Aftermarket replacement part. Independently manufactured — not supplied by or affiliated with the handpiece manufacturer.
- Fitment scope — front and rear turbine bearings and rotors for T3 Racer, T3 Mini, T3 Boost, T2 and T1 heads, standard and mini sizes.
- Ceramic or steel balls — silicon nitride (Si3N4) or 440C stainless within the same envelope.
- ISO P4 / ABEC-7 precision class — built for 400,000+ RPM service.
- Wholesale and repair-shop friendly — tray quantities, consistent tolerances, internal part numbers you can standardise on.
Mini heads on this platform are very small indeed — around 12.7 mm high and under 10.5 mm across — and they do not take the same bearing as a standard head. That single fact causes most of the wrong orders in this range.
Cross-reference: bearings for Sirona T2 and T3 turbine handpieces
All dimensions in millimetres (ID × OD × Width). Aftermarket replacement parts — independently manufactured.
| Handpiece Model | Head Type | Bearing Position | Bearing Size — ID × OD × W (mm) | Confirm your width |
|---|---|---|---|---|
| T3 Racer | Standard Head | Front (chuck side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
| T3 Racer | Standard Head | Rear (cap side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
| T3 Mini | Mini Head | Front (chuck side) | 3.175 × 5.88 × 2.38 mm (GS-X1) | Photo check — free |
| T3 Mini | Mini Head | Rear (cap side) | 3.175 × 5.88 × 2.38 mm (GS-X1) | Photo check — free |
| T3 Boost | Standard Head | Front (chuck side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
| T2 Boost | Standard Head | Front (chuck side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
| T2 Revo | Standard Head | Front (chuck side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
| T1 mini — catalog label “Sirona mini Boost” | Mini Head | Front (chuck side) | 3.175 × 5.88 × 2.38 mm (GS-X1) | Photo check — free |
| T1 Boost | Standard Head | Front (chuck side) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | Photo check — free |
Front and rear bearings differ on many models. Confirm both before ordering.
Note the 5.88 mm outer diameter on the GS-X1 row. That is a real figure from our own catalog, and it is smaller than the outer diameter most suppliers publish for this platform — which is exactly why mini heads and standard heads cannot share a part. Width remains subject to engineering sign-off.
Sirona T3 Racer vs T3 Mini bearing size
The two heads do not share a bearing. T3 Racer takes a standard-head turbine bearing; the T3 Mini’s smaller head takes a narrower one from the same bore family. Bore usually matches, outer diameter and width often do not. Confirm both positions before ordering. Our ID, OD and width lookup tool lets you check your figures against the rest of the range.
| Model | Head Type | Head Size (manufacturer figure) | Bearing Model | Size — ID × OD × W (mm) | Our Part # |
|---|---|---|---|---|---|
| T3 Racer | Standard Head | Ø 11.9 mm × H 13.0 mm | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | 3.175 × 6.35 × 2.38 or 2.78 mm (confirm suffix) | |
| T3 Mini | Mini Head | Ø 9.7–10.2 mm × H 12.7 mm | 3.175 × 5.88 × 2.38 mm (GS-X1) | 3.175 × 5.88 × 2.38 mm (GS-X1) | GS-X1 — |
Head sizes above are the manufacturer’s published figures for the handpiece heads, not bearing dimensions. Two Mini variants exist — fixed-connection at Ø 10.2 mm and quick-coupling at Ø 9.7 mm — so state which you have when you enquire.
Why Sirona dental bearings fail — and what wears first
These are stainless-steel heads with a protective head system and dual anti-retraction, and when that system is intact the bearings are well shielded. When it degrades, contaminated aerosol reaches the raceway on rundown and corrosion pitting starts.
The chuck-side bearing fails first, as always, because it carries the lateral load from the bur. On the higher-wattage T3 Racer that load is substantial — up to 30 W of cutting power transmits real force into the front race during long preparations.
The second failure driver on this platform is reprocessing chemistry. Practices running these instruments through automated cleaning and disinfection cycles expose the cage to both heat and detergent residue. Torlon copes with that far better than phenolic does, which is why we specify it.
The tell-tale sign in this range is not a whine but a change in cut quality — the bur starts to skate on enamel where it used to bite. That is runout, and runout means the front bearing has lost its preload.
One practical note for repair shops: user-replaceable rotor cartridges are a design feature of this platform. That makes bearing-level rebuilds economically attractive, because the head is meant to be opened. We set out how to choose the right next action in more detail on the diagnosis page.
Which Sirona models we cover
T3 Racer
The fixed-connection powerhouse, up to 30 W at around 400,000 RPM, with Ø 11.9 mm × 13.0 mm head. High torque means high front-bearing load, and heavy users get through sets. Available with Midwest four-hole or Borden two/three-hole connection — the connection does not change the bearing, but it does change the back-cover parts.
