Sew a Waterproof Bike Seat Cover in Minutes!

In my last blog post, I showed you how to draft a custom bike seat cover template so it fits perfectly. Today, we’re turning that template into a finished, waterproof bike seat cover you can use.

I’ll walk you through the entire sewing process, complete with step-by-step photos and helpful tips along the way. This is a quick sewing project – no padding or lining, just a snug, waterproof cover that protects your seat (and your clothes!) from the elements.

What You’ll Need to Sew Your Waterproof Bike Seat Cover

Before we jump into sewing, let’s gather a few essentials. This is a nice, quick project, and you don’t need loads of fancy tools – just a few basics you probably already have in your sewing kit.

Here’s what you’ll need:

• Waterproof fabric: Use anything water-resistant, like ripstop, oilcloth, PUL, or even a recycled raincoat if you fancy a sustainable option.

• Bike Seat Cover Template: You’ll need the pattern you drafted in Part 1 of this tutorial. It ensures a snug fit, so don’t skip this step!

• Elastic: To help the cover stay firmly in place. I used a 7 mm elastic, but anything between 5–10 mm should work fine. Just make sure it fits through the tunnel you’ll sew.

• Thread: Polyester thread works best for this project because it handles outdoor wear better than cotton. Go for a matching or contrasting colour, depending on the look you’re after.

• Fabric scissors: For cutting your waterproof fabric. A rotary cutter is also a great option if you have one.

• Sewing machine needle: Depending on your fabric thickness, I recommend a microtex or universal needle, size 80/12 or 90/14. Ensure it’s sharp so it glides smoothly through the waterproof fabric.

• Quilting clips: Waterproof fabric doesn’t like pins (they leave holes), so clips are a must!

• Safety pin or bodkin: You’ll need this to thread the elastic through the tunnel.

That’s it! With these supplies ready, you can sew your own fitted waterproof saddle cover.

How to Stitch Your Own Fitted Bike Saddle Cover

Now it’s time to bring your waterproof bike seat cover to life! This part is really satisfying – you get to see your project come together stitch by stitch. I’ve broken it down into simple steps so you can follow along easily, even if you’re not super confident with sewing. I’ll also include step-by-step photos to guide you through the whole process. So, grab your fabric and let’s get sewing!

Step 1: Cut Out Your Fabric

Use your custom template to cut out the main panel and gusset from your waterproof fabric. Make sure the fabric is facing the right direction, especially if it has a print. Don’t forget to mark the centre points — they’ll come in handy later!

Step 2: Prep the Gusset

Take your gusset piece and fold it in half, with the right sides of the fabric facing each other. Align the short edges and clip them together. Then, head over to your sewing machine and sew along that short edge using your usual seam allowance. This will turn your gusset into a continuous loop that wraps around the bike seat.

Once you’ve sewn the gusset into a loop, open the seam allowance and press it flat. If your fabric doesn’t like the heat (some waterproof materials can’t be ironed), use a bit of fabric glue or topstitch along each side of the seam to keep it nice and flat.

Step 3: Create the Tunnel for the Elastic

Now, it’s time to create the tunnel for the elastic. Depending on your pattern, you might need to fold the bottom edge once or twice. In this tutorial, I’m folding it twice. To ensure my fold is even, I like to draw a guideline on the wrong side of the fabric, marking where I need to make the first fold. This guideline should be twice the distance of your intended fold. For example, if you’re folding the edge by 1 cm (3/8″), draw a line 2 cm (3/4″) away from the edge. This helps keep everything nice, even as you fold your fabric.

Once you’ve marked your guideline, fold the bottom edge towards the line and press it flat if possible. Then, fold it again, enclosing the raw edge and creating the tunnel for the elastic.

Take your gusset to the sewing machine and stitch close to the first folded edge to secure the tunnel in place. Make sure you’re sewing evenly all the way around.

But don’t forget to leave a small gap, about 2 cm (3/4″), so later you can feed your elastic through.

Step 4: Attach the Main Panel to the Gusset

Take your main panel and start lining it up with the gusset, right sides together. Use the midpoints you marked earlier to help with alignment. Start by matching the centre front and centre back, then work your way around.

The fabric may need a bit of easing as you go, especially around the curves, so take your time and use plenty of clips to keep everything in place before sewing.

Once everything is clipped and aligned, take your project to the sewing machine and sew all the way around the edge.

TIP: I like to reduce my stitch length slightly when sewing curves. This helps create a smoother, more flexible seam that hugs the shape of the bike seat better.

Go slowly, especially around the tighter curves, and make sure the raw edges stay lined up as you sew.

Optional: You can grab a pair of pinking shears and trim down the seam allowance. This helps reduce bulk and gives the seam more flexibility, especially around the curves. It’s a small step, but it can make your finished bike seat cover sit a little nicer.

Step 5: Thread the Elastic Through the Tunnel

It’s time to add the elastic. Attach a safety pin to one end to help guide it through the tunnel you created earlier. Take your time and gently work it all the way around.

I like to leave my elastic a bit longer and only trim it down once I’ve tried the cover on the seat, and I’m happy with the fit.

If you’ve already cut your elastic to size, attach a second safety pin to the other end – that way, it won’t disappear into the tunnel while you’re feeding it through.

Once the elastic comes out the other end, pop the cover onto your bike seat and check the fit. Adjust the length of the elastic until it feels just right—not too loose and not overly tight.
I like to hold the ends together with a safety pin first to test the fit.

Once you’re happy, tie a secure knot, then trim off any excess elastic.

Finally, close up the opening where you fed the elastic through. I like to move the knot down into the tunnel to make it easier to topstitch and secure the opening neatly. Once that’s done, simply topstitch along the edge of the tunnel, making sure to catch the fabric and seal the opening.

This will keep the elastic in place and give the cover a nice, polished finish.

And that’s it! Your custom waterproof bike seat cover is now finished. All that’s left to do is pop it onto your bike saddle and take it for a test ride. Enjoy your newly protected seat, and feel good knowing you’ve made something practical and unique for your bike.

Follow Along with My YouTube Tutorial

If you’d prefer to see the whole process in action, I’ve created a detailed YouTube tutorial that walks you through each step of making your custom waterproof bike seat cover. I share my favourite tips and show you exactly how I sew everything together so you can follow along at your own pace.

Check it out and let me know what you think – I’d love to hear how it goes!

I’d love to see your finished bike seat covers! Whether you’ve gone bold with a pop of colour or kept it simple and practical, don’t forget to share your make in the Allsewpetite – Makers Group on Facebook or tag me on social media @allsewpetite so I can cheer you on.

Don’t forget to join my newsletter for more sewing tips, tricks, and inspiration. Plus, you’ll receive an exclusive free sewing pattern when you sign up! Or, if you’re looking for more projects, pop over to my shop and browse some amazing sewing patterns.

And, of course, if you have any questions, feel free to leave them in the comments below. I’m always happy to help!

Stay crafty!