What Size Portafilter Does a Gaggia Classic Use?

A Gaggia Classic / Classic Pro / Evo / E24 takes a 58 mm portafilter — the same commercial diameter Gaggia North America lists on the E24 page, with baskets in the 7–18 g range. It is not a 51 mm Dedica size and not a 54 mm “universal” listing.

You can decide which 58 mm handle and basket will actually lock into *this* group, and which accessories belong on another machine.

58 mm is the diameter, not the whole story

“58 mm” is the basket diameter. The ears (lugs) still have to match the Gaggia group. Many E61 58 mm handles will not cam into a Classic even though the basket number matches.

If a listing only says “58 mm espresso” and shows an E61 spigot, treat it as unproven until the seller names Gaggia Classic / Pro.

How the factory page and the forums agree

Gaggia NA’s Classic Pro E24 spec sheet: 58 mm stainless portafilter, 15-bar Ulka pump, 9-bar OPV on that regional model, baskets 7–18 g. Reddit’s “what size is the portafilter for a GCP?” thread lands on the same 58 mm number.

The box still includes a plastic tamper. That is why “does it come with a tamper?” is a separate question — the tamper is not a 58.5 mm calibrated tool.

What does not fit

HomeBaristaMods sells a 58 mm Gaggia bottomless portafilter (€59) and a 58 mm filter basket for this group. The 51 mm / 58.5 mm tamper is a different SKU — pick 58.5 mm for a Classic double basket, 51 mm for a Dedica.

Bottomless does not change the size

A naked portafilter is still 58 mm. It only removes the spouts so you can see channeling. The HBM product page is explicit: it will not fix a coarse grind. Early shots look messy because the spout is no longer hiding the spray.

If you want the learning tool, use it after the stock tamper question is settled and you have a real espresso grinder.

Baskets: pressurized vs single-wall

Many Classics ship with a pressurized (dual-wall) basket so pre-ground coffee can fake crema. A 58 mm single-wall basket is the same diameter and a different job. Swapping baskets does not require a new handle if the ears already fit.

Dose still has to match basket height. The factory 7–18 g window is a range, not a recipe.

When a 58 mm tool is the wrong first buy

If the handle already weeps at the ears, fix the group gasket before you buy a naked PF. If shots run like water, the 9-bar OPV question and the grinder matter more than chrome.

Frequently Asked Questions

Is the Gaggia Classic Pro 58 mm?

Yes. Gaggia North America lists a 58 mm stainless portafilter on the Classic Pro E24. Classic / Pro / Evo share that commercial diameter.

Will a 58 mm E61 portafilter fit a Gaggia Classic?

Often not. Diameter can match while the lugs do not. Buy a handle that names Gaggia Classic / Pro.

Can I use Dedica 51 mm accessories on a Classic?

No. Dedica is a 51 mm platform. HBM’s 51 mm tamper and distributor variants are for that machine, not the Classic group.

What tamper size goes with a Gaggia Classic?

A 58 mm class basket wants a ~58.5 mm tamper. The plastic factory tamper in the box is not that tool.

Does a bottomless portafilter make espresso taste better by itself?

No. The €59 HBM bottomless set is a viewing tool. Flavor still comes from grind, dose, and a basket that matches the coffee.

References

• Gaggia North America: Classic Pro E24 specifications (58 mm portafilter, 7–18 g baskets)
• Reddit r/gaggiaclassic: “What size is the portafilter for a gcp?”
• HomeBaristaMods: Gaggia bottomless portafilter PDP

Shop 58 mm tools under brewing tools, not a 51 mm cart leftover from a Dedica.