Rolf Prima Black Rock Carbon 27.5IN Wheelset
The Rolf Prima Black Rock is Rolf's 27.5 inch carbon mountain bike wheelset, built for riders who, in Rolf's words, live to rip but do not want to give up climbing speed. It uses a hookless carbon clincher rim, 30mm deep with a 28mm inner width, laced with 24 paired spokes per wheel to Rolf's US-made XST 4.4 hubs. Rolf lists the set at 1585 grams.
The Black Rock is for the trail and all-mountain rider on a 27.5 bike who wants a stiff, playful carbon wheel with a titanium freehub, a fast-engaging hub and a real warranty. The 30mm rim depth is deeper than the Alsea 30, which Rolf describes as built tough enough to handle whatever you throw at it.
Rolf makes a point that the paired-spoke look should not fool anyone on the trail. The balanced tension and stiffness that pairing provides, by canceling the left and right pull of each spoke pair at the rim, apply on singletrack exactly as they do on the road. That is what lets the Black Rock use 24 spokes on a wheel meant to be ridden hard.
Design and construction
The rim is a hookless carbon clincher, 30mm deep, 28mm inner width and 33.5mm at its widest, tubeless ready and shipped taped with a valve.
The hubset is XST 4.4: designed and machined in the USA, assembled in Eugene, with Enduro steel cartridge bearings, a CNC-machined 6Al-4V titanium freehub body and the T2 high-engagement drive. T2 uses a 48-tooth ring with three independently sprung steel pawls, twice as fast as Rolf's older 24-tooth ring.
The Black Rock is laced with 24 round Sapim Race spokes per wheel in Rolf's paired pattern and mounts Centerlock disc rotors. Front end caps are offered in Boost (15mm or 12mm), 15mm, 12mm or 9mm QR, and rear end caps in Boost 148, Boost 141 QR, 142mm thru-axle or 135mm QR. Freehub bodies offered on the Black Rock: Shimano HG 10/11, SRAM 11/12-speed and Shimano Micro Spline.
How it rides
The Black Rock is the more aggressive of Rolf's two carbon mountain wheels. The deeper 30mm rim and Sapim Race spokes, which are heavier gauge than the Laser spokes on the Alsea 30, give a stiffer wheel that holds a line when you push it into a rutted corner or land off a drop. The 28mm inner width suits 2.3 to 2.5 inch tires and keeps them stable at trail pressures.
On the climbs the Black Rock is still light at 1585 grams, and the T2 drive engages quickly enough that technical ratcheting is easy. It is a firm-riding wheel, as hookless carbon with paired spokes tends to be, so it rewards a rider who likes precision over plushness. Rolf pitches it as point and shoot, and that is how it rides. Like every Rolf wheel, the Black Rock is covered by the Certainty program: five-year warranty, lifetime crash replacement and permanent parts availability, and Rolf says routine service can be done at any local shop.
Specifications
| Wheel type | Mountain |
|---|---|
| Rim | Carbon clincher, hookless |
| Rim depth | 30mm |
| Rim width | (ex): 33.5mm, (in): 28mm |
| Brake | Disc Brake |
| Spoke count (F/R) | 24/24 |
| Spokes | Sapim Race, round |
| Hubset | XST 4.4 T2 High Engagement Enduro steel cartridge bearings |
| Front axle | Boost (15mm, 12mm)/ 15mm/ 12mm/ 9mm |
| Rear axle | Boost 148mm/ Boost 141mm QR/ 142mm/135mm |
| Freehub | Shimano HG 10/11-speed, SRAM 11/12, Shimano Micro Spline |
| Tire size | Please refer to chart in product images |
| Weight | 1585g [735g/850g] Diameter: 27.5" |
| Includes | taped |
This version
This page is the Black Rock Carbon 27.5IN Wheelset itself, not a custom build. The choices on this page are front axle: Thru Axle 15x110mm Boost Front, Thru Axle 12x110mm Boost Front, 15mm Thru Axle Front, 12mm Thru Axle Front, 9mm QR Front; rear axle: 148mm Thru Axle Boost Rear, 141mm QR Boost Rear, 142mm Thru Axle Rear, 135mm QR Rear. This listing is the complete wheelset - front and rear together, not a single wheel.
