People are always asking what I'm talking about when I tell them I'm going to make them a bag stiffener. I can't stand floppy bags tugging on my steering imputes and being all floppy and ill fitting and gross.
So I got to do one today for a friend's custom Waxwingco bag. So I took a few photos so you all can see how I make them, and make them yourself. Trust me, they will change your life. Even if you think you don't mind your ill fitting floppy bag, you will be so happy to see how much better it is and not be able to believe you lived without it.
I use some pretty thin one inch alloy strap from my local hardware store. It's $4 and plenty long enough for any bag I've ever done.
Above I've cut it to size and marked the centers for drilling and bending.
The first thing to do is measure the bag. I like to measure the back side of the bag first, then the side. Luke's bag was 24 cm across the back, and 14 cm on the side. I don't like the sides to go all the way to the ends so there is a little more room for over-stuffing. I like to mark the bends, so the first line is at 11 cm, then measure the 24 cm, mark a line, and then another one at 11 cm.
Pictured below is a rounded end. I like to round the ends, just because it's nice and it's less likely to cut or catch on your bag. I like to use the vice and a file. I know files can be awkward if you're not used to them, but I'm just so much faster with a file than a grinder. But, use what works for you.
Pictured below I'm drilling the holes for the mounting bolts. I determine where to mark these by holding the decaileur up to the center of the back at 12 cm for the decaleur center, and the imaginary center of the side pieces at 7 cm from the bend. Then i take the caliper and mark the center line of the strap so the drill holes are centered.
This is a stiffener, not a show piece so you don't have to worry about it being super precise. I like to drill the holes a little over size, usually with a 1/4" bit, just in case they are a little off. You can also use a small file to extend a hole if it's a few millimeters off.
I used my drill press because it's fun and easy and I have an X Y vice. You can do this with a hand drill clamped to the work bench just as easy.
Once all the holes are drilled out to 1/4 inch it's time to bend. I use my vice, but you can do this over the corner of a table or whatever. If you try to bend to thick a piece of alloy it will just snap, so stick to the thin stuff it's plenty stiff.
Pictured above you can see the bending line totally flat and square to the vice. Bending alloy is super easy and you don't need any special jigs. Just make sure it's clamped straight where you are bending it, or the alloy will take on a complex angle and fit poorly.
Flip it over and bend the other side too.
Hold the piece up to make sure it fits the way you like and the decaleur center hole lines up with the center of the bag. then it's time to put holes in the bag.
There are a few ways of doing this. Synthetic bags such as Swift Industries it's best to poke a hole with a hot soldering iron. This hot iron method will punch holes through the bag and melt the material around the holes to seal them up. With leather I use a leather punch or a drill. Honestly the drill works best, especially the sides where the pocket is in the way of getting the leather punch in there.
Above We're using the Nitto decaileur that we get from Cycles Grand Bois. It replaces the stem bolt. This decaileur seems to work pretty well, but your bag has to line up with your stem just right. We had Luke's bag custom made to fit his stem height just right! But the nice thing about this style bag stiffener is that it doesn't stiffen your bag vertically so you can stretch or let the bag sag a tinny bit and it still looks like it fits and sits on the rack correctly.
Nitto stems have a strange bevel on the back side. The more expensive stems come with a threaded triangular nut with the bevel built in, but the threads don't match with the decaleur. So you have to take a drill bit and drill them out a bit and add a nut. Some of the decaleur come with these bits already modified. I sell just the wedge and lock nut separately too if you need them.
It's all about the hardware! use nylock lock nuts! and make sure the threads poke through at least one full thread or they will come loose. If the threads poke out to much they may stab or scratch you stuff.
I once stuffed a six pack of cans in my bag only to find out that the bolts poked holes in a few of the cans and filled my bag with beer.
I typically use 12 mm m5 button heads on the sides and 16 mm m5 button heads on the back with large fender washers. Yes we sell all this, but most decaleur kits come with most of the hardware you will need. For some reason almost everything from Japan comes with regular nuts not nylock. I through them away and replace them with nylock! And, you should too!
Above, the bag side of the decaleur sits in the stem side. Below the bag side is slid out making the bag supper fast and easy to pull on and off the bike while being very stiff and stout while ridding. Seriously the most superior system!
And there you have a quick release bag, that's stiff and stable while ridding. It's the best off all worlds.