea. When you ride with a PM, it measures physical work done, and there isn't have variation in how people ride (like there is with running economy). End result is with a good PM you'll never be more than 2.5% off in either direction in terms of calories. Compare that to a Fitbit that doesn't even claim any accuracy at all.
Also, my Garmin thinks I burned 4,100 calories earlier this week on a steep 11 mile hike. Based on the alignment of the planets or something. When you ride, it's even worse, at least hiking involves a mass over distance calculation but a freewheel nullifies that on a bike. It really has no idea. When you ride with a PM, it measures physical work done, and there isn't have variation in how people ride (like there is with running economy). End result is with a good PM you'll never be more than 2.5% off in either direction in terms of calories. Compare that to a Fitbit that doesn't even claim any accuracy at all.
Im sure its fairly accurate, but what energy you put in to the pedals does not exactly reflect how many calories you burn to produce said output. There is an underlying assumption that about 1/5 what you burn will be converted into useful energy. The rest is metabolic functions, waste heat ect. Thus the power meter accuracy does not apply to the calculated energy consumption, unless the 1/5 model (or what ever model you computer uses) is equally accurate. Most likely its not, as it fluctuates form person to person and with state of fitness.
06-21-19, 11:13 PM
#31
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 18883 Post(s)
Liked 10,646 Times
in
6,054 Posts
Me three. Somewhere along the way I start having fun and get a little too spirited. That want a problem in my 20s.
06-21-19, 11:25 PM
#32
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 18883 Post(s)
Liked 10,646 Times
in
6,054 Posts
Im sure its fairly accurate, but what energy you put in to the pedals does not exactly reflect how many calories you burn to produce said output. There is an underlying assumption that about 1/5 what you burn will be converted into useful energy. The rest is metabolic functions, waste heat ect. Thus the power meter accuracy does not apply to the calculated energy consumption, unless the 1/5 model (or what ever model you computer uses) is equally accurate. Most likely its not, as it fluctuates form person to person and with state of fitness.
Basically, you can estimate walking calories with good accuracy, because it's a simple mass over distance thing. Aerodynamics don't factor in at walking speeds. It's just a matter of work done.
A power meter measures work done. Technically it measures the rate at which work is being done, but 1 watt = 1 Joule per second. That's why your power meter can tell you how many kJ you did. Or mJ on longer rides.
There's a very narrow range of metabolic efficiency for humans on a road bike. It's about 5%. If you just change the label from kJ to kCal you put yourself in the middle of that range, so about 2.5% maximum error on either side. And, as you noted, that uncertainty comes from where you are within that range, not do much from your PM having an accuracy spec of +/- 1.5%.
When I run, I bounce up and down too much (for my stride length). I waste energy fighting gravity. Energy that a better runner gets more forward motion out of. But on a bike, we all sit on a saddle and turn cranks that are somewhere from 165 to 180 mm in circles. I mean you can waste some energy cross chaining but we're talking a fraction of a percent of your total output.
Again, this is based on research people have done with metabolic wards, it's not just some idiot on the internet spouting off.
06-22-19, 06:06 AM
#33
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
There's a very narrow range of metabolic efficiency for humans on a road bike. It's about 5%. If you just change the label from kJ to kCal you put yourself in the middle of that range, so about 2.5% maximum error on either side. And, as you noted, that uncertainty comes from where you are within that range, not do much from your PM having an accuracy spec of +/- 1.5%.
Thread
Thread Starter
Forum
Replies
Last Post
Dudelsack
Training & Nutrition
3
12-27-13 03:31 PM
ethan.g75
Training & Nutrition
20
11-08-13 07:30 PM
pakossa
General Cycling Discussion
0
11-10-12 08:04 PM
