Double row tapered roller bearings used in rolling mills, mining equipment and vehicle axles fall into two totally different construction concepts: paired single-row bearings (DB, DF) and factory manufactured integral double-row bearings (TDO, TDI). Strictly speaking, DB and DF are assembled from two individual single row tapered roller bearings rather than genuine double row bearings. However, they are commonly classified as double-row arrangements in engineering applications.
1. DB & DF: Paired Single Row Tapered Roller Bearings
DB and DF consist of two complete independent single-row tapered roller bearings plus a loose removable spacer. Each inner ring and outer ring belongs to separate single-row bearing units and can be fully disassembled into two standalone single bearings.
- DB (Back-to-Back / O arrangement): The spacer is sandwiched between the back faces of two outer rings. Load pivot points sit outside the bearing set, delivering large support span, strong anti-tilting performance and outstanding resistance to eccentric load. Widely used for heavy gearboxes and construction vehicle axles. Check DB paired bearing products
- DF (Face-to-Face / X arrangement): The spacer locates between small end faces of two inner rings. Load pivot points stay inward, resulting in compact overall mounting space and good misalignment tolerance, ideal for compact reducers and medium-duty transmission shafts. Check DF paired bearing products
The independent spacer controls internal clearance; users can swap spacers of different thickness to adjust clearance during assembly or field maintenance.
2. TDO & TDI: Genuine Integral Double Row Tapered Roller Bearings
TDO and TDI are factory finished authentic double row tapered roller bearings, produced as a single unit without separable spacer parts. The middle separating rib is integrally machined onto one main ring body and cannot be detached or replaced individually.
- TDO Type: Features a single one-piece outer ring with integrated middle separating rib plus two loose inner rings. Its loading property equals DB back-to-back setup, with much higher structural rigidity for rolling mill necks and large mining drums. Browse TDO integral double row bearings
- TDI Type: Built around an integrated single inner ring with cast middle rib matched with two separate outer rings. The integrated inner rib replaces DF’s independent spacer, keeping compact size and excellent coaxiality for truck hubs and small industrial rollers. Browse TDI integral double row bearings
3. Quick Product Selection Tips
- Select DB/DF paired set: Cost-sensitive projects, easy spare replacement if one single bearing fails, regular medium-load working conditions.
- Select TDO/TDI integral double row: Heavy overload, high precision and long service life requirements for metallurgy, mining and rolling equipment.
Our factory manufactures custom paired DB/DF and integral TDO/TDI tapered roller bearings to satisfy diverse equipment installation specifications.
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