School me on P2Max or Quarq

So I got an Tarmac (di2) and was wondering how to set this up with one of the following? What do I need?

Can only comment to say my Power2Max NG has been Flawless in the 3 years I’ve owned it.

Your title answered.

To your question, sounds like a Pairing Issue… Garmin, Wahoo, other?

Can connect over Bluetooth or ANT+

Once Connected, What Fields are of interest to you… Add those! :slight_smile:

I don’t have one but interested. Confused on what I need to buy to get it all working. Spider only, spider and cranks?

Talk to your local bike shop.

Well ok…

I have a Power2max NG eco, it’s been set-and-forget for several seasons. I’m using shimano chainrings, had to buy rotor 3D cranks from p2m as the NG eco is not compatible with the shimano cranks. If you have other cranks they may be compatible. Their support was also helpful and responsive. If you email them this question and details about your bike they’ll point you to a compatible model. I’m not affiliated with them in any way, just have had a great experience with them.


As @aldenhart explains, I did exactly the same. Bought Rotor 3d24 cranks (now they have new cranks ALDHU or you can buy the cheaper option from P2M, slightly heavier) and NG eco P2M. Set it up in May 2018 and since then I only change batteries (and had to re-tighten it once because I didn’t put Loctite on).

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I have P2Max. You can put them on a crank that has a removable spider. I don’t know what crank you have on yours. specialized s-works?

P2Max has a specialized spider than you may be able to fit on it, cheaper, and just remove the rings, put the spider on, and add new rings (P2Max sells with Praxis 5-bolt rings, not the 4 bolt Shimano rings ).

If you have a Shimano crankset, you need a whole new crankset with power meter. That’ll be like buying a Quarg as well.

I have NG and NGeco. I like the battery on the NGeco better than the rechargeable on the NG. The NG has better calibration though, as well as being more expensive.

If you’re buying a crank, make sure it fits. I think you have the OSBB thing, so I would definitely look at 30mm spindles, though 24mm wouldn’t hurt neither.

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Depending on the cranks fitted to your Tarmac, you might only need a PM spider which can be bought on it’s own.
I’m a big Quarq fan but I would be happy with either of those PM’s for solid reliable numbers.

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Thanks all and that is what I was looking for. I am ultegra but will reach out to there support to make 100% sure. I am trying to look and get a ballpark.

It’s not totally accurate, as there are later cranks with removable spiders (such as FSA modular), but it is in the ballpark. Shimano, though, is accurate as it’s not a removable spider.

you can get the 4-bolt Shimano pattern, so you can reuse your rings.

Thanks and appreciate it.

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