Commuting, with power

iPete

Most rides fall under pootle, hammer time, beast mode and power awesome but for years I've been ogling power meters to verify this. New the options are..

power2max FSA Gossamer BSA68 with 52-36 Praxis Works chain rings and Rotor bolts = £800
PowerTap G3 24h hub, Archetype rim, spokes, build = ~£710

I don't feel the need to upgrade my CAAD 8 frameset and my 105 chainset is in need of replacement, is the power2max a no brainer? can I fit and forget, use it all year round and on any type of ride without worry?

meanredspider

Is Power2Max a user-serviceable battery? I forget which one needs to be returned for battery servicing. I'm very happy with my Stages but I actually ordered a Power2Max originally, only cancelling it when they confirmed that it would be nearly a month before I got it.

edds

If I had the money to spare I would go power2max. I have been watching powertaps on ebay recently as a slightly cheeper entry into power monitoring. They seem to hold their resale value quite well, but I just seem to justify the expense at the moment.

tgotb

Yep, P2Max is a good fit and forget solution. User-replaceable batteries, and seems (had mine a couple of years) to be weatherproof. Other benefits are that it only takes 5 mins to swap between bikes, and it doesn't constrain your choice of wheels. I've used mine on the commute, TT-ing with a disc wheel, and if I wanted to I could put it on the cross bike.

iPete

Great. The power2max is winning, I'd look at Stages but I think waiting on v2 might be wise.

I could probably build a wheel that is strong enough for all year riding AND the odd race/TT, something like a 24h Archetype with CX Ray (or other lighter rim?!). I'd then get money back selling my 2 modest wheelsets but I'd miss the whizz of Hope hubs.

Paging ugo to the thread..

spasypaddy

i like my stages.

iPete

Do you move it between the fleet?

aberdeen_lune

Yes plus 1 on the Power2max. Just fit and forget. The battery's are watch type Renato make them you can order from Amazon. Easy to change just don't lose the screws.

spasypaddy

iPete wrote:

Do you move it between the fleet?

yep.

all my bikes run 170mm shimano cranks. takes 1min 20 to swap.

talius

When I vaguely looked into this (and let's be honest I'm not good enough to even come close to needing a powermeter :oops: ), I was quite taken by the Stages ones, just looked so simple to fit / use etc

http://www.sigmasport.co.uk/item/Stages ... YG?wmp=955

barry_kellett99

At the end of the day, stages only measures your left leg power.
Power2Max measures actual power from both legs.
The price difference is a complete no brainer.

Its worth pointing out that I own a stages crank. Its on my XC race bike and it is proving very useful. But options are very limited for me there. If i could have had a power2max MTB crank for the same money I would have went for it instead in a heartbeat.

meanredspider

Personally I think the left leg thing is a red herring relative to the simplicity of the Stages. By all accounts (and my experience) they're now totally weatherproof. I run a standard double on my Foil and a compact on my Volagi and turbo bike - if I had a CX that would be a third different set of chainrings. Unless you have a specific reason to know your power balance, I don't think it's a big deal versus the benefits of the Stages.

iPete

I'm not bothered about LR either. What puts me off stages is being first gen and the number of users reporting niggles.
Saying that, it seems incredibly simple, shouldn't add much weight and replaces(?) the need for a cadence sensor.

However, the price point still feels too high.

105 5700 Chainset and Stages = £680
Ultgra 6700 Chainset and Stages = £825

meanredspider

iPete wrote:

I'm not bothered about LR either. What puts me off stages is being first gen and the number of users reporting niggles.
Saying that, it seems incredibly simple, shouldn't add much weight and replaces(?) the need for a cadence sensor.

However, the price point still feels too high.

105 5700 Chainset and Stages = £680
Ultgra 6700 Chainset and Stages = £825

Reading around, many of the people who had issues at first are now happy. As for weight, my 105 Stages is only 13g (yes, 13) heavier than the Ultegra 6700 crank. It is incredibly simple, uses BT, and I think is more flexible than the P2C.

I would buy the 105 Stages and an Ultegra Chainset (that's what I did - I could sell the SL-K that it replaces) - about £720 in total. You can't tell that the Stages doesn't match - the colour is the same.

iPete

Hmmm, been reading the DC Rainmaker reviews, very tempted now.

It does however feel odd paying £600 for something that weighs less than 20g! An entire wheel or chainset feel a bit more tangible.

elbowloh

iPete wrote:

Hmmm, been reading the DC Rainmaker reviews, very tempted now.

It does however feel odd paying £600 for something that weighs less than 20g! An entire wheel or chainset feel a bit more tangible.

