688 bearing dimensions & suffix variants
Look up recorded dimensions for designations beginning with 688. The table retains complete manufacturer designations so special suffixes and different dimensional variants remain visible.
On this page6 sections ⌄
Find by measured dimensions
Enter bore d, outside diameter D and width B. Use decimals or inch fractions such as 1/2 or 1 1/4.
688 — published size and closure variants
688 is the base grouping for the specific records below. Read the complete designation and publisher on each row. The source unit is retained beside the converted unit. A shield or seal can change the width; equal bore and outside diameter do not establish the same envelope.
7 source-labelled records; 7 shown initially.
| Publisher / full model | Closure / material | d×D×B in mm | d×D×B in inches | Source unit |
|---|---|---|---|---|
| SMB688 | OpenChrome steel | 8× | 0.314961× | mm |
| SMB688ZZ | ShieldedChrome steel | 8× | 0.314961× | mm |
| SMB688-2RS | SealedChrome steel | 8× | 0.314961× | mm |
| SMB688ZZW4 | ShieldedChrome steel | 8× | 0.314961× | mm |
| SMB688-2RSW4 | SealedChrome steel | 8× | 0.314961× | mm |
| SMB688ZZW6 | ShieldedChrome steel | 8× | 0.314961× | mm |
| SMB688-2RSW6 | SealedChrome steel | 8× | 0.314961× | mm |
Keep RS, 2RS, ZZ and width suffixes distinct
The table records the publisher’s open, shielded or sealed column. An unlisted “RS” marking is not rewritten as “2RS”. Keep special endings such as W21, W23 or a fractional bore suffix: they can identify a different width or bore. No automatic cross-brand substitution is approved.
Metric values converted from printed inch decimals inherit the source rounding. For example, 0.2812 in converts to 7.14248 mm; that extra decimal detail is arithmetic, not a tolerance or a machining target. Never silently round an inch bearing into the nearest metric size. Missing speed, clearance, precision, internal ball diameter, material grade or exact lubricant remain unknown.
Publisher references: SMB product charts and Enduro 1600-series data; checked 2026-10-02. Original BearingScope interpretation. No stock, sales, vehicle fitment or redistributable CAD is implied. Material names describe the source page, not a certificate for every item sold under a similar number.
688 dimensions and recorded technical data
The recorded 688 base designation measures 8×16×4 mm (inside diameter d × outside diameter D × width B). This answer uses unsuffixed records from KOYO, EZO. It does not assign the same dimensions or operating ratings to every suffix.
The numeric series boundary is preserved: a longer number is not included merely because its first digits match. 11 recorded variants are listed. A dash means the value is missing, not zero.
No recorded variant matches these filters. Clear a filter to see other records; no substitute has been inferred.
| Brand / full designation | Named dimensions (mm / in) | Dynamic C (kN) | Static C0 (kN) | Reference speed (rpm) | Limiting speed (rpm) | Mass (kg / g) |
|---|---|---|---|---|---|---|
| KOYO688Deep groove ball bearing |
| 1.55 kN | 0.59 kN | — | 42000 rpmLimiting Speeds(Grease Lub.): 42000 min-1Limiting Speeds(Oil Lub.): 50000 min-1 | 0.003 kg3 g |
| EZO688Deep groove ball bearing |
| 1.26 kN | 0.59 kN | — | — | 0.00316 kg3.16 g |
| FAG688-2RSR-HLNDeep groove ball bearing |
| 1.71 kN | 0.71 kN | — | 26000 rpm | 0.004 kg4 g |
| FAG688-2Z>NDeep groove ball bearing |
| 1.71 kN | 0.71 kN | 34000 rpm | 51000 rpm | 0.004 kg4 g |
| FAG688>NDeep groove ball bearing |
| 1.71 kN | 0.71 kN | 30000 rpm | 60000 rpm | 0.0038 kg3.8 g |
| NSK688ADeep groove ball bearing |
| 1.77 kN | 0.71 kN | — | — | 0.00312 kg3.12 g |
| NSK688ADDDeep groove ball bearing |
| 1.77 kN | 0.71 kN | — | — | — |
| NSK688AVVDeep groove ball bearing |
| 1.77 kN | 0.71 kN | — | — | — |
| NSK688AZZ1Deep groove ball bearing |
| 1.77 kN | 0.71 kN | — | — | 0.00402 kg4.02 g |
| EZO688 2RSDeep groove ball bearing |
| 1.26 kN | 0.59 kN | — | — | 0.00383 kg3.83 g |
| EZO688ZZDeep groove ball bearing |
| 1.26 kN | 0.59 kN | — | — | 0.00379 kg3.79 g |
Compare recorded seals, clearance, precision and materials
Manufacturer wording is retained. A missing property is not inferred from another brand or a similar suffix.