Fit and compatibility
The Black Rock is 27.5 inch only. Front end caps cover Boost 110 (15mm or 12mm), 15x100, 12x100 and 9mm QR; rear end caps cover Boost 148, Boost 141 QR, 142x12 and 135 QR.
Freehub bodies are Shimano HG 10/11, SRAM 11/12-speed and Shimano Micro Spline. The rim is hookless, so use tubeless tires the manufacturer approves for hookless rims and follow Rolf's pressure chart on the product images. We recommend 2.3 to 2.5 inch tires on the 28mm inner width. If your Black Rock will see bike park days, tell us; we may suggest a heavier-duty custom build instead.
What Rolf Prima says about testing
Rolf Prima builds every complete wheelset by hand at its facility in Eugene, Oregon. The company states that all orders are built by hand there by its own builders, and describes its process as building each wheel three times with two stress cycles in the build to seat and stretch all components. Rolf Prima says hand building lets it hit uniform spoke tensions that machine building cannot match, and that its design allows higher and more targeted spoke tension than a traditionally laced wheel, which it credits with increasing stiffness and improving spoke durability by decreasing the load cycle on each spoke.
The defining feature of a Rolf Prima wheel is Paired Spoke Technology, introduced in 1997. Bringing the spokes to the rim in pairs neutralizes the left and right outward pulling forces, which Rolf Prima says allows it to build true wheels on lighter rims with fewer spokes. Fewer spokes and lighter rims are the basis of the brand's aerodynamic and weight claims. The wheel systems combine paired spokes with the Delta rim profile, internal nipples, and patented details including the Jacketed Nipple, Self-Aligning Nipple, Differential Flange Diameter and Dish Reducing Design. Rolf Prima cites eleven patents behind its technology.
Rolf Prima runs an in-house engineering and testing lab and states it uses the ISO 4210 standard as a base starting point but considers it not tough enough, so it applies its own in-house standards. Published test capabilities include an in-house drum fatigue tester it calls the Thrasher, which compresses years of riding into days; an impact test using a weight calibrated steel anvil that exceeds the UCI 40 joule requirement, striking at spokes, between spokes and at the valve hole; lateral and radial stiffness measurement of rims alone and complete wheels; brake energy, distance and temperature testing developed for carbon clinchers; wind tunnel evaluation; and field testing by sponsored athletes. The Certainty page cites over 10,000 hours of lab testing to above industry standards.
On racing eligibility, Rolf Prima explains that UCI approval only matters for mass start UCI road races, UCI cyclocross and draft legal ITU triathlon. Its standard wheels (Aspin and the Elan family) do not require approval, while most of its deeper or lower spoke count models are non standard and are listed on the UCI approval registry. Rolf Prima does not publish a fixed rider weight limit; it says every wheel has limits that involve riding style and road conditions as well as weight, and directs heavier or more aggressive riders toward stiffer models such as Vigor, Echelon or Ares6. All road wheels can be set up tubeless with the brand's tubeless kit, and adventure, cyclocross and mountain models ship tubeless ready with tape and valves installed.
Rolf Prima backs its wheels with the Certainty program: a five year warranty against defects in materials and workmanship for the original owner, lifetime crash replacement at a discount for registered wheels, a 30 day trade out or return window in the USA, replacement parts availability for any Rolf Prima wheel regardless of age, and stated service response times of same day to 24 hours on calls and email with service work resolved within three days of receipt.
