New powermeter rumours

Discuss light weight issues concerning road bikes & parts.
maquisard
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by maquisard

What fantasy land do you live in where you think other brands don't work!?

You can achieve the same precision and accuracy in something much much cheaper

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ms6073
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by ms6073

Geoff wrote:
Wed Mar 14, 2018 2:08 pm
say what they want about SRM, but it simply works.
While I agree with Geoff, from my perspective, I was not willing to pony up another $2000+ for a new SRM, when Shimano offered rechargeable batteries, and user update-able firmware for less than $1500.
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by Weenie


mergeforthekill
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Joined: Fri Jun 17, 2016 1:24 am

by mergeforthekill

Quarq is the best option for under a $1000 for dual sided imo.

turlutu
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by turlutu

Seriously
I think we are all being fooled by '' dual sided ''

Unless recovering from an injury witch affect power production left or right , can't see of what's use it is ...
You won't be better by trying to compensate a unbalanced power production between L and right , and it changes also with the intensity or duration of the effort
When you do a bike they check your position , cleats , wedges and there they can adjust to a certain point but that's it .

It's like one more thing to sell

TobinHatesYou
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by TobinHatesYou

mergeforthekill wrote:
Wed Mar 14, 2018 9:06 pm
Quarq is the best option for under a $1000 for dual sided imo.
Except Quarq isn't dual-sided. It measures full power, but spider-based PMs can only estimate dual-sided power based on phases.

c60rider
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by c60rider

Spider based power meters do measure both sides they just aren't able to separate into pure left and right sided without a sensor on both sides. But then can you believe the data the way the Shimano seems to be performing. Or in the case of the Rotor2in there's the spider and one in the axle I believe. It's only meters like stages that measures only off the left crank and doubles it. SRM reliability is no better than many others. Power2max is right up there but with more features and a way better price. You can buy 2 Campagnolo 4 arm type S for the price of 1 SRM right now. If budget is no limit then buy SRM and certainly I could afford SRM but there's nothing about that power meter that I see does anything better than Power2max. But each to their own and I'm not going to criticise anyone's purchase. But measuring and having dual sided power displayed is really a waste of time and perhaps another marketing gimmick to make people think that's what they need to get us all to buy yet more power meters. Buy the one that's in your budget, whichever one that is, test yourself to get some base figures and use that to get fitter.

TobinHatesYou
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by TobinHatesYou

If a power meter can only estimate L/R balance it is not a dual-sided power meter. A spider only measures the torque applied to the whole...it has no real knowledge of which side that torque is coming from. It would be like saying a PowerTap hub is a dual-sided power meter since it could measure changes in torque from biomechanics. All you would need to do is add a magnet to one crank and the hub could approximate L/R balance to an extent, but if you do single-leg pedaling, you would easily see that none of these solutions really distinguish between L/R.

L/R estimation is even more useless than true L/R measurement unless you have a wild imbalance from a poor fit, leg length, range of motion issues, prior injury...
Last edited by TobinHatesYou on Thu Mar 15, 2018 4:30 am, edited 1 time in total.

turlutu
Posts: 55
Joined: Wed Jan 10, 2018 11:55 pm

by turlutu

Seriously
I think we are all being fooled by '' dual sided ''

Unless recovering from an injury witch affect power production left or right , can't see of what's use it is ...
You won't be better by trying to compensate a unbalanced power production between L and right , and it changes also with the intensity or duration of the effort
When you do a bike they check your position , cleats , wedges and there they can adjust to a certain point but that's it .

It's like one more thing to sell

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TonyM
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by TonyM

At least the consensus seems to be that single sided powermeters like the Stages for example are much inferior to dual sided or spider based powermeters and they should be avoided as the total output is not accurate enough.

CrankAddictsRich
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by CrankAddictsRich

TonyM wrote:
Thu Mar 15, 2018 1:06 am
At least the consensus seems to be that single sided powermeters like the Stages for example are much inferior to dual sided or spider based powermeters and they should be avoided as the total output is not accurate enough.
not accurate enough for who??? I've been using Stages power meters for almost 4 years, training and racing... last year, I won my State's TT Cup in the Non-TT class (Eddy). Its plenty accurate enough for me.
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TonyM
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by TonyM

What I understood is that the balance L/R is different depending on the effort that is done. And that doesn‘t give an accurate total power as it multiplies the left leg.

But if you use the same only left only powermeter on all your bikes it is of course better.


hogehoge
Posts: 36
Joined: Mon Feb 25, 2013 11:59 pm

by hogehoge

Details on new Specialized/4iiii power meter
https://www.bikerumor.com/2018/03/14/sp ... ment-tech/
"Claimed weight is 440g (without chainrings, 172.5mm arms)"

guyc
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by guyc

TonyM wrote:
Thu Mar 15, 2018 1:06 am
At least the consensus seems to be that single sided powermeters like the Stages for example are much inferior to dual sided or spider based powermeters and they should be avoided as the total output is not accurate enough.
I disagree.

The only thing that matters to each individual is that whatever they're using gives a repeatable, reliable record.

As has been said above, if you've identified an imbalance, then what do you do? It;s knowledge that can't really be used for much material change.

So, a left-only meter might not give quite as accurate a reading for a given ride, does that matter if you're only using a left-only meter all the time. I'd argue that it doesn't.

I certainly don't believe that there's a consensus for them to be avoided, and, IMHO, they're certainly superior to training based on HR/zones if budget will only stretch to a left-only. Indeed, for most people, getting one of these and using them in a structured way is likely to reap greater rewards than dropping £4k on a pair of Lightweights.

jever98
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by jever98

guyc wrote:
Thu Mar 15, 2018 8:49 am

So, a left-only meter might not give quite as accurate a reading for a given ride, does that matter if you're only using a left-only meter all the time. I'd argue that it doesn't.
It wouldn't matter between rides if your balance was always exactly the same. If it does vary from ride to ride, it increases variance by factor 2.

E.g., 3 rides, all at 200w
Ride 1: 48/52 true balance
Ride 2: 50/50
Ride 3: 52/48

Stages would read:
196
200
204

That's +-2% on top of the variance in measurement.

Based on the last years of power data, I would say that I see changes in balance of up to 3-4% between rides (based on estimated, imperfect p2m estimation). Which would put a stages into the range of 4+% variance.

That's too much IMHO, especially for someone who has ridden a while and isn't making enormous jumps in performance anymore.
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guyc
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by guyc

That's still basing it on 'if's' and ' estimated, imperfect p2m estimation' but I take your point.

I still don't agree that there's any consensus that single-sided meters are a waste of time though. Far from it.

by Weenie


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