Go-Kart Bearing Manufacturer
OTT is one of the few dedicated go-kart bearing manufacturers worldwide. We supply factory-direct kart bearings to distributors, kart builders, and racing teams across Europe, South America, and Asia — with 20+ models in stock for immediate shipment.
Why Source Kart Bearings From a Manufacturer?
Most go-kart bearings sold online come from trading companies that buy generic bearings and repackage them. OTT is different — we are a bearing manufacturer with our own factory, controlling quality from raw GCr15 steel through heat treatment, precision grinding, assembly, and final testing.
This means consistent quality across every batch, the ability to customize specifications for your application, and factory-direct pricing without the middleman markup. Our IATF 16949 certification — the same quality standard required by major automakers — guarantees process control that trading companies simply cannot offer.
OTT has earned a high global market share in the go-kart bearing segment through word-of-mouth from satisfied distributors and kart builders in Denmark, Finland, Brazil, Korea, and beyond. When you need kart bearings, chances are the trail leads back to us.
Where OTT Bearings Go in a Kart
A single go-kart uses 10–15 bearings across wheels, drivetrain, steering, and engine. OTT manufactures all of them.
Wheel Hubs
6905, 6905-12, 6003
Carbon-nitrided deep groove wheel bearings with low-contact seals or ZZ shields. The 6905-12 is the original fitment in OTK / Tony Kart hubs; hybrid ceramic versions are available.
Rear Axle
SB208-50, SB210-50
50 mm insert bearings with set screws and C4 internal clearance, supporting the live rear axle under acceleration, braking and cornering loads. Sealed, ZZ and hybrid ceramic versions.
Steering Shaft
PB8, PB10
Uniballs at the bottom of the steering shaft: zinc-plated steel housing, hardened GCr15 ball and bronze liner for smooth articulation with minimal play.
Main Crankcase
6206
All-steel 100Cr6 main bearing (30×62×16 mm) supporting the crankshaft in ROK GP, IAME X30 and Rotax Max engines.
Tie Rods & Linkage
COS8, COSL8
M8 × 1.25 male rod ends in right- and left-hand thread, with zinc-plated steel housing, GCr15 ball and bronze liner. OEM on OTK / Tony Kart, Kosmic, Exprit, Redspeed and FA Kart.
Engine Accessories
6203
Bearings for water pumps, clutch drums, and auxiliary drives in both 2-stroke and 4-stroke kart engines.
Go-Kart Bearing Catalog
OTT stocks approximately 20 go-kart bearing models for immediate shipment. Below are our most popular kart bearings — contact us for the full list.
6205 Front Wheel Bearing
The most popular go-kart front wheel bearing. 6205 deep groove ball bearing in open, ZZ, and 2RS configurations. Standard fitment for most racing and recreational kart front hubs. High-purity GCr15 bearing steel with P6 precision grinding.
6206 Main Crankcase Bearing 30×62×16 mm
OTT 6206 is a single-row deep groove ball bearing used as the main crankshaft (crankcase) bearing in popular kart engines, including ROK GP, IAME X30 and Rotax Max. It is an all-steel design: balls, inner ring and outer ring are made from 100Cr6 high-carbon chromium bearing steel (GCr15 equivalent), chosen for hardness, wear resistance and dependable running at high rpm. Kart engine builders fit it as a direct replacement when rebuilding an engine or renewing a worn main bearing. Always confirm the bearing specification your engine manufacturer calls for before ordering.
6003 Kart Wheel Bearing 17×35×10 mm
OTT 6003 is a compact 17 mm-bore kart wheel bearing (17×35×10 mm). The steel version has carbon-nitrided races and balls — a hard, wear-resistant surface over a tough core that resists pitting and shock loads — and is pre-filled with kart-specific grease. Non-contact ZZ metal shields keep drag to a minimum and deflect larger debris, making them the right choice for clean, dry track conditions. A hybrid ceramic version with Japanese-made Si₃N₄ balls and low-contact rubber seals is also available for teams chasing lower rolling resistance.
6905ZZ Kart Wheel Bearing 25×42×9 mm
The 6905 (25×42×9 mm) is the most widely used 25 mm wheel bearing size in karting. OTT builds it with carbon-nitrided bearing-steel races and balls for a hard, wear-resistant surface over a shock-tolerant core, and fills it with kart-specific grease that holds its film under braking, cornering and kerb impacts. The ZZ version uses non-contact metal shields: practically zero seal drag and protection against larger debris, best suited to clean, dry conditions. For wet or dusty tracks choose the 6905-2RS low-contact sealed version; for OTK / Tony Kart hubs that take the wider bearing, choose the 6905-12.
