Cassette/crank keep spinning when not pedaling

This is something I’ve noticed the past few times I’ve used my gen 1 Hammer. When I get off the bike after a workout, I’m seeing the cassette and crank continuing to spin as the flywheel decelerates. Could it possibly be the freehub needing to be replaced or maintained somehow? I’m not noticing any issues with performance otherwise.

yes, sure sounds like the freehub body may potentially need to be replaced. It does it off the trainer as well?

When this happens on a bike it means the rear hub has a problem - bearings need to be serviced is the most likely solution.

Can be caused by a number of things, including regular wear and tear, but basically you need to take apart the hub and see what’s ‘wrong’

On a trainer I assume the same would be the cause - something is out of whack with the free hub bearings causing the momentum of the flywheel to transfer directly to the cassette, causing this forward spinning motion

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It’s not unusual for the cranks to spin a little bit due to the drag in the freehub that’s there by nature of the pawls or ratchets. Doesn’t matter while you’re pedaling, can theoretically slow you down ever so slightly when you stop pedaling. You’ll see this a bit more if you use thicker grease in the freehub (more drag) for example.

If the freehub has bid adieu altogether, and things are completely jammed up due to a broken pawl or something else, then service is right away, don’t ride on that. If the freehub can’t freewheel anymore, as soon as you stop pedaling, it’s going to do Bad Things, and you might find your chain and rear derailleur wrapped in your rear spokes before you know it.

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Thanks for confirming all, I’ve asked Saris about getting a potential freehub replacement. I suppose I could try and see if I can service the freehub myself as well but the unit is, gosh, maybe almost 4 years old now and gets nearly daily use.

just to be clear, I’m on a direct drive trainer, not a wheel on the road, I don’t have to worry about spokes and such lol But I get your point!

This is not a problem, every Cycleops/Saris direct drive trainer I’ve had does this, and I’m pretty sure the Kickr I tried did also.

My relatively new H3 does this a little bit. Not to the point of fully spinning the cranks, but enough to slightly turn them during a spindown. I don’t worry about it at all- I’m never coasting indoors, anyway.

That might be even worse! You could throw your chain and derailleur through the plastic body of your $1000 trainer haha

Yeah, I think it might have done it before but I never noticed but my cranks have been spinning for a while when I stop my workout which seems different from the way it usually behaved, just don’t want to get to a point where my trainer craps out and I have to revert to gasp the fluid trainer lol

The Saris rep didn’t think it was an issue based on my email description, but I sent along this video in case it provides a different diagnosis. This was right after a workout and stuff keeps on spinning for a minute. I don’t think it’s affecting my day to day usage (and I’m currently using powermatch with the assioma uno) but given how long I’ve had this I’m definitely keeping my mind on potential points of maintenance which may be needed (like does it need a belt replacement at this point?)

Anyhow I’m rambling! Here’s the vid!

I’d say that the freehub needs a clean.

It wont effect your power numbers when in use but I do wander if the extra resistance might effect the spindown calibration? You will be holding the cranks still when it does this I assume?

Worst case scenario would be if it locks up completely and you end up with a fixie with the flywheel pushing your legs around - but that seems a long way off.

Yeah, I’d pull the freehub off, inspect, clean and relube to see if that fixes the issue.

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I have a set of enve 7.8’s with 240 hubs that have done this for years. I just swapped out the free hub for a new one, cleaned and re-lubed the springs and ratchets with dt red grease and no change.

If your BB has really low drag and freehub high, that’s normal. If there are no abnormal noise from the freehub you are most likely ok. But if you have the tools, just pull of the freehub body and inspect it. Clean and relube while at it. Don’t know about that model but for instance on en Elite Direto you can remove the freehub with casette attached with a single hex key.

Yeah, the Saris rep believes it might be excess grease causing drag. Kind of weird how it’s manifesting after nearly 4 years (I think) of owning it. I’m embarrassed to admit that I don’t have any grease at home, I thought I did but must have lost it.

Just as an aside, would having drag in the freehub affect powermatch smoothness in any way? Reason I ask is that it has felt like sometimes the resistance seems a little less smooth than when I first started using powermatch a few weeks ago (this is using the new powermatch on TR). Might just be in my head though!

Theoretically, since you aren’t coasting, the grease (or lack thereof) in the FH would have no impact on power production. It should only matter for instances when you are coasting or the pedaling input is rotating the cassette slower than the axle and flywheel rotation.

That said, a failed FH or other issue could potentially introduce more drag to the axle rotation, but I think that would be obvious and loud if it were the case.