I been riding Shimano pedals…no real issues.
just been reading more and more about these speedplay aero pedals. it seems pretty convincing they are legit faster. stack height is lower, adjustability is more versatile.
before I spend a bunch of time with buying them and setting them up and riding around:
why would you NOT use these?
I already have assiomas
As someone who used Speedplay pedals for a long time, they required greasing, although I’ve read the new pedals are sealed and you don’t grease them, so this may not apply. The cleats wore out faster. They’re also a pita to clear if you happen to step in mud, so I had to carry covers with me when I rode. I have no way to prove this, but despite being told they’re better for people with knee issues, I actually think they contributed to mine as my knees have gotten better since getting rid of them.
The positives were that depending on the model you can adjust the float and q-factor if needed, but I do wonder if having too much float contributed to my knee issues.
already own 2 pairs of non aero ones, currently only one road (tri) bike, pretty sure my pedals are never coming out of my cranks and I’m cheap.
I am a fan though been using speed plays since 09? and would replace my tri bike ones with the aero ones if needed, but I have a spare pair so also probably not.
I do run the aero cleats on my tri shoes.
As a former Speedplay user I got tired of the cleat and cleat cover issue. Other than that they are good pedals.
They cost a lot and they need an adapter to work with most shoes. Also I remain irritated that they discontinued the X-series, rendering both my sets obsolete when I run out of cleats.
Not to mention the X-Seirs were superior to the Zero pedals. 
I’ve been on Speedplay pedals since literally Day 1 when they came out and I still have a pair of my my original pedals with the all-alloy body. (I did switch to Shimano for a brief period when I was doing tri’s). I love them and think they are the superior system, but lots of people don’t get on with the feeling of the rotation.
I rode Speedplays for several years. I think the low stack height only applies if you have a speedplay-native shoe, of which there are few. Beyond that the cleats are a PITA to live with, especially if you ride in wet/muddy conditions. Look and Shimano road pedals are the closest thing to foolproof components these days, and the “gains” available with Speedplay are incredibly marginal at best.
Before the plastic fairings on the cleats, I didn’t like walking around on the aluminum surfaces and screws and clogging the engaging mechanism to road debris before, after, and during stops when riding. The current plastic fairings solve the issue of walking on metal, but the mechanism still picks up dirt/mud/debris, though to a somewhat less degree. Looks have worked for me for years and and the benefits of switching would be inconsequential.
The availability of spare parts. Debris in cleats and the lifespan of them outside. Discontinuation of products. Faster? it’s not going to make a difference for mere mortals. My years on all sorts of bikes, with all sorts of brands of stuff on it, have tought me one valuable lesson: I will stick to what the majority uses. Purely anekdotal ;)…
I use regular speedplays. They work well, low stack height, good adjustability, I’ve not had any issues with longevity, greasing them is pretty easy once you’ve done it a few times and replacing the bearings and/or spindle also pretty cheap and easy. One of the things I really like about them is the 2-sided clip in. The roads I ride involve a lot of stops, and a lot of situations where getting away quickly is useful. With regular speedplays you pretty much just stomp and go, I notice I nearly always get away quicker than non speedplay users who just need that extra moment to flip the pedal and clip in.
The aero ones are one sided, with the base being dimpled. I’ve not used them but seems to me that clipping into those is likely to be significantly harder than a Shimano or Look type pedal where there is a more distinct shape to flip and clip. Which obviously matters not a jot in a TT or race where you usually only have to clip in once. But I think would really annoy me for every day use. So then you’re into buying a pretty expensive component for racing only, and swapping them on and off for race days. I think if I was more into TTing where every watt counts I’d probably do it. But not sure the hassle/cost-benefit ratio is worth it for road racing!
They are expensive. To get both the TI axle and the aero bottom you have to buy a bunch of parts and assemble one very expensive set of pedals.
That pretty much says what I was about to say.
Except my experience with the post-buyout cleats: RUST!!
