My wife and I just had twins about 10 days ago. In the lead up to the birth, we tried to cover every base we could as time was going to be in short supply. The car seats we purchased were Peg Perego, and we purchased a "universal" stroller to attach the car seats to.
The Baby Trend Universal Double Snap-N-Go is billed as universal. It is far from it. We found on leaving the hospital that all that secured the car seats to the stroller was a strap allowing them to rock about 3" front to back. That didn't instill confidence, and the car seat specific stroller runs another $700, so I started searching for a solution.
The solution takes about 30 minutes and cost about $20. I can't understand why there are not specific aftermarket kits for each brand sold by Baby Trend, but for whatever reason there aren't.
I am short on sleep and time, so I will try to describe what I did and what you will need.
Step 1: Gather Materials
For this Instructable, you will need:
1. Baby Trend Universal Double Snap-N-Go stroller
2. At least one of the car seats you will be using
3. (2) 3/8" solid aluminum rods 48" in length (Available at Home Depot $7.71 ea)
4. Pop Rivets
5. (2) 10-32 x 2" machine screws, washers, and stop nuts
1. Hacksaw or Metal cutting Saw
2. Vice (for bending aluminum)
3. Drill with 1/4" bit and 1/8" (or same diameter as the rivets you are using)
4. Pop Rivet gun
5. Grinding wheel or bench sander or file
Step 2: Measure for Your Seats, Cut the Rods in Half, and Bend
Next you will need to measure for your specific car seat. For the Peg Perego, I started with the rear seat because it naturally laid fairly well. I measured form the bottom of the latch hole to the center of the bar. Make sure you label each piece you measure. Trying to figure out what you were thinking on three hours sleep is difficult to say the least.
Cut the rods in half, but not to size. Bend everything at 90 degrees before making your final cuts. It will make everything easier. The distance between the rails is 14" as I measured it. After your first bend, you can see just how much space is taken up in the bend. A little wide or narrow is fine, as the seats have quite a bit of clearance on each side.
Step 3: Trim the Length of Each Rod, and Round the Edges
Next you will need to trim the rods to length. It is best to start with the longest bend you have in case you make a mistake. You'd think it would be two sets of the same sizes, but it isn't.
When you think you have the size use a file or grinder or bench sander to round the edges and flatten the sides.
Step 4: Drill the First Set of Holes and Attach
For the rear seat, I drilled out the large rivet that acted as a pivot for the handle (see on the top left of this picture). Using a 1/4" bit, drill out the end of the rivet and slide it out. Next, drill the holes for each side of the rod, and attach with the screws, washers, and stop nuts.
Do this before cutting any of the other rods to length to make sure everything sits the way you want in case you want to lengthen or shorten the rods to get the fit right. Set the seat in place and double check your measurements.
Step 5: Drill the Remaining Holes and Attach With Rivets
For all of the remaining holes, you will need to use the 1/8" bit and pop rivets. I made everything line up vertically, I may at a future date make the rods lay at more of an angle to keep the seat from rocking at all.
After your first seat is installed, proceed with the first rod of the front seat, then recheck, and install the final rod. I used rivets with a 1/2" grab to fit well in the narrowed rods I had. With everything tight, test fit each seat. It should not securely click into place. It will make you feel a great deal more confident when you have to go to the store.