jwalther

Pedal based systems provide more information than hub based systems (cadence, balance, power stroke, etc.). This information may or may not be helpful to the OP.

kansukee

But he already has a cadence sensor and based on what he wrote about just getting started with this stuff, I don't know that he wants/needs stuff like balance. 99% of us don't need that crap anyway.

Larry77

The P1s pedals are the single-sided Powertap pedals so they are cheaper, I think MSRP is $699. P1 is both sides, P1s is single-sided. I have a club I ride with sponsored by the below bike shop so my discount is a little bigger but it looks like they are on sale as well...

https://www.westernbikeworks.com/pro...d-power-pedals

chaadster

Ah, P1S...I see. I don't think I knew there was a single-sided P1 system, so that explains a lot. Thanks.

SpeshulEd 

But the greasy chain all over your fingers is a pain.

Also, what happens when you want to run different sized tires on a different bike. I can throw my powertap pedals on either of my two road bikes, my track bike, my beater, etc within a matter of minutes, while you're over there swapping tires so you're not skidding your fancy race tire when you're on the fixed gear.

chaadster

Powertap is offering a power meter trade-in deal-- 20% off P1 and P1S pedals-- today through the 27th, which brings the cost down to $960 for the dual sided system and $560 for the single sided system.

It looks like Excel Sports may be offering the discount straight up, no trade-in: https://www.excelsports.com/main.asp...jor=3&minor=33

124Spider

OP here.

Thanks again for all your help!

Because of the cost, I am not religious about "balance." But I do think I would find it useful; my right knee is what caused me to have to stop running, and it tends to hurt from time to time. Although my right leg is my dominant leg, I clearly have lost muscle mass in it compared to my left leg since I stopped running. Hence, I would like to know whether I'm putting equal power into my stroke. Further, since I'm pretty much out of cartilage on both knees, I expect knee pain to be a regular thing in the future, so I would like balance data.

I'll look at eBay and Craigslist, but I likely will save my pennies for the next year or so, before pulling the trigger.

Thanks again; this has been very helpful.

Mark

124Spider

OP here.

I kept wanting a power meter, and I kept not wanting to spend that much. So I started looking at other options.

None of the hubs would fit in my wheels, and by the time I bought a new set of wheels, there was no point, so I rejected hubs as a solution.

And started looking at cranks. Now, that's complicated, because of the geometry of my bike, and the native Rotor crankset.

One thing led to another, and I finally ordered a Rotor InPower. I'm quite pleased; it seems to be an excellent two-sided solution for much less than the pedals cost, and I don't need a different pair of shoes.

I'll update when it's on and I've used it a bit.

Mark

base2 

Ebay and craigslist to the rescue. My first and only carbon wheels came from Ebay. I HAD to have carbon, and I HAD to have power. So I went on a search and after a few months found a "Buy It Now" of Powertap G3 Amp 35 wheels for $1000. This is back when they were $2500 new.

Then I picked up a "recently overhauled" Pro+ hub that was in a set of DT Swiss R460's with a dangerously worn out brake track for $200 and a free hardly used Alex Rims Race 28's. $100 later, all was swapped around. I bought it because even if it was broken junk, a factoring in a full overhaul was cheaper than new. The seller was legit, so it was a *really* good deal. $300 all told.

My third one was a $800 splurge for a G3 Disc hub. Wanted one for a particular bike for 2 years before the old wheels finally gave out (seized front hub and perma-bended rear) I bought Mavic wheels with the relevant criteria met purposely with the hub in mind. I rode them for 5 months until everything came together. Expensive with out a definite budget, a plan, and a work bonus set aside for the purpose. I don't know the total cost, and even if I did, I'm not sayin' 🤑

And the fourth one was also an Ebay find. $35 after shipping. (sort by price) Yes, thirty-five dollars. Same cheaper to overhaul idea...but Powertap ran a 30% off on trade in deal, so I sent it in and got a new G3 instead for $50 more than a overhaul would've cost. I built up some Velocity A23 rims. Powertap wheelset, hubs, spokes, hoops & labor ~$800...and Made in America at that!

What I mainly use them for is interval training. wattsXminutes type activities, budgeting power resources, and Strava fitness/freshness metrics now that they are on everything I ride.

If you have a wheelset you are happy with, labor cost to swap an overhauled hub is reasonable.

Visit Powertap's website and find out what they won't overhaul before purchasing. I know the LYC (yellow cap ones) are out, the rest may be in with few exceptions. Overhauling is a complete replacement with all NEW G3 internals, bearings, etc... but all in the old shell. The bearings of older units are rumored to not last forever, and they are rumored to have water ingress issues but I have no experience on that last point so you might well find it a worthwhile effort if you are trying to be cheap about things and don't realistically expect 20k miles (?) between bearings and I don't ride it under water. Someone else chime in with a mileage estimate. Please. I've never worn out a rear hub of any kind, just fronts for reasons I can't explain.

124Spider

OP here, with an update. I bought a Rotor InPower crank meter, since my bike has Rotor cranks. It's fine, except that it reads way too high (between 10% and 40% too high, depending on several variables). So it's going back.

Next up is a Power2Max, which has a good solution for a bike with a Rotor crankset, and is full power.

I'll report back after it's in.

PepeM

Too high compared to what?

124Spider

Reality.

As measured two ways. First, it is always way high against my Wahoo Kickr. So I compared it to other Wahoo Kickrs, and it's also very high compared to them. Also, when I look at my segment times on Strava against others with similar times, I'm always showing way higher average power then everyone else (and I'm not an outsized person).

