I’ve ride Speedplay chromos for a while. I was thinking of upgrading to a lighter model. Is there a real significant gain ? It’s rotating weight, so every gram should count, right ?
I already have great shoes, a clean drivetrain (stock pulleys, no oversize or ceramic), good racing tires, etc.
Your thoughts? Thanks !
I love light stuff too. So, if you can afford them, then light pedals are a nice thing. But, they will probably not make a measurable performance difference. The crankset is relatively low RPM, and it is generally always turning. And, the incremental weight savings of the pedals may be 30g on a 700g crankset, so only a 4% weight change on just the crank.
You mentioned other stuff. Changes that do make a difference are things like a fast chain and lube, deep aero wheels, a good aero helmet, aero brakes, a good aero cockpit, etc. All of those would be orders of magnitude more significant than the pedal weight.
Upgrading speedplays specifically for weight wouldn’t be worth the money to me. Even the chromos are fairly light compared to other systems. I prefer the stainless axles to the chromo mostly for looks but the body is more or less the same. If you want lighter, you can get aftermarket ti axles for pretty cheap on ebay, a lot cheaper than a new pair of speedplay ti pedals. I haven’t tried these as I’m a Clydesdale so I am over the weight limit for speedplay ti axles.
If you have budget for, and need new pedals anyways, consider the speedplay zero aero. This will have more overall performance gains compared to the oz or two in weight reduction (pedals aren’t spinning fast enough or far way enough from its axis to concern yourself with rotational mass) . According to Jim at ERO it can be a couple watts compared to the regular zero.
The short answer is no.
The long answer is yes, if you are doing a lot of climbing in the bike, and you add multiple small weight savings. Like aero changes, it all adds up… but less so than aero.
Every gram you save gives a performance improvement, however small (and assuming there are no detrimental side effects e.g. something that is lighter but less aero).
Whether it’s worth it depends entirely on how much money you’re willing to spend on cycling. If money spent on lighter pedals means you can’t afford another upgrade that gives more performance benefit e.g. a more aero helmet, deeper wheels, better tires, then it’s not worth it. If you’ve already gone after all the low-hanging fruit and still have money you’re willing to spend then go for it 
What do you mean by lighter.
If you mean titanium I would not prefer that over steel. Recommended max weight is 84 kg for titanium.
Although titanium is at least as strong as steel, it’s elasticity modus is different such that it bends more. If the geometry is the same with steel and titanium axes, (probably the case) the bearings will wear quicker with titanium than with steel axis due to more bending.
It’ll have virtually no effect except on total bike&rider mass, which is already a very small factor in performance except when climbing. The mass saved in in the pedals is tiny as a proportion of the total bike&rider mass so the benefit will be pretty negligible. It’s certainly not a good value upgrade in terms of performance to cost ratio.
The difference between the impact of rotating versus fixed mass is also IMO constantly overstated in cycling. Rotating weight matters more than fixed when it comes to acceleration, but that’s hardly an issue in triathlon or TTs. Pedals, cranks, chainrings, wheels, tyres, and to some extent shoes, are essentially just flywheels. If anything more rotating mass may be helpful in smoothing out your effort. For track sprints and at a stretch criteriums this might be a performance upgrade worth considering but otherwise I think it’s pretty pointless.