Cylindrical Roller Bearings · ISO 15 / DIN 5412-1 / GB/T 283
ISO 15 NU300 Series Cylindrical Roller Bearings Specification
What ISO 15 fixes, what it deliberately leaves to another document, its equivalents, and the dimensional table.
ISO 15 fixes the boundary dimensions of metric radial rolling bearings: the bore d, the outside diameter D, the width B and the limiting corner radius r, arranged in diameter and width series so that a bore of 20 mm exists in several standard envelopes (6004, 6204, 6304, 6404). It is the reason a 6204 from any manufacturer drops into the same housing.
Standard
ISO 15
Covers
Boundary dimensions of radial rolling bearings
Does not fix
It says nothing about how much load the bearing carries, how fast it may run, how accurately it is made or how much clearance it has. Load ratings are calculated to ISO 281, running accuracy is ISO 492 and radial internal clearance is ISO 5753-1.
Equivalents
DIN 616 restates the dimension plan nationally, with the individual bearing types in DIN 625, DIN 628, DIN 630, DIN 635 and DIN 5412; GB/T 273.3 carries the same plan in China.
Product
NU300 Series Cylindrical Roller Bearings
Governing standards
ISO 15 / DIN 5412-1 / GB/T 283
Equivalence between the ISO, DIN and GB/T documents is dimensional: a bearing made to either mounts in the same seat. It is not an equivalence of load rating, tolerance class or internal clearance, each of which is fixed by a separate standard and declared separately.
For nu300 series cylindrical roller bearings, ISO 15 is one of the controlling documents. The sections below describe its scope, the properties it does NOT decide and which standard does decide them, the equivalent designations, and the full size range.
ISO 15 — Scope
ISO 15 fixes the boundary dimensions of metric radial rolling bearings: the bore d, the outside diameter D, the width B and the limiting corner radius r, arranged in diameter and width series so that a bore of 20 mm exists in several standard envelopes (6004, 6204, 6304, 6404). It is the reason a 6204 from any manufacturer drops into the same housing.
What ISO 15 Does Not Fix
It says nothing about how much load the bearing carries, how fast it may run, how accurately it is made or how much clearance it has. Load ratings are calculated to ISO 281, running accuracy is ISO 492 and radial internal clearance is ISO 5753-1.
This division of labour is the thing to carry away from any bearing standard. A boundary dimension standard makes bearings interchangeable; it does not make them equivalent. Two bearings of the same designation from different makers mount in the same seat and are not required to have the same load rating, the same internal design, the same cage or the same speed limit.
Dimensions Supplied to ISO 15
Designation
Bore d (mm)
Outer diameter D (mm)
Width B (mm)
Chamfer r min (mm)
Rib arrangement
NU304
20
52
15
1.1
No axial location, free at both ends
NU305
25
62
17
1.1
No axial location, free at both ends
NU306
30
72
19
1.1
No axial location, free at both ends
NU307
35
80
21
1.5
No axial location, free at both ends
NU308
40
90
23
1.5
No axial location, free at both ends
NU309
45
100
25
1.5
No axial location, free at both ends
NU310
50
110
27
2
No axial location, free at both ends
NU311
55
120
29
2
No axial location, free at both ends
NU312
60
130
31
2.1
No axial location, free at both ends
NU313
65
140
33
2.1
No axial location, free at both ends
NU314
70
150
35
2.1
No axial location, free at both ends
NU315
75
160
37
2.1
No axial location, free at both ends
NU316
80
170
39
2.1
No axial location, free at both ends
NU317
85
180
41
3
No axial location, free at both ends
NU318
90
190
43
3
No axial location, free at both ends
NU319
95
200
45
3
No axial location, free at both ends
NU320
100
215
47
3
No axial location, free at both ends
NU321
105
225
49
3
No axial location, free at both ends
NU322
110
240
50
3
No axial location, free at both ends
Catalog Products Governed by ISO 15
ISO 15 governs more than this one series. In this catalog it applies to:
ISO 15 is the international reference and the right one to cite on a new drawing or a purchase specification. Adding the national equivalents alongside it costs nothing and makes the requirement legible to a supplier working to DIN or to GB/T.
Other ways to specify the NU300 Series Cylindrical Roller Bearings
The same part is also governed by ISO 5753-1, and where two standards cover one dimension they agree — the numbers are the same, the document is not.
Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the designation snaps the other fields to that size's standard values; you can then override any individual value.
Sends the selected values to the quote form below.
Our facility
The numbers come off our own machines
Every ring is gauged for bore and outside diameter, every assembly for radial internal clearance to ISO 5753-1, and every finished bearing for vibration. That is why the values on this page are quotable rather than indicative.
Request a Quote
The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.
Dimensions & Specifications (ISO 15 / DIN 5412-1 / GB/T 283)
Designation
Bore d (mm)
Outer diameter D (mm)
Width B (mm)
Chamfer r min (mm)
Rib arrangement
NU304
20
52
15
1.1
No axial location, free at both ends
NU305
25
62
17
1.1
No axial location, free at both ends
NU306
30
72
19
1.1
No axial location, free at both ends
NU307
35
80
21
1.5
No axial location, free at both ends
NU308
40
90
23
1.5
No axial location, free at both ends
NU309
45
100
25
1.5
No axial location, free at both ends
NU310
50
110
27
2
No axial location, free at both ends
NU311
55
120
29
2
No axial location, free at both ends
NU312
60
130
31
2.1
No axial location, free at both ends
NU313
65
140
33
2.1
No axial location, free at both ends
NU314
70
150
35
2.1
No axial location, free at both ends
NU315
75
160
37
2.1
No axial location, free at both ends
NU316
80
170
39
2.1
No axial location, free at both ends
NU317
85
180
41
3
No axial location, free at both ends
NU318
90
190
43
3
No axial location, free at both ends
NU319
95
200
45
3
No axial location, free at both ends
NU320
100
215
47
3
No axial location, free at both ends
NU321
105
225
49
3
No axial location, free at both ends
NU322
110
240
50
3
No axial location, free at both ends
Video: ISO 15 NU300 Series Cylindrical Roller Bearings Specification
Third-party video, selected automatically for this topic. It is not produced by Bushing Bearings and is not a specification source — use the tables on this page for dimensional data.
Frequently Asked Questions
Does ISO 15 mean two bearings are interchangeable?
Dimensionally, yes — that is what a boundary dimension standard is for, and a bearing of the same designation from any maker mounts in the same shaft and housing seat. Functionally, not necessarily: the load rating, the internal design, the cage, the clearance group and the speed limit are decided by the manufacturer and by other standards, and two bearings with the same number are not required to match on any of them.
Does ISO 15 fix the load rating?
No. ISO 15 does not set load ratings. Basic dynamic load ratings are calculated to the method of ISO 281 and are declared by the manufacturer; the static rating follows ISO 76.
Which edition of ISO 15 does this table follow?
The table reproduces the dimensions we supply nu300 series cylindrical roller bearings to. We do not publish an edition year against it, so where the edition is contractually significant, cite the edition you require on the enquiry and we will confirm it against the table before quoting.
Can I cite the GB/T number instead of the ISO one?
For the boundary dimensions, yes — the GB/T standards restate the ISO dimension plan and a part made to either mounts in the same seat. The safest drawing note gives both, because it stays legible if the supply moves between a Chinese, a European and an international manufacturer.
How do I request a quotation?
Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.
Need a bearing quote or a spec sheet?Message our engineers on WhatsApp — send a drawing or DIN number and get pricing back fast.Start WhatsApp Chat →
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