| Brand / designation | Closure | Original precision | Clearance | Cage | Material | Lubricant |
|---|---|---|---|---|---|---|
| KOYO 688 | Open | Not recorded | Not recorded | Not recorded | Not recorded | Not recorded |
| EZO 688 | Open (no closure suffix in this catalogue marking) | Not recorded | Not recorded | Not recorded | High-carbon chromium bearing steel | Not recorded |
| FAG 688-2RSR-HLN | 2RSR — Contact seal on both sides | PN — Normal (ISO 492:2023) | CN (Group N) — Normal internal clearance | JN — Steel sheet metal | Not recorded | Lubricating grease |
| FAG 688-2Z>N | 2Z — Non-contact shield on both sides | PN — Normal (ISO 492:2023) | CN (Group N) — Normal internal clearance | JN — Steel sheet metal | Not recorded | Lubricating grease |
| FAG 688>N | Without — Not sealed | PN — Normal (ISO 492:2023) | CN (Group N) — Normal internal clearance | JN — Steel sheet metal | Not recorded | Without — Bearing not greased |
| NSK 688A | Open | Not recorded | Not recorded | Not recorded | Not recorded | Not recorded |
| NSK 688ADD | Contact rubber seals on both sides (DD) | Not recorded | Not recorded | Not recorded | Not recorded | Not recorded |
| NSK 688AVV | Non-contact rubber seals on both sides (VV) | Not recorded | Not recorded | Not recorded | Not recorded | Not recorded |
| NSK 688AZZ1 | Metal shields on both sides (ZZ1) | Not recorded | Not recorded | Not recorded | Not recorded | Not recorded |
| EZO 688 2RS | Two contact rubber seals | Not recorded | Not recorded | Not recorded | High-carbon chromium bearing steel | Not recorded |
| EZO 688ZZ | Two pressed-steel shields | Not recorded | Not recorded | Not recorded | High-carbon chromium bearing steel | Not recorded |
How to compare these values
- Use the displayed dimension names and original symbols. Housing length L, height H2 and flange width are not bearing outside diameter D. A catalogue width with an unverified symbol must not be assumed to be inner-ring width B or assembly width T. Open the product record for mounting dimensions and geometry.
- Inch values are calculated from the recorded millimetres using 25.4 mm per inch, rounded to six decimal places. They do not change a metric bearing into an inch-series bearing. Gram values are converted from the recorded mass in kilograms.
- C and C0 describe different rating conditions. They are not a single safe working-load limit and cannot replace an application load calculation.
- Reference and limiting speeds are separate catalogue values. The source grease/oil context is shown where recorded. Lubricant, seals, loads, fit, clearance and cooling affect the usable operating speed.
- A common base number does not prove equivalent seals, clearance, precision, material or interchangeability. Open the full designation for these fields.
Related prefix matches — other model numbers may appear
These discovery results can contain a longer number or a different component. They are not specifications for the requested exact model. Open the complete product to inspect its original geometry.
688
Deep groove ball bearing
View full technical record →EZO688
Deep groove ball bearing
View full technical record →KOYO6880
Deep groove ball bearing
View full technical record →KOYO68/800
Deep groove ball bearing
View full technical record →EZO688 2RS
Deep groove ball bearing
View full technical record →FAG688-2RSR-HLN
Deep groove ball bearing
View full technical record →FAG688-2Z>N
Deep groove ball bearing
View full technical record →KOYO6884
Deep groove ball bearing
View full technical record →KOYO68/850
Deep groove ball bearing
View full technical record →KOYO6888
Deep groove ball bearing
View full technical record →NSK688A
Deep groove ball bearing
View full technical record →NSK688ADD
Deep groove ball bearing
View full technical record →Check the drawing before substituting
Nominal dimensions are not shaft-fit tolerances. Different variants can add grooves, flanges, wider rings or assembly components. When the table has different dimensions, the complete designation—not the shared prefix—controls.
Reference basis & data limits
Manufacturer terminology is retained in the product records. Technical reference basis: JTEKT Basic Bearing Knowledge (boundary dimensions, tolerance classes and lubrication); NSK Bearing ABCs (lubrication, designations and clearance); NTN technical FAQs (closure codes and component interchange); SKF rolling-bearing selection and maintenance references.
Selection workflows and catalogue grouping are BearingScope editorial aids. Verify the current drawing and application requirements before using a candidate. Missing database information is not converted into an assumed match.