Rolf Prima Eos AR Wheelset
The Rolf Prima EOS AR is the highest specification all-road wheel Rolf makes. It shares its 40mm deep, 25mm inner width rim shape with the Ares4 AR but uses a different carbon lay-up developed for this model, drops to 16 spokes per wheel, and moves up to the XST 7.0 hubset with Enduro XD-15 ceramic bearings and a ballistic armor coating. Rolf lists the pair at 1385 grams.
This is a wheel for the rider who wants one set for road racing and gravel racing and wants the lightest, fastest option in both. Gravel Cyclist called the EOS AR arguably the best all-rounder they had ridden and noted that the low spoke count did not compromise durability.
Sixteen spokes on a 40mm carbon rim only works because of Rolf's paired-spoke design. Pairing the spokes at the rim cancels the left and right pulling forces, so each spoke can be tensioned higher and more evenly than in a conventional lacing. That is what lets the EOS AR combine a climbing-wheel weight with a deep, aero rim.
Design and construction
The rim is a carbon, tubeless-compatible clincher with a mini-hook bead, 40mm deep, 25mm inner width and 31mm at its widest. Rolf says the mini-hook takes anything from a 28mm road tire to a 50mm gravel tire. The set ships with tubeless tape and valve stems installed.
The hubs are XST 7.0 Centerlock: US-made, Cerakote ballistic armor coated for corrosion resistance and easy cleaning, with Enduro XD-15 ceramic bearings and a CNC-machined titanium freehub body. The T2 high-engagement drive uses a 48-tooth ring and three sprung steel pawls.
Lacing is 16 front and 16 rear with bladed Sapim CX-Ray spokes in Rolf's paired pattern. Brake interface is Centerlock disc. Front axle options: 15mm, 12mm thru-axle or 9mm QR. Rear options: 142mm thru-axle or 135mm QR. Freehub bodies: Shimano HG 10/11, SRAM XDR, Campagnolo and N3W.
How it rides
The EOS AR is the fastest-feeling wheel in Rolf's all-road range. It is light enough that a steep climb on 30mm tires feels like a climbing wheel, and the 40mm depth keeps it rolling on flats and descents. The ceramic bearings and T2 drive contribute to a wheel that spins up with very little effort and picks up instantly. Crosswinds are well controlled for a 40mm rim thanks to the wide, blunt profile.
On gravel, the EOS AR is a race wheel. The wide bed supports a 40mm tire at low pressure and the carbon rim takes the sting out of washboard, but with 16 spokes and CX-Ray blades it is a precise, firm wheel rather than a forgiving touring one. It suits lighter to mid-weight riders chasing speed on mixed surfaces. Bigger riders or those loading the bike should consider the 20-spoke Ares4 AR or 24-spoke Hyalite Carbon. Ridden within that envelope, the EOS AR is the rare wheel that is competitive on a road race start line on Saturday and at a gravel race on Sunday without swapping anything but tires.
Specifications
| Wheel type | Adventure / Gravel |
|---|---|
| Rim | Carbon clincher |
| Rim depth | 40mm |
| Rim width | 31mm, 25mm internal |
| Brake | Disc Brake |
| Spoke count (F/R) | 16/16 |
| Spokes | Sapim CX-Ray, bladed |
| Hubset | XST 7.0 Centerlock Ballistic armor coating T2 High Engagement Enduro XD-15 Ceramic Bearings |
| Front axle | 15mm, 12mm, 9mm |
| Rear axle | 142mm, 135mm |
| Freehub | Shimano HG 10/11, SRAM XDR 11/12, Campagnolo 11/12, N3W |
| Tire size | Please refer to chart in product images |
| Weight | 1385g [610g/775g] |
| Includes | Tubeless tape, valve stems and Rolf Prima's Certainty |
What this page sells
About this Eos AR Wheelset listing. The choices on this page are front axle: 15mm Thru Axle Front, 12mm Thru Axle Front, 9mm QR Front; rear axle: 142mm Thru Axle Rear, 135mm QR Rear; driver type: Shimano HG 10/11, SRAM XDR, Campagnolo, Campagnolo N3W. This listing is the complete wheelset - front and rear together, not a single wheel.
Fit and compatibility
The EOS AR is 700c and disc only with Centerlock mounts. Front end caps cover 12x100, 15x100 and 9mm QR; rear end caps cover 142x12 and 135 QR. Boost spacing is not offered on this model.
Freehub choices are Shimano HG 10/11, SRAM XDR, Campagnolo and Campagnolo N3W. Rolf approves 28mm to 50mm tires on the mini-hook rim. We suggest 28mm to 32mm for road use and 38mm to 45mm for gravel events. Because the EOS AR is Rolf's most expensive all-road wheel, we encourage you to confirm your frame spacing and cassette type with us before ordering rather than after.
Rolf Prima's testing and certifications
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
Rolf Prima builds by hand in Eugene, Oregon. Hand-built at the factory means what it means here, that each wheel is tensioned and trued by a person rather than released by a machine, which is why we are comfortable selling them beside the wheels we build ourselves.
Ordering it from ProWheelBuilder
Rolf Prima hand-builds every EOS AR to order in Eugene, Oregon. We sell it here at ProWheelBuilder in Georgia and review each order for the correct axle and freehub before it goes to Rolf. If you are unsure whether you need XDR or HG, or whether your frame is 142 or 135, ask us and we will sort it out with you.
We also build custom wheels on Astral rims, Rolf Prima's rim brand. If you like the idea of a 40mm carbon all-road rim but want a different hub or a higher spoke count for your weight or terrain, we can build 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. This is a complete wheelset built by its manufacturer rather than in our shop, so the maker's warranty above is the one that applies to it. ProWheelBuilder's own one-year wheel warranty covers the wheels we build. We will still handle a manufacturer claim on your behalf.
Full terms are on our Policies & Warranty page.
Eos AR questions
Is ProWheelBuilder the manufacturer of the EOS AR?
No. Rolf Prima makes the EOS AR in Eugene, Oregon. We are a reseller and handle order review and configuration advice.
What makes the EOS AR different from the Ares4 AR?
Same rim shape, but the EOS AR uses a model-specific carbon lay-up, 16 spokes per wheel instead of 20, and XST 7.0 hubs with Enduro XD-15 ceramic bearings and armor coating instead of XST 4.4 with steel bearings. Rolf lists 1385 grams versus 1515 grams.
What tire sizes fit the EOS AR?
Rolf states 28mm road up to 50mm gravel on the 25mm inner width mini-hook rim.
Do the ceramic bearings need special care?
Rolf says its ceramic bearings are serviced by cleaning and re-greasing rather than replacement, and any local shop can do routine service.
Is the EOS AR available in Boost spacing?
No. Rolf lists 142mm thru-axle and 135mm QR rear options only.
Is the EOS AR covered by a warranty?
Yes. Rolf's Certainty program includes a five-year warranty, lifetime crash replacement and permanent parts availability.
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.
