A few weeks ago I did this conversion with the Zipp kit on a Zipp 808.

Zipp gives you a new axle that slightly moves the hub to give more space to the wider 11sp freehub-body. So you need to redish the wheel, because post-conversion the rim will be slightly off-center.

I don't exactly know about the ebay offer because I have never tried this. I believe there is a trick to machine the 10sp freehub-body making space for the wider 11sp cassettes.

Alternatively you could consider using a Campagnolo 11sp free hub body.

If there is any possibility I would go with what Zipp recommends.

There is more interesting information in this thread:

https://forum.slowtwitch.com/...=zipp%20xdr#p7227151

I had my LBS use the zipp kit last year and with labor total cost was about $120

The easiest and cheapest way to do this is to buy an Ultegra 11 speed cassette and have a machine shop remove 1.85mm off the back of it.

He could also buy an Ultegra 11-34 and not do anything else. It will fit on a 8, 9, 10 speed hub.

https://www.competitivecyclist.com/...ra-cs-hg800-cassette

https://bike.shimano.com/...000/CS-HG800-11.html

Edit: You'll need a GS Rear Derailleur

The 11-34 cassette is CS-HG800.

Ultegra cassettes are CS-R8000.

I'm aware of that option, looking to just have it work as-is without modifying cassettes.

I guess my main concern is a lack of understanding on the technical aspects of how the rim/spokes/hub interact, or wheelbuilding in general. With the existing hub, does the kit+redish have some tensioning/balance aspect that keeps things within tolerance, aside from just centering it afterwards? I know Zipp has had trouble with their hubs in the past. As much as I'd like to save ~$70 or more over the OEM solution I'd rather not have any drastic effects under high load. I do road race/sprint with these on occasion.

I suppose that line of thought will end up making my decision for me unless advised otherwise, but I try to learn as much as possible along the way.

If you look at the links I posted they both say Ultegra. Even the one from bike.shimano.com

That is really weird that the Shimano website says Ultegra for the 11-34 cassette.

Notice that the lockring does not say Ultegra on it.

I know, they should have called it M8000 or XT.

I suppose that since their GS derailleur is rated to 34 teeth they felt a need to put the Ultegra name on a 34.

I think that an 11-34 cassette would look weird on a Zipp 808 wheel.

The spoke tensions should remain the same pre and post redishing. A LBS would check with a tension meter.

And why would you get a 11-34 cassette for a Zipp 808 wheel outside a 1x setup?

To solve the original poster's problem for about $80 - or -

Average 60+ man/woman AG doing a hilly to mountainous triathlon

Just about anyone racing Triple T Ohio

Not everyone that owns aero wheels is a super-biker.

Perhaps this is the part I was missing when trying to visualize the process. So both sides are adjusted, and there's no net change as the hub is recentered?

I'm probably just overthinking it, as usual. The effect I'm expressing concern about would be absolutely minimal, it's a shift of <2mm and only represents an actual change at the end of the cassette, the rest is overlapped with the existing.

Yeah, 11-34t would really be excessive for me, even with 1x and a dinner plate (detrimentally, at that point, as tooth counts are so widely spaced). I race mostly in FL so would rarely use anything approaching a bailout gear.

No, they wouldn't remain the same tension. Any wheel builder would know that.

That's cool.

The next thing I would do is what jimatbeyond said in post #4

I've had that done for 2 of my friends.

Some guy sells modified Ultegra 11 speed cassette’s on eBay. He does the machining for you (to fit 8/9/10s hubs)and of course it’s a little more $ but not too much. Seems to be easier to buy that than any of the other options.

The guy on eBay is selling the modified Ultegra cassettes for $135.

You can buy an Ultegra cassette for $65 and have it modified for about $30.

Where, your local machinist shop where a buddy of yours works? Being factious of course but is that your experience? If someone walks off the street into a machine shop (hopefully with mask on but wait— depending on the characters working there no mask might be more accepted, LOL) they would charge about 30 bucks? TIA

I have a friend who owns a machine shop that charges me $10. It only takes about five minutes.

About a month ago I had an 11 speed cassette machined to fit an older Zipp 10 speed disc. Bought a used 105 cassette for $20. Grabbed the disc and cassette and walked into the closest machine shop I found on Google maps. Explained what I wanted with some detail (1.8 mm), and he banged it out in like 10 minutes. He charged me $15, but I gave him $20 because he dropped whatever he was doing to help out some random guy (me).

Depending on the cassette you are machining, it may essentially last forever. For an 11-28, you are just machining the carrier that holds the largest three cogs together. I'm not in those cogs very often, so that machined part shouldn't wear out too fast. In theory, I can just toss the 8 smallest cogs in the trash when they become worn, keep the machined 3 largest cogs, and swap in 8 cogs from a new cassette.

One thing to be aware of if you do go this route is that your largest cog is somewhat cantilevered over the hub (inboard) more than it would be on a proper 11 speed wheel. People say this can cause issues with smaller/tighter cassettes like an 11-23. The smaller outside diameter of that 23 cog can get awfully close to the spokes. A 28 tooth gives more clearance because the spokes are dished toward the rim. This wouldn't have been an issue on my flat disc application. I may drop another $20 and get a 11-23 machined. That close ratio would be ideal for many courses I do.

Hey good to know it’s cheaper than I thought from a local machine shop. Thanks

For a bunch of reasons, it makes a lot more sense to modify a cassette than to use a different freehub. If it helps, we have a bunch of info here about this and a simple free way of getting an equivalent mod:

https://darkspeedworks.com/blog-11speed.htm

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