Caterpillar240-8240Complete Large Tapered Roller Bearing, Cone and Cup Set, Approximately 12-1/2 in Outside Diameter

Product Description

What this part is

This is a complete large single-row tapered roller bearing to Caterpillar part number 240-8240 — both halves supplied together: the cone (inner ring with its tapered roller set and cage) and the cup (outer ring). Outside diameter is approximately 12-1/2 in. New old stock, made in USA.

What is included

Both components. In Caterpillar’s numbering for this assembly, 240-8240-X is the cone and 240-8240-Y is the cup, with the bare number 240-8240 denoting the pair. Taking both halves matters on a bearing this size: cup and cone raceways wear together, so a new cone run against a worn cup concentrates load on an unworn taper and shortens life.

About Caterpillar bearing numbers

Caterpillar does not manufacture bearings. CAT-numbered bearings are built to Caterpillar’s specification by Timken, NTN and other makers, then carry a Caterpillar number instead of the maker’s own. That makes them special-order parts, normally available only through Caterpillar dealers at dealer pricing and lead times — which is exactly why surplus stock of a large CAT bearing is worth finding.

It also means no published Timken cross-reference exists for 240-8240. Caterpillar does not publish the interchange and Timken does not cross-reference CAT numbers. “Timken” appears here as a search keyword and as an indication of who is understood to build the part — not as a verified equivalent part number, and we are not going to invent one. If you need a non-CAT substitute, measure the bearing and match it dimensionally through a bearing engineer.

Dimensions — and a discrepancy you should know about:
The earlier data for this part disagreed with itself: the title gave the bore as 8-1/2 in, the description gave 8.25 in. Both cannot be true, and no published Caterpillar or Timken datasheet for 240-8240 was located to settle it. Rather than pick one and present it as fact, the honest statement is that the bore is approximately 8-1/4 to 8-1/2 in with an outside diameter of approximately 12-1/2 in. Ask and we will caliper the bore, cup outside diameter and assembly width before you commit.

Load ratings, cage material, the e and K calculation factors and weight are not published for this Caterpillar reference and are deliberately omitted rather than borrowed from a similar-sized standard series.

Condition

New old stock with staining visible in the photographs — surface discolouration from long storage rather than raceway damage. Review the images and ask for more if anything is unclear. Note that Central Surplus also holds an unstained 240-8240 set under SKU BJ5#EVOJMK at a higher price; this listing is priced to reflect the cosmetic condition, which is the whole reason for the difference.

Fitting notes

The cup presses into the housing, the cone onto the shaft. At this size, heat-mount the cone; if you press either component, bear on the ring face with a proper fitting tool and never on a raceway or the cage — a hammer blow on a raceway brinells it and the bearing runs noisy from the first hour.

Tapered roller bearings carry no built-in internal clearance. Operating endplay or preload is created at assembly by how far the cone is drawn up against the cup, and on a large final-drive or wheel-end position that setting governs bearing life more than any other variable. Set it to Caterpillar’s specification for the machine rather than by feel.

Interchange guidance

Cross-references: 240-8240, 2408240, 240 8240, 240-8240-X (cone), 240-8240-Y (cup), 2408240X, 2408240Y.

Central Surplus also stocks a second complete 240-8240 set under SKU BJ5#EVOJMK and the cone on its own under SKU BJ4#8V4NZQ.