NTN7316BGP5Precision Angular Contact Ball Bearing 80x170x39 mm, 40 Degree Contact Angle for Heavy Thrust, Universally Ground Single, ABEC 5

Product Description

What this part is

An NTN precision angular contact ball bearing in the heavy 73-dimension series, 80 mm bore × 170 mm outside diameter × 39 mm width, with a 40° contact angle, universally ground and held to ISO class 5. At 3.72 kg it is a substantial bearing built for heavy thrust duty.

Decoding the designation

7316 — 73-dimension series angular contact, 80 × 170 × 39 mm.
B — 40° contact angle in NTN’s scheme.
G — single, universally flush-ground. The faces are ground so that any number of these bearings can be combined back-to-back, face-to-face or in tandem and the correct relationship results from simply clamping them together.
P5 — ISO tolerance class 5, equivalent to ABEC 5.

Quantity and configuration

The G code denotes a single universally ground bearing, not a pair. This matters because NTN’s pair code is GD2, and the two are different products. Universal grinding is what makes a single useful: two of these mounted back-to-back behave as a matched duplex set, so stacks can be built and repaired without buying factory-matched pairs. No pair-count claim is published on this listing.

Why the 40° angle decides the application

40° is the thrust-capacity extreme of the angular contact range. It carries far more axial load and resists axial deflection much better than a shallow-angle bearing in the same envelope, which is why it is specified for pump and compressor shafts, worm gear drives, vertical shafts carrying rotor weight, and heavy thrust positions in gearboxes. The price is speed and radial capacity.

The magnitude of the difference is worth seeing in numbers, because the envelope is identical and the substitution looks harmless. The 30° version of this same bearing, plain 7316, is rated at Cr 163 kN and Cor 119 kN with limiting speeds of 4,500 rpm grease and 5,900 rpm oil. This 40° B version is Cr 149 kN and Cor 109 kN at 3,800 and 5,100 rpm — lower radial rating and lower speed, in exchange for substantially greater thrust capability and axial stiffness. Choosing between them is a real engineering decision, not a formality, and the two must never be mixed in one stack.

Published ratings and mounting data

Dynamic load rating Cr — 149 kN
Static load rating Cor — 109 kN
Fatigue limit load Cu — 7.65 kN
Limiting speed — 3,800 rpm grease, 5,100 rpm oil
Mass — 3.72 kg
Chamfer rs / r1s minimum — 2.1 mm / 1.1 mm
Abutment dimensions — da 92 mm, db 87 mm, Da 158 mm, Db 163 mm

For a back-to-back, face-to-face or tandem pair of these bearings, NTN publishes set ratings of Cr 243 kN and Cor 218 kN with limiting speeds of 3,100 rpm grease and 4,100 rpm oil. Note that a pair’s dynamic rating is not simply double a single’s — it is roughly 1.62 times, because the two bearings share load unevenly. Doubling the single figure would overstate the set’s capacity by more than 20 per cent, which is a common and costly sizing error.

Fitting notes

The abutment dimensions above are the practical ones to work to: shaft shoulders and housing shoulders must clear the ring faces without fouling the cage or the relieved shoulder. Observe thrust direction on each bearing — a single angular contact bearing takes thrust one way only. When stacking universally ground bearings, align the etched face marks to suit the arrangement intended. Bearings ship preserved, not charged with service lubricant.

Interchange guidance

Angle-equivalent designations in other schemes include 7316B in NSK and FAG style and 7316BECBM or 7316BEP in SKF style, all denoting 40°. Note that plain 7316 without the B is a 30° bearing and is not a substitute despite the identical envelope, and that a 7316C would be 15°. A carton cross-reference reading 7316B-SUL-P5 also circulates against this part — SU and DU are mutually exclusive designations, and since this bearing’s own code is G for a universal single, the SUL form is consistent with it as an equivalent single-universal designation.