how to choose a grinding cup wheel
Size, segment, arbor, grit and RPM — the five decisions that decide whether a cup wheel grinds fast or burns out. Here's what matters, in plain terms.
by peter zhang · aug 16, 2026 · updated sep 16, 2026
105mm double-row, 30/40 grit — the concrete default
M14 arbor for wall grinders, max 12,250 RPM. Step to 50/60–60/80 grit for finishing; 180mm wheels max out at 8,500 RPM.
1. size — match the diameter to the machine
Diameters are not interchangeable: a 105mm (4") cup wheel is the standard for wall grinders like the CIR-16 and CIR-34L, while 125mm (5") cups fit standard angle grinders and 180mm (7") cups suit larger machines and open areas. Bigger diameter means more surface contact per pass, so 180mm removes material faster but is heavier to control.
2. segment — double-row for speed, turbo for finish
Double-row segments cut the fastest and are the default for concrete. Turbo segments cut with less chatter and leave a cleaner surface on granite, marble and stone. If you do both rough grinding and finishing, buy one of each rather than a compromise wheel. Segment height matters too: 5mm is standard, 7mm and 10mm last longer between replacements.
3. arbor — M14 vs 22.23mm
Wall grinders and many European machines take M14 thread; angle grinders take a 22.23mm bore (also sold as 5/8"-11). Our cup wheels come in M14 or 22.23mm. If you're unsure which your machine takes, send us a photo of the spindle — we verify compatibility before you order.
4. grit — coarse to remove, fine to finish
30/40 and 40/50 grit remove material aggressively for leveling concrete. 50/60 and 60/80 grit leave a smoother surface for polishing stages. Most jobs start coarse and step down — our 105mm cup offers 30/40 up to 60/80.
5. max rpm — never run a wheel faster than rated
A 105mm wheel is rated to 12,250 RPM, a 180mm to 8,500 RPM. Exceeding the rating risks segment ejection — match the wheel's max RPM to your tool's no-load speed. When in doubt, the higher-rated wheel is the safe choice.
faq
What size concrete grinding cup do I need?
105mm (4") cups fit wall grinders such as the CIR-16 and CIR-34L and are the standard for concrete wall grinding. 125mm (5") cups fit standard angle grinders. 180mm (7") cups suit larger machines and bigger surface areas where more aggressive stock removal is needed.
Double-row or turbo grinding cup?
Double-row segments remove material fastest and are best for concrete and rough surfaces. Turbo segments cut more smoothly and are preferred on granite, marble and stone where you want a cleaner finish. Single-row is a lighter-duty option.
M14 or 22.23mm arbor?
Wall grinders and many European machines use M14 thread. Angle grinders use a 22.23mm (5/8"-11) center bore. Check your tool arbor before ordering — or send us a photo and we'll verify compatibility.
ready to order?
Browse cup wheels, or send us your machine model and we'll match the right size and arbor.