Lightweight bike-transporter bag

Edit: Realised that this might be in the wrong category. Thankful for directions if this is the case!

Hi I'm posting here to see if I'm trying to invent something that allready exists and to have som helpful criticism of my idea.

Basically I want bring my Bianchi pista with me on the commuter train and the subway. For this i need a bag that lives up to the following criterias:

1. Lightweight
   
2. Foldable
   
   

I don't really have any need of padding as there will be rough handling and it's more a way for me avoid the hassle from the MTR. Also the bag itself will only need to carried on the train and of the, so there is little use for good handles and suchlike

After having looked around and realising that the Cinelli bag seems to be discontinued, I have decided to buy some rip-stop nylon ( as per from here per example http://www.profabrics.co.uk/products/crisp-pu-coated-nylon-ripstop?variant=6809886467) and then adding straps to get a kind of big tote-bag(http://www.profabrics.co.uk/collections/nylon-webbing-outdoor-camping/products/traditional-weave-webbing-50mm?variant=5940930883)
. My plan is for them to loop around under the base of the bag to releave some of the weight from the ripstop fabric. To close it all up I intend to use self-adhesive velcro (http://www.profabrics.co.uk/collections/self-adhesive-velcro-outdoor-camping ) .

So the real question(s) is:

1. Does this bag already exist?
   
2. Are there any obvious faults in my?
   
   

Any input appreciated!

BO gear

or for something more basic there's duff bag but their website looks a bit dead.

Ground Effect do something too but it's somewhat longer as you leave the back wheel on.

I think there are quite a lot of other options out there too although I've thought of doing something similar to yourself to make something for flying-touring-flying without having to return to original airport.

Thanks for the input mustard.

I think that none of the bags are really what I'm looking for even though the Ground Effect-one does come close.
I'll go ahead an order material (as well as some extra fabric for a one-person tarp) and if I'm not shamed by my lack of sowing skills I'll post pictures and measurements in here.

TBC

Subbed, I'm looking for something similar...

I actually recently spoke to alpkit about something along these lines. Might be worth dropping them a call (I will be at payday) as they'd offered to do a custom one.

Here's the drawing I sent them.

1 Attachment

I really like the straps and zipper. If I had the patience I would try to add eyelets and go for a lace up solution, that would be quite easy to do and would be repairable. I'm also looking for some kind of saddle fastening furing the actual ride.
If you do get one come payday, please let me know how you liked it and weight, cost etc.

Yes, the plan would be to use the straps to integrate it either onto a saddle bag/carradice loops or to use it on top or instead of the normal bar bag roll. The original brief was for the straps to be the same width apart and thickness as those used on the airlok bar bags already for easy transportability.

I'll let you know how I get one come payday/if I end up getting one.

How about one of these: http://www.ebay.com/itm/RockBros-MTB-Road-Bike-Transport-Carrier-Bag-Folding-Bicycle-Carry-Bag/201393382820?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3D88c0b97fbdf44a93a4405159a9f75c3c%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D172132479065 you can probably add some straps to make it easier to roll up.

Seems to be what I'm looking for! The weight of 1,5 kilos might be beaten by silnylon but can one be bothered with making ones own and that price is any idea to try to compete?