Start with a dimensioned drawing
Specify tube outside diameter D, shaft diameter d, length L2 and tube wall thickness S using the notation in your selected manual. Also show overall length and mounting length separately: these dimensions are not interchangeable.
Describe the bearing, shaft ends and environment
Include the bearing reference, shaft-end detail and seal requirement. Tell us whether the roller carries the belt, supports the return belt or works at an impact point. Describe dust, moisture, material, belt speed and loading; load capacity needs an application-specific assessment.
Use reference ranges carefully
The carrying-roller table includes a D 89–108 mm group with d 20–30 mm, L2 200–800 mm and S 3–3.5 mm. This is a selection range, not confirmation that every combination is available. Return-roller lengths can differ.
Make the inquiry ready to review
Send a drawing or sample reference, quantity, destination, packing requirements and requested delivery date. Mark critical dimensions and acceptance checks. We can then discuss a specific configuration instead of quoting from diameter alone.