Timken39575-3Tapered Roller Bearing Cone Only, 2 in Bore, Class 3 Precision, Single Row – Mates With Cup 39520, Cup Not Included

Product Description

What this part is

An inch-series tapered roller bearing cone: the 2.0000 in bore inner ring with its tapered roller complement and cage. Single row, open, in bearing steel. Paired with its cup it carries heavy radial load together with thrust in one direction.

What is included and what is not

This listing is the CONE ONLY. A tapered roller bearing is separable — the cone (inner ring, rollers, cage) and the cup (outer ring) are two distinct parts with two distinct part numbers. The cup is NOT supplied here. The cone will not run without one; there is no outer raceway in the box.

The mating cup for 39575 is 39520. Replacing only the cone is a legitimate repair when the cup pressed into the housing is still smooth and unspalled and you want to avoid pulling it. If the cup is worn, or you are building the assembly from scratch, order the 39520 alongside this part.

Decoding the designation

39575 – the cone part number; the matched pair is written 39575/39520.
-3 or *3 – Timken precision class 3, a tolerance class tighter than standard, consistent with the class 3 marking recorded on this item.

What these specs mean in practice

Class 3 precision tightens bore, width and running accuracy against the standard class. The practical gain is lower runout and a more predictable mounted fit, which shows up as less vibration, more even load sharing across the rollers and easier, more repeatable preload setting. The catch is that precision is a system property: fit a class 3 cone into a shaft and housing machined to ordinary commercial tolerance and you have bought accuracy you cannot use. Match the cup class too where you can.

The 39575/39520 pair has a combined width T of 1.1875 in against a cup width C of 0.9375 in. That difference matters when you calculate the shim stack — the cone stands proud of the cup, and the axial setting is made across the mounted pair, not against either part alone.

Published ratings and mounting data

Bore d: 2.0000 in (this cone)
Assembly outside diameter D: 4.4375 in (with cup 39520)
Assembly overall width T: 1.1875 in (with cup 39520)
Cup width C: 0.9375 in (cup 39520 — not included)
Rows: 1
Closure: open
Precision: Timken class 3
Mating cup: 39520

Timken publishes, for the complete matched 39575/39520 assembly: dynamic C1 = 167,000 N (ISO method, 1 million revolutions), C90 = 43,300 N (Timken method, 90 million revolutions) and static C0 = 224,000 N. These are assembly figures. They are not cone-alone ratings and this SKU does not include the cup. A load rating describes cone, rollers and cup working as a set; quoting it against a bare cone would overstate what is in the box. Note also that C1 and C90 are two different rating conventions over two different lives — comparing a C90 against a competitor’s ISO dynamic figure will mislead you badly.

Fitting notes

Press only on the cone bore face. Never transmit mounting force through the rollers or cage. Tapered roller bearings have no internal clearance until mounted; endplay or preload is set on assembly against the opposed bearing. Confirm the shaft shoulder is square and the shoulder fillet clears the cone back face.

Interchange guidance

39575 and cup 39520 are widely used inch-series numbers offered by several manufacturers on the same boundary dimensions. Mixing brands across a cone and cup is not recommended unless the pair is confirmed interchangeable, since taper angle and raceway finish must correspond. Search terms that reach this part: 39575, 39575-3, 39575*3, and the assembly designation 39575/39520. Fafnir bearing numbers are now handled under Timken.