I recently swapped out a rear wheel from a backup bike that I've not ridden much to my main bike. No problems on the first couple of rides, but yesterday and today I've had several instances where I spin the cranks without resistance for a bit before things catch and I'm back in the business of moving the bike forward. Only happens after I've coasted for a bit. For what it's worth, it's been quite cold here. What's happening, and how can I fix it?

Could be a couple of things. The cold (assuming we're talking single digits or below) might be causing the lubricant in the freehub to thicken and bind the freehub pawls. Or it could be the lubricant is old and sticky. Either way, the solution is the same: Remove the freehub body and lube the pawls with Phil Wood's waterproof grease. It never gets sticky and temperature doesn't change its consistency. It works well for me.

You MIGHT be able to get away with a quick/dirty fix of laying the wheel down, freehub side up, and spraying WD40 into the seam between hub body and freehub as you turn it by hand. Assuming some WD40 actually gets in there, that will thin out the lube that's in there now.

BL

If you are going to use grease, Phil's is as good as any but grease isn't needed. Remove the freehub body and the rubber seal found on the back of most of them. Flush out the bearings with kerosine or mineral spirits, shake out the excess and lube with a light oil such as Tri-flow. Drain the excess oil, reinstall the seal and reinstall the freehub body. That should cure the problem unless something inside is really broken.

I've used nothing but Ti-flow to lube my freehub bearings and have one set of Dura Ace hubs with well over 50,000 miles on the original freehub and several more 105 and Ultegra hubs with 30,000 miles and have never had a failure in hot or cold weather.

+1
Ratchet mechanisms needed only the lightest of lubricants. That's because there's never movement under load.

When pedaling, the unit is locked and there's no movement.
When coasting the only load is that exerted on the pawls by the springs, which is pretty tiny.

That's why ratchets never wear out. When the do die it's because of rust, and sometimes (rarely) because of chipping from hard engagements before the pawls have time to settle into the pockets on the ring.

I prefer something slightly heavier than Tri-flow not because of better lubrication, but because it resists washout better and tends to make the mechanism quieter. I use Chain-L (since I have tons of it), but Phil oil, or any slightly heavier sticky oil is fine. If you use grease, apply only a thin film. Otherwise grease can fill the ramps in the ratchet ring and keep the pawls from pocketing fully.

Thanks for the responses. I tried to get at the pawls and springs yesterday night, but failed. These are Mavic Classics Elite wheels that came on a bike I bought used. I found a few U-Tube vids for servicing Mavic freehubs, but mine are different - instead of a 10mm allen socket, I have a nut on the drive side. Got that off and the axle out, as well as a couple of loose cover/washer components underneath - but that's as far as I got. Couldn't figure out how to get the freehub body off, and didn't want to force things.
I managed to get a few drops of light oil into the internals, but it hasn't (completely) cleared the problem.
Any suggestions on how to proceed?
Thanks

Without knowing it was a Mavic hub, I guess we all thought it was a typical Shimano. All I can suggest is to add more oil while rotating the outer shell around the inner core to get the oil into the internals and distribute it thoroughly.

can I ask something? both wheels are the same speeds and cassette yes? you not putting a Campi 9 spd wheel into a shimano 9 shifting system right? is the chain riding over or betwen the cogs? even if both wheels are the same the spacing could be off a bit. check the distance from the outside of the locknut to the first cog.

Pics??

So the hub internals in this style of freehub are not serviceable? From what I can tell, these wheels go back a bit in time...

I think that depends on how it is built. how old are they and how do the hubs differ from the 571 and 577 hubs?

Pics?

When I have it apart again, I'll take a few pictures.
I suspect they're newer than the 571 hub, for which I found the service manual (https://www.yellowjersey.org/mavic571.html). That references an 8-speed cassette, mine is a 9-speed; and there is no circlip or serrated locknut in my hub assembly.

that is what I was looking at too.

but both wheels are the same spacing right? either Campi or shimano?

Cassette is Shimano. Here's some pics:

I could be (and likely I am) but I think that is a shimano cassette and you need a 10mm allen wrench to remove it. look down inside. I also think a standard shimano 9spd cassette is what you need to replace it

I use Phil's tenacious oil on freehub pawls

Yep, my cassette is Shimano 9-speed. No problem there - it's obviously already removed in the pix above. The challenge comes after the cassette is off - I can't figure out how to remove the freehub body (or if that's not meant to be removed, how to extract the bearings from the hub/freehub so that I can get at the interior bits that need cleaning. For now, my dripping a bit of light oil into the interior appears to have fixed the problem (or is it the warmer temperatures we've had the past few days?), but I'd still like to properly service the wheel.

I think you misunderstood the intent of BianchiGirl's reference to the cassette, when she meant the freehub body. Try slipping an allen key through the bearing and see if you can engage the head of the retaining screw in the back (you might shine a light and try to see it down there).

not familiar with that mavic hub but the others than i have worked on just pull off once the axle is out

I had expected the same. And maybe, if more force is applied, it will come off without further steps - but I'm hesitant to push it too hard, for fear of messing it up. When I look straight through the axle slot from either end, I see just a nice and circular opening - nothing that an allen wrench could grip into.

I think Bianchigirl may be right. Sometimes it's hard to see, so I would reach in there with a long 10 and move it around just to be sure. Also if it is a 10mm, be aware it may be reverse threaded. Some of them are.

BL

Just because it's a Shimano pattern freehub body doesn't mean it's built the same way as Shimano (and Shimano analog) hubs are.

Usually manufacturers are consistent in how freehub bodies are attached, and other Mavic hubs do not use the locking screw. We could all speculate how it might come apart, or the OP could email his photo to Mavic's technical support staff for a definitive answer.