DT Swiss XR 421 Disc Brake Rim
The DT Swiss XR 421 is a 29in cross-country rim built for lap after lap at race pace. It has a 30 mm inner width on a flat 20 mm profile, weighs 548 g, and DT optimizes it for tires up to 2.7in so you keep grip in technical corners.
This page covers the DT Swiss XR 421 Disc Brake Rim in 29in, 28h drilling. We build it to order on the hub and spokes you choose; it is not sold loose from this listing.
Design and construction
DT welds the XR 421, drills it without eyelets for its PHR washers, and gives it an asymmetric shape to even out spoke tension. ASTM class 3, 120 kg maximum system weight, e-bike approved up to 32 km/h or 250 W. It comes in 29in only, 28 holes, with three extra decal sets.
How it rides
An XR 421 wheel accelerates willingly and the 30 mm bed lets a modern XC tire run at pressures that grip on roots and off-camber turns. The flat profile keeps weight low without making the rim fragile, which matters on the rough descents modern XC courses include.
Cross-country racers and fast trail riders on 29in bikes. If you want the lightest rim DT makes for XC, look at the carbon XRC 310.
Specifications
| Wheel size | 29in |
|---|---|
| ERD | 602 (29in) — DT's published figure is 604; ours is net of the spoke washer allowance our calculator adds back |
| Inner width | 30 mm |
| Outer width | 35 mm |
| Depth | 20 mm |
| Drillings | 28h |
| Weight | 548g (29in) |
| Material | Aluminum |
| Joint | Welded |
| Bead | Hooked tubeless |
| Brake | Disc |
| Max. system weight | 120 kg |
| ASTM class | 3 |
| Eyelets | None |
| Nipples | External |
| Finishes | black |
About this listing
Version notes. 29in, 28h, about 548g, 30mm inside, 20mm deep, disc. The size and drilling options on this page are the ones our distributor stocks; anything it runs out of is marked unavailable until it is back.
Sizes, fit and compatibility
The DT Swiss XR 421 Disc Brake Rim comes in 29in with 28h drilling and is a disc-brake rim. DT optimizes it for tires up to 2.7in. Pick your bike type and weight in the configurator and it recommends a spoke count and lacing pattern for this rim.
Build it with us
We build this rim to order. Open the Custom Wheel Program with the DT Swiss XR 421 Disc Brake Rim already selected and pick the parts around it; it is offered for mountain bike and MTB single-speed builds, and the configurator will not let you assemble a combination we would not build.
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.
Testing, standards and warranty at DT Swiss
DT Swiss tests rims as part of complete wheels in its Performance Test Center in Biel. DT Swiss states that test methods and parameters vary with the intended use, the maximum system weight and the ASTM F 2043 riding conditions, and are written into an internal factory standard which "ensures compliance with the current international standards (e.g. ISO 4210)". Published methods include a wheel impact test (with and without tire, monitoring rim buckling, spoke tension and run-out), a drum test in which a wheel loaded to its permissible system weight rolls over obstacles on a steel drum for a set mileage, a lateral stiffness test and a burst pressure test. No impact energies or cycle counts are published.
Each rim page states a maximum system weight and ASTM classification: the R 460 road rim is rated "Max. System weight 110 kg", "ASTM classification 1" and not approved for e-bikes; the RR 481 is rated 130 kg, ASTM classification 2 and "Approved for e-bikes Yes (max. 32Km/h or max. 250W)".
DT Swiss's videos
From DT Swiss
Certifications
- ISO 4210 / ASTM F 2043 — DT Swiss states its internal factory standard 'ensures compliance with the current international standards (e.g. ISO 4210)' and sets test parameters by ASTM F 2043 riding conditions (self-declared, no certificate published) (source)
- ASTM classification per rim — R 460: ASTM classification 1, max system weight 110 kg, not e-bike approved; RR 481: ASTM classification 2, max system weight 130 kg, approved for e-bikes (max. 32 km/h or max. 250 W) (source)
- UCI approved wheels — UCI list version 2024.10.02 lists DT Swiss complete wheels, e.g. ARC 1100 DICUT 700C 38 SPO (02.05.2024), GRC 1100/1400 DI 700C CL 30 and CL 50, AR/ER 1600 SP and A/E 1800 SP 700C/650B CL 30, ARC 1100/1400 DI 700C CL 38 (all 13.06.2024); earlier ARC/ERC/PRC/GRC models 2016-2023. Component rims are not listed individually (source)
- Warranty — 24 months legal warranty on all products; lifetime warranty for first owners of carbon component rims bought after 1 March 2025; Fair-Share crash replacement for carbon rims available 10 years after purchase (source)
Sources on DT Swiss's site:
- Performance test center | DT Swiss
- Warranty & Fair-Share | DT Swiss
- Fair-Share Policy & Warranty | DT Swiss
- R 460 | DT Swiss
- RR 481 | DT Swiss
The figures, certificates and media above are DT Swiss's own. ProWheelBuilder does not run these tests; our part is the wheel we build on the rim.
Building it at ProWheelBuilder
DT Swiss makes the XR 421; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. We measure the rim before we cut a spoke, and on this asymmetric rim we cut each side's spokes to its own length, bring the wheel up in three or four rounds with a tension gauge, stress-relieve it between rounds and true it last, then tape it and fit a valve if you want it tubeless.
Only compatible hubs and spokes appear in the configurator, impossible combinations are struck through rather than hidden, and the price is live.
Warranty
DT Swiss's warranty. DT Swiss covers its products against material and manufacturing defects for 24 months from purchase, excluding wear parts such as bearings and tubeless tape. Carbon rims and carbon wheels bought new since 1 January 2020 carry an extended guarantee to the first owner against defects in material and workmanship, and DT Swiss runs a paid crash-replacement scheme on carbon wheels for up to ten years from purchase.
ProWheelBuilder. Our one-year wheel warranty applies to any wheel we build around this part, alongside whatever the manufacturer offers. Inside that year, broken spokes are replaced no matter how they broke, and the wheel labor is ours - truing, re-tensioning or a full rebuild. A rim or hub failure that the maker covers, we claim for you and see through; one the maker declines, we answer with an eligible replacement at 25% off current retail. Shipping both ways is yours, and components you supply yourself fall outside this cover.
Full terms are on our Policies & Warranty page.
XR 421 Disc Brake Rim questions
What tires does the XR 421 suit?
DT optimizes it for tires up to 2.7in wide; most XC riders run 2.3 to 2.4in.
Is the XR 421 available in 27.5in?
No. DT makes it in 29in only.
Is it tubeless-ready?
Yes. DT Swiss lists the XR 421 as tubeless; we tape it and fit a valve when you choose the tubeless option.
Which spoke count should I choose?
It depends on your weight, terrain and the hub, not the rim alone. The configurator recommends a count from your bike type and weight.
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.