Also personally I bought in to the ‘knee problem’ mystique and after spending time adjusting the (original) cleats, felt dialed in, but sometimes tweaked them (and the screw heads eventually failed). Hard to say it, but there was too much flexibility in the cleats. The adapter for the cleats is included, but installation is not for the ‘low intelligence’, or easily frustrated. (A friend did his own install, (skipped the adapter) and crashed several times before getting a LBS to tell him he did it totally completely tragically wrong 
AND that’s after multiple people offered help! (He went on rants about how they sucked too 
))
I switched to Shimano SPD-SL after the rusting issues on the trainer, and even with ‘knee issues’ (multiple ‘scopes’) was perfectly fine. IMO Speedplay is for some people who really need more adjustment than the SPD-SL system provides, but seem like ‘gluten free’ to me in that I’d wager most people don’t actually need them, and likely have too much float which could be a problem because they didn’t adjust their cleats (which is a PITA sometimes)…
The Aeros being single sided is same as SPD-SL (obviously) but if used with Speedplay compatible shoes, should have a low(er) stack height. 
The Aero should be ‘slick’ when riding, but how much would an SPD-SL user lose? If you already use the Shimano system, why change for a minuscule possible gain. At one point, I was running three different pedal systems, it got ridiculous.
But dirt in the cleats? I never had an issue with that during normal road use. I also used spray lube for the cleats every month or so. Greasing the pedals was what I rarely did, and they survived just fine (except on my trainer). Spraying the cleats helped allow that ‘c’ ring to rotate in the cleat body. If that ring seizes, the cleat can be disassembled and cleaned. If the ring gets warped (I’ve seen it happen) the cleat needs to be disassembled and straightened/replaced. I did pull the cleat screws out of the adapter on a pair of shoes once, leaving the cleat on the pedal. YMMV
Because I’ve had the same Ultegra road pedals since about 2008.
so my situation is I need new pedals anyway.
I just got a new road bike and ordered it with Dura Ace SPD-SL +4mm pedals. I guess I measured wrong and want to move my Q factor in a touch and ran out of room with my cleat. so I was gonna get the Dura Ace regular pedals PD-R9100 (and sell the +4mm on ebay).
so the price for speedplays ~ gonna be the same for me in my situation. I weigh more than the titanium version allows so that’s not an option.
stack height is 3mm difference for my current shoes. 6 mm difference if I get 4 holes with my next pair of shoes (I’m good for a few more years with my current shoes - but at some point). I feel like that’s not nothing - especially the 6mm. especially if I need pedals anyway 
lowering my saddle 3 or 6 mm has gotta be worth a watt or two I would imagine.
I guess if I was gonna try speedplay the 2 sided would be the most practical since I do stop and start quite a bit on my rides. just super compelling to get 3-4 “free” watts with the aero ones. my current shimano are one sided anyway. I average ~25-27 km/hour on my most common rides. so I guess over 25% of that will be in the 30+km/hour range where aero will matter more.
but yeah none of that matters if I hate the pedals or they are a pita or rust.
I mean I know there’s only one good way to find out - but just wanted to hear your thoughts before I spend a bunch of hours tinkering…tyty
There is absolutely nothing that will convince me those watts are real over the course of a ride when you add in all the other factors that go into riding a bike. It’s great marketing though.
Yeah, as someone who is an habitual “toes down” peddler, there is zero chance those watt savings apply to me (if anyone!)
True, but…
The new post-buyout cleats are pressed steel: rust. I have a NIB (New In Box) pair of Zeroes that I was going to change to but after the cleat issues, they sit in a drawer somewhere, unused. (And I’ll be the first to say the pre-buyout aluminum cleats were really tight and tended to break at the beginning of the ‘c’, but at least didn’t rust)
For the SPD-SL, I found a template measurement device that actually works rather well to copy a setup from one pair of shoes to another. The side effect of the Speedplay system is that it’s easier to replicate the ‘fit’, where the SPD-SL has been a problem before I found that thing. I thought of passing the Zeroes to the wife because she doesn’t ride much, but she hates clipless so Maybe if I save them long enough, they might be worth something as an antique. (I was wearing my CBGB shirt while traversing the airways last week and was confronted by a Delta gate agent who complimented me on ‘still getting out there, in spite of your age’. 
I’M NOT THAT OLD DAMMIT!!! (My wife laughed, she hates that shirt) ) Maybe Speedplay will outlive me.
ME TOO!! I was ripped for my ‘pedaling style’ on several rides, thought I was the only one. Mean people SUCK!! I call them ‘mashers’: flat footed… Although ‘mashing’ does stretch out the achilles more.