Ideal for riders or home mechanics replacing a worn cartridge bearing in a compatible wheel hub, especially DT Swiss hubs that use the 18 x 30 x 7 mm MR18307 size.
The MARWI MR18307 is a cartridge hub bearing in the less-common 18 x 30 x 7 mm size, used in DT Swiss and other compatible hubs. If you’re replacing a worn wheel bearing, the main thing that matters is getting the size right, and this one matches the official MR18307 / 18 x 30 x 7 mm format rather than the more common 6903 17 x 30 x 7 mm size that can look similar at a glance.
For buyers, the appeal here is straightforward: a sealed 2RS design, ABEC-3 tolerance, and a format intended for hub use where you want dependable rolling performance without fuss. Cartridge bearings like this are typically a replace-when-worn part rather than something you adjust internally, so they suit riders and home mechanics who want a clean, standardised fix when a hub starts feeling gritty or develops movement.
This is the right pick if you already know your hub uses MR18307, or you’ve measured the old bearing and confirmed 18 mm inner diameter, 30 mm outer diameter and 7 mm width. It’s especially worth checking carefully because 17 x 30 x 7 mm 6903 bearings are common in wheel hubs and are not interchangeable with this size.
Exact MR18307 size
Built to the specific 18 x 30 x 7 mm format, so it suits hubs designed for MR18307 rather than similarly sized alternatives.
Hub-focused application
A practical replacement choice for hub / wheel use, including DT Swiss and many other brands where this bearing size is specified.
Rubber 2RS sealing
The light-contact rubber seals help keep out water and grime while maintaining smooth rotation for everyday riding.
ABEC-3 tolerance
A sensible balance of precision and durability for wheel hub use, where consistent running matters more than chasing marginal gains.
CrMo races and balls
Uses CrMo races and balls with a steel retainer for a conventional steel-bearing construction that suits regular service replacement.
11-ball design
Configured with 11 balls in the cartridge, following the official bearing construction for this model.
Known replacement format
The MR18307 designation is a recognised bearing size, which makes matching and future replacement more straightforward once you’ve identified it correctly.
General
Dimensions & weight
Materials & construction
Features
Great for
Maybe not for
This bearing is 18 x 30 x 7 mm. Double-check the old bearing markings or measure it with callipers before ordering. It is commonly referenced for DT Swiss hub use, but fitment depends on the exact hub model. Do not confuse it with 6903, which is 17 x 30 x 7 mm and not the same bearing. Cartridge hub bearings generally require proper extraction and pressing tools for installation.
vs Enduro MR 18307 LLB A5 ABEC-5 (C3) Hub Bearing 18x30x7mm
A direct same-size alternative aimed at buyers chasing a higher stated precision grade and a premium aftermarket option.
vs Kogel 18307 Ceramic Bearing Cross Seal
A ceramic same-size alternative for riders prioritising lower-drag upgrade territory over value and straightforward replacement.
vs DT Swiss 18/30x7mm hub bearing
A same-dimension replacement sold specifically within DT Swiss’s own hub bearing range.
Measure before you buy
With hub bearings, size is everything. This one is 18 x 30 x 7 mm, and it’s easy to mistake it for a 6903 because the outer diameter and width are similar.
Check the old bearing marking first
If your existing cartridge is marked MR18307 or you’ve measured 18 mm ID / 30 mm OD / 7 mm width, you’re on the right track. If not, stop and confirm before ordering.
Use the right tools for installation
Cartridge bearings need to be removed and pressed in square. A proper bearing puller and press help avoid damage to the hub shell or the new bearing during install.
Replace when roughness or play appears
Cartridge hub bearings are usually a service replacement item rather than an adjustable one. If the wheel feels gritty, notchy or develops movement, replacement is normally the clean fix.
MARWI is a bicycle component manufacturer with roots in Taiwan and an international production and distribution footprint. The company operates across multiple countries, including Taiwan, Indonesia, the Netherlands, the Czech Republic and Germany, and is known as a large-scale supplier within the cycling industry.
The brand is particularly well known for pedals and aftermarket bicycle parts, with more than 30 years of experience in the bicycle sector. Alongside OEM supply, MARWI has built a broad replacement-parts offering for shops and riders looking for practical service items and components.
