Deep Groove Ball Bearing Open 65x140x33 mm Heavy 6300 Series Pressed Steel Cage

What this part is:
This is a single row deep groove ball bearing measuring 65 mm bore by 140 mm outside diameter by 33 mm wide. It is open on both sides — no shields, no seals — with a pressed steel cage and standard CN radial internal clearance. There is no oil hole or lubrication groove in the outer ring. Deep groove ball bearings of this type carry radial load as their primary duty plus moderate axial load in either direction, and they are the highest-speed, lowest-friction rolling bearing type for a given envelope.

Decoding the designation:
6313 splits into two meaningful parts. The 63 identifies a deep groove ball bearing in ISO dimension series 03, which is the heavy series. The 13 is the bore code, and bore codes in this range multiply by five: 13 × 5 = 65 mm bore. There is no suffix, and that absence is itself information — it means the bearing is open, normal tolerance class, and normal (CN) internal clearance.

The 6300 versus 6200 versus 6000 series distinction:
This is the single most important thing to understand before ordering, because it is where buyers most often get it wrong. All three of those series use the same bore code system, so a 6013, a 6213 and a 6313 all have exactly the same 65 mm bore. They are not otherwise the same bearing. Each step up in series increases the outside diameter and the width, which means bigger balls, a deeper groove, and substantially more load capacity and shock tolerance.

Concretely: a 6213 is 65 x 120 x 23 mm. This 6313 is 65 x 140 x 33 mm. Both slide onto a 65 mm shaft. Neither will fit the other’s housing bore — the outside diameters differ by 20 mm and the widths by 10 mm. If you are cross-shopping on bore diameter alone, or matching a number off a worn part where only the first digits are legible, you will order the wrong bearing. Measure the outside diameter of the bearing you are replacing, or measure the housing bore, before you buy.

The reason the heavy series exists is capacity. The larger balls and deeper races of the 6300 series give it markedly higher dynamic and static ratings than the 6200 series at the same bore, which is why it turns up in electric motors under heavy belt load, gearboxes, pumps, crushers and drive shafts that take shock. The penalty is size, weight and a slightly lower speed limit than the lighter series.

Published ratings and mounting data:
Bore diameter d: 65 mmOutside diameter D: 140 mmWidth B: 33 mmNumber of rows: 1Cage: pressed steelDynamic radial load rating Cr: 103 kNStatic radial load rating C0r: 60.0 kNLimiting speed: 4,900 rpm with grease lubrication, 5,800 rpm with oilRadial internal clearance: CN (normal)Closure: open, no shields or sealsLubrication features: no oil hole, no oil grooveOperating temperature range: −40 to +120 °CMass: 2.080 kg

What these specs mean in practice:
The dynamic rating of 103 kN is the load at which the bearing achieves its nominal fatigue life under rotation, and it is the figure you feed into an L10 life calculation. The static rating of 60.0 kN is the different question of how much load the bearing can take at rest, or under momentary shock, before the balls permanently indent the raceways. Note that on ball bearings the static figure is typically well below the dynamic figure — the opposite of what you see on full complement roller bearings — because a ball makes point contact and concentrates its load into a very small area. That is precisely why a heavily shock-loaded application often wants a roller bearing instead, and why you should not assume a ball bearing rated 103 kN dynamically will survive a 100 kN standing impact.

The two limiting speeds reflect lubrication method rather than the bearing itself. Grease has to be churned by the rolling elements and generates heat doing it, so 4,900 rpm is the practical ceiling on grease. Circulating oil carries heat away and permits 5,800 rpm. If your application sits near either number, the lubrication decision is part of the bearing decision.

The −40 to +120 °C range is the bearing steel and standard dimensional stabilisation limit, not a lubricant limit. Grease is almost always the narrower constraint in a hot application, so check the grease specification before assuming the upper figure applies to your installation.

Being open matters for sealing and relubrication:
This bearing has no closures, which has two direct consequences. First, it depends entirely on the housing for contamination exclusion — there is no lip or shield keeping dirt and water out of the raceways. In a dirty or wet environment an open bearing needs a properly sealed housing or an external seal, or it will fail from contamination long before it fails from fatigue. Second, and more usefully, being open means grease can pass through it. If the housing has a lubrication port, you can relubricate on a schedule and purge old grease, which extends service life considerably compared to a sealed-for-life bearing that gets one fill and no more.

For reference, NTN’s closure suffixes on this family are ZZ for metal shields on both sides, LLB and LLU for contact rubber seals, and NR for a snap ring groove in the outer ring. None of those is present on this bearing. If your application needs a shielded or sealed version, or a snap ring for axial location in a through-bored housing, you need the suffixed part number rather than this bare open one.

Interchange guidance:
6313 is an ISO-standard designation, so a 6313 from any major manufacturer shares the same 65 x 140 x 33 mm envelope. Search forms that reach this part include 6313, 6313C3 (increased clearance version), 6313ZZ and 6313LLU (shielded and sealed versions of the same size), and NTN 6313. Verify the suffix and the clearance class against what your application actually requires — the size is standard, but the closure, clearance and cage are not.