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. Buying the complete set matters on a bearing this size: cup and cone raceways wear together, and fitting a new cone against a used cup gives you an unworn taper running on a worn one, which concentrates load and shortens life. If you are doing a full rebuild, take both halves.

About Caterpillar bearing numbers

Caterpillar does not manufacture bearings. CAT-numbered bearings are built to Caterpillar’s specification by Timken, NTN and other makers and then carry a Caterpillar number instead of the maker’s own. That classes them as special-order parts, normally available only through Caterpillar dealers at dealer pricing and dealer lead times — which is precisely 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. The word “Timken” appears in this listing as a search keyword and as an indication of who is understood to build the part; it is not 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 while the description gave 8.25 in. Those cannot both 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.

If you are matching this to a machine, ask and we will caliper the bore, the cup outside diameter and the 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 left out rather than borrowed from a similar-sized standard series.

Fitting notes

The cup presses into the housing and 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, because a hammer blow on a raceway brinells it and the bearing runs noisy from the first hour.

Tapered roller bearings have 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 BE6#OSOXGD, and the cone on its own under SKU BJ4#8V4NZQ. If you need two sets, or only a cone, both are available from the same source with the same provenance.