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

British cycling members get a big TP discount.

180usd

@mdcc_tester or anyone else.
I couldn't resist that SRAM rival P2M offer. I've got it here now and I have a Force 22 crankset.

Fit wise- they are compatible. Is the suggested incompatibility due to material choice or just P2M being cautious. Changing a SRAM spider is pretty simple

My guess, just from looking is that there should be no difference. Esp as the type S is Rival/Force22 compatible, and the spindle on the Force22 is alloy....
Am I just being stupid?

Where is it stated by P2M that they aren't compatible?

Its not stated anywhere, but from googling- another forum thread suggests a correspondance to that effect.

Having them both here, I can't see a reason why it should be the case.
I mean this is a weight saving of 129g... A bit silly.

Yeah it's weird. When I asked P2M a while ago, they stated that the S900 version isn't compatible with Force 22 because the mechanical interface is different.

But looking at the SRAM S-type, it seems to fit S900, Force 22 and Rival 22.

So I just reckon they sent me the wrong infos.

Got a forum link?

Stick the spider on the Force 22 and then run a set of Powertap wheels to validate the data?

I happen to know where you might get said wheels from...

@Hovis and I compared cranks, he on f22 and me on s900. they're practically identical, and we're running the same p2m without issue.

I don't need more than 1 powermeter/ bike... I'm not @hippy
@Howard http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=132243
Made quite the mess...
Obligatory Murtle Hammer for OG fun.

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OK, so I haven't yet heard about my Vector warranty (I'm due to talk to the LBS tomorrow), but if I wanted to sell the vectors to buy a P2M, which unit would I need?

I currently run an OEM FSA chainset on the TT bike (with Ultegra mech etc), and Sram Rival on the road bike. I have absolutely zero understanding about different BB systems, but both have conventionally threaded BSA BB shells, one fitted with a GXP BB and the other with a FSA Mega Exo BB.

I think I prefer the look of the Rotor options, but what exactly are the differences between the different cranks? Some seem to say they are compatible with different BB systems etc. Obviously I would want to be able to switch the power meter quickly and easily between bikes, and hopefully I don't want to shoot myself in the foot by being tied to a particular BB standard if I upgrade either bike so which ones should I buy and why? Also presumably I'd need to buy two of the associated Rotor BBs for compatibility?

Also I presume all the rotor offerings are compatible with both 10 and 11sp chainrings?

This is all way too confusing for me... I understood how to change pedals...

As @6pt says, the Force 22 and s900 cranks are identical. Same interface, same shape, same everything. Just logos are different. And the spiders + chainrings but they are irrelevant.

The Rotor 3D24 has a 24mm spindle and is compatible with standard Shimano BBs. The 3D+ and 3DF have 30mm spindles. To use these in a BSA threaded frame, you would have to use the Rotor BSA30 bottom bracket. If you don't want to be tied to a particular BB standard then I'd go for the 24mm version. Having said that, I've got 3 BSA threaded bikes all running 30mm Rotor cranks with the BSA30 BB, and have had no problems with them.

Ride it - if it produces goofy values then pop it back on the rival arms and use them.

To answer the question definitively- they are not compatible.
And the reason for this is the P2M Classic's shape doesn't allow for the wider Force22.
Diagram to follow (shit diagram, but whatever:)
The extra bulge at the spindle edge of the Force 22 will not fit within the P2M classic....
Oh well. Back to reassembling everything.

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ahhh, classic not S. I missed an important detail in all the proceedings.

hypothetically, if I wanted two power meters on a tandem (one for each rider), could I just split a pair of pedal meters (like gamins) between the two riders, with the added benefit of the L/R balance telling me which rider was doing which proportion of the total work? I'm assuming the timing chain would fuck up crank based options and wheel based is only good for total power.

I have no interest in actually knowing our numbers, just curious how it would be possible.

Get a powertap and divide all numbers by two. #science

Is someone not pulling their weight?

Sometimes it's hard to tell that either person a or b is smashing it while you pootle along. or vice versa. or whatever. communication can help with this, but a nice little read-out that suggests, for example, that the usual balance of 60/40 is currently 80/20 would encourage a little attempt at equalisation, maybe. but I have no desire to implement anything of the kind (we roll in perfect tandem harmony, obviously), it's just a hypothetical that came up while my brain was wandering down the avenue of 'power on ALL THE THINGS' while dawdling in the lanes this afternoon.

I just took my Vector 2 out for their first ride, having got them in warranty replacement after my original Vectors went wonky. All good so far.

Wouldn't work. Due to leg discrepancy anyway.

If I did that, I'd be telling my left leg off for only doing 40% of the work a lot of the time.

You'd need 2 power meters.

I've been through this thought process. Even had dreams of hooking it to an alarm that is rigged to sound to the slacker should the balance fall below a certain threshold. Or even electricity in the saddle.

I think two powermeters wouldn't really work either. Person A will affect the readings of Person B and vice versa no? How do powermeters deal with back pedalling? Maybe a track powermeter might work. I have no idea to be honest, and shouldn't be talking

pedal power meter for captain (a), power meter in rear hub (c), c-a= power from stoker, b?