In this edition of Ask a Wrench, pulled from the members-only Geek Warning podcast (June 12, 2025), Dave Rome is joined by Australian pro mechanic Peter Arch to tackle four listener questions. This episode, they cover hub engagement issues that won’t go away, how hydraulic disc brakes work, whether heat can damage carbon wheels, and eco-friendlier alternatives to Tri-Flow for cable lubrication.
As a reminder, this is just a brief summary of what was discussed. For the full conversation, including all the information, we recommend listening to the Ask a Wrench segment of the podcast.
Q1: Skipping freehubs
Michael from Toronto: “My Salsa Journeyer has started skipping like a chain or gear slip, but it’s not the drivetrain –it turned out to be a hub issue. The shop cleaned and re-greased the freehub of my Prime alloy wheels, but the problem keeps returning. Can I save this wheelset?”
Peter Arch: Sticky pawls are a known problem when the wrong grease is used. If the pawls can’t spring back into place quickly enough, you’ll get skipping –especially under load. Thick grease or degraded old grease often causes this.
Try using a thin lubricant instead of grease – light oil can prevent stickiness without gumming up the springs. Give the hub internals a thorough cleaning, remove all grease (especially from beneath the pawls), and apply a sparing amount of oil only where it’s needed.
Dave Rome: If your hub uses a ring spring that actuates all the pawls at once (like many budget OEM designs), that single spring often doesn’t provide strong enough tension when contaminated with grease. That makes using a suitably light grease or oil even more critical.
If wear has already occurred to the pawls or drive ring, you may need replacements – but sourcing parts can be tough. Prime wheels [the brand on Michael's Salsa - Ed.] were from Wiggle/CRC, and that brand is now under new ownership. If parts aren’t available, it may be time to look at new wheels.
Q2: How do hydraulic brakes actually work?
Peter K.: “How do hydraulic disc brakes actually work? I can bleed and reset them, but I’d like to understand the internal workings. Especially the fluid reservoir – what’s really happening in there?”
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