NU205 bearing dimensions are 25 mm bore, 52 mm outside diameter and 15 mm width, written as 25x52x15 mm. That boundary size is fixed by ISO, so an NU205 from NTN, NSK, SKF or TFL will fit the same shaft and housing. What changes between brands is the inside of the bearing, and that’s where most buying mistakes happen.
The NU205 cylindrical roller bearing is a single row design from the 02 dimension series. “NU” tells you the outer ring has two ribs and the inner ring has none, so the inner ring can slide axially. The “05” is the bore code, and 05 x 5 = 25 mm. You can see the full range of sizes in our cylindrical roller bearings catalogue.
NU205 bearing dimensions in mm chart
These NU205 bearing dimensions and specifications come from NSK’s published data for the NU205ET. They match the boundary numbers NTN and SKF list for their versions.
| Dimension | Symbol | Value |
|---|---|---|
| Bore (inner diameter) | d | 25 mm |
| Outside diameter | D | 52 mm |
| Width | B | 15 mm |
| Inner ring raceway diameter | Fw | 31.5 mm |
| Chamfer, ribbed side | r min | 1 mm |
| Chamfer, plain side | r1 min | 0.6 mm |
| Shaft abutment (db) | min / max | 29 / 30 mm |
| Housing abutment | Da max | 47 mm |
| Weight | approx. | 0.13 to 0.15 kg |
In inches, the NU205 bearing dimensions are 0.9843 in bore, 2.0472 in outside diameter and 0.5906 in width.
Most charts leave out Fw, the 31.5 mm raceway diameter, and it matters more than people expect. You might replace only the outer ring and roller set, or fit an RNU205 (an NU205 with no inner ring) straight onto a hardened shaft. In both cases the shaft has to be ground to that raceway diameter. SKF sells that exact part, listed as an RNU 205 ECP with a 31.5 mm ID.
Weight depends on the cage. NSK lists 0.132 kg for the polyamide cage version and 0.153 kg for the machined brass version. The brass accounts for the 20 gram gap, so a scale is a quick way to tell the two apart.
Same 25x52x15 size, very different bearings
This is the part that trips up buyers. At least three common bearing types share the NU205 bearing dimensions of 25x52x15 mm: the 6205 deep groove ball bearing, the 7205 angular contact ball bearing and the NU205 roller bearing. They all fit the same housing bore, but they don’t carry the same load.
A 6205 is rated at about 14,000 N dynamic and 7,900 N static. The NU205 is rated at roughly 29,000 to 36,000 N dynamic and close to 27,700 N static. For radial load, the roller bearing carries about two to two and a half times as much dynamic load and about three and a half times as much static load. That’s why many electric motors put an NU205 on the drive end, where belt or gear pull is strongest, and a ball bearing on the other end.
The trade-off is axial load: an NU205 takes almost none. NTN’s own product description says this type can’t take even light axial loads and is widely used as the floating side bearing. If your shaft sees thrust, you need an NJ or NUP version, or a ball bearing on the locating side.
NU205 bearing load capacity and speed rating by brand
Matching NU205 bearing dimensions don’t tell you the load rating. The suffix does. Older standard designs and newer high-capacity designs (E, EC, ET, EG) have the same outside size, but the newer ones use bigger or more rollers.
| Bearing | Cage | Dynamic Cr | Static C0r | Speed notes |
|---|---|---|---|---|
| NTN NU205 (standard) | Steel | 29.3 kN | 27.7 kN | 16,000 rpm oil, 14,000 rpm grease |
| NSK NU205ET | Polyamide | 36.0 kN | 27.7 kN | 12,000 rpm grease, 14,000 rpm oil bath |
| NSK NU205EM | Brass | 36.0 kN | 27.7 kN | 14,000 rpm thermal rating |
| SKF NU 205 ECP | Polymer | 32.5 kN | 27 kN | 15,000 reference, 16,000 limiting |
Be careful with the SKF line. Distributor listings for the same SKF NU 205 ECP disagree: RS Components UK shows 32.5 kN dynamic, while the RS New Zealand page shows 28.6 kN. That’s probably an old catalogue value next to a newer one. If the dynamic rating drives your life calculation, get the current data sheet from the manufacturer, not from a reseller page.