Rolf Prima's videos
From Rolf Prima




Warranty and certifications
- Limited warranty — Five years from original retail purchase against defects in materials and workmanship (2016 and newer wheels), original owner, non transferable; decals and bearings two years (source)
- Certainty program — Five year warranty, lifetime crash replacement, 30 day trade out or return in the USA, replacement parts for any Rolf Prima wheel regardless of age, same day to 24 hour service replies, service work resolved within three days of receipt (source)
- Crash replacement — Lifetime crash repair or replacement discount for the original owner; wheels must be registered within 30 days of purchase; proof of purchase and serial numbers required; freight not covered (source)
- UCI approval — Non standard models (rims taller than 25 mm, fewer than 16 spokes) are listed on the UCI approval registry; Aspin and Elan are standard wheels that need no approval (source)
- Test standards — ISO 4210 used as the base with tougher in-house standards; impact test exceeds the UCI 40 J requirement; in-house drum fatigue, stiffness, brake and wind tunnel testing (source)
- Hand built in USA — All wheels hand built in Eugene, Oregon; each wheel built three times with two stress cycles; eleven patents (source)
Sources on Rolf Prima's site:
- Rolf Prima: Testing
- Rolf Prima: Paired Spoke Technology
- Rolf Prima: Our Technology
- Rolf Prima: Certainty Program
- Rolf Prima: Warranty
- Rolf Prima: FAQ (UCI, rider weight, build process)
Everything in this section is published by Rolf Prima. ProWheelBuilder is the seller, not the tester, and the wheel reaches you as the maker builds it.
A note on Rolf Prima
The Vigor is Rolf's longest-running profile and their best seller, and the ES version has been a staple of triathlon wheel choices for fifteen years. A rim shape that survives that long in a market this faddish is usually telling you something.
Ordering it from ProWheelBuilder
Rolf Prima builds each Black Rock to order in Eugene, Oregon. We sell it from ProWheelBuilder in Georgia and check your axle spacing and freehub body against your bike before the order is placed with Rolf. If your bike is a mullet or you are unsure about Boost versus non-Boost, ask us and we will confirm. Decal colors and hub options for the Black Rock are chosen at order time as well.
Custom mountain wheels on Astral rims, Rolf Prima's rim brand, are another option we offer. If you want a 27.5 carbon rim with a different hub, a 28 or 32-spoke build, or a matching 29 inch front for a mullet setup, we can quote that for you.
Warranty
Manufacturer's warranty. Rolf Prima gives a one-year limited warranty on its wheels under normal use. Astral is Rolf Prima's rim brand; ask us and we will confirm the current terms for the exact rim before you buy.
ProWheelBuilder. Because this wheelset comes assembled from its maker, the warranty that applies is theirs, set out above; ProWheelBuilder's one-year wheel warranty is for wheels we build here. Either way, a claim goes through us and we will manage it.
Full terms are on our Policies & Warranty page.
Black Rock Carbon 27.5IN questions
Is ProWheelBuilder the manufacturer of the Black Rock?
No. Rolf Prima builds the Black Rock in Eugene, Oregon. We are a reseller and handle your order.
Black Rock or Alsea 30?
The Black Rock is 27.5 inch, 30mm deep with a 28mm inner width and Sapim Race spokes. The Alsea 30 is 29 inch, 25mm deep with a 30mm inner width and Sapim Laser spokes. Both use XST 4.4 hubs and 24 paired spokes.
Is the Black Rock rim hookless?
Yes. Use hookless-approved tubeless tires and follow Rolf's pressure chart.
Does the Black Rock fit Boost frames?
Yes. Boost 110 front and Boost 148 or Boost 141 QR rear are offered, plus non-Boost options.
Which freehub bodies are available?
Shimano HG 10/11, SRAM 11/12-speed and Shimano Micro Spline.
What does the Black Rock weigh?
Rolf lists 1585 grams, about 735 grams front and 850 grams rear.
Not sure? Text or leave a voicemail on 470-253-0929 or email info@prowheelbuilder.com — you will be talking to the people who build wheels for a living.