Astral Outback Carbon Rim
The Astral Outback is the carbon gravel rim from Astral, the rim brand of Rolf Prima in Eugene, Oregon: a wide inner bed for 38 to 50mm tires, Astral's Tubeless Easy bead, and a carbon layup with extra material at the bead and spoke bed that makes it the tough, light gravel and adventure rim in the Astral range. It is the carbon version of the Wanderlust for riders who want the weight saving and the damping of carbon on rough gravel.
This page covers the Astral Outback Carbon Rim in 27.5in. The Outback is not sold bare. You choose the hub and the rest of the build in the configurator, and it ships from our shop in Georgia laced, tensioned and trued by hand.
Design and construction
The Wanderlust is a welded double-wall aluminum rim with a 24mm-class inner bed that gives a 42mm gravel tire a square, stable shape at low pressure, a Tubeless Easy bead shelf that seats and holds a tubeless tire without drama, and spoke holes angled toward the hub flanges so the nipples sit straight and the wheel builds to even tension. The section is deep enough to be stiff under a loaded bike and the walls are thick where rock strikes land. Standard nipples, J-bend spokes, disc only.
How it rides
An Outback wheel is light, quick and forgiving on rough gravel. The carbon rim takes the sting out of washboard, the wide bed keeps a 45mm tire stable at low pressure, and the reinforced bead shrugs off the rocks that dent alloy gravel rims. It is the Astral rim for gravel racing and fast adventure riding; for a lower price the alloy Wanderlust is the same profile.
Specifications
| Wheel size | 27.5in |
|---|---|
| ERD | 544.5 (27.5in) |
| Inner width | 28 mm |
| Depth | 30 mm |
| Drillings | 24h, 28h, 32h |
| Weight | 360g (650b/27.5in) |
| Material | Carbon Fiber |
| Tire type | Clincher Tubeless Compatible |
| Brake | Disc |
| Profile | Triangle |
| Spoke bed | Offset 2.5 mm |
| Nipples | External |
| Finishes | black |
This listing
This is the 27.5in listing of the Outback, 24h, 28h, 32h, about 390g, 28mm inside, 30mm deep, disc. Pick the size that matches your frame; the profile and construction are the same across the range.
The disc version of the Outback has no brake track, so the sidewall is a plain extrusion that saves a little weight and never wears; it is the one to choose for any disc-brake frame. The rim-brake version, listed separately, has a machined sidewall.
Sizes, fit and compatibility
The Astral Outback Carbon Rim comes in 27.5in and 24h, 28h, 32h drilling. It is a disc-brake rim. We build the Outback on DT Swiss 350, 240 and 180, White Industries CLD, Industry Nine 1/1 and SOLiX, Chris King R45 and Hope RS4 hubs, usually with Sapim CX-Ray, D-Light or Race spokes or DT Aerolite and Competition, and brass nipples.
Tire range on the Outback is 38 to 50mm. Pick gravel or bikepacking as your bike type in the configurator and it recommends a spoke count and lacing pattern.
Put it in a custom wheel
Build a custom wheel around the Astral Outback Carbon Rim — the link drops you into our Custom Wheel Program with this rim pinned, ready for you to choose the rest. It is set up for gravel and road disc, tandem and e-bike, mountain bike and MTB single-speed builds.
Spoke head is decided by the hub, not the rim: this rim builds equally well with J-bend or straight-pull spokes, and the configurator only offers the spokes that match the hub you pick.
What Astral says about testing
Astral Cycling is the rim brand of Rolf Prima; both operate from one facility in Eugene, Oregon, where Rolf Prima states alloy rim production has been in-house since 2014. Astral joins alloy rims with a press-fit sleeve about 2.5 inches long weighing 4-5 g that doubles the wall thickness at the joint, avoiding the heat-affected zone of welding. All wheels are hand-built in Eugene. Rolf Prima states it does not farm out testing and has logged "over 10,000 hours of lab testing to above industry standards."
