DT Swiss RR 421 Disc Brake Rim
The DT Swiss RR 421 is the road disc rim we build when a customer wants light, tubeless and well made in aluminum. The RR 421 is welded, asymmetric and 20mm wide inside, which is a natural fit for the 28 to 32mm tires modern road and endurance bikes run, and at around 430 grams it builds into a disc road wheel that undercuts most factory alloy sets while being far easier to keep true.
This page covers the DT Swiss RR 421 Disc Brake Rim in 700c. The RR 421 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 factory extrudes the RR 421 from high-quality aluminum and welds the seam, then smooths it, which gives the strongest and roundest joint in the DT range. The profile is asymmetric: the spoke bed is offset toward the non-drive side, which balances left and right spoke tension on a disc rear wheel and makes the RR 421 one of the easiest road rims to build evenly.
The 20mm tubeless-compatible inner width suits high-volume road tires; the section is 21mm deep, so the RR 421 is light rather than aero. It uses PHR washers under the nipples, and DT calculates the ERD with the washers in place, which we account for when we cut spokes. Standard nipples, disc only.
How it rides
An RR 421 wheel is light and lively. With a 28mm tubeless tire it accelerates like a much more expensive wheel and rides comfortably over rough tarmac, and the asymmetric bed means the rear wheel stays true far longer than a symmetric alloy rim. It is a road rim that is happy on light gravel with a 35mm tire.
The RR 421 is not an aero rim; if you want depth, the carbon road rims in the catalog are the answer. For an everyday road disc wheel, club rides and long endurance days, the RR 421 is the DT Swiss alloy rim we recommend first.
Specifications
| Wheel size | 700c |
|---|---|
| ERD | 599 (29in) |
| Inner width | 20 mm |
| Depth | 21 mm |
| Drillings | 28h, 32h |
| Weight | 430g (700c/29in) |
| Material | Aluminum |
| Tire type | clincher tubeless compatible |
| Brake | Disc |
| Profile | Triangle |
| Spoke bed | Offset -2.7 mm |
| Nipples | External |
| Finishes | black |
This listing
This is the 700c listing of the RR 421, 28h, 32h, about 430g, 20mm inside, 21mm deep, disc. Pick the size that matches your frame; the profile and construction are the same across the range.
The disc version of the RR 421 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 DT Swiss RR 421 Disc Brake Rim comes in 700c and 28h, 32h drilling. It is a disc-brake road rim. We build the RR 421 on 350, 240 and 180 hubs, Bitex BX 106, Hope RS4, White Industries CLD, Industry Nine 1/1 and Chris King R45 hubs, usually with Sapim Laser, CX-Ray or D-Light spokes or Competition and Aerolite.
Tire range on the RR 421 is 25 to 38mm. Give the configurator your bike type and weight; it picks a sensible spoke count and lacing pattern, which you can override.
Build it with us
We build this rim to order. Open the Custom Wheel Program with the DT Swiss Rr 421 Disc Brake Rim already selected and pick the parts around it; it is offered for gravel and road disc, track and road single-speed and touring 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.
What DT Swiss says about testing
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.
DT Swiss gives a 24-month defects warranty on all products; first owners of carbon component rims bought after 1 March 2025 receive a lifetime warranty against material and workmanship defects, and under the Fair-Share policy a carbon rim damaged by a riding error is replaced for a fixed contribution for 10 years after purchase. UCI approval is granted to complete wheels: DT Swiss wheels such as the ARC 1100 DICUT 700C 38 SPO (approved 2 May 2024) are on the UCI list, but component rims are not listed individually.
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 makes the RR 421; ProWheelBuilder is an independent wheel builder in Georgia, not the manufacturer. Every RR 421 wheel we build gets spokes cut from the rim's measured ERD with the PHR washers in place, 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
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. Built into a wheel by us, this part is covered by our own one-year wheel warranty on top of the maker's. For a year we replace broken spokes whatever caused them, and we cover the labor on the wheel - truing, re-tensioning, a rebuild if it needs one. If a rim or hub fails and its maker covers it, we run that claim for you; if the maker says no, you get an eligible replacement rim or hub at 25% off retail. You pay the shipping each way. Wheels built from parts you send us are excluded.
Full terms are on our Policies & Warranty page.
RR 421 Disc Brake Rim questions
What tire width suits this rim?
At 20mm inside this is a road width. It suits roughly 25 to 32mm tires, which is where most road bikes now sit, and it will run a 23 if you still want one. Go much wider than 32 on this rim and the tire starts to balloon above the sidewalls and squirm when you lean on it.
What does asymmetric mean on the RR 421?
The spoke holes are offset toward the non-drive side, which evens out the tension between drive-side and non-drive-side spokes on a disc rear wheel. The wheel stays true longer.
What tires fit the RR 421?
25 to 38mm. A 28 to 32mm tubeless tire is the pairing most of our customers run.
Is the RR 421 tubeless?
Yes. It is tubeless-compatible with tape and valves, which we fit on request.
How does the RR 421 compare with the R 470?
The RR 421 is welded, asymmetric and lighter; the R 470 is sleeved, symmetric, deeper and rated for heavier riders at a lower price.
Is it tubeless-ready?
Yes. DT Swiss lists the RR 421 Disc Brake Rim as clincher tubeless compatible; we tape 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 rider weight, within the drillings this rim is made in.
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.