T3 Mini
Two versions exist: fixed connection at Ø 10.2 mm and quick coupling at the smaller Ø 9.7 mm, both 12.7 mm tall. This is the narrowest head on the platform and takes the narrowest bearing. Our catalog carries GS-X1 at 3.175 × 5.88 for the mini fitment, labelled in our own records as “Sirona mini Boost”.
T3 Boost and T2 Boost
Quick-coupling stainless heads built around dynamic speed control and a four-nozzle spray. They are the volume sellers of the economy and mid tiers, which means they turn up at repair benches constantly. Standard-head bearing set, front and rear differing. Check the water filter while the head is open.
T2 Revo
A stainless standard-head turbine in the mid tier with a rebuild-friendly layout. Units in this family often reach the bench with the bur retention already marginal — replace the bearings and test chuck retention force in the same visit, because a slack chuck will destroy a new front bearing quickly.
T1 Boost and T1 mini
Premium-tier heads with DLC-coated ceramic ball bearings from new, quick coupling, and a 12.7 mm mini variant at Ø 9.7 mm. Owners of these expect the quiet running they paid for, so ceramic replacement balls are usually the right specification rather than an upsell. GS-X1 covers the mini fitment.
We also stock more than loose bearings
For this platform we hold high-speed bearing GS-X1 and rotor cartridges H-08, H-09, H-15, H-16 and H-33 — six re-orderable line items. Because the rotor cartridge is user-replaceable by design on these handpieces, most repair shops keep both: cartridges for same-day turnaround, loose bearings for scheduled rebuilds where margin matters more than speed. If you are stocking across more than one platform, browse the full parts catalog.
A note on ceramic ball options
Premium heads on this platform ship with ceramic ball bearings from the factory, so replacing them with steel is a downgrade the owner will hear. Silicon nitride balls are roughly 60% lighter than steel, which lowers centrifugal load and keeps running noise close to as-built. Ceramic is a material option, not a fitment change. Full comparison on our ceramic dental bearings page.
Sterilization, cage material and service life
These instruments are sterilizable and thermally disinfectable to 135 °C, and many practices run automated reprocessing daily. That is the dominant wear factor on the bearing, not cutting hours.
Our high-speed bearings use a Torlon (polyimide) cage, 440C-grade stainless rings, and are autoclave-compatible to 134 °C.
Lubricate before sterilizing, run the head briefly to spread the film, and dry fully before storage. Where an automated cleaning and disinfection unit is in the workflow, add lubrication immediately after the drying phase.
Bench service life is 1,000 hours+ under continuous testing at 2.5 kg air pressure, and 500 hours+ in dry, no-oil testing. Manufacture is to ISO P4 / ABEC-7, tested to GB/T 30701-2005, under an ISO 9001 quality system.
Not sure which bearing fits? Don’t guess. Send us a photo of your turbine or your old bearing — our technicians identify the correct size and part number within 1 business hour.
Include the head-size stamp if visible — width varies by head.
Or send a photo of your old bearing and we will confirm the width before you order.
FAQ
What is the difference between T3 Racer and T3 Mini bearing size?
The Mini head is physically smaller and takes a narrower bearing with a smaller outer diameter. Our catalog carries GS-X1 at 3.175 × 5.88 for the mini fitment. Racer takes the standard-head set. They are not interchangeable.
Can I rebuild a T3 Racer head, or do I need a new cartridge?
Both routes work. The rotor cartridge is user-replaceable by design, so a cartridge swap is the fast option. Bearing-level rebuild costs less per unit and suits shops with a bench and a press. Check chuck retention either way.
Are there two versions of the T3 Mini?
Yes — a fixed-connection version at Ø 10.2 mm and a quick-coupling version at Ø 9.7 mm, both 12.7 mm tall. Tell us which you have, because head diameter is the variable that determines the bearing.
Should I fit ceramic or steel to a premium T1 head?
Ceramic. These heads leave the factory with ceramic ball bearings and are marketed on quiet, low-vibration running. Steel will fit and function but the owner will notice the change in sound.
Which rotors do you stock for this platform?
H-08, H-09, H-15, H-16 and H-33, plus high-speed bearing GS-X1. Send a photo of the head if you are unsure which rotor matches your unit.
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Related pages
- dental turbine bearings — the full high-speed category
- bearing cross-reference lookup — search by handpiece or part number
- SR144 bearing specifications — one part number, two widths
- ceramic dental bearings — Si3N4 versus steel, in detail
All brand names are trademarks of their respective owners, used solely to identify compatible applications. Products are independently manufactured and not OEM parts.
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