Hi everyone!
I saw a post from one of the pros following the Ironman 70.3 Melbourne last weekend.
They referenced multiple chain slips as the reason they lost a lot of time on the bike. Just wondering if anyone has heard this term before?
I’ve heard of a chain dropping before, but not chain slip?
When the mech is between gears and its not engaged to either cog, so as you are riding then the chain ‘slips’ forward over a couple of teeth. Varies from mildly annoying to potentially lethal depending on which gears and what you are doing (if out the saddle sprinting this is not good at all). Most of the time it’s only going to happen in a certain area of the cassette so you can get away by swapping the front mech and then cross chaining a bit more than you normally would. Obviously that doesn’t work if you’re running 1x, but look on the bright side you are freewheeling at 0.000001cda less due to the areo benefits of no front mech.
Mark Cavendish can also describe this fairly well…
When the mech is between gears and its not engaged to either cog
That’s not how shifting is supposed to work. When you move the rear derailleur the chain goes through a sequence of “unwrapping” from the old cog while it starts to “wrap” around the new cog. There might be a few chain links in the middle without teeth in them, but the design is supposed to have the bulk of the cassette teeth engaged with the chain throughout the process. It should always be “engaged.” And it takes around a rotation of the cassette to complete the transition.
I don’t know what Cavendish is talking about, but it might be about how that process doesn’t work well at extreme torque or cadence or something. Shifting “under load” can cause issues - though it’s gotten much better with modern drivetrains. Particularly in the changes between the 11t and 12t cogs where they aren’t many teeth engaged in total anyway, so losing just the few cogs in the middle doesn’t leave much margin for error. A sprinter like Cav might have to briefly “float” the pedals during a shift.
I assume the person the OP is talking about was referring to chain drop, and “slip” is just a regional term or translation error or something. Second guess would be chain “skip” caused by a poorly tuned derailleur.
Chain skip is a new term to me, but as you described is what I know as chain slip, and referred to above. And yes indeed, it’s not an intended event, occurring more commonly in the smaller cogs as there are less teeth ‘wrapped’.
The Cavendish comment was in relation to a pretty major story from the tour this year. I’ll leave you to investigate if that’s something that you think you’d find interesting. If not (and noting you weren’t following the tour) I’ll not distract the thread with further irrelevancies.
Sounds like chain skip - my guess is they installed a “race-day chain” on a system with a worn-ass cassette
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Yeah, if you mean the Jaspher Phillipsen sprint where Cav said his chain was going back and forth between the 11t and 12t, that sounded like poor RD tuning of some kind. Bummer, as it’s super annoying when your RD “self shifts.” And I think for him it was on a bike he’d recently gotten in a bike change so he didn’t have much of a chance to test out the gearing before the finale.
Slip/Skip can also occur when a really really experienced home bike mechanic that has been building his own wheels for 20 years, and maintaining / building full bikes for 30years swaps cassettes and doesn’t move over the final spacer ring needed for an 11 speed cassette, then heads out without noticing that the cassette is loose, and so shifting that 2mm around. So despite being a renowned bike self maintenance know it all then they can still make rookie mistakes.
Note that I only heard that from a friend. It most definitely didn’t happen to me last night on a quick test ride of my new wheels. Not at all and I defy anyone to prove it.
And can also occur when the screws in a P2C aren’t in the same distance causing the wheel to be ever-so-slightly at an angle and then standing on a climb putting out higher power.
I also heard this from a friend, and it didn’t happen to me in my last Oly.