2780-70 – Center Support Bearing – Bmw Application – 1.181″ ID – 1.750″ Center Bearing To Base

Q: The 2780-70 and 2780-75 are both BMW 1.181" bore -- how do I choose between 1.750" and 1.625" height? A: Measure the removed bearing center-to-base height with a digital caliper. The 0.125" (3.2 mm) difference between 1.625" and 1.750" is measurable with digital calipers but not a standard rule. Both heights exist because different BMW models route their 30 mm propshaft at different positions relative to the floor crossmember.

Q: What BMW models use a 30 mm (1.181") bore propshaft center bearing? A: BMW 30 mm bore center bearings appear on all-wheel-drive variants of certain compact and mid-size BMW models, including specific variants of the X1, X3, and X5 generations where the AWD transfer case drives a thin-section rear propshaft. The 2780-70 center support bearing covers applications at the 1.750" height in this group.

Q: Is a bearing press mandatory for BMW 30 mm bore center bearing installation? A: Yes -- BMW specifies hydraulic press installation for the inner race. The stub shaft must be supported at the opposite end to prevent bending load during pressing. Pressing force for a new 30 mm inner race on a properly sized BMW stub shaft is typically 2--5 kN. Heating the bearing to 60--80°C before pressing reduces the required force and prevents micro-cracking of the inner race during installation.