Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

There's very little reason not to commit to and own a 24mm PM crank. They fit pretty much any frame under the sun, even Trek's stupid BB90, and take a couple of minutes to swap between bikes.

likewise rotor's 3d+ 30mm axle fits pretty much everything - including bsa and ita threaded bb's

You can usually pick up a 3d+ for £100-130 2nd hand if you don't mind waiting.

It won't fit BB90 tho

24 -> everything, with adapters
30mm* -> everything, mostly without bodges, except BB90 in which it won't work at all

*Not to be confused with BB30 :)

Can p2m on a bsa frame?
Looks like the answer is yes.

Now tempted by rotor 3d+ p2m... Just need to decide on a crank length and the trigger will be pulled. Cheers gents.

duh ..

I'd go 3D instead of 3D plus if you are concerned with future compatibility and dont want to pay a lot for BB to Rotor ..

Arrrgh my eyes it burns

I'd go 3D instead of 3D plus if you are concerned with future compatibility and dont want to pay a lot for BB to Rotor ..

This too, see my post above.

The answer is yes. Rotor do a specific BB for BSA frames for the 3d+.

Thanks again. Time to seek some internet based crank length advice...

Where can you actually get P2M from in the UK? The only place I can find anything about them is on their main European website.

I was going to get a Stages (and still more than likely will do), but the hype P2M gets on here makes me feel i should at least investigate. I would need cranks and the unit itself as i run Ultegra - what kind of price would I be looking at?

You can only buy p2m direct from the manufacturer.

FAQ states they deal direct only.

P2M sell direct, from Germany. You could pay from £600ish for one* including chainset and rings, depending on your preferences.

*FSA Gossamer classic, on sale.

There's no hype - it's just a crank based PM that works and doesn't cost as much as a new SRM.

OK thanks folks. So, what does a P2M have over a stages? I'm a beginner at this.

I guess the P2M gives the L/R balance which I think would be pretty valuable as I think I'm quite one-sided in my pedalling

Time to seek some internet based crank length advice...

Turn off your computer if there is still time. Go out on your bike for the 3 hours you'll waste sorting the wheat from the chaff on crank length, the ride will make more difference than any change in crank length within the full range available from Rotor, and they have about the biggest range available.

@jim1985 P2M are a few years ahead of Stages - they've got the experience and ironed out the kinks. If you buy one, it will work as advertised. If you buy a Stages, it may feel like you are still doing beta testing for them*

The L/R stuff is a bit of a red herring, but P2M measures both legs, so if you have an imbalance (you probably do) the numbers are going to be a bit more real. This may or may not matter to you.

* or you might be just fine. Have a good trawl through this thread.

The stages only actually measures the left leg. Then makes a rough Guess that the right is doing the same, and doubles it.

The P2M, being in the spider, measures total Power through the cranks.

The P2M L/R Balance is a bit of a Guess. It knows where you are in the pedal stroke, and it knows the Power output. So it asigns L or R depending on which leg is going Down, basically. Works well enough.

It's been done to death, but the Stages only measures on the left hand side then doubles it so is not totally accurate. P2M measures output on each side so is more accurate.

Does this really matter? Well it depends on how serious you are, but for most of us probably not.

If this thread is anything to go by, then P2M seems to offer a quality product, whereas a number of people have had issues with their Stages pm. At least one of these was swiftly resolved though, so the Stages aftermarket care seems quite good.

The stages only actually measures the left leg.

I am thick but does that mean I'll get more FTP with stages? All my rides power balance is at least 52% and 48% .. not concerned just wondering; last thing I look for in PM is accuracy as a Cat 6-er

This thread needs a FAQ.

Google.

/ask first, Google later

Yes. But if you measure Your FTP With a Device that over estimates, then Train With that Device to set Your zones. It really doesnt matter. So long as its consistant.

I know my L/R is very balanced when putting in a decent effort. But that I favor my right leg when cruising. But as I'm not overly concerned With cruising Power. Its no big deal.

At the end on the day, on paper at least, the Stages Method is fine. But as you can buy better for Close to the same Money. It doesnt make sense unless you want to swap it between track and road.

L/R balance was never an issue until someone made a unit that measured it. If you're that wonky get a bike fit and do some stretches.

Dweebs.

More riding, less staring at numbers.

power was never an issue until someone made a unit that measured it.

.

Your RPE thread is over there, old timer >>>

Or get some Power Cranks*.

*anyone remember those?