Here’s why the suffix matters in practice. If your old bearing reads NU205E and you replace it with a plain NU205, you could lose around 20% of rated dynamic capacity in the same space. For roller bearings, rating life scales with the load ratio to the power 10/3, so a 20% drop in Cr cuts calculated life roughly in half. Our bearing cross-reference guide helps you match suffixes across brands so this doesn’t happen.
Clearance, tolerance and material
None of these options change the NU205 bearing dimensions. They change how the bearing behaves inside the same 25x52x15 envelope.
Most NU205 bearings ship in ISO Normal (P0) tolerance class with CN clearance. NTN lists its standard NU205 as ISO class 0 with CN radial clearance. C3 is common in electric motors, because the inner ring runs hotter than the outer ring and expands into the clearance.
For reference, CN clearance on the related NUP205EG is about 0.020 to 0.045 mm. Choose C3 if you have a tight shaft fit or a high running temperature.
Rings and rollers are high carbon chrome steel (52100 or GCr15 class). Cages come in pressed steel, polyamide or machined brass. Polyamide is light and quiet but tops out at around 120 °C, while brass copes better with heat and vibration. If stray current is a problem, for example in inverter-driven motors, an electrically insulated cylindrical roller bearing in the same 205 size stops electrical pitting on the raceways.
NU205 vs NJ205 bearing differences
The NU205 and NJ205 have identical 25x52x15 mm dimensions, so either fits the same seat. The difference is the inner ring.
The NU205 inner ring has no ribs, so it floats in both directions along the shaft. The NJ205 inner ring has one rib, so it can take light axial load in one direction and locate the shaft one way. The NUP205 adds a loose rib plate, so it locates in both directions.
On a pump or gearbox shaft, a typical setup puts an NJ205 or a ball bearing at the fixed end and an NU205 at the free end, so thermal growth of the shaft doesn’t load the bearings. You’ll see this layout across our industrial machinery applications.
How to measure NU205 bearing dimensions
If the markings have worn off, measure the NU205 bearing dimensions with a digital caliper, ideally at room temperature.
- Measure the bore at two points 90° apart. You should see 25.000 mm. Normal class tolerance allows up to 0.010 mm under that.
- Measure the outside diameter the same way. Expect 52.000 mm, with up to 0.013 mm under size allowed in Normal class.
- Measure the ring width. Expect 15 mm.
- Check the rings. If the outer ring has ribs on both sides and the inner ring is a plain sleeve that slides out, it’s an NU. One rib on the inner ring means NJ.
Calipers are only accurate to about 0.02 mm, so they confirm the size but not the tolerance class. For that you need a bore gauge and a micrometer.
NU205 bearing installation guide
The NU205 is separable, so you can mount the inner ring and the outer ring with its rollers separately, which makes installation easier.
Use an induction heater to bring the inner ring to about 80 to 90 °C above shaft temperature, then slide it on. Press the outer ring assembly into the housing, pushing on the outer ring only. When you join the two halves, rotate the shaft slowly while the rollers slide over the inner ring. If you push them on dry and straight, you’ll score the raceway, and that scratch is where spalling starts.
Use the abutment figures from the NU205 bearing dimensions chart above. The shaft shoulder should be between 29 and 30 mm, and the housing shoulder should be no larger than 47 mm.
Applications and uses
You’ll find the NU205 in small electric motors, gearboxes, pumps, compressors, machine tool spindles and textile machinery. It’s also used in automotive bearings for transmissions, and in agricultural drive lines.
Because the NU205 bearing dimensions are the same across brands, sourcing a replacement is simple, as long as the suffix and clearance match the original.
FAQ
What are the NU205 bearing dimensions?
The NU205 bearing dimensions are 25 mm bore, 52 mm outside diameter and 15 mm width (25x52x15 mm).
Is NU205 the same as 6205?
They share the same NU205 bearing dimensions on the outside (25x52x15 mm) but are different bearings. The NU205 carries far more radial load but almost no axial load.
What is the NU205 bearing weight?
About 0.13 kg with a polyamide cage and 0.15 kg with a brass cage.
Can I swap NU205 for NJ205?
Yes, the dimensions match. Make sure the shaft layout still has one free end, or thermal growth will load the bearings.
What does C3 mean on NU205C3?
It means greater than normal radial internal clearance, used when the shaft runs hot or has a tight fit.
If you need a data sheet with full NU205 bearing dimensions and tolerances, check our download center first.
For volume orders, or an NU205 matched to a specific suffix and clearance, request a quote from the TFL team. Send your old part number and running conditions and we’ll confirm the equivalent.
