7-speed cassette on a Direct Drive trainer

Sounds good @Joel_Larner ! I really enjoyed reading all the responses because I still can’t see how a 7 speed frame is going to fit into a modem direct drive trainer that comes with an 11 speed cassette body. It just seems to me that your rear triangle is too narrow. Of course I am making the assumption that the cassette body is fixed and can not be replaced. AND the splines on the body need to match up with the 7 speed cogs. However there are others here who say they have done it so I’m sure it’s me that is totally missing something and I hope it all works out for you.

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@Bob_Gorman_TFC The Kickr’s say they are compatible with standard 130/135mm quick release skewers. The dropouts measure 130mm so I expect it will fit on there. The cassette comes off the freehub the same as a 9 or 11 speed does and the alignment grooves are the same pattern. So it’s a question of the dropouts fitting on the Kickr, can spacers take up the additional width of a 9-speed cassette, and with the spacers does the cassette end up in a position within the throw of the derailleur. If I decide to go this route I’ll post the results.

That should work then. My 1988 Bianchi 7 speed is 126mm and would be an issue. Plus back in the day we rode freehubs so I don’t even have cassette cogs for it. It sounds like your 7 speed is a lot more modern. Keep us posted!

130 mm is what current quick-release road bikes have as well. The rear end didn’t get any wider, only the freehub got a little wider but mainly the cog spacing just got tighter and tighter.

There is plenty of extra movement in the derailleur (hence the limit screws) so that shouldn’t be an issue, the only thing is that you may have to adjust cable tension and possibly the high and low limit screws as well if the cassette does not end up in the exact same place relative to the dropouts. (But the difference will probably be one millimeter or less, unless there is something very unusual about your setup.)

@Anna_Ronkainen yes I agree, theoretically the adjusting cable tension and limit screws should enable biasing the deraileur to whatever the center and limits of the cassette are. I’ve also seen situations like this that the cassette is beyond the reach limits of the deraileur as mounted. Hopefully this is pretty easy.

We shall see what happens. I ordered a Kickr Core (no-one has the Kickr v5) and picked up a 4.5mm spacer. Will post on this thread what I get for results.

It works ! I successfully mounted the 7-speed cassette on the new Wahoo Kickr Core and it works great. As the video previous referenced asserts, it required a 4.5mm spacer with notches ground out for the cassette rivets (see spacer and cassette pictures). I used a Dremel to grind down the notches and it was easy to align the notches in the right spot behind the cassette. I’ve also included a picture of the bike mounted on the Kickr Core.

Ultimately the Kickr Core rides sooooo much nicer than the Kickr Snap. Far smoother and most notable is easier. Given today’s training plan workout and how it felt vs previous workouts, I’d estimate I was consuming about 5% power in the friction and deflection of the tire on the Wheel-on trainer roller. That power is not measured or seen by the trainer or therefore Zwift because it is occuring outside the measureable system. It’s possible the spindown test tries to account for this, but I definately felt a difference. In the end, the change to Direct Drive, even with just a 7-speed bike is well worth it.

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Going back to this, I have a 9 gear 11/32 cassette on my bike, if I go for a Kickr Core, do I just need to buy a similar one and fit in the machine?

Thanks

You may need to install a small spacer (which comes with the Kickr Core) behind the cassette. The Core states it works with 9-speed cassettes. Having not installed a 9-speed I can’t speak for sure, but that’s what the literature says.

Oh ok I don’t need to buy an additional spacer then ? They all come with it?

I can’t say that for a fact since I have not mounted a 9-speed cassette. What I know is simply the Wahoo Kickr Core is spec’d to work with 8, 9, 10, and 11 speed cassettes and it comes with a spacer. I don’t know about other direct drive trainers and what they ship with.

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Thank you for this! It worked great for me with a very small investment!

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Excellent, glad it helped. These forums are a wonderful resource. Enjoy your Zwifting.

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Hi Joel,

I just got a Kickr Core and I’m trying to install with a 7 speed cassette.

I put a 4.5mm spacer on and then the matching cassette so it’s the same as my bike. However, my gears are rubbing a bit on the front derailleur, and the chain doesn’t reach the smallest cog of my 7 speed cassette. The other 6 can be reached, and it doesn’t fall off the top either.

Did you only add a 4.5mm spacer? or also the 1.8mm that came with it? and if so… all before the cassette?

I have 135mm QR drops.

Hope that makes some sense.

Any help is appreciated, thanks!

@NomadicVelo There is a sequence I went through to get this to fit. Here’s my suggestion to get the best shot at it fitting as well as possible. See the attached photo for what my setup looks like.

  1. Before doing any of this, ensure you have a good chain. Measure your chain for stretch. If it is old and stretched it will never align well and you will just burn time being frustrated. If it is stretched beyond 0.5 on a measuring guage, replace it now. This hold for when on your wheel as well. Just standard bike maintenance.

  2. Use the the shortest Kickr Core axle inserts provided. Your bike dropouts must slide onto the Core’s axle easily, just like sliding a wheel on. If you have to use force to spread your droupouts/rear triangle at all, the bike will not fit on there well as the rear derailleur will not span across the cassette because it is no longer in the correct location relative to your right dropout. I’ll assume your bike is dropping on there smoothly as mine did. Once you see it drops on smoothly, remove the bike to install the cassette.

