Pacenti's I35-END Carbon wheelset marries decent quality hubs to super solid asymmetrically profiled carbon rims with a broad 35mm width best suited to tyres over 2.6" wide. They're not particularly light, but they make up for that with the ability to cope with plenty of abuse and the price is respectable for carbon too.
Unlike many brands, Pacenti doesn't tout carbon fibre as a method to drop weight, rather preferring to use it to boost strength in their mountain bike wheels, something that's shown in the 1,802g weight (no valves or tape) for this 650b pair. They've certainly stayed totally true despite some decent beatings and there was nary a hint of detectable lateral movement in use.
While the name hints at these being the rims for enduro riders and racers in the lineup, they have a broad 35mm internal width which makes any tyre under a 2.6" feel overly square in profile. Tried with 2.5" Maxxis WT and Michelin rubber (a fairly common choice for enduro types, I'd say) it threw the tyre profile out of whack when cornering and when run at pressures low enough to get grip from the more upright sidewall, rim strikes became much more common. Sticking with 2.6" and above tyres was perfectly fine, so be warned.
If you're running rubber slimmer than that, you'll almost certainly be best off with the I30-TR wheelset, which has a 30mm profile and is also claimed to be a smidgen lighter, using the exact same hubs and a rim that's very similar, just scaled down. There's also a 27mm wide XC setup too.
The asymmetrical carbon rims use a hookless bead, but you needn't worry about burping them under hard use; a hooked bead doesn't have much effect on how well your tyre stays put and the I35 rims have an inner groove that really locks the tyre in place as extra insurance anyway.
Both front and rear wheels have a count of 32 Sapim spokes, though the front is laced two-cross and the rear three-cross to better deal with pedalling forces. The hubs are cartridge bearing units from Bitex, which proved to be smooth rolling and reliable throughout the test period.
It's possible to get them in Boost or non-Boost spacings, while there's a full range of interchangeable freehub bodies on offer, with HG, XD and Micro Spline all available - all with a nicely rapid 54 tooth/6.6° engagement.
One small grumble is that the rims don't come pre-taped for tubeless. Pacenti will sell you a roll of tape for £7 and valves for £12, but you'll have to do the work yourself; they say it's because doing the job immediately before tyres are put on leads to a better seal, but I'd still prefer someone to do the faff for me.
All in all, if you're a serial wheel beater that's looking for a set of sturdy carbon wheels to run with high-volume rubber, then the I35-END Carbon wheelset hits the spot. The I30-TR setup is probably the one to look at if you run anywhere from 2.4" to 2.6" tyres, however.
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