Spannring 58mm: Replace the Group Head Gasket When It Leaks
By Kaffeemacher.de | Published: 2026-11-03
Category: ハウツーガイド
Learn the real signs of a worn 58mm group head gasket, how to diagnose a leak before buying parts, and when a fresh Spannring is the right fix.
Quick answer
Replace the 58mm group head gasket when water escapes around the portafilter rim during extraction, the lever feels loose, or the basket drops out during knock-out. A fresh Spannring 58mm restores the clamping tension, but confirm the leak is at the gasket—not the basket or shower screen—before ordering.
Why the gasket fails before the rest of the group head
The group head gasket is a wear part. Heat, moisture, and the repeated friction of locking in the portafilter harden the rubber and flatten its sealing lip. On 58mm setups, the gasket also holds the basket in place, so a tired gasket often shows up as a loose basket before a visible leak.
A 58mm Spannring is not the same as a 51mm or 54mm ring. The diameter must match your group head, and the ring must seat fully in its groove. If the old ring comes out distorted or cracked, replacement is the right move; if it looks intact but the portafilter still leaks, look elsewhere first.
Leaks that are not gasket problems
Water can also escape from a worn shower screen seal, a loose dispersion screw, or a portafilter that is not seated squarely. Before buying a Spannring, lock in an empty portafilter and watch where the water appears. A leak at the spout or handle usually points to the basket or portafilter, not the group gasket.
If your machine uses a different group head standard, a 58mm ring will not fit. The Spannring 58mm is sized for KM 58mm group heads, including bottomless and two-spout versions. Check your machine’s group head diameter before assuming a 58mm part is correct.
Diagnose your group head leak
- Symptom: water drips around the portafilter rim during extraction: Lock in an empty portafilter and run the pump briefly. If water appears at the rim where the portafilter meets the group head, the gasket is the likely cause. Dry the area and repeat to confirm the source. If the leak moves with the portafilter or only happens with one basket, test that basket in a different position before replacing the gasket.
- Symptom: portafilter locks in too easily or feels loose: A worn gasket flattens, so the lever swings further than usual. Compare the locking angle to when the machine was new. If it now goes past 6 o’clock, the gasket has likely compressed. A loose lock alone is not enough—check for rim leaks under pressure to avoid replacing a gasket that is still sealing.
- Symptom: basket falls out during knock-out: The Spannring provides the friction that holds the basket. If the basket drops out when you tap the puck, inspect the ring for cracks or loss of spring. Replace the Spannring 58mm if the ring no longer grips. If a new ring still lets the basket fall, the basket rim may be worn or the wrong size for the portafilter.
- Corrective action: replace the Spannring 58mm: Remove the old ring with a gasket pick or blunt screwdriver, clean the groove, and press the new ring in evenly. Lubricate with a food-safe silicone grease only if the manufacturer allows it. Lock in the portafilter and test with water before pulling a shot. If the new ring does not seat flush or the portafilter will not lock, stop—the ring may be the wrong size or the groove may be damaged.
- When to stop and choose another option: If a new Spannring 58mm does not stop the leak, the problem is likely the shower screen, dispersion screw, or a cracked group head. Do not keep tightening the portafilter or adding force. At that point, inspect those parts or contact the machine manufacturer. Replacing the gasket twice in a row without solving the leak means the gasket was not the cause.
Product facts
- Spannring 58mm: Ersatzteil für KM Siebträgerkopf: Spring steel construction resists moisture, heat, and repeated installation stress. A ring that keeps its tension longer means fewer loose-basket surprises between replacements.
Spannring 58mm: Ersatzteil für KM Siebträgerkopf - Spannring 58mm: Ersatzteil für KM Siebträgerkopf: Exact 58mm fit for KM portafilter heads (bottomless and two-spout). Correct diameter and seating are what restore the clamping force that holds the basket during knock-out.
