A 25580 and 15123 bearing kit in our range is a 25580/25520 inner (44.45 mm bore) with a 15123/15245 outer (31.75 mm bore), and the seal decides the kit. Our Dexter 2 tonne kits come in an AU version with a 33940 seal (listed at about 49 mm inside) and a US version with a 34040 seal (2.250 in, 57.15 mm).
If your cones read 25580 and 15123 and the old seal measures about 49 mm across the inside, order the AU kit. About 57 mm inside and 12.7 mm wide, the US kit. Anything else, read on.
| Part | What it is | Maker's size |
|---|---|---|
| 25580 | Inner cone | 44.45 mm (1 3/4") bore, 25.40 mm wide |
| 25520 | Inner cup | 82.93 mm outside, 19.05 mm wide; 23.81 mm wide overall with its 25580 cone |
| 15123 | Outer cone | 31.75 mm (1 1/4") bore, 19.05 mm wide |
| 15245 | Outer cup | 62.00 mm outside, 14.29 mm wide; 18.16 mm wide overall with its 15123 cone |
Source: bearing makers' published part and set data for 25580, 25520, 15123 and 15245 (see Sources), read 5 October 2026. These are the makers' figures. Our Dexter listings write the pair as 25580/20 and 15123/245: the cone number, then the end of the cup number.
The bearings are the same in both versions: the seal is the difference
Dexter makes axles, not bearings, as our supplier points out. A "Dexter bearing" is a standard tapered roller bearing number, and in our Dexter 2 tonne kits it's the 25580 and 15123 pair, AU or US. The "2 tonne" in our kit names is not a load rating for the bearings, and we don't quote load ratings for bearings or kits. Match the numbers that came out.
What changes is the grease seal. Our supplier tells us US Dexter axles use the 34040 seal (2.250 x 3.375 x 0.5 in). Our AU version carries the 33940 seal instead. Two more seal sizes turn up on the same 25580 and 15123 bearings in our ModCon camper kits:
| Kits with 25580 + 15123 bearings | Seal as listed | Inside | Outside | Width |
|---|---|---|---|---|
| Dexter 2 tonne, AU version | 33940 | 1.937 in (49.2 mm) | 3.375 in (85.7 mm) | 0.5 in (12.7 mm) |
| ModCon standard kits | No number given | 2 in (50.8 mm) | 3.375 in | 0.5 in |
| Dexter 2 tonne, US version | 34040 | 2.250 in (57.15 mm) | 3.375 in | 0.5 in |
| ModCon kits with seal 22533737 | 22533737 | 2.25 in (57.15 mm) | 3.375 in | 0.35 in (8.9 mm) |
Source: Bearings Express product data (kit and seal listings), checked 5 October 2026. Millimetres converted by us from the listed inches. The 33940 seal is listed as 1.937 in on our seal-only listing and rounded to 1.93 in on the AU kit listings.
All four kit seals are listed at the same 3.375 in outside diameter, so the outside of the old seal won't tell you which kit you have. The inside diameter will, and for two of them so will the width.
How to tell which Dexter kit you need
- Read the cones. Wipe the grease off and read the numbers. 25580 on the inner and 15123 on the outer means one of the kits above. A 25580 with a different outer cone is a different kit (our Cruisemaster 10-VC kit pairs it with L68149, our Kimberley disc brake kit with LM67048).
- Read the cups. Our kits come with 25520 and 15245 cups. Bearing makers also list the 25580 cone with other cups, such as the 25521 (83.06 mm outside) and 25518 (81.97 mm), and pair the 15123 cone with other cups too, such as the 15250X (63.50 mm). Check that your cups read 25520 and 15245 before you order.
- Measure the old seal's inside diameter. Use a vernier calliper across the hole in the seal. About 49 mm is the AU 33940. About 57 mm is the US 34040. The ModCon standard seal (about 51 mm) is only about 1.6 to 1.8 mm bigger than the AU seal, so measure carefully rather than eyeballing it. If the seal is too damaged to measure, measure the smooth band on the axle that the seal lip runs on (the seal journal): the seal's inside matches it.
