Which Trailer Hub Grease Cap Do I Need?
Answered by Kaleb Carter
Customer Question: “How do I know which grease cap fits my trailer axle?”
Simple answer: just count the number of lugs (studs) on your trailer hub — and we’ll match the correct grease cap for you.
4-lug and 5-lug hubs use the same size, and the rest go up from there.
Grease Cap Size by Lug Count
| Lug Count | Grease Cap Diameter | Fits Axle Rating | Part # | Buy Link |
|---|---|---|---|---|
| 4 or 5 Lug | 1.98” | 2K–3.5K Axles | TPU21-41 | Buy Now |
| 6 Lug | 2.44” | 5.2K–7K Axles | TPU21-42 | Buy Now |
| 8 Lug | 2.72” | 5.2K-8K+ Axles | TPU21-43 | Buy Now |
Quick Tip: If your trailer wheel has 4 or 5 lugs, it uses a 1.98" OD grease cap. For larger axles, the cap size increases to match
Grease or Oil Bath?
If your trailer uses oil bath hubs or you're looking for aluminum caps, check out the full lineup here:
https://trailerpartsunlimited.com/categories/trailer-axle-parts/oil-grease-caps.html