C250/U-D Rotor Complete
General-purpose rotor complete for medium to coarse counts (Ne 10–30) on the Rieter R923 and R35 semi-automatic platform. Diamond-coated working face. 73-1-69 bearing rated to 80,000 rpm with a recommended ceiling of ≤ 72,000 rpm — dimensionally identical to the original, at 40–60% below OEM price.
C250/U-D — Complete Specifications
All measurements in millimetres. Every rotor complete assembly is 100% dynamically balanced on our own balancing line before shipment.
Why U Groove for General-Purpose Spinning
Where a mill runs mixed orders the U groove earns its place: a broad operating window through the medium-to-coarse range, tolerant of both fibre changes and count changes. Because the count band is not published, the selection is checked against your fibre and target count before quoting.
U Groove — Applicable Yarn Count Range
Suited to medium-coarse counts. For fine counts (Ne 30–40), the T groove is the tighter match. Groove and cup size are confirmed together when the order is placed.
U Groove — The Mixed-Order Profile
Mills running several orders on the same machines need a rotor that does not have to be changed when the count moves. The U profile’s wider zone is exactly that: stable at medium counts, still comfortable when the schedule goes coarser. The wider window is what makes one rotor serve a mixed schedule, at the cost of some fine-count control.
Wide Count Window (Ne 10–30)
A broad operating band means fewer rotor changes when the count schedule shifts, cutting machine downtime.
Stable Fibre Collection
The wider deposition zone holds collection steady across mixed fibre lots, keeping yarn strength consistent between deliveries.
Lower Change-Out Cost
Fewer rotor swaps per week means less labour on the spin box and a simpler, cheaper spare-parts inventory.
Tolerant of Fibre Change
General-purpose geometry absorbs the variation that comes with running several raw materials on one line.
What D Means: Base and Working Surface
The trailing letters of the model code are two independent codes, not one word: B is the substrate, D is the working surface. Diamond top layer (HV 1000-1200) with a friction coefficient of 0.05–0.1, which reduces fibre damage at the groove face. Every assembly is 100% dynamically balanced before it leaves the balancing line.
B = boronized (boron-steel) substrate. A diamond film is only microns thick, so the steel underneath decides whether it survives: a soft substrate deforms under fibre and grit impact and the film cracks and spalls off. The boronized base is the hardening step that keeps the diamond layer intact. This code does not carry the B step; it is the -BD- variant that pairs the diamond layer with the boronized base.
D = diamond top layer, grown on the prepared substrate as a micron-scale film. It takes the fibre and grit contact directly, which is where the wear resistance, the friction coefficient of 0.05–0.1 and the anti-stick behaviour come from that hold the groove profile over long runs. Diamond coating technology of US origin, applied on JSM’s own treatment line.
Which Rieter Machines Use C250/U-D?
This rotor runs the 73-1-69 bearing, shared by the Rieter R923 and R35 semi-automatic machines. Models in the group differ by groove and rotor size, not by bearing fit.
What to Spin with C250/U-D
How this rotor is applied on Rieter R923 and R35 machines, with the U groove’s count window where one is published.
✓ Medium–coarse counts, Ne 10–30
✓ Mixed-order mills running several counts on one line
✓ Cotton and blends across a wide fibre range
◇ Strictly single-count fine spinning — XTC extra-narrow
◇ Fine yarns Ne 30–40 — T narrow family
◇ Blends and speciality fibres — S groove
→ GL: Large (Ne 3–16)
→ G: Standard (Ne 16–40)
→ T: Narrow (Ne 16–40)
→ TT: Extra narrow (Ne 16–40)
→ S: Special (Ne 16–40)
→ See all 6 Rieter R923 and R35 rotor models →
C250/U-D — Frequently Asked Questions
Answers to the questions buyers ask most often about this rotor. If yours is not listed, send it with your machine model and current rotor code — we reply within 24 hours.
Is C250/U-D compatible with my Rieter R923 and R35 machine?
What does the model code C250/U-D mean?
What yarn counts does the U groove suit?
What do the letters BD mean in the model code C250/U-D?
How much does an OEM-equivalent rotor save versus the original?
Can I order the rotor spindle or rotor cup separately?
Order C250/U-D Rotors
Pre-filled: C250/U-D · Rieter R923 / R35 · diamond coating
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