6205 Bearing Dimensions

Tolerances and fits for 6205

FULI makes 6205 to P0 as standard, with P6 on request. P0 is the Normal tolerance class of ISO 492; P6 limits are tighter. These are the P0 limits for the 25 × 52 × 15 mm size.

Dimension	Nominal, mm	Deviation, µm	Limits, mm
Bore d (Δdmp)	25	0 / −10	25.000 / 24.990
Outside diameter D (ΔDmp)	52	0 / −13	52.000 / 51.987
Width B (ΔBs)	15	0 / −120	15.000 / 14.880

Δdmp and ΔDmp: deviation of the mean bore and mean outside diameter in one radial plane. ΔBs: inner ring width; the outer ring width has the same limits.

Shaft and housing fits (general guidance)

For an inner ring that turns with a solid steel shaft under normal load, bearing makers’ fit tables give 25 k5 for the shaft of 6205. The housing bore is usually H7, or J7 where the outer ring must not creep.

Seat	Deviation, µm	Limits, mm	Fit with 6205
Shaft 25 k5	+11 / +2	25.011 / 25.002	2 to 21 µm interference
Housing 52 H7	+30 / 0	52.030 / 52.000	0 to 43 µm clearance
Housing 52 J7	+18 / −12	52.018 / 51.988	12 µm interference to 31 µm clearance

Taking the loosest and the tightest combination of limits, a P0 6205 on a 25 mm k5 shaft has 2 to 21 µm interference. Its outer ring has 0 to 43 µm clearance in an H7 bore and 12 µm interference to 31 µm clearance in a J7 bore.

This is general guidance, not a FULI specification. Heavy or shock loads, a hollow shaft, a thin-walled, split or light-alloy housing, or a large temperature difference between shaft and housing call for other classes, and the drawing of your machine takes priority. A tight shaft fit or a hot housing uses up internal clearance, and that is when C3 is chosen instead of C0.

If the outer ring turns and the shaft stands still, as in an idler pulley or a wheel hub, the fits are reversed: the housing gets the interference fit (for example N7 or P7) and the shaft a sliding one (g6 or h6).

Sources: ISO 492 tables as printed in the NTN catalogue CAT. No. 2203/E (Tables 6.4 and 6.5) and the RKB tolerance catalogue; ISO 286-2 for the seats; SKF and NTN fit tables for the shaft and housing classes.

The 6205 bearing dimensions are 25 mm bore, 52 mm outside diameter and 15 mm width, the same in every catalogue that follows the ISO 15 general plan. The specification table above gives the FULI values for the open, ZZ and 2RS versions. This page explains what the three numbers mean, how the variants differ, and what to check on a sample before you order a full quantity.

6205 bearing dimensions: 25 x 52 x 15 mm explained

A 6205 bearing is a single row deep groove ball bearing in dimension series 02 with bore code 05: the first digit 6 is the bearing type, the 2 is the diameter series and 05 multiplied by 5 gives the 25 mm bore. The ISO 15 general plan fixes the preferred boundary dimensions for radial bearings of diameter series 7, 8, 9, 0, 1, 2, 3 and 4, and the 6205 sits in series 2. That is why the bore, outside diameter and width interchange between makers, while load ratings, grease and cage material do not.

Two dimensions are not in the table because they rarely affect a purchase: the chamfer r at the ring corners, which the general plan specifies as a minimum, and the shoulder heights, which decide how much of the ring face a housing or shaft shoulder may touch. If your drawing calls out either value, put it in the inquiry and we will confirm it against the batch.

6205 open bearing, 6205ZZ bearing or 6205-2RS bearing

The three versions share the same boundary dimensions and differ only in what covers the gap between the rings. Makers write the suffix differently: 2Z, ZZ or Z for shields and 2RS, 2RSH, DDU or LLU for contact seals.

Version	Cover	When we recommend it
6205 open bearing	No cover; lubricated by the housing oil or grease	Gearboxes and other housings with their own lubrication
6205ZZ bearing	Two pressed steel shields, non-contact	Motors and fans, where speed matters and dust is light
6205-2RS bearing	Two rubber contact seals, greased at the factory	Pumps, agricultural machines and outdoor equipment

Sealed bearings rank first for keeping contaminants out, shielded bearings second and open bearings last. The price of that protection is seal drag, so for a small motor running fast and clean, our customers usually specify ZZ, and for anything that sees water or dust, 2RS.

Clearance is ordered on the same line as the seal. C0 is the standard radial clearance and C3 is the larger one; both are standard codes in the major catalogues. We recommend C3 for a 6205 when the inner ring is a tight press fit on the shaft or the housing runs hot, because the fit and the heat both use up clearance. Write the full code, for example 6205-2RS C3.

