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Details
| Specification | Value |
|---|---|
| Brand | OPTIMAL |
| MPN | g3-129 |
| Fitting Position | Front Left |
| Fitting Position | Front Right |
| Fitting Position | Interior |
| Fitting Position | Bottom |
| Cone Size [mm] | 14.9 mm |
| External Thread [mm] | M14 x 1.50 RHT M mm |
| Outer Diameter 1 [mm] | 41.4 mm |
| Outer Diameter 2 [mm] | 50 mm |
OE/OEM numbers (3)
Search by this OE number to find compatible parts
- ALPINA / BMW—31121126253
- ALPINA / BMW—31121126296
- ALPINA / BMW—31121139131
About this product
The OPTIMAL Ball Joint (G3-129) is a professional-grade replacement component engineered for long service life and reliable operation across all conditions your vehicle encounters. The part is built to the following specification: Fitting Position: Front Left, Fitting Position: Front Right, Fitting Position: I, Fitting Position: U, Required quantity: Aluminium. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Verified to fit ALPINA, BMW models. All compatibility data is cross-checked against the TecDoc database — select your vehicle to confirm the part matches your specific engine and year. This part supersedes original equipment references: 01.99887.0, 027290165515, 03822, 0400327 and 56 more. Matching these numbers confirms a like-for-like replacement with no loss of function. OPTIMAL is a recognised supplier of automotive replacement components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched from our UK warehouse with a 30-day money-back guarantee and free hassle-free returns.
About OPTIMAL
OPTIMAL, founded in Germany, is a well-regarded aftermarket brand specialising in steering, suspension, and wheel bearing components. OPTIMAL produces ball joints, tie rod ends, control arm bushings, wheel bearings, and stabiliser links for European, Asian, and American vehicle applications. Manufactured to stringent quality standards with comprehensive testing protocols, OPTIMAL parts deliver OE-matching fit and performance. Known for excellent value and wide vehicle coverage, OPTIMAL is a popular choice among professional workshops across Europe.
Suitable cars
Equivalent products (59)
Show all 59 OE numbers
Ball Joint OPTIMAL G3-129 — compatible car models
| Car models | ALPINA: B3 Convertible (E30), B3 (E30), B3 Touring (E30), B6 (E36), C1 (E30), C2 Convertible (E30), C2 (E30); BMW: 3 Compact (E36), 3 Convertible (E30), 3 Convertible (E36), 3 Coupe (E36), 3 (E30), 3 (E36), 3 Touring (E30), 3 Touring (E36), Z1 Roadster, Z3 Coupe (E36) (+1 more) |
|---|---|
| Engines | 2.7; 2.8; 2.3; 2.5; 316 g; 316 i Baur TC; 318 i; 316 i; 315; 2.8 i; 1.8 i |
| Year of manufacture | 1982-2003 |
| Manufacturer article number (MPN) | G3-129 |
| OE part numbers | 31121126253, 31121126296, 31121139131 |
Compatibility check
Loading vehicle data…
Please wait while we load vehicle compatibility information.Description and what's included
OPTIMAL g3-129 . Cone Size [mm]: 14,9 mm. Control/Trailing Arm Type: 10. External Thread [mm]: M14 x 1,50 RHT M mm. Fitting Position: I. Fitting Position: U. Fitting Position: VL. Fitting Position: VR. Notches/Holes Number: 2
- 1x Ball Joint
Shipping, returns, warranty
Free UK delivery on orders over £99.00. Express and standard shipping available.
- Standard delivery: 2-5 business days
- Express delivery: 1-2 business days
- Free returns within 14 days
- All parts backed by manufacturer warranty
Warranty: 12-month manufacturer warranty on all parts. 14-day money-back guarantee if the part doesn't fit your vehicle.
Frequently Asked Questions
Is this Ball Joint compatible with my car?
This Ball Joint fits ALPINA, BMW vehicles. Use the vehicle selector at the top of the page to check exact compatibility — enter your car's make, model, and engine for a confirmed fitment match. All fitment data is verified through TecDoc.
What specifications does this OPTIMAL Ball Joint have?
This OPTIMAL Ball Joint has the following specifications: Fitting Position: VL; Fitting Position: VR; Fitting Position: I; Fitting Position: U; Required quantity: 2; Cone Size [mm]: 14,9 mm. Check the full specifications table above for complete details.
What OE part numbers does this Ball Joint replace?
This Ball Joint replaces OE part numbers: 31121126253, 31121126296, 31121139131. Cross-reference these numbers with your vehicle's original part number to confirm compatibility.
How much does a Ball Joint cost?
This OPTIMAL Ball Joint is available for £13.99. Ball Joint prices vary depending on brand, specifications, and vehicle compatibility. OPTIMAL parts offer a balance of quality and value, backed by our 14-day money-back guarantee.
How do I know when to replace my Ball Joint?
Signs include clunking or knocking noises from the front suspension, wandering steering, uneven tyre wear, or vibration in the steering wheel.
What tools do I need to replace a Ball Joint?
Tools needed: ball joint separator (fork or press type), 18-21mm socket, hub nut socket (32-36mm on driven axles), torque wrench, new cotter pin. Difficulty: Moderate DIY. Safety warning: Never reuse an old split pin (cotter pin) after disturbing a ball joint nut. A loose ball joint can allow the wheel to detach from the vehicle at speed -- this is a critical safety component.
Can I use this part as a replacement for OE 31121126253?
Yes, this OPTIMAL Ball Joint is a direct replacement for OE part number 31121126253. It is manufactured to meet or exceed original equipment specifications, ensuring proper fitment and performance. All cross-reference data is verified through TecDoc.
Related categories
Common OE numbers for this part
Common original equipment numbers linked to stocked alternatives.
