unikid

If you have your heart set on getting IPS then you need to be ready to pay some money to get it. Here is why:

1. Most IPS systems use a right-side sync chain design. Your Dualie (like most tandems) has the sync chain setup on the left side. So at minimum you are going to have to convert your front crankset to a right-side drive before any IPS system will work.
2. Your Dualie (like most tandems) also has a triple crankset in the rear which requires a more complex/expensive solution than if you just had a single drive system. However if you are willing to give up the triple in the rear then you might be able to reduce your cost.

To set up your stoker for IPS with a single chainring crank, here is one option I found:

• TerraTrike Rover IPS Rear: https://www.bikepartners.net/crankse...ml?id=65194428

To set up your stoker for IPS with a triple chainring crank here are 2 options I found:

• TerraTrike Pro IPS: I cannot find anybody selling these. You might have to contact TerraTrike directly to see if they will sell you one. You can see good pictures of both TerraTrike IPS systems (Rover and Pro model) here: https://www.terratrike.com/product-c...trikes/tandem/
• Vision IPS: Bike Crank Set - Vision IPS Crankset

To set up the captain for IPS, here is one option I found (note: you don't need this unless you also want to be able to coast while the stoker continues pedaling):

• TerraTrike Rover IPS Front: https://www.bikepartners.net/crankse...ips-front.html

There are likely other options out there. I see that Bike Friday and a few other tandem bike makers also offer an IPS system. Just not sure if they sell theirs separately or how much they cost.

To get a taste of IPS another option you could take is to try to find somebody who owns or is selling a Greenline tandem. Or a Greenzone folding tandem.
Both of these tandems (no longer made) came with a basic IPS system (front and rear) already on it.
They apparently sold quite a few of these since I regularly see these pop up on Craigslist or Offerup. At least in my area (SoCal).
Note: these only have the single chainring in back, plus they don't appear to have as easily replaceable/customizable chainrings like the systems above appear to have.

Here are some links to the Greenline tandem plus one for sale near me and one for sale closer to you as an example:
x GreenLine Tandem 7 Spd Shimano Tourney Independent Pedaling Yellow (check out image 5 of 6 for a close up of the cranks)
https://inlandempire.craigslist.org/...399637983.html
https://www.facebook.com/marketplace/item/6259545984086604/?ref=search&referral_code=marketplace_search&referral_story_type=post

Here are some links to the Greenzone folding tandem:
(he shows the IPS system directly)
https://offerup.com/item/detail/225691961