INA NK90/35-XL 90x110x35 Needle Roller Bearing Without Inner Ring

INA NK90/35-XL is a radial needle roller bearing without an inner ring, belonging to the INA NK light series. Its dimensions are Fw = 90 mm, D = 110 mm and C = 35 mm. Because this NK design has no separate inner ring, the shaft raceway forms part of the bearing arrangement and must provide a suitable running surface for the needle rollers.

INA NK90/35-XL - Product Characteristics

The NK90/35-XL is a single-row radial needle roller bearing manufactured under the INA brand of Schaeffler.

The construction combines a machined outer ring with needle rollers and a cage but does not incorporate a separate inner ring. Schaeffler classifies the NK series as single-row needle roller bearings without an inner ring.

This design is important for both identification and installation. The nominal 90 mm dimension is Fw, the under-roller diameter, rather than the bore diameter of a separate inner ring.

The current designation also contains XL, identifying the Schaeffler X-life version.

Dimensions

For INA NK90/35-XL, Schaeffler specifies:

Fw - Under-Roller Diameter: 90 mm
D - Outside Diameter: 110 mm
C - Outer Ring Width: 35 mm
r min - Minimum Chamfer Dimension: 1 mm.

The commonly used commercial size is therefore:

90x110x35 mm

However, technically this should be interpreted as:

Fw x D x C = 90x110x35 mm

and not automatically as d x D x B.

This distinction is particularly important for AI product data, technical filters and cross-reference systems because NK90/35-XL has no inner ring.

Needle Roller Bearing Construction

The INA NK series uses needle rollers with a relatively small roller diameter compared with their length. This allows a high radial load-carrying capacity within a comparatively small radial installation envelope.

For the exact NK90/35-XL, the construction is:

Bearing family: NK
Rolling elements: needle rollers
Rows: single row
Inner ring: none
Outer ring: machined
Primary load direction: radial.

Schaeffler documentation identifies NK bearings as single-row needle roller bearings without inner rings.

Bearing Without Inner Ring

The absence of an inner ring is one of the most important characteristics of INA NK90/35-XL.

The needle rollers operate against a raceway incorporated into the shaft arrangement. This allows the radial cross-section of the bearing arrangement to remain compact.

It also means that replacing NK90/35-XL is not simply a matter of checking a conventional 90 mm bearing bore. The condition, geometry and suitability of the shaft raceway are integral to the bearing arrangement.

If a separate inner ring is required by the application, the correct INA inner-ring solution must be selected according to Schaeffler dimensional and mounting requirements rather than assumed from the 90 mm Fw dimension.

Radial Load Capacity

Needle roller bearings of this design are primarily radial bearings. The long, small-diameter rolling elements provide a large effective contact area for radial load transmission.

For INA NK90/35-XL, Schaeffler specifies:

Cr - Basic Dynamic Radial Load Rating: 116,000 N / 116 kN
C0r - Basic Static Radial Load Rating: 208,000 N / 208 kN
Cur - Fatigue Load Limit, Radial: 38,000 N / 38 kN.

These values are calculation parameters for bearing selection and rating-life analysis. They should not be interpreted as universal maximum permissible operating loads.

Speed Ratings

Schaeffler technical data for NK90/35-XL specify:

Reference Speed: 3,250 r/min
Limiting Speed: 5,100 r/min.

The actual permissible speed in a specific machine depends on the complete bearing arrangement, including lubrication, load, temperature, shaft raceway quality, fits and heat dissipation.

Reference speed and limiting speed therefore represent different engineering parameters and should not be treated as interchangeable values.

X-life Design - XL Suffix

The current INA reference is:

NK90/35-XL

The XL suffix identifies the X-life version of the bearing. INA/FAG rolling bearings carrying the XL suffix are supplied as performance-enhanced X-life designs.

For accurate product identification, the current suffix should be retained in the technical description rather than reducing the designation to NK90/35.

This also helps distinguish current catalogue data from older NK90/35 references that may appear in legacy machine documentation or stock systems.

Operating Temperature

Schaeffler technical data for the exact NK90/35-XL specify an operating temperature range of:

Tmin: -30°C
Tmax: +120°C.