6905-2RS Low-Contact Sealed Kart Wheel Bearing 25×42×9 mm
Sealed version of the OTT 6905 kart wheel bearing and a common OEM fitment on many kart brands. Its low-contact rubber seals keep grease in and dirt, dust and water out without the drag of traditional full-contact seals, so the wheel still rolls freely. Races and balls are carbon-nitrided bearing steel for wear and pitting resistance. Also available as a hybrid ceramic bearing with Japanese-made silicon nitride (Si₃N₄) balls, which lowers rolling-element weight, friction and heat build-up.
5090 Insert Bearing — Rear Axle
Insert bearing with set screw locking for go-kart rear axle housing assemblies. The set screw design allows secure mounting on the axle shaft without requiring a press fit, simplifying installation and replacement in the field. Pre-greased and sealed.
PB8 Steering Shaft Uniball 8 mm
OTT PB8 is the uniball (spherical bearing) that carries the lower end of an 8 mm kart steering shaft. It is made to OEM standards and fitted by kart manufacturers: a zinc-plated carbon-steel housing, a hardened and ground GCr15 bearing-steel ball and a bronze bushing liner, machined to tight tolerances so the shaft articulates smoothly with very little free play. A worn or low-grade steering bearing develops play, roughness or binding that dulls steering feedback — a fresh PB8 restores precise, consistent response. Dimensions 8 mm ID × 22 mm OD × 12 mm height; sold individually, retaining clip not included.
PB10 Steering Shaft Uniball 10 mm
OTT PB10 is the 10 mm version of the OTT steering shaft uniball and the OEM part on OTK / Tony Kart steering systems. It supports the bottom of a 10 mm steering shaft and measures 10 mm ID × 26 mm OD × 14 mm height. Construction matches the PB8: zinc-plated carbon-steel housing, hardened and ground GCr15 bearing-steel ball and bronze bushing liner, precision-machined for smooth articulation with minimal play. Fits steering shaft carriers with a 26 mm bore and 14 mm seat height used on many European chassis. Sold individually; retaining clip not included.
COS8 Tie Rod End — M8 × 1.25 Male
OTT COS8 is a male-thread rod end for kart tie rods, built to OEM standards and used as original equipment by leading kart manufacturers. The zinc-plated carbon-steel housing holds a hardened and ground GCr15 bearing-steel ball running in a bronze bushing liner, giving smooth steering articulation with minimal unwanted play and a long service life. Thread is M8 × 1.25 mm, offered in right-hand (COS8) and left-hand (COSL8) versions — a typical adjustable tie rod uses one of each. OEM / replacement fitment includes OTK / Tony Kart, Kosmic, Exprit, Redspeed and FA Kart.
SB208-50 Kart Axle Bearing 50×80 mm — C4 Steel
OTT SB208-50 is the 50 mm kart rear-axle bearing for 80 mm bearing carriers, an insert-type bearing locked to the axle with set screws. It is engineered for real karting loads rather than unloaded free-spin: carbon-nitrided bearing-steel races and balls with low non-metallic inclusions for long fatigue life, and C4 internal clearance that leaves room for heat, axle flex, side load and high speed so the bearing does not tighten as it warms up. It comes pre-filled with kart-specific grease. Choose replaceable low-friction rubber seals (spare seals available separately) for the best protection against dirt, water and grease loss, or non-contact ZZ metal shields for minimum drag in clean, dry conditions.
SB208-50 Hybrid Ceramic Kart Axle Bearing 50×80 mm
Performance version of the OTT SB208-50 axle bearing. Steel balls are replaced with premium Japanese-made silicon nitride (Si₃N₄) ceramic balls — light, very hard, heat- and corrosion-resistant — running on carbon-nitrided bearing-steel races. The lighter rolling elements cut friction and heat build-up at the rear axle. Like the steel version it has C4 internal clearance for heat, axle flex and side load, kart-specific grease and replaceable low-friction rubber seals (spare seals available separately).
SB210-50 Kart Axle Bearing 50×90×20 mm — C4 ZZ
OTT SB210-50 is the 50 mm kart axle bearing for chassis that use a larger 90 mm bearing carrier. It shares the construction of the 50×80 mm SB208-50: carbon-nitrided bearing-steel races and balls, C4 internal clearance to cope with heat, axle flex and side load, kart-specific grease, set-screw locking and non-contact ZZ metal shields for low drag in clean, dry conditions.
