Hi Zwift Community,
I would need your help please with a question where I am not sure. I have the Zwift Hub and use the CS-HG700 cassette 11-34 on it. Now I have the info from Zwift that I don´t need the spacer for 11 speed cassettes, but Shimano told me I have to use the spacer when I use this cassette on roadbike freehubs. Now I´m not sure what I have to do right. Maybe somebody has the same constellation and can help me here.
Thank you,
Christian
If you install the cassette without the spacer, it should be pretty obvious if the spacer is needed. When the lockring is tight, the cogs will be loose if you need the spacer. (I haven’t tested this cassette on a Zwift Hub.)
I can recommend https://www.cyclingtips.com/2022/08/a-guide-to-freehub-body-and-cassette-compatibility/ as a guide to freehub bodies and compatible cassettes.
Without owning a Zwift hub myself, I would assume it comes with the freehub for Shimano Hyperglide 11-speed road cassettes. This freehub is wider than the original freehub for Hyperglide 8-, 9-, and 10-speed cassettes. You can directly mount the (real) road 11-, and 12-speed cassettes from Shimano. Some cassettes, the article mentions 11-34 11-speed cassettes from Shimano are originally mountain bike cassettes. These fit the original freehub but need a spacer for the current freehub. I think you need a 0.85mm spacer in this case.
@Christian_Van_Nucks welcome to Zwift forums.
TLDR: Shimano is correct in this case - use the 1.8mm spacer for their CS-HG700-11 or CS-HG800-11 cassettes with 11-34 tooth spec.
Shimano designed these two 11 speed 11-34 cassettes to squeeze onto older Hyperglide10 freehub bodies that have been around since ~1991. The two largest cogs are concave, and their cupped design positions them slightly over the drive-side hub flange. This allows use on the millions of bikes out in the wild that came with HG10-compatible wheels.
Shimano introduced HG11 freehub bodies about ~2013 that are 1.8mm longer. The Zwift hub comes with an HG11-compatible driver and that 1.8 mm spacer is needed to take up the extra space.
Other 11 speed Shimano cassette models are 1.8mm wider and use a different model naming convention. CS-R7000 and CS-R8000 come in the narrower gear ranges (11-28, 11-30, 11-32 etc). The two largest cogs on these models aren’t big enough to do the cup-over-drive-flange trick, so they can fit only on the longer HG11 freehub drivers.
Hope that wasn’t too much bike nerdism, but that’s the complete answer.
Hi,
thank you all for your feedback & help. 
Best,
Christian
Thanks for asking this question. I had the same question, now solved.
Thanks for being so helpful!
Hi guys,
Sorry for bringing this back to life some months later.
I have the same cassette (Cube Cross Race Pro 2022). I have a Zwift Hub Classic with pre-installed 11x cassette. From the first attempt on, it did not run smoothly on the highest gears. Last winter pure frustration, I paused cycling until March to go back outside (started only in Sep 22…).
2023 fully into road cycling, subscribed to Zwift in November. I ignored the issues for a while - it works fine cycling up mountains in Zwift…
Now it bothers me a lot, tried whatnot but issue remains. The video shows, it is like the cassette is just a bit too far right. This is my CS-HG700-11 from my bike. Without the spacer the cassette is loose, so thanks for your info earlier. The Zwift cassette (Sunrace 11x Road) does not use the spacer, I understand (MTB cassette vs. road cassette), but the result is the same. Just like the cassette should be 1mm further to the left.
Any ideas what I could possibly be doing wrong?
h t t p s ://files.fm/u/naqh7x2drt
Thanks, Daniel
Hi @DanielG
Thanks for the in-focus video. You’re right - it does look like the chain should move a millimeter or two to the right, but that’s also because you’re backpedalling. When backpedalling, the top part of the chain will have no tension on it, and settle into a position that’s determined more by chainline. When pedaling forwards, you’re putting tension on the chain and its true lateral position will be revealed.
That said - if the true position looks like above, you may want to loosen the high limit screw on your derailleur a quarter turn, possibly a half turn to allow the derailleur to shift to the right. it’s called a limit screw because it sets the physical limit of how far outward your rear derailleur can move.
This is also common when you swap wheels made by different manufacturers. That offset distance between the smallest cog to the inside face of the dropout varies more than you’d think. That’s because Shimano never licensed its original Hyperglide technology circa 1990. Any other company that makes a HG-compatible hub / freehub body / wheel / trainer is reverse-engineering Shimano’s tech. There are going to be variances in that offset dimension unless you’re using a hub / freehub body / wheel manufactured by Shimano.
So: bottom line is you may have to make small adjustments to your derailleur by changing cable tension (or electronic micro-adjustments if using Di2 or something like it), to compensate for these dimensional differences.
Thanks a lot for the quick response @shooj!
However, I have tried all that before. Generally, I understand how to adjust the derailleur and understand the basic concept of the different screws.
Changing gears works smoothly, hi/lo delimiters are correct, playing with the barrel adjuster does not change the fundamental issue.
Here a slowmo shot after I turned the barrel adjuster clockwise as suggested. The chain does not run smoothly at all and this remains independent of how I turn the barrel adjuster, both clock- and counterclockwise. You see how it jumps? It’s also annoyingly loud, because it’s making these jumps. It’s a quite new chain, waxed, runs smoothly at a friends’ bike, so it’s surely not the chain itself.
h t t p s ://files.fm/u/4a7d7bqjjq
No idea?
