Ibis Blackbird Send 2 Rim
The Ibis Blackbird Send 2 is the rear-specific version of the alloy trail rim: the same 35mm width, 17mm depth and hollow box-section bead walls that resist pinch flats and sidewall cuts, reinforced under the bead for the loads a rear wheel sees, at about 625 grams in 29in. It uses Stan's Bead Socket Technology for tubeless and comes in 27.5in and 29in, 32 hole. The Send 1 is the lighter front rim.
This page covers the Ibis Blackbird Send 2 Rim in 29in, 27.5in. The Blackbird Send 2 is sold here only inside a wheel we build: choose the hub, spokes and nipples in the configurator and the finished wheel ships from Georgia, laced, tensioned and trued by hand.
Design and construction
Most alloy rims have a solid bead wall with a sharp inner edge, which is what cuts a tire on a rock strike. The Blackbird Send's bead walls are hollow boxes, wide and rounded on top, so a hard hit squeezes the tire against a broad surface instead of a blade; the idea was borrowed from the maker's carbon rims and it works just as well in 6061 aluminum. The BST bead, licensed from Stan's, seats a tubeless tire with a floor pump and holds it at low pressure. The 35mm width suits 2.4 to 2.6in tires.
How it rides
A Blackbird Send 2 rear wheel takes the hits a rear wheel takes. The reinforced bead shrugs off the square-edged strikes that dent rear rims, the hollow bead walls protect the tire, and the 35mm bed keeps a 2.5in tire square at low pressure. It is heavier than the Send 1 by design, and on the rear you do not notice.
We build it behind a Send 1 front as a matched pair, which is how the factory builds them.
Specifications
| Wheel size | 29in, 27.5in |
|---|---|
| ERD | 604 (29in), 566 (27.5in) |
| Inner width | 35 mm |
| Depth | 17 mm |
| Drillings | 32h |
| Weight | 625g (700c/29in), 590g (650b/27.5in) |
| Material | Aluminum |
| Tire type | clincher tubeless compatible |
| Brake | Disc |
| Nipples | External |
| Finishes | black |
This version
This version is the Blackbird Send 2 in 29in, 27.5in, drilled 32h, about 625g, 35mm inside, 17mm deep, disc. Where the same rim is sold in another size or brake type, that is a separate listing with its own page.
This is the disc-brake Blackbird Send 2: plain sidewalls, no brake track to wear, a touch lighter. It fits any disc-brake bike and it is the version most of our customers now build; the rim-brake version is a separate listing.
Sizes, fit and compatibility
The Ibis Blackbird Send 2 Rim comes in 29in, 27.5in and 32h drilling. It is a disc-brake rim. We build the Blackbird Send 2 on Industry Nine Hydra 2 and 1/1, DT Swiss 350 and 240, Hope Pro 5, Onyx Vesper and Bitex BX 211 hubs in Boost spacing, usually with Sapim Race, D-Light or DT Competition spokes and brass nipples.
Tire range on the Blackbird Send 2 is 2.4 to 2.6in with tubeless-ready tires on the BST bead. The configurator recommends spoke count and lacing from your bike type and weight.
Put it in a custom wheel
Build a custom wheel around the Ibis Blackbird Send 2 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 tandem and e-bike, mountain bike, MTB single-speed and fat bike 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.
How Ibis tests its rims
Ibis Cycles' S-series carbon rims (S35 and S28) were developed with Stan's NoTubes; Ibis states it licenses Stan's patented Bead Socket Technology (BST), which lets it reduce rim cross-section height so the rims are more compliant vertically. Ibis states the rims use Toughened Hybrid Carbon, a proprietary toughened resin in the beadwall that lets the wall flex and shrug off impacts, and at the 2019 launch Bikepacking.com reported Ibis' claim that the new rims were 9% better at resisting impacts than the previous Ibis wheels. Ibis publishes no impact-energy, fatigue-cycle or ISO/EN test figures.
The S35 29 in rim is 41 mm outer and 35 mm inner width, 18.3 mm section height, 604 mm ERD, 445 g, drilled 32h with a 5 mm spoke offset, the same rim front or rear, for 2.35 in to 2.8 in tires. Ibis lists wheel build location as USA for the S35 and S28 carbon wheelsets and Taiwan for its aluminum wheels. No rider weight limit or maximum tire pressure is published on the rim pages.
Certifications
- Warranty — Lifetime warranty against defects in materials and workmanship for the original owner; impact damage case by case or via no-fault replacement at a minimum charge; rims bought before January 1st 2023 covered 7 years against impact and defects (source)
Sources on Ibis's site:
- Ibis Warranty Policy
- S35 Carbon 29" Rim - Ibis Cycles store
- Ibis Wheels
- Ibis wheelset details (S35/27.5 Carbon i9)
- Bikepacking.com: Ibis Cycles and Stan's launch new S-Wheels and rims (2019)
The figures, certificates and media above are Ibis's own. ProWheelBuilder does not run these tests; our part is the wheel we build on the rim.
Building it at ProWheelBuilder
Ibis makes the Blackbird Send 2; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. Spokes are cut from the ERD we measure on the actual rim, the wheel comes up in stages on a tensiometer, and it is stress-relieved and trued before it goes in the box; tape and a valve go on if you ask.
The configurator filters to what fits, crosses out what is not made, and prices the build as you go.
Warranty
Manufacturer's warranty. Ibis warrants this product against defects in materials and workmanship. The duration, conditions and claim process are set by Ibis and can change without notice, so ask us and we will confirm the current terms 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.
Blackbird Send 2 Rim questions
What tire width suits this rim?
35mm inside is an enduro width, meant for 2.3 to 2.6in tires. It gives a big casing a square, supported profile so you can drop pressure for grip without the tire folding, which is the whole point of a rim this wide.
Which spokes and nipples suit the Blackbird Send 2?
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 Blackbird Send 2 from your bike type and weight.
Send 1 or Send 2?
Send 1 is the lighter front-specific rim; Send 2 is reinforced under the bead for the rear. We build them as a pair.
What do the hollow bead walls do?
They give the tire a broad, rounded surface to hit on a rock strike instead of a sharp edge, which resists pinch flats and sidewall cuts without adding weight.
Is the Blackbird Send tubeless?
Yes. It uses Stan's BST bead; we tape and fit a valve on request.
What tires fit the Blackbird Send?
2.4 to 2.6in. A 2.5in trail tire is the pairing most of our customers run.
Is ProWheelBuilder the manufacturer of the Ibis Blackbird Send 2 Rim?
No. Ibis makes the rim. ProWheelBuilder is an independent custom wheel builder in Georgia that builds it into a finished wheel to your spec.
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.
