Bearing Cross Reference

Bearing cross reference: size equivalents by bore, OD and width

A bearing cross reference works because the size is not a brand property. ISO 15 fixes the bore, outside diameter and width for every standard designation, so a 6205 from any catalogue is 25 × 52 × 15 mm and the ENRO 6205 is dimensionally interchangeable with it. What differs between catalogues is the way prefixes and suffixes are written, and occasionally the internal design behind the same number. Strip the number to its base, match the three dimensions, then deal with the suffixes.

If the marking is unreadable, measure bore, outside diameter and width on clean rings and use the size finder. The bearing size chart lists every series ENRO carries; the deep groove ball bearing and spherical roller bearing pages have the full filterable tables.

Variants: Open, ZZ or 2RS seals, cylindrical or K taper bore, W33 groove

Suffixes are where cross referencing goes wrong. The same closure is spelled several ways across catalogues, and some catalogues put clearance before the closure while others put it after. Translate each suffix to the ENRO code below before you send the list; if a suffix is not in the table, send it as written and we will identify it.

Cage codes (CA, CC, E, MB, MA, TVP, TN9 and similar) describe construction and are not part of the ENRO designation; ENRO lists spherical roller bearings by base number plus K, K30 and W33 only, and deep groove ball bearings by base number plus Open, ZZ, 2RS or NR. The suffix selector helps you pick a version when the drawing gives you a choice.

How to read a bearing number before you cross reference it

A standard designation has three parts and only the middle one fixes the size. Prefixes describe a special construction or a matched set. The base number carries the type, the series and the bore code. Suffixes describe closures, clearance, cage, bore type and lubrication features. When a number from another catalogue looks unfamiliar, split it into those three parts first; nine times out of ten the base number is a plain ISO number with maker-specific letters around it.

Bore codes 00 to 03 are the exceptions: 00 is 10 mm, 01 is 12 mm, 02 is 15 mm and 03 is 17 mm. From 04 upwards multiply by 5, so 6204 has a 20 mm bore and 6310 a 50 mm bore. Spherical roller numbers follow the same rule after the four-digit series, which is why 22220 and 23220 share a 100 mm bore but differ in width and outside diameter. Bores above 480 mm are written as a slash and the bore in millimetres.

What can differ behind the same number

Two bearings with the same base number and the same boundary dimensions can still differ inside, and a cross reference should list those differences so that the buyer can decide whether they matter. None of them changes the fit in the housing or on the shaft; all of them can change life, speed limit or noise in a particular position.

• Radial internal clearance: CN unless a suffix says otherwise. Changing from C3 to CN on a motor shaft with an interference fit can leave the bearing preloaded when warm.
• Cage type and material: pressed steel, machined brass or moulded polyamide. Cage letters differ by maker and are not part of the ENRO designation.
• Seal or shield design: a contact seal from one catalogue and a non-contact shield from another can both be written with a Z or an R in different positions.
• Grease fill and grease type on sealed bearings, which sets the speed limit and the temperature range.
• Tolerance class: P0 (normal) unless a P6 or P5 suffix is written. Ask if the position is a spindle or an instrument.

The ENRO model page for each size gives the boundary dimensions, the catalogue ratings and the versions listed. Where a line on your list carries a cage, tolerance or grease requirement, write it beside the line and it is answered on the quotation rather than assumed.

Checking a cross-referenced bearing on receipt

When the replacement arrives, three checks confirm the cross reference before the bearing goes on the shaft. Measure the bore and outside diameter with a micrometer and the width with a caliper, and compare with the model page. Read the marking on the outer ring face: base number, ENRO name and suffix should match the quotation line. Turn the bearing by hand; it should run smoothly with no catch, and a sealed bearing should show grease at the seal lip only when pressed. Keep the box and its anti-counterfeit label with the bearing until the machine is back in service.

How to order from a cross-referenced list

Send the list as it stands, in any format, with quantities. Each line is matched to an ENRO model by boundary dimensions, the suffixes are translated, and the quotation names the model page for every line so you can check d, D, B and versions before you confirm. Where a size is not in the ENRO list the quotation says so rather than substituting a near size. Payment terms are as set out in the sales contract. Free samples are available. We reply within 24 hours on business days.

• Number as written on the old bearing or drawing, including every prefix and suffix.
• Measured d, D and B when the marking is gone.
• Quantity per line and destination country.
• The bearing supplier page shows what ENRO supplies by series; motor sizes are grouped on the electric motor bearing page.