Hello. I bought a Specialized Crux last week, and since then the fork is vibrating under hard braking. At any speed, but mostly noticeable at low speeds. The headset and plug expander are both well adjusted and tight to spec. I upgraded day 0 to brand-new straight 160mm XTR rotors that I correctly broke in. I swapped the rotor and didn’t fix the problem. I also swapped the entire front wheel/rotor for a new one at a Specialized shop and didn’t fix the vibrations. I went to many bike shops, and none were able to find the source of the problem. Could it be a defect in the fork that created a weakness inducing a harmonic oscillation or something? It’s so bad that during a big ride with 2500m of elevation in gravel the other day, and my thru-axle untightened itself… My next step is to go through the Specialized lifetime warranty, but anyone has an idea what the problem might be?
by une_olive
3 Comments
Replace the brake pads. I had a contaminated pad causing vibration through my entire frame on the rear under hard braking at higher speeds. They also make a paste/sand you can treat the pad and disc with that heats up/grinds off contaminates.
Sounds like you’ve not bedded the pads in correctly, so there’s an uneven buildup of pad material on the rotor which is stick-slipping. Sanding the rotors and bedding in the pads properly should help.
What a great photo. Sorry I can’t help. I just want to ride there!