Indeed! You can get an entire Ultegra 6800 Groupset with the money and get change.....however since you've started this thread, I'm tempted by the Stages, especially I already have an ultegra crankset.

slowbike

I intend to go down the stages route - reasoning is that I already have 105/ultegra cranksets on the bikes and this would mean I can take the powermeter with me with minimal fuss.

The only slight niggle I have is that with no speed/cadence sensor required the GPS speed will not be as smooth - so will probably end up with both.

il_principe

http://www.brimbrothers.com/

tgotb

Il Principe wrote:

http://www.brimbrothers.com/

Hmmm. Pretty sure I own more pairs of cycling shoes than I own bikes; not at all unusual for me to take 3 sets to a race...

Agent57

Talius wrote:

http://www.sigmasport.co.uk/item/Stages-Cycling/Shimano-Ultegra-6800-Power-Meter-Crank-Left-Arm-Only/2OYG?wmp=955

"STAGES CYCLING SHIMANO ULTEGRA 6800 POWER METER CRANK - LEFT ARM ONLY"

But I want it to measure my leg power.

barry_kellett99

meanredspider wrote:

Personally I think the left leg thing is a red herring relative to the simplicity of the Stages. By all accounts (and my experience) they're now totally weatherproof. I run a standard double on my Foil and a compact on my Volagi and turbo bike - if I had a CX that would be a third different set of chainrings. Unless you have a specific reason to know your power balance, I don't think it's a big deal versus the benefits of the Stages.

In what way is it a "red herring"?
It's got nothing to do with power balance.

dhope

barry_kellett99 wrote:

meanredspider wrote:

Personally I think the left leg thing is a red herring relative to the simplicity of the Stages. By all accounts (and my experience) they're now totally weatherproof. I run a standard double on my Foil and a compact on my Volagi and turbo bike - if I had a CX that would be a third different set of chainrings. Unless you have a specific reason to know your power balance, I don't think it's a big deal versus the benefits of the Stages.

In what way is it a "red herring"?
It's got nothing to do with power balance.

Do enlighten. I was under the impression that there wasn't a great deal of benefit knowing the difference between right and left leg power.

spasypaddy

there is a benefit.

basically the stages is guessing your power from knowing what your left leg is doing.

but what if your right leg is 60% stronger. stages is giving you a reading of:
200 which is 100 watts for each leg. but your real reading should be 260 or something

however at our level of performance IMO all we should really care about is consistent readings and that is why the stages is more than sufficient.

and this is from a stages user

meanredspider

spasypaddy wrote:

there is a benefit.

basically the stages is guessing your power from knowing what your left leg is doing.

but what if your right leg is 60% stronger. stages is giving you a reading of:
200 which is 100 watts for each leg. but your real reading should be 260 or something

however at our level of performance IMO all we should really care about is consistent readings and that is why the stages is more than sufficient.

and this is from a stages user

But what are you going to do with the information (that makes it a benefit)?

For starters, everybody on "Road Fitness" or whatever the BR sub-forum is called, will tell you that power is to do with your cardiovascular system and very little to do with leg strength. If your left leg is a little different (figures of 2-4% typically get quoted) it really doesn't matter - it won't alter what you do as a result. Now, like my son, your left leg is substantially different from your right (through surgery and nerve damage in his case) then maybe there's an argument to measure both but, as you say, for most of us consistency is key.

I've red a lot about these PMs and I've yet to find anybody who can actually explain how power balance can help. Now, if the left leg thing isn't about power balance, then I'm lost.

And all this from someone who tried buying two different L&R PM systems before I gave up and ended up with a Stages.

spasypaddy

all im saying is that by having the two sides giving readings you get a more accurate representation of your power.

however what that means is nothng when you're comparing figure a to figure b from the same power meter off two different rides.

hence i said consistency is all that matters.

barry_kellett99

dhope wrote:

Do enlighten. I was under the impression that there wasn't a great deal of benefit knowing the difference between right and left leg power.

Stages can't give you that information. Neither can the majority of powermeters on the market. Some will say they can, but they are also making assumptions rather than taking actual readings.

The point I was making is that, as paddy has pointed out, Stages is guessing your right leg output. Whether that is important to you or not is not really the issue. The issue is that some of the power2max sensors are in the same price bracket and measure actual power from both legs.

There have been a few studies that also suggest that your legs fatigue differently over long durations of effort, meaning that potentially on a long ride, stages could be guessing it accurately at the start of a ride, but as the ride goes on it could become further and further out.

