Power meter any day.
A disc wheel will save some time but depends on what you are moving away from with the disc wheel, but even over a longer distance event the time saved is not massive.
A power meter will do so much more for you overall.

PM, and then a disc cover for $100 FTW

QFT.

If you really want to win the value game, buy a used meter in a crank based setup for like $250.

We have a couple "Power Meter or..." threads. So, I'll consolidate:

1. Power Meter
2. Disc wheel
3. Di2
   

Knowing what I know now, I wonder if not having my 4 different PMs if I could train to be just as fast. My best year on the bike I just road a hell of a lot. Average was almost 16hours/week with big weeks just over 24, if my recall is correct. Now, I didn't do any intensity in my riding and used races to get that intensity in. Not sure how a PM would have been beneficial in that scenario.

For pacing a time trial it's a valuable tool, but outside of blowing my load right out the gate I pretty much just ride a steady and hard effort for my TTs. That is, I try to hit my target but usually end up below and I am just pushing the whole time to get up to it. Then there is the whole TSS deal and managing stress, but I also have found just eating and sleeping well handles that better than watching my TSB or whatever we are calling it now.

So, all the above is open to debate and I am sure plenty will dismiss and or slam me for saying such a thing. For example, I could have been faster had I done intensity in training, used my PMC to better structure my training, raced less recovered more, had a better target for race day, etc. Well, woulda/coulda/shoulda, I'll never know. What I do know is that a disc makes me faster, as does Di2. I know that second bit sounds wonky, but I have found that Di2 takes stress out of shifting, allows for me to be in a better position on the bike, and gives me the freedom to shift more. And all of that is with running 1X.

Therefore, my personal ranking:

1. Di2
2. Disc
3. PM

As I have gotten older I have gotten away from training and have gotten back to just enjoying the ride. Yeah the PMs are still there because I like the numbers. ;) But, following the simple concept of ride more, get plenty of rest, and watching my diet I get fitter and therefore faster. PMs play zero roll in that facet.

All that being said, I know the value PMs provide and my rankings are more of a 1a, 1b, 1c. I just don't feel PMs are the break through in training that others claim them to be to place them above a disc wheel or di2. Just one man's opinion.

---

My YouTubes

Powermeter without question.

Power meter. If you will use the power meter correctly in training and racing, there is no question. (If you treat it as a curiosity and don't work it, it too would be a waste.) There are several equipment purchases that I would place between the two.

Depends on the wheel you have now and what type of power meter.

I recommend the Garmin Vector pedals as they can go from bike to bike, indoor, outdoor, etc.

If you are going hub based power meter, you can get them on a disc or aero wheel.

If you already have an aero wheel (like a ZIPP 404 or deeper), go for the power meter.

If you don't have an aero wheel on front, don't get a rear disc without upgrading the front wheel.

Power meters will help improve your performance if used right long term over aero wheels.

---

Ryan
http://www.SetThePaceTriathlon.com
http://www.TriathlonTrainingDaddy.com
I got plans - https://www.trainingpeaks.com/...dotcom#trainingplans

Neither have to be particularly expensive. Wheel covers are less than $100 and I recently bought a Stages left side meter (ver 2) for $100. Shimano 105 crankset to pair with it, $90. Stages dash $130. Now I can swap that meter between multiple bikes--one road and one gravel. When I get an mtb, if I do, it will work there too. Considering that I remember paying $1300 for my first PM, that is astounding to me. I actually used the PM for a while with just Strava, but felt like the numbers were suspect.

Disc Wheel...

I tend to agree with Lai above...I train indoors enough now, and have a power meter on my Hammer...just don’t see the need anymore to have it on my race bike...my $.02

Depends on what you are looking to gain in your sport.
A powermeter will allow to measure your effort. Along with a coach and structured plan it can help you to train better, hence lower your times on the bike.
A disc wheel will automatically lower drag in most situation, so you'll likely lower your times too. But it won't help you improve your fitness.
Funny fact, many cyclists learned how to get a better RPE with the powermeter on their bikes. Now they are more interested in putting money elsewhere to get better gains on such as variables drag, aero, etc...

Louis :)

This is me too, I have a kickr for power based workouts. I do have a PM on my bike, but honestly have never used it. I didn't find I really paced by it during various races, more went by feel. I plan to sell my PM.

This of course assumes you have a power based trainer. You can get a Tacx Flow Smart for about $400 US.

For me its
1. Smart trainer
2. Disc
3. Di2
4. Comfortable quality skinsuit
5. Aero helmet that fits well and is cool enough
6. Good Quality tires
7. Anything else kit related
8. Maybe a PM just for eye candy

You are almost making my point...power meter can be great for training...and the emergence of indoor training takes care of this for me...so I do not feel the need to have a power meter on my bike. For me...if i am really paying attention during training...just using HR and Perceived Exertion is good enough on race day...for my enjoyment of participating.

The OP’s question leaves necessary details out...so really no one answer in this thread is wrong...

There is a HED jet disc with a PowerTap on EBay for under 400$.

How much? what is it?

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

In my mind, it all comes down to one question....

How many watts would a disc wheel save you?

---

Alan Couzens, M.Sc. (Sports Science)
Exercise Physiologist/Coach
Twitter: https://twitter.com/Alan_Couzens
Web: https://alancouzens.com

9100 stages gen3 165mm. Honestly haven't thought about price yet as I hadn't decided for sure about selling....but probably will.

I think I'm really looking for a 170. Whatever I get will wind up doing double duty on tri and road bikes, at least until I can afford a second one. But if you do decide to get rid of it, keep me in mind.

Damn, toddlers are expensive creatures.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

the cost isn’t even close to the same for a disc wheel that is “comparable” to a powermeter. I would compare a HED Jet disc to a Power2max—both very solid in their respective fields, neither is top of the line but both get great results. But the disc is wheel (retail price) more than double the price of the powermeter. So I think your question is based upon a fallacy.