What kind of tension do you prefer ? Red or yellow carbon parts ?

16nm is perfect for me, could even be more and I wouldn't care. I'm 200 lbs.

I agree, 16Nm. I struggled with the same decision and am very glad I went with the stiffer spring. I'm not particularly big or powerful (165lb., Cat. 2 in Nor. Cal. if that means anything to you) and find the tension fine. In fact, like the previous poster, I'd be fine with a few Nm's more, tho' 16 seems pretty good. I do like a very solid entry/exit, so if you prefer an easier feel go with the 12. You're not gonna pull out of either (like all previous Keos you're only getting out if you twist out intentionally) so it's really a personal preference. FWIW, I use grey or red cleats.

I also wonder if the tension might lessen a bit over time. The carbon spring itself shouldn't change, but the metal ends on the spring and the contact points between spring and pedal might wear a bit.

I'm not specially powerfull and definitively not a sprinter.
Is the blade tension decreases with time ?

I wonder this too, though I highly doubt it. You'd think that they could do enough testing cycles in a month or two to simulate typical clip ins/outs over a few years of riding to see if any issues developed.

I thought my 16Nm Blades were very heavy when I first got them compared to my old Shimano SPD-SL's.

Acclimatised very quickly though, and have to say they are perfect now. Couldn't imagine riding with any less tension. Very nice and positive clip in action, though the way Look pedals hang demands some adjustment if you're not used to it...

I've done a few thousand km's on mine, and can't say for sure that the tension has reduced, rather I think its just me that has gotten used to them.

Definitely the 16nm, the 12nm feels like you are going to fly out of the pedals. As a matter of fact, my speedplay zero's have more release and entry tension than my 16nm blades.

16Nm. It's really easy to clip in, and getting out is definitely not a problem even if it's a little stiffer. 16Nm blades might be thicker/stronger too.

I have the 12 Nm, and definitely have not felt ever that my foot was going to pull out, even when bunnyhopping. My friend disengaged from his Time iclics while bunnyhopping and almost crashed. If anything, even the 12s are more difficult to click into than Look Keo Plus or Look CX6 with the old delta cleats, and the iclics. I'm glad I went 12, and would go 12 again.

I've got almost 10,000 miles on 12s and while I don't feel like I'm going to accidentally clip out, I think I'd rather have the 16s.

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2013 Wilier Cento1 SR || 2009 Ridley Crossbow || 2011 Yeti AS-R 5 Carbon

I have the 12s, never tried the 16s. The 12s have a more positive engagement than the standard Keo's and I can't recall anybody complaining flying out of the pedals with those... barring worn cleats.

How many of you who posted in this topic actually tried both ?

16 nm without question, they are easy and fine, best pedals ever. beautiful snap in and out, carbon hopefully wont loosen or soften like springs do. I used previous the keo carbon ti's they replaced (nice and light but springs got too loose) as well as dura ace and various other look, bonti, etc including time atacs on all my bikes. Keo blade 16 nm is perfect and not nearly too tight, best pedal ever (so far) imo.

I think it's really a perception issue. I've used 12Nm for 1000miles so far with never coming close to accidentally clipping out.

I bought them mainly because I was able to find them cheaper than the 16Nm. But still more than happy with them. Just wished the yellow stripe matched my bike.

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My 09 DiS2
My 10 Vigorelli
My 09 Kilo

16Nm for sure

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@racecarbrian

I've been using the 12Nm for over a year now, and I've never had a problem. I recommended a buddy get the 16Nm because he is about twice my size, and just yesterday I clipped into his bike to try and figure out a rattle he was hearing... I couldn't believe how stiff the 16 felt. I personally found them much too firm for my liking.

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"Deserve's got nothing to do with it." William Munny