Bionic Blog

Monday, July 11, 2005

Quinny Stroller

This is a description of a custom Quinny stroller. Basically, a Quinny "Freestyle 4" stroller has been adapted so that two seats can be fitted. An adapter frame was built without modifiying the original stroller chasis. The standard disclaimer applies -- I am not responsible for any damages or injury this modification may cause. If you are unsure of what you are doing, especially since it involves small children, stop and go buy a Quinny "Freestyle 4XL Plus" with and extra seat instead.

We wanted a tandem stroller -- the common side-by-side configuration did not appeal to us. There was a cool story, "Quinny Freestyle 3 and 4 in Wal-Mart Fire Sale", on Daddy Types, and there was a discussion about adding an extra seat to the Quinny. It turns out that the extra seat, only available for the "Freestyle 4XL Plus", will not work with "Freestyle 4" sold at Walmart.

After analyzing Quinny pictures on Babycare, I decided that I could build an adapter frame for the stroller. I bought two Quinny "Freestyle 4" strollers from Walmart for half the price of a new "Freestyle 4XL Plus" with an extra seat. I wanted to be able to reverse any changes I made to the stroller so that I could return the strollers to Walmart if things didn't work out.

The second prototype, shown in the pictures, was constructed using 1 x 2" boards, 5/16" rod, 1/4-20 x 1/2 machine screws and large zip ties. The hardest part of this project was drilling straight holes -- for which a drill press comes in handy. The adapter frame is constructed by inserting the rods into the boards. The rods are locked into place using machine screws. The adapter frame is attached to the stroller chasis using large zip ties. The seats can then be attached to adapter frame using the regular seat latches.

I found that the stoller is more manuverable with the center-of-mass shifted toward the rear tires. Our older child (36 pounds) sits in the front seat and our younger child (25 pounds) sits in the back seat. Basically I shifted the adapter frame as far back as I could without kicking the footrest from the rear-facing seat. But, with the rear wheels loaded, I noticed a "tick-tick" noise coming from the rear of the stroller.

At first I thought it might be the springs from the suspension, but it turns out that the spokes on the wheels were loose. After a trip to the local bike shop the problem was fixed. The stroller has a tendency to tip backward with only one child in the rear seat. To fix this we always have our older child buckled into the front seat while buckling/unbuckling our younger child in the back seat.

My wife and I have been using the stroller for a few weeks now and we really like it. The children are comfortable in their seats. The tires and suspension offer a smooth ride and I can steer with one hand if needed. The unit still folds up normally and fits in the trunk of a Camry (including the seats).