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WTF happened to my hub (Zipp Service Course 30)?
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These wheels are on my gravel bike. I got a flat tire yesterday and when I got the wheel off, I set it down and the whole cassette fell off the axle. I noticed a small piece of metal also fell out and was able to find another one, but could not find the third. Ultimately I could not even get the wheel back on the bike because the end cap at the cassette lock ring had separated from the axle (came off with the cassette) and I could not get the cassette and carrier back on the axle sufficiently to seat the end cap. With the loose end cap I just could not get the wheel to seat in the dropouts sufficiently well to put the through axle in and I had to walk out with the bike.

I am trying to understand how to get this working again (if possible). The biggest problem is I lost one of the small pieces of metal that fell out, I only have 2 of three. I figured out where these are supposed to seat in the cassette carrier assembly I interpret they are some part of the hub pawl assembly? So at a minimum I need to be able to buy another one of these parts.

Assuming I had all the parts, is this something that just press fits together? If so, what would have cause it to become disassembled. The whole cassette carrier just fell off the axle when I set the wheel down. No direct force was applied. I will note I have had some "creaking" the last couple of rides, I hadn't really investigated it, don't know if this could have been a sign that this was happening.

Just looking for some guidance, I have been very happy with these as my gravel wheels and nothing looks "broken" but I have at least one missing part and I also want to understand why they whole assembly just came apart for no apparent reason (is this common).

Cassette and carrier that fell off the axle




small pieces that fell out




wheel and axle



figured out where the small metal pieces are supposed to go, but am missing one of them. This whole thing fell apart out in the woods, in leaves, dirt and I couldn't find the other part. I'm actually lucky I even noticed that any of these fell out as they are quite small and since I don't know much about hubs they weren't anything I was expecting.
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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those little things are the pawls. and yes, with some hubs the freehub just slaps back on with very little effort (and comes off with very little effort); it is extremely annoying. you'll have to get a 3rd pawl if you want that back on correctly, unfortunately.

ETA - there should be a spring, also, i think. once you have all the pawls you slot them where they belong and then rotate the cassette/freehub as you push it back in, allowing the pawls to push down. it makes more sense once you try it
Last edited by: jkhayc: Jul 31, 20 12:40
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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Go find the other pawl and put it back together.
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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I believe the rubber "seal" holds that in place. Mine was doing that and I cleaned it all up and replaced the seal. It just needs a little lube on the pawls and "tooth area". You'll need to find another pawl.
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Re: WTF happened to my hub (Zipp Service Course 30)? [Flanders] [ In reply to ]
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Just disassembled another hub....there are a rubber seal, 3 pawls and one round string spring which holds the pawls into place. Wasn’t a zipp but to get an idea.
But the whole carrier is fixed to the body by a nut which only can be removed when the cassette is off but it could loosen itself.

-shoki
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Re: WTF happened to my hub (Zipp Service Course 30)? [shoki] [ In reply to ]
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Looking at the photos the 3 springs (1 per pawl) are still in place. They are like leaf sorings and push the pawl out.

When you refer to on round 'string spring, I think you're talking about a single loop about 40mm diameter ish made from thin (0.8mm ish at a guess) wire ? Is that right ? If so the hub in the photo won't have one of those- what you describe is what Fulcrum and Campag use instead of the 3 separate pawl springs (sitting in a groove in the pawls to 'rock' them outwards (bit of a shiiite design from Campag that saves 2 grams and introduces a single point failure that leaves you stranded).

As others - you need to replace the missing pawl.

On some hubs the end cap can have an internal O ring to make it a snug fit so it all doesn't fall apart like yours. Others have a tiny grub screw you screw in that helps lock the ring in (like a tiny version of an old cotter pin on an olde worlde crank)
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Re: WTF happened to my hub (Zipp Service Course 30)? [jkhayc] [ In reply to ]
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jkhayc wrote:
those little things are the pawls. and yes, with some hubs the freehub just slaps back on with very little effort (and comes off with very little effort); it is extremely annoying. you'll have to get a 3rd pawl if you want that back on correctly, unfortunately.

ETA - there should be a spring, also, i think. once you have all the pawls you slot them where they belong and then rotate the cassette/freehub as you push it back in, allowing the pawls to push down. it makes more sense once you try it

I didn't see any spring, but the individual pawls interfaced with a "leaf spring" in the recessed spot where they fit into the cassette carrier assembly. Unfortunately the other pawl is missing somewhere in the wood, maybe I will take a trip out to see if I can possibly find it. Looking online, you can buy the whole cassette carrier/pawl/bearing assembly as a replacement part (it is like $100), but not individual pawls.

Based on responses here and looking at schematics of the hub online it seems like if I just had that pawl I could just put the whole thing back together and it should be fine. Lesson learned, I guess be careful when I have the wheel off and never set the wheel cassette side down, especially when you are out in the woods changing a flat.
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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You can buy a new set of pawls, do a search for Zipp 177 Freehub Pawls, I think a set cost like $25 or so when I had to replace mine. Buy another one or two of the rubber seals that go with it.
When assembling it, put the pawls and leaf springs as they are supposed to go, roll the rubber seal half way down holding the pawls down. Once the pawls are held in place, then continue to insert the freehub in place. If you force it or try to rotate it back a little as some others it won’t work.
Last edited by: mike s: Jul 31, 20 14:03
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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This happened to me as well. My question with this is: is the whole cassette assembly supposed to be able to come off once the wheel off the bike? Every time I remove the wheel, it’s a pain to keep the hub from falling out, and if it does, I need to use the rubber seal halfway out to hold the pawls down in order to slide it back on. I can handle it in my own house when not in a time crunch, but different story if fixing a flat during a race.
Last edited by: Spudzj6: Jul 31, 20 14:54
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Re: WTF happened to my hub (Zipp Service Course 30)? [BobAjobb] [ In reply to ]
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Thanx for specifying, that’s why I mentioned I just worked on another hub/brand.

-shoki
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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"Looking online, you can buy the whole cassette carrier/pawl/bearing assembly as a replacement part (it is like $100), but not individual pawls"


It's called a freehub body.
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Re: WTF happened to my hub (Zipp Service Course 30)? [tri_yoda] [ In reply to ]
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Re: WTF happened to my hub (Zipp Service Course 30)? [mike s] [ In reply to ]
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nice find, thanks.
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