6228 Bearing Dimensions

Tolerances and fits for 6228

FULI makes 6228 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 140 × 250 × 42 mm size.

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 140 m5 for the shaft of 6228. The housing bore is usually H7, or J7 where the outer ring must not creep.

Taking the loosest and the tightest combination of limits, a P0 6228 on a 140 mm m5 shaft has 15 to 58 µm interference. Its outer ring has 0 to 76 µm clearance in an H7 bore and 16 µm interference to 60 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.

6228 compared with nearby sizes

6228 measures 140 × 250 × 42 mm: bore d, outside diameter D and width B. Other deep groove ball bearings on this site for the same 140 mm shaft are 6028 (140 × 210 × 33 mm).

6028 is the lighter option on the same shaft, with an outside diameter 40 mm smaller (210 mm) and 9 mm less width (33 mm), for housings with less room.

6420 has the same 250 mm outside diameter with a 100 mm bore, so it fits the same housing bore on a smaller shaft.

In the 62 (light) series the sizes either side of 6228 are 6224 for a 120 mm shaft.

Cr and weight from FULI's catalog; — = not listed on this site.

6228 versions: open, ZZ, 2RS and C3

Every version of 6228 has the same 140 × 250 × 42 mm boundary dimensions; only the cover between the rings and the internal clearance change. FULI supplies open, ZZ and 2RS versions, with C0 clearance as standard and C3 on request. Other makers write the same covers as 2Z or ZZ for shields and 2RS1, DDU or LLU for contact seals.

6228 dimensions in inches

The nearest common inch shaft size to the 140 mm bore of 6228 is 5-1/2 in (139.70 mm), 0.3 mm smaller than the bore, so 6228 would be loose on it. Inch shafts need an inch bearing, not a metric one with a sleeve or shim.

Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.

Grease for 6228

FULI fills sealed 6228-2RS and 6228-ZZ bearings to about 30% of the free internal space as standard. The fill is set on an automatic greasing machine after sample sets are weighed before and after greasing. Sealed bearings are not regreased in service. A different fill level, a low-noise grease or a grease for a stated temperature range can be written on the order; for North America a range of −40 to 120 °C is often asked for.

Relubricating 6228 from the side takes about 52.5 g each time by the formula in our grease calculator: 0.005 × D × B = 0.005 × 250 × 42. This applies to the open 6228 in a housing with a grease supply.

How FULI supplies 6228

The standard 6228 from FULI has GCr15 chrome steel rings and balls, P0 precision, C0 radial clearance and vibration grade Z3V3; P6, C3 and other vibration grades are made on request. Radial clearance is set on automatic assembly equipment and sampled during production. Orders with a noise or vibration requirement are tested set by set before packing.

Rings are marked with a brand you are authorised to use, with the FULI brand, or left neutral, as your order states. The box is printed with the model, precision class and brand.

Inquiries that leave out the prefix or suffix letters are the usual cause of a wrong quote, so write the full designation, for example 6228-2RS C3.

Tools and guides for 6228

• Bearing size finder: look up a size from bore, OD and width
• Bearing weight chart
• Bearing grease fill calculator
• Shaft and housing tolerance chart
• Open, ZZ or 2RS seal selector
• Bearing internal clearance: C0, C3 and when to change
• Bearing lubrication basics
• Noise grade and precision class
• Ball bearing vs roller bearing
• All bearing products and model pages