Tapered Roller Bearings

The tapered raceway geometry means that a single bearing can only react axial load in one direction, the direction that pushes the rollers toward the rib. Axial load in the opposite direction would separate the cone from the cup. For bidirectional axial location, two bearings are arranged back-to-back (O-arrangement, wider effective span, better moment resistance) or face-to-face (X-arrangement, narrower span, more compact housing design). Axial clearance or preload is then set during installation by adjusting the locknut or spacer.

All three series use the same operating principle and similar contact angles. The difference is cross-section geometry. The 30200 series is the lightest, smallest OD and width for a given bore, suited for moderate loads. The 30300 series has a larger OD for the same bore, accommodating larger rollers and providing roughly 30 to 50 percent higher dynamic load capacity. The 32000 series keeps a similar OD to 30200 but increases the bearing width, allowing longer rollers and maximum load capacity within a compact radial envelope. Choose 30300 when you need more capacity and have housing space; choose 32000 when radial space is limited but axial length is available.

Both TDO and TDI are double-row tapered roller bearing configurations that carry radial and bidirectional axial loads in a single unit. TDO (double outer ring, two inner rings with spacer) provides higher rigidity and is preferred for rolling mill and heavy machinery applications where the housing must resist large overturning moments. TDI (two outer rings with spacer, single integrated inner ring) is preferred where a one-piece inner ring must be mounted on a large shaft, or where the inner ring needs to be installed in one operation. For rolling mills, the four-row TQO configuration combines TDO and TDI elements for maximum load capacity in the most compact cross-section.

Unlike deep groove ball bearings, tapered roller bearings are adjusted during installation, internal clearance or preload is not fixed at manufacture but set in the machine. The standard method is to tighten the locknut or adjust the end cap until the desired axial play is measured, or preload is confirmed by measuring starting torque. Precision applications such as machine tool spindles require controlled preload, usually specified by the machine designer. Incorrect adjustment, either excessive clearance or excessive preload, significantly reduces bearing service life. Consult BOM's engineering team for application-specific adjustment recommendations.

Yes. BOM supports full-specification custom tapered roller bearing manufacturing, including non-standard cone angles engineered to match specific axial load requirements, non-standard bore and OD in both metric and inch dimensions, alternative ring and roller materials, factory-matched paired arrangements with defined preload and inspection certificate, and complete bearing architecture redesign for applications that require a fundamentally non-standard solution. Contact BOM's engineering team with your load data and shaft envelope to initiate a custom bearing specification.