How to Build a "Big Wheel" Replacement Seat With PVC Pipe




Introduction: How to Build a "Big Wheel" Replacement Seat With PVC Pipe

Even modest riding by a 4-year-old can be enough to crack and tear away the pegs from the seat of a Big Wheels tricycle.  The manufacturer's replacement is $13 -- and just as likely to fail again!  So instead, for around $4-$5 (excluding cost of glue) I built a replacement out of PVC pipe.

Step 1: Parts and Assembly

The measurements below should be taken as rough guides.  Note that there are slight variations among manufacturers of PVC pipe and fittings, some may be more "loose" or "snug" than others, and/or fit more shallow/deep into the fittings, so you'll want to "dry fit" your pieces before gluing.

Materials List:
(1) 2' length of 1" Schedule 40 PVC
(2) 1" PVC Tees
(2) 1" PVC Ells
PVC Cement

Cut List:
(2) 4-1/2" horizontals
(2) 1-3/4" verticals
(2) 2-3/4" pegs

Optional:  A simple but very useful "jig":
a piece of scrap lumber cut to 4-3/4" width

Dry fit the lower portion (2 pegs, 2 tees, 1 horizontal) and confirm that the resulting dimension between the inner edges of the pegs is 4-3/4" (or that the center-to-center dimension is 6", a little harder to measure, but more accurate).  Insert the piece on the Big Wheel to confirm proper fit.  Mark the exposed pipe along the edge of fittings to serve as a stop-guide during glue-up, and confirm that your jig (if using one) produces proper spacing.

During glue-up, use your stop-guide marks and jig to prevent inserting the pipe too far into the fittings (the pipe often slides more easily and deeper into fitting once glue is applied).  Work quickly, PVC glue (cement) sets up almost instantly.  Have a flat surface upon which you can lay the piece during assembly to prevent "racking" (that is, to keep the Tees and pipe "flat").

Assemble the lower portion, then assemble the upper portion, verify that they line up properly, then assemble top to bottom with the vertical pipe sections.

Step 2: Optional Finishing

You'll likely want some type of cushion to cover the top bar of the seat, otherwise your rider is likely to develop a couple of nasty bruises along their lower back where they push against the exposed upper edges of the Ells.

(Note that original seat design also has a raised curved edge near the top that produces similar bruising, depending on how your child "fits" into it -- it's worth adding padding even to the original seat!)

Here's a couple ideas:

A foam "water noodle" (a type of water play toy) works well - cut it to length, then slice lengthwise, then wrap over top bar.  (You won't need to add cushioning to the verticals or lower bar as no contact is made with them when riding.)

Similarly, you may be able to find actual pipe insulation material,  serves same purpose.

Or use whatever other sort of "pillow" material as you might have on hand.  We had already crafted a pillow for the original seat that attached with elastic, and simply reused it here (upside-down).

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3 years ago

I used four 1" tees and two 1" ells (connected vertically with four 1.75" long pieces of 1" pushed tight so there were no gaps), three 4.5" pieces of 1" for the horizontals, then cut three 2.75" long pieces of 1.25" for sheaths over the 1" horizontal pieces (for a nice smooth overall effect), and two 2.75" pieces of 1" for the pegs. Finished by spray painting with a white paint that bonds to plastic, and foam pipe insulation for cushioning. I ended up wrapping some duct tape around the pegs to get a slightly tighter fit, but still easy enough to remove. PS I did not follow davbol's advice to work on a flat surface when gluing to prevent any "racking". I had to use a heat gun to get a slight bend in one of the horizontal pieces, which worked fine. PPS Needed more traction on the front plastic tire, so I glued a used bicycle tire (in pieces using 4200) to make it a true off-road toy - now has traction uphill and even on grass.

Big Wheel.jpgBig Wheel closeup.jpgBig Wheel off-road tire.jpg

4 years ago

High-five davebol if you're still on here. This worked great for a bike we've neglected for a year.