Miniature bearings 604 to 609: sizes, seals, and which one you measured

A 604 bearing is 4 mm bore x 12 mm outside diameter x 4 mm wide. From 604 to 609 the last digit is the bore, so a 605 is 5 x 14 x 5 and a 609 is 9 x 24 x 7. We sell all six, plus the 626, as rubber sealed 10-packs, 604RS to 609RS and 626RS.

Know your number? Find it in the first table. Only have measurements? Use the reverse lookup below it.

Miniature bearing sizes: 604, 605, 606, 607, 608, 609 and 626

Source: bearing makers' published dimension tables (see Sources), read 12 October 2026, and our product listings. The RS 10-packs are the size options of our 604RS to 609RS and 626RS listing.

In both makers' tables we checked, each of these seven is the same width open, shielded or sealed. The seal or shield letters after the number don't change the size.

Reverse lookup: I measured it, which bearing is it?

1. Measure the bore (the hole) with vernier callipers, to one decimal place.
2. Measure the outside diameter (OD) across the outer ring.
3. Measure the width of the outer ring.
4. Find your OD x width below, then pick the row that matches your bore.

Source: bearing makers' published dimension tables (see Sources). Bold = sizes we list.

The searches we see most:

• 22 x 8 or 22 x 8 x 7 is a 608 written outside diameter first: 8 mm bore, 22 mm OD, 7 mm wide.
• 17 x 6 is a 606 (6 x 17 x 6).
• 19 x 6 fits four bearings. A 607 has a 7 mm bore and a 626 a 6 mm bore, so measure the bore before you order.
• 24 x 7 is a 609. A 24 mm ring that's 8 mm wide is a 628 instead.

If nothing matches, send us the three measurements and the number on the old bearing before you order.

How a 604 to 609 number reads

• 6 is a deep groove ball bearing.
• The single last digit is the bore in millimetres: 604 = 4 mm, 609 = 9 mm.
• The second digit is the series. A 626 has the same 6 mm bore as a 606, but a bigger outer ring: 19 mm against 17 mm.
• The letters after it are the closures: RS or 2RS for rubber seals, Z or ZZ for metal shields. Whether "RS" means a seal on one side or both depends on who wrote it, so look at both sides of the old bearing. Our bearing seal codes guide has each maker's letters.

Sealed or shielded?

Shields give the lowest drag where the bearing stays clean and dry. Bearing makers rate contact rubber seals well ahead of shields against dust and water, at the cost of more drag and a lower top speed. Our 608 guide has the full comparison. The drag and sealing trade-off is the same for the other sizes.

In our range:

• The 604 to 609 and 626 RS packs have rubber seals. That listing says metal shielded versions may be available on request.
• The 606, 608 and 609 also come as ZZ shielded 10-packs.
• The Victa HA25436 pair is listed with 609-2RS among the numbers it replaces.

Match what came out unless you want to trade drag for sealing.

The 608 and the 609

The 608 is 8 x 22 x 7 mm whatever its seals, and it's the one with its own guide: our 608 bearing size article covers 608ZZ vs 608-2RS and skate wheels.

The 609 is the next size up, 9 x 24 x 7 mm. Besides the RS and ZZ 10-packs, we list a 9 x 24 x 7 pair for the Victa Late 550, as the drive bearing, under Victa part number HA25436.

Which Bearings Express miniature bearing fits

• Pick the 10x 604RS to 609RS and 626RS sealed bearings for any of the seven sizes with rubber seals. Choose the size from the drop-down.
• Pick the 10x 606-ZZ or 10x 609-ZZ if the old bearing had metal shields.
• Pick the 10x 608-ZZ or 10x 608-RS for a 608.
• Pick the 2x Victa HA25436 bearings for a Victa Late 550 drive bearing.

More sizes, from 6000 to 6310, are in our ball bearings collection.

Questions people also ask

What size is a 604 bearing?

4 mm bore x 12 mm outside diameter x 4 mm wide. We list it as the 604RS, rubber sealed, in a 10-pack.

What are the 605 bearing dimensions?

5 mm bore x 14 mm outside diameter x 5 mm wide, the same for the 605RS and 605-2RS.

What size is a 606ZZ bearing?

6 x 17 x 6 mm, with a metal shield on both sides. The 606RS is the same size with rubber seals.

Is a 607 bearing the same as a 626?

No. Both are 19 mm across and 6 mm wide, but the 607 has a 7 mm bore and the 626 a 6 mm bore.

Do you sell 623, 625 or 688 bearings?

Not in our miniature bearing listings, which run 604 to 609 plus the 626. Send us the number or the three measurements and we'll check.

Related reading

• 608 bearing size: 8 x 22 x 7 mm, and 608ZZ vs 608-2RS
• 2RS vs ZZ bearings: what the seal codes mean
• Bearing size chart 6000 to 6310, with a reverse lookup by measurement

Sources

• NTN, Ball and Roller Bearings, Cat. No. 2203/E: Miniature and Small Size Ball Bearings, metric series pp. B-48 to B-51, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_b03.pdf, read 12 October 2026.
• Koyo (JTEKT), Ball & Roller Bearings, CAT. NO. BS004EN: extra-small and miniature ball bearings, pp. B 42 to B 45, https://koyo.jtekt.co.jp/en/support/catalog-download/uploads/catbs004en_b.pdf, read 12 October 2026.
• Seal ratings: NTN, Cat. No. 2203/E, Table 1 "Sealed ball bearings: construction and characteristics", p. B-17, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_b02.pdf, read 2 October 2026.

Checked against bearing makers' dimension tables and Bearings Express product listings on 12 October 2026.