When tensioner pulley timing belt performance matters, the DAYCO ATB2178 delivers — built to the same dimensional and material standards as the original part it replaces. The part is built to the following specification: Weight [kg]: 0, Copper kg, Height 1 [mm]: 20, Rubber mm, Height 2 [mm]: 27, Rubber mm, Belt Pulley Ø [mm]: 72, 0 mm. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Compatible with AUDI, SEAT, VW vehicles; use the vehicle selector above to confirm exact fitment for your make, model, and engine variant. Fitment data is sourced from TecDoc, the authoritative European parts catalogue. This part supersedes original equipment references: 0066400, 026109243, 026109243A, 026109243C and 31 more. Matching these numbers confirms a like-for-like replacement with no loss of function. DAYCO is a recognised supplier of automotive engine timing 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 with tracked delivery and a 14-day money-back guarantee with hassle-free returns.

Dayco, founded in 1905 in Dayton, Ohio, USA, is a global leader in engine belt drive systems and power transmission products. Dayco specialises in timing belts, serpentine belts, tensioners, idler pulleys, and water pumps. As an OE supplier to major manufacturers including Fiat, Ford, General Motors, and Volkswagen, Dayco products meet exact factory specifications. With over a century of belt technology expertise and advanced polymer engineering, Dayco delivers reliable, long-lasting belt drive components trusted by professionals worldwide.