It sounds like the actual physical COG cassette is mounted on an HG compatible freehub body (usual HUB version), so it could presumably be removed from the one that is HUB compatible and installed on other smart trainers with an HG freehub. But that is only part of the issue with using it on a non-HUB trainer.
The Zwift app must communicate with the specific trainer to adjust resistance level in accordance with the CLICK or PLAY controllers. That software side is presumably possible, but we donât know if/when Zwift will make that step for non-Zwift trainers.
In reality, the physical COG is not the core issue, since you could still use the virtual shifting via Zwift and the CLICK and/or PLAY on a regular 10-12 speed cassette. The key again is Zwift altering trainer resistance once triggered and that comes via app and trainer communication only in place for the HUB right now.
Hereâs the hypothetical scenario I canât quite square to see if it works:
I have a KICKR V5
I have Shimano 12 speed and my partner has Sram XDR. Two different freehub bodies (though really insert any mismatched combination of freehub bodies, speeds, etc.)
We both use erg mode 100% of the time (and for argument say itâs in TR or other non-Zwift app).
Would putting the Zwift Cog on the KICKRâs stock Shimano HG freehub body allow us to interchangeably use our bikes? That is, since the only thing the Cog is providing is a universal âcassetteâ (ie, a mechanical component) and TR is controlling resistance in erg from the KICKR, everything should work, right?
If the SRAM XDR is one with the Flattop chain, itâs larger rollers arenât a perfect match to a typical 1/2" pitch and tooth diameter present in all other non-FT chains. Despite that issue weâve seen plenty of people using FT chains on non-FT cassettes, so it works with a potential of chain roller wear.
But importantly, you could do the same with any of the many geared to single-speed conversion kits available, you donât need a Zwift COG. It may be possible to put one together for less than the current $60 intro price.
The main mechanical benefit to the COG that I see is the plastic shell making bike install possibly a bit easier than without, but it may not be all that useful. I wouldnât be surprised to see 3D print options or other hacks down the line, from this inspiration.
The other reason to snag a COG at the discount now could be hopeful aim that Zwift adds function to other trainers in the future and youâd also have a CLICK to use at that time. But may only matter for those that intend to use Zwift down the line with the COG and virtual shifting.
Could you not hack a two-cog cassette together?
Take a middle cog from an 11-speed and one from a 12-speed cassette, and some spacers from a single speed conversion kit, and put both on at the same time. One bike then uses one cog, and the other bike the other cog. Just never shift!
Is the virtual shifting different from adjusting âtrainer difficultyâ (think that is what its called, havenât used zwift in a long time)
Or maybe zwift just set some sort of resistance multipliers, that are send to the hub to simulate shifting.
I donât really think itâs something unique to the Hub, so it should work with other trainers too. But maybe zwift only enable virtual shifting if a zwift hub is connected.
One issue I have with swapping 11 to 12 speed and back is that I have to reindex or things are noisy and jump around. How does the COG (and the DIY single speed alternatives) avoid this?
Yeah, I donât know if they come apart, 12 speed hasnât made it to my house yet. But maybe there are after-market ones that have separate sprockets?
Unless your indexing is very out of whack (basically indexed on the next sprocket), mosr of the noise and jumping around is because the chain is rubbing on the side of the other sprockets. The jumping is when it catches some of the shifting ramps and tries to move over. If you only have one cog, there isnât any rubbing on the sides, and much less incentive for the chain to move sideways.
What @Splash wrote, but also because single speed sprockets have full height teeth which hold the chain more securely in the same way that single chainrings does.
As someone whoâs stuck with a wheel-on, due to sharing the trainer with an incompatible drivetrain, this looked really tempting to me. Until I realised that itâs hobbled to only work with Zwift.
Since all itâs doing is essentially applying a differential to the grade-based resistance, there doesnât really seem to be any practical reasoning to this - merely âwalled-gardenismâ. And I can see patent issues blocking the entry of anyone who wants to do something similar but with a more open approach that would work with any sim programme. Which is extremely frustrating.
I might be wrong but I think it would work with TR or another programme without the Zwift shifters, its the same as I think sticking the bike in one cog and controlling the resistance with the keyboard or ERG or any other program that controls resistance. Although I do prefer to do it the other way round, set resistance to one value or let ERG/another programme smartly adjust it and change gear around them.
Yep - TR would be fine, but the limitation is on other sim platforms - no Rouvy, Fulgaz, RGT, MyWhoosh, etc., unless youâre happy being stuck on a single-speed.
I canât see patent issues. All the program needs to do is apply some sort of gear-related multiplier to the resistance setting, before sending it to the trainer. Then obviously they need to implement a form of virtual shifting, which then changes the multiplier value.
For example, if you ride up a 5% hill in zwift, zwifts tells the trainer to set a resistance that simulates that. But if you shift to a lighter gear, the resistance is something 0.x times the 5% resistance.
(In reality, outdoor resistance also dependa on speed, so shifting to a lighter gear and slowing down will both have an impact on the power you need to produce. But considering how bad zwift physics are in other aspects, I wouldnât bet on them implementing that.)
Well, there are patents on both the cog attachment(!) and the virtual shifting implementation itself:
I donât have the time, inclination, or patent expertise to dig in to how much that might limit others from coming up with their own, more open, solutions, though.
Someone gave me a free Zwifthub recently. I started to use TR for interval training so I never shift, ever. The cassette on the hub doesnât match my bike, but it doesnât really matter since I donât shift. The only issue is, the cassette is quite noisy when pedaling. Iâm wondering if getting the upgrade kit for my Hub would be a good idea here. Or is it not since I donât ever shift?
In terms of noise, you will most likely appreciate the upgrade (based off initial reviews). In terms of trainer performance, you likely wonât notice any difference.
Been digesting this release and several tangential thoughts came to mind:
I am amazed I havenât seen wide cries for getting shifting info displayed in Zwift for the existing smart bikes. Likely I just missed the places these show up, but I expect getting this info displayed in Zwift for Wahoo, Tacx, Stages and Wattbike would be welcomed by those users. One case of the new Wahoo Kickr Shift Bike in particular since it ditched the on-bike indicators on the regular Kickr Bike. I know some of the other bikes have on board or app based indicators, but see the on-screen option as likely a preferred choice if/when Zwift decides to open that up.
With the new Cog option, I am curious to see the actual width of that cog installed. I wonder if that width is a possible restriction for some 12 speed or even 13 speed chain options? Specifically the cog width against the chain inner width between the narrow plates. They probably have clearance, but it could be an issue in addition to the roller diameter problem with stuff like the SRAM Flat Top chains.
I was initially confused about why Zwift chose to setup the Click operation as they did:
The fact that it pairs with the Zwift app, which then relays to the trainer seemed like an extra step = Click device > Zwift app > Hub trainer
I thought a more direct Click to Hub would be more straight forward, but now think there are good reasons for the actual setup they chose.
First and foremost, connection with the Zwift app in the middle allows the Play controller to be used for shifting which is a great function from what I have seen. That alone may be the only reason since it opens that door within the Zwift ecosystem at least.
But the Zwift in the middle also at least makes it possible for the Click and/or Play to eventually be paired to non-Zwift trainers. They donât do this now, but it is an apparent possibility from what Iâve seen. Adding that to other trainers could lead to more device sales (Cog+Click or Play) for Zwift to expand revenue on that side.
