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

Yes - but you'd need the other half - the drive side - of the rival crank. Or any Gxp crank.

I see, that is what Skinny was suggesting above then...not ideal really. Thanks.

Yeah it would kind of suck. But you could use it as a pair of training cranks then drop the bb30 ones back in for racing etc. depending on the adapter you used.

Not at all ideal though. Race data being pretty essential.

If it were me I'd want to use a BB30 crank in a frame designed for it.

If you sold the Stages (to one of the circling forum vultures) and the Red crankset that would be fairly cash neutral for P2M I imagine?

Doubt it. New SRAM Red cranksets are only 240ish on CRC at the moment - I've just got some for Cycliste's new build. Can't see a used one getting good money, particularly as BB30 ones usually go for less than GXPs. It'd get you close, but there would still be a hefty shortfall.

£850 for the Rotor 3DF with Power2Max, so minus the £599 for the Rival/Stages we've got a £251 shortfall, so yeah- £150ish would need to be found, maybe a little more maybe a little less.

prompt reply from Stages:

"**Unfortunately none of the SRAM road BB30 left crank arms work with our power meter. The carbon crank arms will not work and the other alloy BB30 option is the S300, which is hollowed out on the inside of the arm and so we can’t attach there.
We will be offering an FSA Energy option in BB30 very soon, but this would require a whole new crankset for you.

The only other possible solution would be if you returned it for a complete Rival crankset and used a bottom bracket adapter**."

Before I commit to a P2M. Are there really any other options?

I've decided on crank based power. I have a 30" inseam measured via the standard bike fit method. So ride 165mm cranks on all my bikes (except SS offroad). All the integrated crank based power meters seem to have a minimum length of 170mm. Which I guess would be OK. Its what I always rode before getting all hung up on silly details.

I have 165mm Rotor 3D cranks though. So I'm a bit tempted to watch Ebay for something with compatitble with swapable crank arms. But which have this....?

TLDR - shut up Smallfurry and just buy the P2M.

P2M I think, or possibly Rotor- but that hasn't got a stellar rep for actually working.

I was looking at a Quarq Cinq. It'd be a touch cheaper asumming I get monies for chainrings, and crank arms. But there isnt much info on swapability of crank arms. I've seen a few seperate SRM spider units. But maybe they all cannondales types?
The Rotor seems a touch over priced to my uneducated eye.

The Rotor had significant issues with cadence- the software was the culprit, it couldn't determine what was a pedal stroke and what was a pothole in terms of the output of the accelerometer.

That is now meant to have been addressed in the latest firmware update, but other companies seem to do that better.

Given your climate and the legion of stories about Quarqs being all over the place for Zero Offset in the wet I'd really struggle to recommend them- plus the look significantly overpriced these days I'd say. What price have you seen for it to be the cheap option?

I have two SRM's and they are great- but there is no getting away from the price.

However, if one comes up that is affordable I'd have no reservations about recommending one- if you scan the Wattage lists for "this is broke"+"type of powermeter" the SRM is generally the least mentioned.

Cheers Dammit.

The Quark Cinqo is currently $900. But it has crank arms and chainrings that are surplus to requirements. Thats a ssuming I could swap my cranks arms in (its also rotor 3D).

I tend not to bother taking the road bike out when its raining. Its already been set-up for winter turbo use. But thats not to say I dont get caught out often enough.

I guess I'll keep an eye out for a SRM bargin for a bit then just order a P2M

Just been reading this interesting user review.

http://jibbering.com/sports/power2max-review.html

Does seem to confirm P2Ms position as the best crank solution for those on a budget.

As a note, I'm aware of the person that wrote that, in racing circles.

I'd trust his judgment hevily. He's a mathematician by profession and a perfectionist obsessive by passion towards cycling.

I did like the mathmatical explanations of zero offset etc. Nice and concise.

So cheap if you can get someone to buy for you.

http://www.power2max.de/northamerica/Produkt/power-meters-en/power2max-fsa-gossamer-power-meter/#!prettyPhoto

Interesting conundrum, I hadn't considered it before, posted on wattage about stages. And a clear issue, drawback.

Stephen - I had the same feeling that data from my stages did't match with what I expected from experience with a PowerTap, then I got the Garmin Vector system and did a ride with it and Stages at the same time - it was clear that Stages was underreporting, as less then 50% of my total power was generated by my left leg - Stages doubles left leg power to estimate total. Vector measures left and right then adds together. I posted the data here (https://groups.google.com/forum/#!searchin/wattage/stages$20vector/wattage/fJ42Uon52Z4/LJnuTgyxoGYJ)

Surely so long as it's consistent it doesn't really matter too much if you only have a stages PM?

Doesn't really matter too much

Yeah. So it does matter, and a fair bit.

We all knew that Stages aint great if you have a significant right / left leg imbalance, no?

Yes.

I think its more of an issue if your power balance changes - so for example at the start of a ride you may be fresh and your power balance is very close to 50/50.

As you tire then your dominant leg may "take up the slack" as it were, and if that's your right leg you'll start to under report, or vice versa.

Personally I've decided that this is something I can live with- but the Stages is not going on my "race" bike, or my training bike- those both have SRM (albeit one of those bikes doesn't exist yet).

Same. Will do for CX and XC races. For everything else there's SRM.

Does it matter? Does anyone really understand whether left and right power is important?

This is a good read on the topic;

http://alex-cycle.blogspot.co.uk

It's not about left or right with stages.

It's about only having left leg power and interpreting right from that. Thus it will not be 100% true power.