Every few weeks someone brings in a wheel with an 11-speed road freehub and a cassette meant for a 10-speed body, and asks why the lockring will not tighten. The answer is a 1.85 mm ring that was in the box and is now in a drawer.
Shimano made the 11-speed road freehub body about 1.85 mm longer than the 8/9/10-speed one. A cassette built for the shorter body sits flush on it; on the longer body there is a gap behind it, and the spacer fills exactly that gap. Our vocabulary says it in one line: the 11-speed road body accepts the 8/9/10 body, one hop, with a spacer — and the resolver reports that hop as "match with a spacer", never as a plain "match".
One cassette, two bikes, two honest answers
| SRAM PG-1230 — freehub required | Shimano HG, 8/9/10-speed body (also 11/12-speed MTB HG cassettes) |
|---|---|
| SRAM PG-1230 — rear speeds required | 12 speeds |
| SRAM PG-1230 — largest cog the derailleur must reach | ≥ 50 t |
| Giant Defy Advanced 2 (2025) — freehub on file | Shimano HG, 11-speed road body (+1.85 mm) |
| Giant Defy Advanced 2 (2025) — rear speeds on file | 12 speeds |
| Giant TCX Advanced Pro 2 (2023) — rear speeds on file | 11 speeds |
Take the SRAM PG-1230, a 12-speed Eagle cassette for the 8/9/10 body. On the Giant Defy Advanced 2 the freehub line reads "match with a spacer" and the speed count matches — and the verdict still reads "unknown", because the third thing the cassette needs, a rear derailleur that reaches a 50-tooth cog, is not on file for that bike. On the Giant TCX Advanced Pro 2 the answer is shorter: an 11-speed bike and a 12-speed cassette — "does not fit". Neither verdict is typed; both are computed from the rows above.
Fitting it, step by step
Fit a 10-speed-body cassette on an 11-speed road freehub
- Clean the freehub Wipe the splines; old grit under a cassette is what makes a lockring feel tight when it is not.
- Fit the 1.85 mm spacer It goes on the freehub body first, flat against the shoulder. If you skip it, the lockring bottoms out before the cogs are clamped.
- Slide on the cassette Line up the wide spline; the loose cogs and their thin spacers go on in the order they came out of the box.
- Torque the lockring The usual figure is 40 N·m — check your cassette maker. Hand-tight is not enough; the cogs will creak and eventually notch the freehub.
- Check the chain line Shift to the smallest cog and look for the chain rubbing the frame or the derailleur cage; if it does, the spacer is missing.
If the lockring stops before the cogs are tight, you are missing a spacer — not a tool.
SRAM PG-1230 Eagle cassette 11-50T, 12-speed — The cassette in question: freehub settled with a spacer, derailleur limit still unknown on the Defy.
Giant Defy Advanced 2 (2025) — The 11-speed-road-body bike: "unknown" on this cassette, for the reason above.
Cassette — Giant Defy Advanced 2 (2025)
- Do I need the spacer on an 8/9/10-speed freehub?
- No. The cassette was designed for that body and sits flush without it.
- Can I use a different 1.85 mm spacer?
- Any 1.85 mm cassette spacer does the same job. The one in the box is the right thickness; keep it.
- Why does the Defy page say "unknown" if the freehub and the speeds both match?
- Because the cassette also requires a derailleur that reaches a 50-tooth cog, and the largest-cog limit of the derailleur fitted to the Defy is not on file. Two matches and one missing fact is "unknown" — not "probably".
What to remember
- An 11-speed road freehub body is 1.85 mm longer than the 8/9/10-speed one; the spacer fills the gap.
- The resolver records that as "match with a spacer" on the freehub dimension — a positive answer with an extra part, never a plain match.
- A verdict needs every required fact: a settled freehub and a matching speed count still read "unknown" while the derailleur limit is missing.
- A lockring that stops early means a missing spacer, not a stripped thread.