If all you need to see is a number in front of you, thats grand. Its acceptable to me for XC racing because it is notoriously hard to estimate TSS using just heart rate alone, and due to the short punchy nature of the riding, I am prepared to accept the possible innacuracy, as I agree with you, it will be relatively small and I feel even less so when cranking out 30-60 second bursts followed by coasting

The point I made above was that I can't understand why anyone would go down the stages route unless you already had a standard crank (length/manufacturer/model) on all your bikes.

rower63

Power balance matters if you want to know what your total power output actually is compared to what it’s showing. I don’t know the Stages, but if it’s been properly designed there should be some way of calibrating it for this.
For example, if your balance is such that you know your right-leg contribution is always 10% more than your left, and your (uncalibrated) Stages is showing 250 W, your true output is actually 262.5 W.
If you’re only interested in comparing against yourself, then perhaps that doesn’t matter.
But if you’re ever comparing against others, or you have a TT course gradient-map and all the cycling-related physics equations and you want to simulate an elapsed time for a given average power, or if you have a package that can do that, then true power matters.
I own a Powertap hub, but if I was investing now I would seriously consider either a Stages (for the price) or the Garmin Vector pedals (for the left/right and flexibility of swapping, but they’re expensive!).

tgotb

meanredspider wrote:

For starters, everybody on "Road Fitness" or whatever the BR sub-forum is called, will tell you that power is to do with your cardiovascular system and very little to do with leg strength.

For something like time trialling this is a fairly accurate assertion. For anything involving anaerobic power (eg track sprints, sprints at the end of road races or at the start of cross races) your cardiovascular system may not be that relevant at all.

rower63 wrote:

But if you’re ever comparing against others, or you have a TT course gradient-map and all the cycling-related physics equations and you want to simulate an elapsed time for a given average power, or if you have a package that can do that, then true power matters.

One very important example of this is using something like Golden Cheetah to determine your CdA (aerodynamic drag), which is a key tool for TTers working to refine their equipment/position. To have even a chance of getting meaningful numbers, your power meter needs to be accurate and calibrated.

meanredspider

Is there anyone (of reasonably regular physical capability - not like my son, for instance) who has a measured power balance difference of anything close to 10%? As I say, most people talk of figures around 2-4% - not a million miles away from the overall accuracy of these units. By the time you throw in the vagaries of normalized power (related to wind, inclines etc) and then TSS, you start to look like you're worrying about accuracy that you simply can't use.

Does Power2Max actually measure proper L2R balance or does it measure torque at the crank and calibrate according to the pedal position? For sure, it would be a complete PITA to swap between my current bikes because of the different chainring sizes (standard vs compact).

My point is this (as someone that actually ordered a Power2Max) - a lot of criticisms of Stages are unfounded and it will do a fab job for most of us. Even leg fatigue doesn't really matter - you need to train so that your leg doesn't fatigue. Sprinters are possibly the only people who might want their balance data a bit better - though it still begs the question what you will do with the information as there seems to be no clear coaching technique for solving an imbalance.

ugo.santalucia

iPete wrote:

I could probably build a wheel that is strong enough for all year riding AND the odd race/TT, something like a 24h Archetype with CX Ray (or other lighter rim?!). I'd then get money back selling my 2 modest wheelsets but I'd miss the whizz of Hope hubs.

Paging ugo to the thread..

If you want a 24 with aero spokes, I would use a less weight weenie spoke, that actually does the job. I can get hold of DT Aero Comp (surprisingly only in black... ) the cross section is similar to CX Ray (1.1 mm Vs 0.9) but it builds a significantly stiffer wheel. They are also a bit cheaper.
Would probably still keep the Hope for those dreadful days (are they not due new rims by now? :shock: ) as the Powertap is a Novatec thingy after all, not the most durable hub/freehub mechanism and you are not exactly easy on your wheels

meanredspider

I do think that over time, there will be better research in how exactly to use left/right power data to increase cycling fitness, but even once those recommendations are made – the ‘estimation’ factor of the current Power2Max implementation would likely mean that they wouldn’t be realistic to utilize it in a left/right setting due to the lack of accuracy in the estimation method (assumption of no residual power). In fact, even Power2Max themselves says there’s little value in it other than from a marketing standpoint

From DC Rainmaker review of P2M. It measures power at the cranks and determines L2R balance just by dividing the crank rotation into two 180deg halves and assumes the torque from one half comes from one leg and the torque from the other half from the other leg. Even if you were sprinting, you couldn't be sure that the power imbalance is actually correct. A perceived lack of power from the left leg (measured on left's downstroke) might actually be caused by the right leg not lifting well on the upstroke.

When it comes down to it, I think the choice is better made just by looking at your personal circumstances: number of bikes, types of crank/chainring etc.