I asked this same question in the Long Distance forum but probably should have posted it here.

I have a set of American Classic wheels on one of my bikes that I do long distance rides on. I have the opportunity to pick up a set of Krsyium SL’s at a reasonable price but wondering if there’s much to gain?
I don’t know what model AC these are so posted a couple of pictures.

Always need another set of wheels : ]

Hard to tell exactly what model without more shots of the rim, especially any labels on the rim. Anyway, I had a custom set of wheels with those hubs and I liked them a lot. Older by today's standards, but free spinning and solid. I personally wouldn't want a set of Ksyriums in their place.

unfortunately all the decals were removed prior to me getting them. I guess for all I know the hoops are not even AC?

AC made some of the best wheels ever IMO, however, these are not their top spec model. If the point is to get a better wheelset, you need to decide what that means and compare features, stuff like internal width, tubeless compatibility, weight, rim height and spoke type. Maybe you want faster hub engagement or some future-proofing with axle type changeability? Or maybe you want more stiffness and need to look at flange height and width and bracing angles.

We don’t even know which Ksyriums you’re looking at specifically so what can really be said here? I think hose said it best upthread: it’s alwys good to have a second set of wheels. You can just get them then decide which pair you like best, or you can even mix and match…that’s kinda weird though.

Correct. They sold those hubs by themselves as well as on the CR420 and Victory 30 (and probably others) wheel sets. Super light hubs, but someone just mentioned width and the models I just mentioned (and most rims offered at the time those hubs were new) are narrow by today’s standards.

I have the American Classic Victory 30 set. If you can believe the published specs, they are lighter than most carbon wheels and moderately aero. In the five years that I have had them, I have never had to true them even once. The hubs are not the prettiest, but bullet proof and have never been serviced in over 20k miles.

Sadly though, AC is out of business. Again.

Oh, and FWIW, when I built my bike I asked about Mavic wheels, but the LBS strongly urged me to get the AC instead. I am glad I did.

Yeah, I have a years-old Victory30 wheelset that has been perfect, too. I think AC published weight as 1547g the year I bought them, maybe back in ‘15, so I dunno that’d I’d say they’re lighter than most carbon fiber, but they are rather light for 30mm deep aluminum wheels and were 18mm internal width back when virtually nothing else was. I also have two pairs of their crazy Argent wheels, which are a shocking 1390g, 30mm, 19.4mm internal alu wheelset, but it was the 1285g Road Tubeless set which were the real lightweights!

Anyhoo, the brand name now belongs to one of their old project managers, and is a going concern offering some impressive value tires at the moment: https://www.amclassic.com

I just looked a set of Chris King Enve wheels going for $3000 and not even in stock. Published weight is 1583 g. They look cool as heck, but for $3k I can buy another bike. What am I missing here?

It's not clear if you're asking a serious question or making the point that the Victory30s were a good value, but in case it's the former, there are certainly more affordable CF wheel options which weigh less. Comparing apples-to-apples (meaning, rim brake, around 30mm deep), how does the in-stock availability-- and I don't even know why that's relevant since the AC wheels have been out of production for probably three years-- of Lun Hyper 38 rim brake from Winspace at 1267g and $1,200 change your assessment? Or what about a wheelset like the Dura Ace 9100 C40 rim brake at 1508g and $1.6k which are in-stock at CompetitiveCyclist? ProBikeKit have the 30mm deep, 1340g Racing Zero Carbon in-stock for $1,700, and the Vision SC30 are 1,330g and $1200. Point being, there are available, lower-weight and -priced alternatives to the $3k, 1580g King/Enve wheels.

That said, I'd not have preferred any of those to the ~$600 Victory30, but I think we're in agreement that AC really ruled the roost when it came to performance, quality, and value.

Not trying to hijack this thread, so this is my last comment: Alloy rims can be as light as carbon. And while there are some real aero advantages to the carbon shapes, I don't think that the typical recreational ride with see any of those, at least not a significant amount. If you are racing, then sure, get whatever incremental gains you can. For me.....group rides at 15-18mph....probably not worth it.

Maybe up to a point, defined by rim depth, which I’d put somewhere around 25mm - 28mm. I don’t know that there are many CF rims below that profile height—what would the point be of not maximizing the material’s advantages?— to compare to, but looking at the examples I gave above, it’s pretty clear that once you hit 30mm, CF rims really have a lower weight advantage.

Regardless of whether a rider thinks they’re getting aero benefits from a deep section rim, or whether the weight makes a difference to them, I’d think they want the deeper rims anyway for the improved wheel strength.

The only reasons not to go CF are costs and possibly looks, because low weight, strength, and aerodynamics are firmly advantages to carbon fiber.

I have a Micro 58 front and a 205 Rear hub that I believe I will build up this year. I have a ten year old set of the same, and they're on their second rim each. A lot of trouble free miles on them.

I wish they had made some early changes to avoid their demise. I had a set of their Am Classic Argent Disc Tubeless wheels that were fantastic. Smoother and those hubs just rolled forever...easily bypassing the DT240s which I think roll well. The rims were light and maybe too light for tubeless tire changes but they were probably the best light alloy wheels I have ever seen.