[bigevil]

bit of a head scratcher here so any help in advance is great!

I think I've spent more time than anyone in the world now reading about the various offsets for their threaded chainring options when installing the transmission power meter spider.

I'm running a S Works Epic Evo (which according to specialized is 52mm chainline). The bike came stock with the XX SL Eagle Crankset in 168mm Q Factor with a 32T 0mm offset chainring. (I even verified the Q factor with Sram via the serial number on my cranks) and so based on everything I've seen I should get the 3mm offset right? this page on power meter city (screenshotted below) is great ...... (also this screenshot below from SRAM support).

Problem is, when I installed it all shifting went to hell, the installed chainguard no longer fit and so I swapped it for the 0mm offset (i'd ordered both) and whala, works perfectly. Any idea why this is? I even went to the local Specialized dealer and looked at a bunch of their EVO and Epic Evos with the new power meters already installed and they all have the 0mm offset threaded chainrings. A few friends have all said 0mm offset is how they're running, so I'm wondering why SRAM and everyones literature is so off on this.

 

[SunsetRide]

You state a 52mm CL the bike came with OEM which I'd question. The T-type cassette is offset outwards 2.5mm from a standard cassette which should move the CL out to 55mm from the standard 52mm boost hub w/ std. cassette. You also state the OEM cranks came with a 0mm offset chainring which would seem to indicate a 55mm CL per PM City. Seems to me the T-type power meter with a 0mm offset chainring threaded on matches what the OEM setup was which is a 55mm CL. Is it possible the stated 52mm chainline is for a conventional drivetrain and they didn't update it to 55mm for the Transmission?

My X0 (174Q) runs great with the PM + 3mm offset ring which replaced the stock 3mm offset ring keeping the 55mm CL.

 

[bigevil]

You state a 52mm CL the bike came with OEM which I'd question. The T-type cassette is offset outwards 2.5mm from a standard cassette which should move the CL out to 55mm from the standard 52mm boost hub w/ std. cassette. You also state the OEM cranks came with a 0mm offset chainring which would seem to indicate a 55mm CL per PM City. Seems to me the T-type power meter with a 0mm offset chainring threaded on matches what the OEM setup was which is a 55mm CL. Is it possible the stated 52mm chainline is for a conventional drivetrain and they didn't update it to 55mm for the Transmission?

My X0 (174Q) runs great with the PM + 3mm offset ring which replaced the stock 3mm offset ring keeping the 55mm CL.

funny, that was kinda my conclusion. that their stated matching is for a conventional drivetrain and not transmission. it's the simplest answer and makes the most sense. the bike itself most certainly does come with a 52mm chainline but the transmission is most certainly 55.

 

[rmabreu00]

funny, that was kinda my conclusion. that their stated matching is for a conventional drivetrain and not transmission. it's the simplest answer and makes the most sense. the bike itself most certainly does come with a 52mm chainline but the transmission is most certainly 55.

Hi @bigevil , I’m a step behind you, so your experience can greatly help me! I’m getting a brand new S-Works Epic Evo Ltd, which comes with the new Eagle XX SL 32T, but without a power meter (what I can’t understand in such a high spec!). So I plan on adding the appropriate Quarq power meter, and wondered which model I should be buying, would it be the same as the one which comes in the S-Works Epic World Cup? (I have one, and it comes with a Quarq XX SL power meter crankset, Carbon, 168 Q-Factor, DUB, 34T). I also plan on switching the 34 chainring for a 32 (Cape Epic next year), what I assume should be pretty standard, right? or have you gone a different route? thanks In advance for helping!

 

[SunsetRide]

Power Meter City has the best info on comparability that I have seen.

SRAM XX Eagle AXS Transmission Power Meter Spider

The SRAM XX Eagle AXS Transmission Power Meter Spider is SRAM's newest, most accurate dual-sided mountain bike power meter. Click for information!

powermetercity.com

What Chainring Offset for SRAM Eagle T-Type Cranksets and Power Meters?

SRAM XX SL, XX and X0 Eagle Transmission (T-Type) Cranksets are available in different Q-Factors (168 mm and 174 mm). The chainrings that fit these cranks come in both 0 mm and 3 mm offsets in order to fit both Boost (52 mm chainline) and Wide (55 mm chainline) bikes. Therefore, you need to be...

powermetercity.com

 

[bigevil]

I did probably more research and phone calls / emails than any one should ever do on this matter.

basically though the tech info (both from SRAM and Power Meter City) would indicate you'd want to run a 3mm offset [because its a 52mm chainline bike as per Specialized ] the 0mm offset actually end up working perfectly for this and what I'd recommend. I think it's because the transmission drivetrain ultimately runs a 55mm chainline and so it kinda doens't matter that the Epic Evo is 52mm [this is if you're on the 168Q factor cranks because its non boost spacing]