- Measure the width. A 57 mm seal that's 12.7 mm (1/2 in) wide is the US Dexter seal. One that's about 9 mm wide is the ModCon 22533737.
- Count the hubs. A 1x kit does one hub. A 2x kit does two.
When to get a mechanic
Replacing the bearings means taking the hub off, pressing the old cups out and the new ones in, fitting the new seal and setting the bearing up again on reassembly. If you haven't done it before, have a trailer service centre or mechanic do it. Have it checked before you tow further if a hub ran hot, a bearing grinds or has play, a cup is pitted, or the axle journal is scored or blue. Our kit listings say all parts should be fitted by a licensed professional to vehicle specifications.
Which Dexter kit to buy
- Pick the 2x Dexter 2 Tonne Wheel Bearing Kits, AU version if your cones read 25580 and 15123 and the old seals measure about 49 mm inside (33940), or the 1x AU kit for one hub. ACCOR bearings.
- Pick the 2x Dexter 2 Tonne Wheel Bearing Kits, US version if the seals measure about 57 mm inside and 12.7 mm wide (34040), or the 1x US kit for one hub. ACCOR bearings. We also list the US version with ITJ bearings, made in Japan, in the trailer collection.
- Pick the 2x Seals to fit Dexter 2-Tonne kits, 1.937 x 3.375 x 0.5 if the bearings are fine and you only need the AU seals.
- Pick the 2x Seals for Dexter 2 Tonne kits, US version, 2.25 x 3.37 x 0.5 if you only need the US seals.
- Pick the 2x Standard Trailer Wheel Bearing Kits for ModCon Campers if your seals measure about 51 mm (2 in) inside.
Questions people also ask
What size is a 33940 seal?
Our seal listing gives it as 1.937 x 3.375 x 0.5 in, about 49.2 x 85.7 x 12.7 mm (inside, outside, width): the seal in our Dexter AU kits, also sold as a pair.
What is a 34040 seal?
The seal in our Dexter US version kits, listed as 2.250 x 3.375 x 0.5 in, about 57.15 x 85.7 x 12.7 mm. Our supplier tells us it's the seal US Dexter axles use. Our Cruisemaster 10-VC kits list a seal of the same size, but with different bearings (L68149 and 25580). We sell it as a pair on its own too.
What size is a 25580 bearing?
The 25580 cone has a 44.45 mm (1 3/4") bore and is 25.40 mm wide. With its 25520 cup the bearing is 82.93 mm across and 23.81 mm wide overall.
Related reading
- 2 and 2.5 tonne caravan wheel bearings: HR30210, 15123 and the other 2 tonne kits
- Trailer bearing sizes: Holden, Ford and the other Australian kits
- Parallel trailer bearings explained: L68149/L68110 vs 25590/25520
Sources
- Timken, part pages 25580, 25520, 15123 and 15245, https://cad.timken.com/item/all-categories/tapered-roller-bearings-2/25580 (and the matching page for each number), read 5 October 2026.
- Timken, set pages 25580/25520, https://cad.timken.com/item/tapered-roller-bearings-ts-tapered-single-/tapered-roller-bearings-ts-tapered-single-imperi-2/25580-25520, and 15123/15245, https://cad.timken.com/item/tapered-roller-bearings-ts-tapered-single-/tapered-roller-bearings-ts-tapered-single-imperi-2/15123-15245, read 5 October 2026.
- Timken, cups listed for the 25580 cone, https://cad.timken.com/group/related-products-12851/tapered-roller-bearings-single-cones-imperial, and part pages 25518 and 25521, read 5 October 2026.
- Timken, set page 15123/15250X, https://cad.timken.com/item/tapered-roller-bearings-ts-tapered-single-/tapered-roller-bearings-ts-tapered-single-imperi-2/15123-15250x, read 5 October 2026.
Checked against Timken's part data, our supplier's advice and Bearings Express product data on 5 October 2026.
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