Anna demonstrates how, with a few tweaks and a steady hand with a sewing machine, it's possible to turn an Airlok XTra drybag into a lightweight saddlebag.
This technique was first developed by Nick who needed a saddlebag for the Welsh Ride Thing. Airlok Xtras were already being widely used as a handlebar bag, but to effectively attach one below the saddle was a trickier proposition. With a strategic cut and 5 minutes behind a sewing machine, Nick solved the problem and not only saved a few extra quid but, by keeping things simple, he also had the lightest bike at the weigh in!
We can't guarantee the saddlebag will be 100% water tight, and it might take you a couple of attempts before you are totally happy, but if you want to give it a go here is what you will need:
1 x 20l Airlok XTra
6 Durable nylon patches about 3 x 3cm
4 x plastic D-Ring
Step 1. Use a sheet of card to mark out the basic shape of the saddlebag.
Step 2. Turn the Airlok inside-out and lay it flat. Using the chalk, mark out the cut line under the seat. Be careful to avoid going directly through any of the hyperlon tabs on the Airlok. Don't worry if these tabs get cut off, it really just depends on the geometry of your frame.
Step 3. Sew along the lines, then cut along the seam leaving a 2 cm overlap of fabric.
Step 4. Apply seam sealant between the seam, then fold over your 2 cm overlap and sew again to strengthen the seam. Apply seam sealant again.
Step 5. Offer your reshaped Airlok up to your saddle, it should be a nice tidy fit. Mark the 3 points where your compression straps will attach. Their exact placement will depend on your set up. It is a good idea to stuff your Airlok to give a better idea of how it will sit. Avoid making your straps too long, otherwise you will not be able to pull the bag tight onto your seat.
Step 6. Strengthen the attachment points by glueing reinforcing patches on the inside of the Airlok. These can be made out of your offcuts, or heat adhesive patches if you have them.
Step 7. Cut the red strap which comes with your Airlok into 4 equal lengths and thread them through the d-rings. Seal the cut ends with a lighter to avoid fraying.
Step 8. Sew the straps onto the Airlok making sure to stitch into the reinforcing patches. You may want to apply seam sealant when you have finished to the inside of the stitch.
Step 9. Attach securely to your bike. Techniques include passing a strap through the saddle bars and under the Airlok passing through the hyperlon tab, cynching in the Airlok to hug the seat post with zip ties, webbing or string. Play around, trial and error will find the most stable option. Enjoy your ride!