Astral and Rolf state they use ISO 4210 "as a base starting point but it is not tough enough." Their drum fatigue tester runs at 47 mph against the ISO 15 mph, putting over 3 times the energy into the wheel, with a life requirement 66% higher than ISO. Impact tests use a calibrated steel anvil to the UCI 40 J standard and then a higher in-house level, at spokes, between spokes and at the valve hole, including pre-heated rims. Rolf's carbon brake protocol runs ISO 4210 dry and wet tests, 300 W for 15 minutes twice, 400 W for 16 minutes twice, 450 W and 500 W for 16 minutes, and 500 W for 3 minutes followed by the UCI impact test with no failure allowed. No rider weight limit is stated.
Astral's videos
From Astral
Certifications
- Made in USA (alloy rims and wheels) — Astral and Rolf Prima state alloy rims are rolled and all wheels hand-built in their Eugene, Oregon facility; rim production in-house since 2014 (source)
- ISO 4210 base + in-house standard — Fatigue drum at 47 mph vs ISO 15 mph, life requirement 66% above ISO; UCI 40 J impact plus higher in-house level; ISO 4210 dry/wet brake tests (source)
- UCI note — Rolf Prima FAQ: Aspin and Elan family are 'Standard' wheels not requiring UCI approval; no approved-model list verified (source)
- Rolf Prima Certainty — In-house engineering and testing lab, eleven patents, over 10,000 hours of lab testing, 5-year warranty, lifetime crash replacement (source)
Sources on Astral's site:
- Testing – Astral Cycling
- FAQ's – Astral Cycling
- Astral Rim Warranty – Astral Cycling
- Technology – Astral Cycling
- Rim Joining: The Process and the Mystery – Astral Cycling
The figures, certificates and media above are Astral's own. ProWheelBuilder does not run these tests; our part is the wheel we build on the rim.
Building it at ProWheelBuilder
Astral makes the Outback; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. Every Outback wheel we build gets spokes cut from the rim's measured ERD, is tensioned in stages with a gauge, stress-relieved and trued before it ships. Tubeless tape and a valve are fitted on request.
In the configurator you will only see parts that fit this drilling; combinations that are not made are struck through, and the price updates as you pick.
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. If we lace this into a wheel for you, that wheel also carries ProWheelBuilder's own one-year warranty, which covers broken spokes regardless of cause and all wheel-related labor, including truing and rebuilding, for a year from purchase. Where a rim or hub is covered by its maker, we make the manufacturer's claim for you and coordinate it; where it is not, we offer an eligible replacement rim or hub at 25% off current retail. Shipping to and from us is the customer's. This cover does not extend to wheels built from components you supply yourself.
Full terms are on our Policies & Warranty page.
Outback Carbon Rim questions
What tire width suits this rim?
At 28mm inside this is a trail width, sized around 2.1 to 2.4in tires. That is wide enough to stop a modern trail casing rolling under you in a corner without pushing the tread so flat that it wears down the middle.
Which spokes and nipples suit the Outback?
For most riders a double-butted spoke such as Sapim Race or DT Competition with brass nipples; lighter riders can go to Sapim Laser or CX-Ray. The configurator recommends a gauge and count for the Outback from your bike type and weight.
Is the Wanderlust tubeless?
Yes. Astral's Tubeless Easy bead seats a tubeless tire with a floor pump; we tape and fit a valve on request.
What tires fit the Wanderlust?
38 to 50mm. A 42 to 45mm gravel tire is the usual pairing.
Wanderlust or Outback?
Wanderlust is the alloy gravel rim; Outback is Astral's carbon gravel rim, lighter and stiffer at a higher price.
Who is Astral?
The rim brand of Rolf Prima, the wheel company in Eugene, Oregon; Astral rims are designed by wheel builders for wheel builders.
Is it tubeless-ready?
Yes. Astral lists the Outback Carbon Rim as clincher tubeless compatible; we tape and fit a valve when you choose the tubeless option.
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 the wheels.