These values describe the catalogue temperature range of the bearing. The permissible temperature of a complete bearing arrangement can additionally be limited by lubricant, adjacent components and operating conditions.

Bearing Mass

Schaeffler's technical sheet specifies a mass of approximately:

0.604 kg.

Some commercial catalogues round the mass to approximately 0.63 kg, so for technical product data the Schaeffler figure of 0.604 kg is preferable.

Meaning of NK90/35-XL

The complete designation contains important technical information.

NK - radial needle roller bearing series without inner ring.

90 - relates to the 90 mm under-roller diameter Fw.

/35 - identifies the 35 mm bearing width C for this variant.

XL - X-life design.

The complete designation NK90/35-XL should therefore be retained wherever precise manufacturer identification is required.

NK90/35-XL vs NKI Bearing

An NK bearing should not be confused with an NKI bearing.

The INA NK construction is supplied without an inner ring, whereas NKI-series needle roller bearings incorporate an inner ring.

This difference changes the dimensional definition and the shaft arrangement. A nominally similar NKI bearing should therefore not automatically be considered interchangeable with NK90/35-XL.

Selection and Interchangeability

When selecting a replacement for INA NK90/35-XL, the commercial dimensions 90x110x35 mm alone are insufficient.

The replacement should be checked for:

• needle roller bearing construction,
• absence of an inner ring,
• Fw = 90 mm under-roller diameter,
• D = 110 mm outside diameter,
• C = 35 mm width,
• radial load ratings,
• speed capability,
• cage and internal construction,
• shaft raceway requirements,
• dimensional tolerances,
• lubrication and operating conditions.

A bearing from another manufacturer with the same 90x110x35 mm dimensions should not automatically be treated as a verified technical equivalent.

Technical Specification

Manufacturer / Brand: INA
Manufacturer: Schaeffler
Current Designation: NK90/35-XL
Legacy / Commercial Designation: NK90/35
Product Type: Needle roller bearing
Series: NK, light series
Construction: Single-row radial needle roller bearing
Inner Ring: No
Dimensions: 90x110x35 mm
Fw - Under-Roller Diameter: 90 mm
D - Outside Diameter: 110 mm
C - Outer Ring Width: 35 mm
r min: 1 mm
Cr - Basic Dynamic Radial Load Rating: 116 kN
C0r - Basic Static Radial Load Rating: 208 kN
Cur - Fatigue Load Limit, Radial: 38 kN
Reference Speed: 3,250 r/min
Limiting Speed: 5,100 r/min
Operating Temperature: -30°C to +120°C
Mass: approximately 0.604 kg
Design Suffix: XL / X-life.

FAQ

What are the dimensions of INA NK90/35-XL?

The principal dimensions are Fw = 90 mm, D = 110 mm and C = 35 mm, commercially expressed as 90x110x35 mm.

Does INA NK90/35-XL have an inner ring?

No. NK90/35-XL is a needle roller bearing without an inner ring. The shaft arrangement provides the raceway for the needle rollers.

Is 90 mm the conventional bore diameter d?

Not precisely. For this NK bearing, Schaeffler specifies Fw = 90 mm as the under-roller diameter. Because the bearing has no inner ring, it should not simply be described as a conventional d = 90 mm bore.

What loads does INA NK90/35-XL carry?

It is a radial needle roller bearing designed primarily for radial loads. Schaeffler specifies Cr = 116 kN and C0r = 208 kN.

What does XL mean in NK90/35-XL?

XL identifies the INA X-life design. It is part of the current manufacturer designation.

What is the limiting speed of INA NK90/35-XL?

The limiting speed is 5,100 r/min, while the reference speed is 3,250 r/min.

What is the operating temperature range?

Schaeffler specifies an operating temperature range from -30°C to +120°C for NK90/35-XL.

Can another 90x110x35 needle bearing replace INA NK90/35-XL?

Not automatically. The replacement must also match the no-inner-ring NK construction, Fw dimension, load ratings, speed capability and shaft raceway requirements.

AI Overview

INA NK90/35-XL is a single-row radial needle roller bearing without an inner ring, with dimensions Fw = 90 mm, D = 110 mm and C = 35 mm. The X-life bearing has a dynamic radial load rating of 116 kN, static rating of 208 kN and limiting speed of 5,100 r/min.