  3. start with a 4.5mm spacer. Cut 2 notches in it about 1/2 to 1 mm deep exactly aligned with the 2 rivets on the inside of the 7-speed cassette. See the photo above in one of my previous posts. If you have a dremel or grinder, that is great as it will cut the notches in seconds. Else you can use a hand file, just take a little more time. When you think you have the notches cut to the right depth, hold it u to the inside of the cassette and confirm the 2 rivets align cleanly in the notches so the rest of the space sits flat against the inside of the cassette. This is critical. If you need to cut the notches a little too deep or wide to have plenty of margin, go for it. This is not structural or life critical, you can make those things big.

  4. Slide the 4.5mm spacer onto the Core’s splines. Align the 2 notches so they will perfectly fall under the cassette rivets and slide the cassette onto the hub splines. The spacer can rotate easily on there. As you slide the cassette onto the splines, ensure the rivets drop cleanly into the notches. When it all looks good, install the locking ring onto the Core’s hub.

  5. Spin the cassette/hub and ensure it is sitting flat on the hub. There should be zero wobble as it spins. If there is wobble, either your rivets are not aligned in the slots or the cassette is not tight on the hub.

  6. Grab the cassette and pull and push sideways to see if there is any play at all. Mine in initially felt tight so I finished the rest of the steps. I rode if to for a number of days and was very frustrated that it did not shift well and clicked all the time. I removed the bike and found after a little riding the cassette actually had a little play side to side. The cassette was sliding left and right a fraction of a mm on the hub under chain load. Thus I removed it all and added another 0.5 mm spacer. Your results may differ.

  7. Put your bike on. You will need to adjust your rear derailleur. The Kickr Core will not have the cassette exactly aligned where your rear wheel does. Just a reality of kludging a 7-speed cassette on there. The axle spacers are designed for 9 and above. So simply use the barrel adjuster on the derailleur to move your derailleur left or right as needed to align as well as you can. Your right dropout is now referenced to the right axled spacer that you put into the Core’s axle. It should align pretty well but will not be the same as your wheel. If you have to move it more than a few mm, you will likely also have to adjust the low and high limit screws on the derailleur to let it get to the lowest (largest) and highest (smallest) cog. They will go in opposite directions. Since you are saying you can’t get in to your smallest cog, you will likely need to loosen the high limit screw to let the derailleur go further to the right. If so, then tighten the low limit screw to move that end of the derailleur motion right also. If you don’t do this, you will drop the chain when shifting to the lowest gear. Remember, never adjust the limit screw when the chain is in the low or high gear you are adjusting. Shift a couple gears away from that cog, adjust, check it, and repeat. Play with it until you get it as good as possible.

  8. Shift through the range while pedalling and it should shift pretty well to all cogs. Optimize the adjustment in step 6 to run smoothly in the middle cogs. The smallest cogs may make noise, that’s the nature of this game.

  9. Once you have the chain running well on the cassette you may find it rubs on the front derailleur when in either the smallest or largest cog in back. If you had to do a good bit of movement in the adjustment of the rear derailleur, this is expected. That says your cassette is not in exactly the same place in reference to the dropouts as it is on the wheel. Thus you can expect the chain angle is different than where it was on the wheel and thus it enters the front derailleur at a different angle, Now adjust your front derailleur cable to get it as quiet as possible. Go through the same kind of steps as in #6. Especially with the low and high limit screws. Remember, it is not good to cross up the chain, meaning largest cog in back and largest chainring in front, or vice-verse. If it is only rubbing in one of those configs, leave it be, you are likely not going to get rid of that, and you shouldn’t be riding in those configurations on a 7-speed system.

Now you should be good. Give it a few rides then check if there is an side-to-side motion in the cassette on the hub like I had.

If you are still having problems, DM me and we can talk about the specifics of what you are seeing.

Good luck.

Hi all

Brand new to cycling so apologies for the dumb question.

I just bought a 7 speed road bike and wondering if I can pop it straight onto a Wahoo Kickr (which comes with 11 speed cassette).

Or do I need to buy a 7 speed cassette and a spacer as per the topic of this thread?

Cheers

You will need a 7 speed cassette as the derailleur/shifter pull ratio is specifically for that cassette. Good news is that 7 speed cassette should work on the Kickr freehub but I’m not 100% sure on the spacer required to avoid re-indexing. I think its ~ 6.35mm but a few cleverer folks that float around here likely know shite loads more than me and should be along shortly to provide wisdom.

@Paul_Southworth / @Tom_J

EDIT: Welcome to the forums @Navi

Another issue would be that the 7 speed chain is too wide for an 11 speed cassette and might get jammed.

Yep I bought a 7 speed cassette but now need the right tool to remove the existing 11 speed cassette that’s attached to the Wahoo Kickr.

The joys of being a newbie.

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Yes I tried putting it straight onto the 11 speed cassette and basically the chain “jumps” on the higher gears (4-6). Strangely enough it works well on gears 1-3 but I need more than 3 gears for an enjoyable Zwift experience!

Ahh, back to the drawing board.