How to Read a Bearing Number

Bearing numbers follow an international standard, so the number stamped on the bearing tells you its type, its dimensions and how it is sealed. If you can read the number, you can order the correct replacement without measuring anything. This article explains how to read a bearing number.

Bearing နံပါတ်သည် နိုင်ငံတကာ စံနှုန်းအတိုင်း ဖြစ်သည်။ နံပါတ်ကို ဖတ်တတ်ပါက အရွယ်အစား တိုင်းစရာမလိုဘဲ မှန်ကန်သော bearing ကို မှာယူနိုင်သည်။

The three parts of a bearing number

Take the example 6204-2RS. It breaks into three parts:

1. 6 — the type. 6 means deep groove ball bearing.
2. 2 — the dimension series, which sets how heavy-duty the bearing is for its bore.
3. 04 — the bore code. 04 means a 20 mm bore.

The suffix -2RS describes the sealing. So 6204-2RS is a deep groove ball bearing with a 20 mm bore, sealed on both sides with rubber.

ဥပမာ 6204-2RS သည် အတွင်းအချင်း 20 မီလီမီတာ ရှိသော deep groove ball bearing ဖြစ်ပြီး နှစ်ဖက်စလုံး ရာဘာ seal တပ်ထားသည်။

The first digit — bearing type

• 6 — deep groove ball bearing (6204, 6305)
• 7 — angular contact ball bearing (7205)
• 2 — spherical roller bearing (22210, 21310)
• 3 — tapered roller bearing (30205, 32210)
• NU, NJ, N — cylindrical roller bearing (NU205, NJ305)
• HK, NA, NK — needle roller bearing (HK1512)

The last two digits — bore size

For bore codes 04 and above, multiply the code by 5 to get the bore in millimetres. Codes 00 to 03 are exceptions and must be memorised:

Bore code 04 နှင့် အထက်တွင် ကိန်းဂဏန်းကို 5 ဖြင့် မြှောက်ပါ။ 00 မှ 03 အထိမှာ ခြွင်းချက်ဖြစ်၍ မှတ်ထားရမည်။

Suffixes — sealing and clearance

• 2RS or RS — rubber contact seals, both sides or one side. Best where dirt and water are present.
• ZZ or 2Z — metal shields, both sides. Lower friction than rubber, less protection from water.
• No suffix — open bearing, lubricated by the housing oil.
• C3 — larger internal clearance than standard. Fit C3 where the bearing runs hot or has a tight shaft fit. If the old bearing was C3, the replacement must be C3.

If the number is worn away

If the old bearing is too damaged to read, measure three dimensions with a vernier caliper and send them to our trade desk:

1. Bore — the inside diameter | အတွင်းအချင်း
2. Outside diameter | အပြင်အချင်း
3. Width | အထူ

Send the vehicle make, model and year as well. Three dimensions plus the vehicle is almost always enough to identify the bearing.

Related Articles

• Bearings — Frequently Asked Questions
• Fitting a Bearing Without Damaging It
• Choosing the Right Bearing Type — Load, Speed and Alignment
• Why Bearings Fail — Diagnosis Guide
• What Is a Bearing? Types Used in Commercial Vehicles
• Thrust Bearings — Ball, Roller and Needle Roller