Specialized Front Road SL Thru-Axle

Thru-axle length is not a universal number. It changes with fork design and frame generation, which is why a 12x100mm axle pulled from one road bike will not necessarily thread correctly into another. The Road SL Front Thru-Axle from Specialized is the factory replacement for the current road platforms, a bolt-on alloy axle measuring 121mm overall with M12x1.0 threading and 100x12mm front hub spacing. If your original walked off at a race, got cross-threaded, or stayed behind in a travel case, this is the part number that puts the front wheel back in the fork.

The head takes a 6mm Allen key and seats conically against the fork dropout, so there is no lever to fold away, no tension adjuster to set, and nothing protruding from the fork leg. Bolt-on axles trade the roadside convenience of a lever for a flush dropout interface and no lever to catch on a wheel bag, and most riders already carry the 6mm on a multi-tool.

Check your length before ordering. Earlier road frames in the lineup used a 127.5mm front axle under a different part number, and while 12x100mm spacing and M12x1.0 thread pitch are shared across both, the 121mm axle will not engage the dropout threads correctly on those bikes. Measuring your old axle end to end settles the question before you order.... Read More