Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It only takes a minute to sign up.
Sign up to join this community
Suddenly during the ride, strange cracking noise started to happen. It happens even without a chain. The crank seems to rotate smoothly otherwise. There are more cracking noises when rotating forward. Much less rotating backward.
This is how it sounds when rotating cranks:
2 days ago there was a rain and I washed the bicycle. Otherwise nothing special happened what could be causing this. The bottom bracket is Race Face BB92, PressFit, shell 41x92mm.
EDIT: One day later it got even worse:
That's an ominous sign you have a bearing going out or there is piece of debris (like a sand grain) that has infiltrated the bearings. Either situation can cause a bearing ball to "catch"--momentarily getting jammed and the noise comes from the jam releasing.
You'll need to remove the cranks to access the seals of the cartridge bearings. You can leave the cartridge bearings in place in the shell (although it would be best for thorough cleaning to remove them properly with an appropriate bearing press/extractor. Pounding them out or using a poorly chosen homemade press system risks damage to the bearing and leaving them in place is far better than botching the press out and back in).
Once you have access to the cartridge bearings seal, use a thin, sharp edge (like a utility knife razor blade, exacto knife, etc) to get under a part of the seal. Be gentle as you don't want to damage the seal or bend it's metal core. Once a little section of the seal circumference is out of its seat, a pick or the blade can be used under the seal going around the bearing, dislodging the seal from its seat. Using a spray degreaser product--most effective would be an aerosol can with a straw that can accurately direct a pressure spray into the bearing. Compressed air can help with clean out as well. Be mindful of blowing gunk and degreaser all over the place so eye protection is a must and you'll want to prevent contaminating your brakes and rotors. A shop rag covering the periphery of the bearing when your using compressed air is a good idea.
Flush, flush, flush. Use a tooth brush or small paint brush to remove clots of dirty grease. As the innards become cleaner, do your best to examine the parts within. With the metal cage in the way (don't try to remove it), it's hard to accurately judge the condition of the balls. Severe damage or missing balls is usually quite evident. Inspect as you clean. It may be that you'll have to replace the cartridge bearings, especially if they've seen a few seasons.
Check your progress by sticking your fingers in the spindle hole and rotating the bearing. There's a difference in a gritty feeling from dirt or damaged bearing balls and the slight, fairly uniform roughness of a cartridge bearing with grease washed out. Let the solvent dry for a time. Then use a grease filled syringe or grease gun to infuse clean, waterproof grease back into the bearing. I usually hit 3 or 4 spots along the ring, spin the inner bearing race and repeat until the cartridge is full. When replacing the seal, be attentive they edge of the seal is seated properly around the entire circumference. Ideally, there will be no gritty feel whatsoever in a cartridge bearing filled with clean grease.
Here's what you're up against as well. Based on your video and the info provided in your question, you have a Raceface Next crankset that has a 30mm spindle within a PF92 bottom bracket. That particular bottom bracket standard was designed around cranks with 24mm spindles. With the smaller spindle, there is room for larger bearings. Larger bearings in this situation are more durable. With the 30mm spindle, the compatible bearings are much smaller, making them prone to premature wear and sensitive to contamination. Bearing problems are often noted in PF92 systems compatible with 30mm spindles.
A second situation that I would be concerned about with that noise, is a published history of the Raceface Next cranks, which are carbon fiber, to encounter issues related to the aluminum inserts for pedals becoming loose. In addition, the bonding around and involving the spider or cinch ring can become compromised. The timeline for the most of these problems to occur seems to converge on the 3 year mark. I don't mean to degrade the Raceface Next cranks, which are very light and very expensive, but the aforementioned problems are undisputed facts (bearing size in 30mm compatible PF92 BB's) and frequently encountered anecdotes when querying for general information on Raceface Next cranks, including owner reviews posted on the Raceface website.
Inspect the cartridge bearings and determine when they should be changed out for a fresh set.
