Onza Tires are now based and designed in Switzerland, although this is an entirely different company than the one that gave us the white Porcupine rubber you may remember from the 90's. The Citius has been around for a few years and is available in 26" and 27.5" size in a 2.4" width.
I opted for the 1230 gram DHC downhill casing, though Onza also makes a lightweight FRC casing, along with an EDC casing which was one of the first 'enduro specific' tires that weighed in at just over a kilo with a great casing. There are also three compounds to choose from with two dual compound rubbers in 45/55a and 55/65a, and this super soft, single compound, 40a Visco GRP rubber.
Onza Citius Details
• 27.5" x 2.4"
• 40 x 40 TPI
• Wire bead
• DHC casing
• Visco GRP 40a compound
• Weight: 1230 grams (actual)
• MSRP: €70.90 EUR / $84.90 USD
Being Swiss, the Citius is not cheap, and the DHC/Visco model is the most expensive Onza option retailing at €75 / $90 USDImpressions
At 1230 grams, my tire weighed 60 grams less than Onza's stats and falls in line with other downhill tires. The dual layer of 40x40 TPI casing is tough and has a similarly well-damped feel to Maxxis DH casing tires. Even though the tire is not officially tubeless ready, it set up easily and sealant and air didn't seep through the sidewalls, something that can happen over time with other DH tires that aren't tubeless ready. Onza do offer a TLR version combined with other carcasses.
We found the Citius to suit 25mm rims best; 30mm rims seemed to be the limit as the tire started to become too square and we didn't entertain the idea of going wider. The casing measured up at 56.5mm (2.23") on a 25mm rim and nearly 60mm (2.36") on the 30mm rim.
There are many great tire choices out there, and the most important factor in performance is matching tread to terrain. The Citius is best suited for rocky and dry trails, where the dirt doesn't get too deep. Under braking, the Citius doesn't squirm on hard terrain but lacks a shovel like edge for hooking into soft ground. The traction area of the tire has been maximized by using sipes and shapes and this really helps the tread to mold and track on to harder surfaces and edges, especially immovable rocks and roots, wet or dry.
The super soft Visco compound and not-so-chunky side knobs were vague on fast, hard packed bikepark turns, the feeling being closer a Maxxis High Roller edge than the sturdier edge of a Maxxis Minion, for example, but they loved biting and tracking through softer, but not deep dirt. That deep dirt was where the Citius would lose traction with its 4mm deep central tread.
The damping qualities of the Swiss formulated Visco rubber are superb, and although it's a soft 40a durometer, the rubber has worn much better than some equivalent softer tires, with no cracking or knobs tearing off. Pinkbike's Take