I have no doubt it reads very, very high.

PepeM

First of all, to be clear, I am not trying to tell you that you're wrong. I've never seen neither the device nor the numbers, so I have absolutely no way to know anything about it. Now, with that said: Smart trainers are widely known to be unreliable when it comes to power measurements. When discrepancies arise between a power meter and a smart trainer (and they always do,) the power meter is the one to trust. As for Strava, well, that is even worse. Many, many times are done within group rides. Also in different days obviously, with different conditions, which can affect times, or the power required to achieve the same time.

Again, not saying you're wrong. My point is that once you find a power meter that you are happy with, don't try to make the numbers match with everything, especially not with much less reliable methods, it just doesn't happen. Even among real, high quality power meters there are discrepancies some times. That is the main advantage, imo, of getting something higher end as opposed to, say, a Stages (or relying on the numbers from a smart trainer that when you get another (higher end) power meter, you have a much higher chance of getting both devices to agree to a reasonable extent.

DaveLeeNC

I bought Garmin Vectors a couple years ago (before the P1 option) and am happy with that decision. While I am unlikely to move those bike to bike, I really like having 'normal freedom' to choose any wheels I want to chose and not have to mess around with them to get power. Right now I only have two sets but I can imagine acquiring a 3rd soon.

Based on my experience if your power readings against similar speeds on Strava are consistently high, then it probably is an issue with the readings.

dave

cthenn

Or you can just buy a plug-and-play crank based power meter. There are cheap options out there, and for a rec cyclist, more than adequate.

ddub

Had the Garmin pedals but they had some drop out issues and I sold them. First generation so perhaps they are more reliable now. I went to a crank based PM and have been very happy with the SRAM Quark and the Power2Max. Both come in cheaper in most cases than the Garmin pedals and once set up they are accurate and reliable.

DrIsotope

Going against the grain of seemingly most on this forum, I have had no issues with my Stages whatsoever. Pairs quickly, stays paired, holds calibration well, and the output is more than precise enough for my needs. I see a weird power spike no more than maybe twice a month.

Plus, a PowerTap hub to fit my bike would set me back about $700. NOPE.

ddub

I totally forgot about Stages. My daughter-in-law has one and it's been virtually flawless. She even swaps it between her road and cross bikes, Shimano cranks.

124Spider

OP with an update.

I got the Power2Max Type-S yesterday; it was fairly easy to swap the InPower out and the Power2Max in. I just did a session on the Kickr, and the Power2Max tracked the Kickr exceptionally well.

So first impression is very good. I'll check back in with an update after I've used it for a while.

alathIN

I wouldn't expect power numbers to match in the different scenarios OP is describing.

Ex, trainer vs. real life: I use my Quarq on my trainer with trainerroad.com, AND for real life rides. So it's the exact same power meter. And I routinely generate numbers on real life rides that I can't match on the trainer. Normalized power and FTP are pretty close, but peak power, like climbing a steep hill, is radically higher on real life rides.

Also I would never expect my power numbers to match someone else's for a real life ride, and especially not for Strava. I go on group rides with people who are more experienced cyclists, roughly the same size as me, similar bikes and tires, we're together the whole time, and their power numbers are much lower at the end. They're just better riders, more efficient, whereas I am working harder because I'm wasting energy all over the place. Someone could have different tires or tubes or pressure and easily throw in another 10-15 watts discrepancy. Then there are different head units and how they are reporting the raw power data. I would expect Strava to be even more random - some riders aren't actually generating actual power data, it's just being estimated by whatever app they're using.

Just about all the strain gauge power meters on the market are as accurate as any of us need in the raw data. But once you start reporting and comparing, you introduce a million other variables that are much more random than the meter data.

124Spider

alath, we'll have to agree to disagree on this. I'm now happy that I have a power meter that reports rational levels of power, rather than the ridiculously high numbers the InPower meter reported (being a Zwift god wasn't worth having faulty data ).

When my power number always was a couple of standard deviations above anyone else's numbers for the same speed in the same segment, something was wrong; I don't like paying big bucks for faulty data, so I didn't.

alathIN

I don't blame you, and I didn't mean to be contradicting you. I should have clarified, I was commenting that your experience is an outlier.

Did you say up thread that you were using a rotor crankset? That is actually one of the things that DC Rainmaker talks about that it's very tricky to get accurate power data from asymmetric chain rings. I wonder if that's why you had the problems you did?

124Spider

Yeah, I have a Rotor 3D30 crankset/BBright. I agree that my experience was an outlier, but it surprised me since it was a Rotor power meter that was giving me the odd readings. The Power2Max I got to replace it uses my stock crank, except replaces the spider. And I'm confident it's working as advertised.

124Spider

OP here with an update.

I continue to love my Power2Max; it just works. It's a PITA to replace the battery, but the battery lasts a long time, so that's not so bad.

As a lesson learned, for anyone reading this thread who is contemplating buying a power meter, my wife and I bought a tandem, and wanted power meters. That required getting pedal-based meters (obviously), so we bought Garmin Vector 3S pedals. They work just as well, except (i) the batteries don't last nearly as long, but (ii) the batteries are much easier to change. Had I suspected that I would be buying another bike, a more transferable power meter would have been in order (but the Garmin Vector 2 wasn't very good, so it's not a disaster. But with the Garmin Vector 3 being so good, I'd just get that.