6205 bearing size checks before you order

A 6205 bearing size check on a sample takes a caliper and two minutes. Measure the bore at two points, then the outside diameter, then the width across both rings; you should read 25, 52 and 15 mm within the tolerance of the precision class. Then check the markings: the designation and suffix should match the order, and the packing should show the batch reference that ties the bearing to its inspection report.

At FULI every batch is checked before shipment for rotation smoothness, dimensions, grease fill, rust and appearance. Precision P0 as standard and P6 on request (P5 by model); radial clearance C0 as standard and C3 on request. Rings and balls are GCr15 chrome bearing steel; the steel maker’s GCr15 material certificate is available on request for OEM and industrial orders.

If you are matching an old part number, note that the old Chinese designation for 6205 was 205 for the open version, 80205 for ZZ and 180205 for 2RS.

Our 6205 clearance order: C0 shipped, C2 needed

A domestic customer in China ordered 6205 bearings from us. No clearance group was agreed before production, so our factory made and delivered the batch in the standard C0 clearance. The customer passed the bearings on to a drum manufacturer it was bidding to supply. Those drums have to be held to very little wobble while they turn, and that put the bearing clearance requirement at C2. The customer returned the batch, and our factory ran a second, full clearance inspection before shipping replacements.

C2 is the group smaller than Normal. For a 25 mm bore, NTN’s clearance table gives C2 as 1 to 11 μm and Normal (CN, also written C0) as 5 to 20 μm [6]. NSK lists smaller-than-normal clearance for cases where sound and vibration must be cut sharply, and where clearance is adjusted to reduce shaft runout [7]. A drum held to very little wobble is that second case, and a bearing can be right on every dimension and still be in the wrong clearance group for it.

C2 has a cost as well. A tight fit on the shaft and a warm inner ring both take clearance away after mounting, and NSK notes that bearing life falls sharply once the running clearance goes too far below zero, which shows up as heat [7]. NSK lists C2 for cases where both rings have a loose fit [7]. So a C2 order should come with the shaft and housing fits and the running temperature, so the factory can check that the bearing still has room to run.

The order did not state a clearance, so the batch was built to the default. If your 6205 bearings are going into another company’s machine, ask that company for the clearance group before you order, and write it in the full code with the seal suffix. Say what the bearing goes into as well: a drum, a pump or a motor, and whether runout or noise is limited. When no group is written, our factory builds to C0, the standard clearance. If you need C2, state it in the inquiry and we will confirm it.

Where the deep groove ball bearing 6205 is used

A deep groove ball bearing 6205 takes radial load first and axial load in both directions, and its point contact keeps friction low at high speed. The 25 mm bore matches shaft sizes found in motorcycle wheel hubs, single-phase motors, water pumps and agricultural gearboxes, which is where most of our 6205 orders go. Catalogues list the same family of uses for this bearing type.

For a gearbox, the 6205 is often paired with a tapered roller bearing on the output shaft. When the load is heavy and mostly radial, a roller bearing of the same bore may be the better choice; the deep groove ball bearing range page explains the limits.

Neighbouring sizes: 6204, 6206, 6005 and 6305

If the 6205 is close but not right, the same bore in another series or the next bore up or down is usually the answer. Values are from the FULI specification sheet.

Model	Bore (mm)	OD (mm)	Width (mm)	Note
6204 bearing	20	47	14	One bore size down in the 6200 series
6205 bearing	25	52	15	This page
6206 bearing	30	62	16	One bore size up in the 6200 series
6005	25	47	12	Same bore, lighter 6000 series
16005	25	47	8	Same bore, thin section
6305	25	62	17	Same bore, medium 6300 series
6405	25	80	21	Same bore, heavy 6400 series

The complete 6200 series list runs from 6200 to 6220. Send the model, suffix and quantity to sales@fuli-bearings.com or WhatsApp +86 152 6352 1305 for a quotation with packing detail.

Sources

1. SKF Rolling bearings catalogue (PUB BU/P1 17000/1 EN) (SKF)
2. ISO 15:2017 Rolling bearings - Radial bearings - Boundary dimensions, general plan (preview) (ISO via iTeh Standards)
3. Timken Engineering Manual (Order No. 10424) (Timken)
4. Deep Groove Ball Bearings (product page) (NSK)
5. Timken Ball Bearing Catalog - Radial and Angular Contact Ball Bearings (Order No. 10734) (Timken)
6. NTN Ball and Roller Bearings catalog 2203-E, Section 8: Bearing internal clearance and preload (NTN)
7. Fits and Internal Clearance (ABC of bearings) (NSK)