My new frame has some fastenings under the top tube, which are spaced the same as a bottle cage. I want to use them to affix a small bag to store an innertube and c02 cartridges etc. Does anyone know of a suitable bag? I dont want to use a cage and bottle caddy, just a small directly attached bag/case.

I know Revelate do their top tube bag for bolt mountings https://backcountry.scot/product/revelate-designs-mag-tank-bolt-on/ but I’m not sure it’d work upside down.

I’ve not seen mini-frame bags that bolt on only full frame bags, in fact my fat bike has one, but that doesn’t mean they don’t exist. Check out something like bikepacking.com – they do lots of reviews of kit including group reviews of particular types of things like frame bags so there might be something there. Alternatively contact someone like Alpkit or Restrap and ask if you can have a bespoke one made.

The Monkii Wedge is a QR framebag that fits on bottle bosses
https://www.cyclemiles.co.uk/shop/cycle-products/monkii-v-wedge-frame-bag-tool-roll/#.XSbrKf_TWfA

What you could do is find a bag that you like and hack it. Find some plastic with a good combination of stiffness and toughness (washing liquid/fabric softener bottles are ideal) and cut out a lolly-stick shaped plate that’s enough to cover the bolt holes and provide a little lateral support. Measure the holes, drill it, and use it as a template to drill the bag. Then fit it to the inside of the bag, put some decent-diameter washers on the outside, add some glue to the surfaces of both to keep them in place and prevent fraying, bolt them together with some nuts and leave overnight. Then take the nuts off and bolt into the frame.

Means you get free choice of bags, and the conversion costs nothing—unless you normally never wash your clothes, of course.

You don’t even have to restrict yourself to bike bags 😉

https://www.instagram.com/p/BzIOVMyFc7D/

What you need is one of these….

https://www.76projects.com/shop?category=On%20Bike%20Storage

That piggy pouch looks about perfect for what I want, bit spendy for what it is but I guess that is the price of low volume products. Wolftooth do something similar, but just with a drybag, I think the zip pouch is better.

That piggy pouch looks about perfect for what I want, bit spendy for what it is but I guess that is the price of low volume products. Wolftooth do something similar, but just with a drybag, I think the zip pouch is better.

I think its not too bad if you buy it with the dry bag. Heres a link to review I wrote on them.

76Projects On Bike Storage

If you sign up to the website (its free) you can get discounts on these and other products from the website sponsors.

What you could do is find a bag that you like and hack it. Find some plastic with a good combination of stiffness and toughness (washing liquid/fabric softener bottles are ideal) and cut out a lolly-stick shaped plate that’s enough to cover the bolt holes and provide a little lateral support

Does it work very well? Was thinking a really small bag would be useful for the Brompton front carrier sometimes – a bag big enough for key, glasses case, and a few bits a pieces that are toobig or would be more comfortable out of pockets. Smallest ‘genuine’ bag i can find is the small O bag but it’s still £100 new.

But nearly £20 for a clip from eBay, probably at least £20 for a small bag – it’s a fair bit to spend to find it just tears itself off the bracket the first time you use it…..

https://www.wolftoothcomponents.com/products/pump-bag

I’ve got one of these, been quite impressed. It sat under my downtube on a fairly long off road ride and kept the crap out nicely.

Does it work very well?

Dunno, not tried it, but I’ve hacked a couple of bags with vaguely similar approaches. As long as you give it some structure that prevents it falling apart at the holes, without inducing a failure elsewhere (eg by using something overly stiff with sharp corners), why not?

You could use these and strap a small dry bag to it…
http://www.bikemonger.co.uk/problem-solvers-bow-tie-strap-anchors-15432-p.asp