A few months ago I wrote here (now updated) that I was disappointed that the Ioniq 6 promised to be such a great long-range road car, yet lacked a spare tire - something experience has shown me is crucial for road trips:
www.ioniqforum.com
The car seemed so good otherwise that I went to a dealer to take some measurements. I came away thinking I might just be able to squeeze a spare in there. It took some research and a bit of fabrication, but I made it work. I ended up with what I think is a used 2019-2021 Genesis G70 compact spare with a T135/80R18 tire:
These wheel/tire/tool combos are used on several Hyundai/Genesis/Kia models. They only seem to differ in tire size (and brand, Kumho or Hankook) and lug bolt holes (to accommodate conical or shank-type lug nuts). I think there are also some 19" versions, but I stuck with 18s. They all have the same 7 mm offset (seemingly very different from the original wheels, but not - because offset is partially dependent on rim width) and 67.1 mm center bore. The 6 uses conical lug nuts so I limited my search on eBay to those only. (It's never included in the descriptions, you have to look for it in the photos.) Also, the winch hook from the Genesis is shorter than what comes with the Ioniq 6 - so keep the one that came with the car.
It's worth mentioning here that Modern Spare makes a kit for the Ioniq 5. It's more expensive than what I ended up paying (also note their shipping costs), but they have nothing listed for the 6. [EDIT: They do now.] The photo of their jack suggests it might be a better fit than the one Hyundai uses. All of the Hyundai/Genesis/Kia jacks have a deep slot in the saddle, which means the saddle will interfere with what appears to be a mounting flange for the battery pack at the rear (the aluminum plate just behind the jack point, first photo, no issue at the front, second photo):
I fixed that by making an adapter for the saddle that would fit in the slot, with much shallower rails to hold it in alignment with the jack points (the gap between the rails is big to accommodate drain channels visible behind the jack points - front and rear channels are different depths). The part that goes in the slot is slightly deeper than the slot so weight is applied to the jack where it's supposed to be - at the bottom of the slot, not the top of the saddle:
Everything works. I tried the tire on the car before getting into anything else. The overall diameter is a bit smaller than the stock wheels (the revs/mile figures I found for the spare might be wrong), but the car still drives just fine. No warnings, brakes/ABS work fine, no traction control issues. And everything clears the brakes and other components. Some will worry there will be internal wear in the differential from different diameters on the same axle, but the loads are so small it should be inconsequential.
And the best news is that it fits in the trunk with just enough room for luggage (even with the optional trunk liner). Note that the bags shown here are a bit on the large size for their type, but they still fit. Any tire larger than the 135/80 I used will reduce the space for luggage. As you can see, there is still space left over for a soft satchel, backpack, computer bag, etc.:
We CAN travel with luggage AND a spare, without having any of it on display in the passenger compartment!

Disappointed - Ioniq 6 not the great road-trip car I...
EDIT See new post showing how a spare can fit in the Ioniq 6 and still leave room for road-trip luggaget: https://www.ioniqforum.com/threads/spare-tire-for-ioniq-6.46626/ Road trips, here I come! End Edit I was fairly stoked about getting an Ioniq 6 RWD until I realized something today. The...
The car seemed so good otherwise that I went to a dealer to take some measurements. I came away thinking I might just be able to squeeze a spare in there. It took some research and a bit of fabrication, but I made it work. I ended up with what I think is a used 2019-2021 Genesis G70 compact spare with a T135/80R18 tire:
These wheel/tire/tool combos are used on several Hyundai/Genesis/Kia models. They only seem to differ in tire size (and brand, Kumho or Hankook) and lug bolt holes (to accommodate conical or shank-type lug nuts). I think there are also some 19" versions, but I stuck with 18s. They all have the same 7 mm offset (seemingly very different from the original wheels, but not - because offset is partially dependent on rim width) and 67.1 mm center bore. The 6 uses conical lug nuts so I limited my search on eBay to those only. (It's never included in the descriptions, you have to look for it in the photos.) Also, the winch hook from the Genesis is shorter than what comes with the Ioniq 6 - so keep the one that came with the car.
It's worth mentioning here that Modern Spare makes a kit for the Ioniq 5. It's more expensive than what I ended up paying (also note their shipping costs), but they have nothing listed for the 6. [EDIT: They do now.] The photo of their jack suggests it might be a better fit than the one Hyundai uses. All of the Hyundai/Genesis/Kia jacks have a deep slot in the saddle, which means the saddle will interfere with what appears to be a mounting flange for the battery pack at the rear (the aluminum plate just behind the jack point, first photo, no issue at the front, second photo):
I fixed that by making an adapter for the saddle that would fit in the slot, with much shallower rails to hold it in alignment with the jack points (the gap between the rails is big to accommodate drain channels visible behind the jack points - front and rear channels are different depths). The part that goes in the slot is slightly deeper than the slot so weight is applied to the jack where it's supposed to be - at the bottom of the slot, not the top of the saddle:
Everything works. I tried the tire on the car before getting into anything else. The overall diameter is a bit smaller than the stock wheels (the revs/mile figures I found for the spare might be wrong), but the car still drives just fine. No warnings, brakes/ABS work fine, no traction control issues. And everything clears the brakes and other components. Some will worry there will be internal wear in the differential from different diameters on the same axle, but the loads are so small it should be inconsequential.
And the best news is that it fits in the trunk with just enough room for luggage (even with the optional trunk liner). Note that the bags shown here are a bit on the large size for their type, but they still fit. Any tire larger than the 135/80 I used will reduce the space for luggage. As you can see, there is still space left over for a soft satchel, backpack, computer bag, etc.:
We CAN travel with luggage AND a spare, without having any of it on display in the passenger compartment!