Freewheel body

The three main standards for road bikes are HG (Shimano), XDR (SRAM) and Campagnolo, which are incompatible with one another. Shimano’s HG (Hyperglide) body is the universal standard with 13 splines: it is compatible with Shimano and SRAM 8- to 11-speed cassettes. The SRAM XDR body is required for SRAM AXS 12-speed cassettes (minimum 10-tooth sprocket); it is 1.85 mm longer than the MTB XD to compensate for road spacing. Campagnolo uses its own proprietary standard for all its 9- to 12-speed cassettes, which is incompatible with the other two brands.

No, not for Shimano Dura-Ace 12-speed cassettes, which use the new 18-spline HG+ (L2) standard. The standard HG body (9 splines) accepts Shimano 11-speed cassettes and most 8–10-speed cassettes with a spacer. Shimano introduced the HG+ body (known as L2) with the launch of the Dura-Ace 12-speed R9200 and Ultegra R8100 groupsets: this standard is distinct, wider and incompatible with standard HG bodies. Always check the technical specifications of the wheels before purchasing a Shimano 12-speed groupset.

Check that the body is marked XDR and that the smallest sprocket on the cassette has 10 teeth. SRAM AXS 12-speed road cassettes (Rival, Force, Red) all use the XDR standard with a 10-tooth sprocket. If your current wheels have a Shimano HG freehub body, you will need to either buy a replacement XDR freehub body (if the hub allows it) or buy new XDR-compatible wheels. Some high-end hubs (DT Swiss, Chris King, Roval) offer interchangeable HG/XDR/Microspline freehub bodies.

A freewheel body generally lasts between 15,000 and 30,000 km, depending on the quality of the materials and maintenance.Signs of wear: the ratchet mechanism slips under heavy load (the wheel turns but the crankset doesn’t follow), the splines are worn or deformed, or a clicking noise occurs during sprints. On entry-level aluminium freehub bodies, the splines wear out more quickly due to the steel cassette, which gouges the metal. A stainless steel or titanium freehub body is more durable. Lightly lubricating the freehub bearings every 5,000 km significantly extends its lifespan.

Yes, on wheels fitted with interchangeable freehub bodies, which is the case for most high-quality wheels. DT Swiss, Shimano, Mavic, Fulcrum and the majority of premium manufacturers offer freehub bodies sold separately (€15 to €80). Replacement requires a specific tool depending on the brand (DT Swiss spanner, Shimano TL-FH40 tool) and takes around 15 minutes. Entry-level freehub bodies welded to the hub are not replaceable. Before purchasing, check that the wheel’s hub is compatible with a replacement freehub body of the desired standard.

No, only the standard needs to match, not necessarily the brand. A Shimano HG body is compatible with Shimano cassettes, SRAM HG-compatible cassettes, Sunrace cassettes and other third-party brands using this standard, regardless of the body’s brand. However, there is one exception: Campagnolo is completely proprietary. Campagnolo cassettes only work with Campagnolo freehub bodies. As for SRAM, an XDR freehub body can accommodate an XD (MTB) cassette with a 1.85 mm spacer, offering a degree of versatility.

The bearings in the freehub body determine the smoothness of rotation and the lifespan of the unit. Entry-level freehub bodies use standard steel bearings that require lubrication every 3,000 to 5,000 km. Premium freehub bodies feature ceramic bearings (Swiss Side, CeramicSpeed) or sealed stainless steel bearings that last longer in wet conditions. A freehub body with worn bearings causes noticeable lateral play in the rear wheel and increased rolling resistance. Maintenance involves injecting grease through the designated port or dismantling the unit to clean and regrease it.

It depends on the standard: yes on HG with a spacer, no on XDR. On an HG road freehub body (9 splines), a Shimano 11-speed cassette fits directly. A 10-speed cassette requires a 1 mm spacer, an 8- or 9-speed cassette a 1.85 mm spacer. On an XDR body, HG-compatible cassettes (minimum 11 teeth) cannot be fitted without an adapter because the spline profile is different. On an HG+ body (Shimano 12-speed), only compatible Shimano 12-speed cassettes are accepted.

Cleaning and re-lubrication every 3,000 to 5,000 km, or after every very muddy ride, are the key steps. For basic maintenance: remove the wheel, clean the body with degreaser and a brush, dry it, then inject light grease through the body seal. On removable bodies, remove the body, clean the pawls and springs, lightly re-grease (caution: too much grease slows down the pawl engagement) and reassemble. A well-maintained body runs silently. Excessive scraping or clattering indicates insufficient lubrication or early wear of the pawls.