6905-12 OTK / Tony Kart Wheel Bearing 25×42×12 mm
The 6905-12 is a 12 mm-wide version of the 6905 wheel bearing and the original fitment in many OTK / Tony Kart wheel hubs — also found on Kosmic, EOS, Exprit, Redspeed, Gillard and similar chassis. OTT manufactures it to OEM specification for fit, durability and low rolling resistance: carbon-nitrided bearing-steel races and balls, plus low-contact rubber seals that keep lubricant in and dirt out while letting the wheel roll freely. A hybrid ceramic version with Japanese-made Si₃N₄ balls is available for lower friction and heat. For hubs that take the standard 9 mm-wide bearing, use the 6905.
6203 Engine Accessory Bearing
Standard kart engine accessory bearing for water pumps, clutch assemblies, and auxiliary drive components. The 6203 is one of the most versatile kart bearing sizes, used across multiple engine platforms in both 2-stroke and 4-stroke kart engines.
Go-Kart Bearing Size Guide
Quick reference for the most common go-kart bearing sizes, applications, and recommended configurations.
| Model | Dimensions (d×D×B) | Application | Racing Config | Rental Config |
|---|---|---|---|---|
| SB208-50 | 50×80 mm, C4 | Rear axle (80 mm carrier) | ZZ / Hybrid ceramic | Low-friction seals |
| SB210-50 | 50×90×20 mm, C4 | Rear axle (90 mm carrier) | ZZ | ZZ |
| 6905 | 25×42×9 mm | Wheel hubs (25 mm) | ZZ / Hybrid ceramic | 2RS (low-contact) |
| 6905-12 | 25×42×12 mm | OTK / Tony Kart wheel hubs | Hybrid ceramic | 2RS (low-contact) |
| 6003 | 17×35×10 mm | Wheel hubs (17 mm) | ZZ / Hybrid ceramic | ZZ |
| 6206 | 30×62×16 mm | Engine main crankcase | All-steel, open | |
| 6203 | 17×40×12 mm | Engine accessories | 2RS | 2RS |
| PB8 / PB10 | 8×22×12 / 10×26×14 mm | Steering shaft uniball | Standard | |
| COS8 / COSL8 | M8 × 1.25 male (RH / LH) | Tie rod / steering linkage | Standard | |
Open vs Shielded vs Sealed: Which to Choose?
The right configuration depends on whether you prioritize speed or maintenance intervals.
Open
No shields or seals — absolute minimum friction. The fastest configuration, used in competitive racing where bearings are serviced frequently.
Best for: Sprint racing, competition karts
Shielded (ZZ)
Metal shields on both sides keep out large debris while adding minimal drag. A good balance for club racing and indoor tracks where conditions are relatively clean.
Best for: Club racing, indoor tracks
Sealed (2RS)
Rubber contact seals on both sides provide maximum protection against dust, water, and mud. Extended maintenance intervals — ideal for rental operations that need reliable uptime.
Best for: Rental karts, outdoor tracks, wet conditions
Who We Supply
OTT is a go-kart bearing manufacturer. Kart shops and racing teams can order from 10 pcs per model; kart builders and distributors get volume pricing.
Kart Bearing Distributors
Stock OTT bearings under your own brand with our OEM branding and custom packaging options. Volume pricing for larger orders.
Kart Manufacturers
Supply complete bearing kits for chassis assembly lines. Consistent quality batch-to-batch backed by IATF 16949 process control.
Racing Teams
Bulk bearing supply for season requirements. Open bearings for competition use, matched sets available for critical applications.
Indoor Karting Facilities
Sealed bearings for rental fleets that need extended maintenance intervals and reliable uptime. Bulk pricing for fleet operations.
Frequently Asked Questions
What bearing sizes are most common for go-karts?
Should I use open or sealed bearings for racing karts?
Does OTT manufacture go-kart bearings or resell them?
What is the minimum order quantity for go-kart bearings?
What go-kart bearing types does OTT make besides deep groove ball bearings?
Can OTT supply go-kart bearings with custom branding?
Source Go-Kart Bearings Factory Direct
Whether you need 1,000 front wheel bearings or a complete bearing kit for your kart production line, OTT delivers — with in-stock inventory, factory pricing, and quality backed by IATF 16949 certification.
MOQ: 10 pcs per model. Reply within 12 hours including weekends.