Hey,
I‘ve got a road bike with a 12-speed 11-34 shimano 105 cassette. Is the standard 12-speed 11-30t (that comes with the zwift hub) fine for my bike or do I have to install a 12 11-34 cassette?
Thanks in advance;)
You should be fine. Your current cassette, a 12sp 11-34, has the following cogs, right? 11-12-13-14-15-17-19-21-24-27-30-34T
The 12sp 11-30 should have these: 11-12-13-14-15-16-17-19-21-24-27-30
So you’re already running from 11 to 30 as-is (just with one more step available). Your current drivetrain would work if you never shifted into the 34, so it’ll work here. 
You’ll lose those 4 teeth in your granny gear, but it’ll work okay.
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have you seen the zwift hub one with the cog?
comes with 24 Virtual gears and allow any speed bike to be used.
Shhhhhh. Older is always better
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