some general thoughts

There is a fair disparity between one Chinese seller and another... so hard to compare. You pretty much know what you're getting with the CS.

That said, there's nothing terribly unique about the CS ones... if you buy the knock off's, just lube the bearings yourself (or replace if need be)

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There are other options between CS and aliexpress as well. SLF Motion has been teasing some "revolutionary" new products. Not sure if those are related to the OSPW systems, but on that front they did at least just revamp the carbon process. More to come on December 1st apparently.

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I guess it depends upon how attached you are to $350.. there are otehr options as well like Kogel, and a few others I can't think of right now. That said the benefits are small gains but so is a good chain lube. In some cases the thing is you need to replace the cage to get the over sized pulleys to fit which I think in many cases is part of the expense as well, beyond exotic 3d printing and ceramic bearings.

I have bought a chinese version from aliexpress (this one, I see the solid 9000 'TT' version is out of stock now). It was ~$56usd and likely one of the cheaper options out there.

I'd hardly say they're crap (rather, the opposite). The jockey wheels spin 'forever'. I haven't actually measured how long they spin for (i could take a video of it if you'd like), but I can say that I don't know what more to expect from something that's $350 more.

The carbon cage is very thick in comparison with my Dura Ace cage. It looks like it's overbuilt and I'd imagine this translates into it being a little stiffer at the cost of a slight increase in weight. I'm fine with that compromise (the weight of these is irrelevant to me).

In my case, I needed one of these to replace a broken D/A cage and I think was a good call for me.

Lots of different versions/sellers of these carbon pulleys out there to consider. Good luck in your search.

Thanks! Great review.

I've been running a kcnc one. Seems smooth and stiff enough. No idea if it equates to watt savings, but positives are:
1. Looks good
2. Alloy wheels don't collect the same amount of crap the plastic ones do.
3. Looks good

Bad points:
Noisier, but any alloy jockey is.

No way id drop the money on a CS one, but if you've got the cash then go ahead.

I've got several thousand miles on the Digirit OSPWs. I can't offer any concrete evidence they've made me faster, although when I spin my crank backwards it definitely turns easier than with the stock pulleys (same wheel & freehub) and it does make the drivetrain feel a bit smoother. I'm sure it's a very small savings but I think there may be some minor benefit to be had. The pulleys definitely spin very easily.

One thing I'd note is that the oversize pulleys increase the wrapping capacity of the derailleur and you have more flexibility in setting the chain length to what you prefer. I'm not sure if it increases the max cassette size but that's something I'd like to test some time as I wouldn't be surprised if it does.

I think the Digirit is a bit more sensitive to shifting adjustment than the stock Dura Ace 9000 cage it replaced, it shifts fine when properly adjusted but the range of proper shifting adjustment seems narrower.

No way I'd pay for the Ceramicspeed OSPW but for the modest price I paid for this item I can't complain.

Did you have to replace your chain (to something longer) when you replaced you pulleys/cage?

I believe I did move to a slightly longer chain, yes.

Ceramic speed's own website listed a DA pulley set at within 1/4 watt of their best set. They're often online for around $40 instead of the ludicrous amounts for the larger diameter ones.

Ultegra ones, often what someone already has.......was listed as only 1/2 a watt slower.

I get there are supposed to be bend radius gains, but some guys on one website I came across did a study where the aero penalty of a longer cage (that isn't a RALTech) plus weight penalties and such..........you weren't winning out at all much any longer.

The UK TT scene seems pretty split on this. Folks do both the DA pulleys with a custom carbon aero cage and folks do the OSPW stuff.

I've just purchased a shadow clutch RD and will probably experiment with what I can do with a RALTech style cage while trying to avoid a kludgy and often not per the rules "cover".