Hi, this is Pam and Gilbert from 2 Bikes 4 Adventure.
While i use my Brompton C-Bag on our touring adventures, Gilbert prefers his do-it-yourself bags.
In this video, we will discuss various ways to hack your own low-cost touring bags.
Until recently, very few waterproof bags were specifically designed for the Brompton front
carrier block. Those that existed like the Carradry City Folder or the Ortlieb O-Bag
were expensive, too small for touring or not easily available.
Brompton introduced a larger waterproof bag in 2020, the 25 liter Borough, but it's a costly choice.
Through the years, we came up with do-it-yourself alternatives that address the shortage of
affordable waterproof touring bags. Our primary design criteria were low cost,
$100 or less, fit on the Brompton front carrier block and waterproof without needing a rain cover.
We will rate each solution based on the following factors: no or minimal tools to assemble,
secure mounting, sufficient storage capacity and ease of use.
We start with a frame that attaches to the Brompton front carrier block. The block dimensions
haven't changed in decades. The corresponding carrier frame has however seen some transformation.
Its initial design was a robust all-metal version which was redesigned to a lighter riveted plastic
metal composite style. The latest version in 2020 eliminated the handle to permit better
compatibility with all handlebar types. Needless to say no high-end touring bike rack would be
made of riveted plastic, so we suspect that cost saving was the motivation for this evolution.
On the other hand, this rack should only be used to carry 10 kilograms
on relatively good roads, so we haven't been worried nor have we experienced any failures.
All our DIY solutions are built around the standard 30 by 40 centimeter frame dimension.
This 13 millimeter tube structure was previously found in C and T-Bags
and is still available in stores and online.
Note that other non-standard configurations are available for third-party bags and may be more
appropriate for your particular DIY project. We have found options in the 20 to 35 dollar range.
For a handleless version of the frame, bear in mind that any bag you attach
will need a strap or handle of its own in order to carry it separately from the bike.
Before we ever cycled on Brompton's we were using Ortlieb front roller bags, a gold standard among
bicycle tours around the world. The rolltop design offers excellent protection against dust and rain
while still permitting a certain level of volume adjustment depending on the load carried.
We will favor this type of closing mechanism when designing our DIY
solutions.
We didn't want to cut, drill or modify the existing rack
and wanted as much as possible to keep the original waterproof bag intact.
The only tool required for our modification should be a Swiss Army Knife or a Leatherman.
The mounting mechanism between the rack and the bag should remain
secure throughout any vibration while in motion.
The solution should have a capacity of at least 20 liters and if possible be expandable when needed.
Finally, it should be easy to access the contents while the bag is mounted on the bike.
As we already own Ortlieb Front Rollers, we wanted to see if we could simply mount them on the
Brompton carrier frame. Unfortunately, there are two complications: first, the mounting rail is not wide
enough to clear the top handle assembly a minimum of 16 centimeters clearance would be required
also the support hooks location is too high to fit on the baggage frame.
To mount securely we would either need to cut the bottom frame bracket
which could compromise the support block locking mechanism or relocate the bag support rail lower
to reach the 27.4 centimeter maximum clearance (10 3/4 inch) or ultimately build a
custom frame to fit the Ortlieb, such a solution can be seen here on Susanna Thornton's channel.
As we do not want to alter the bag nor the luggage frame,
an easier solution could be to mount the bag horizontally, the waterproofness would not be
compromised in this position as its IPX4 rating protects against flashes from any direction.
Although meeting the no tool and secure mounting requirements,
the 12 liter capacity of one horizontal Front Roller bag is too restrictive for our travel
needs. A larger 20 liter Ortlieb Back Roller could probably work, but we haven't tried it.
In both cases however, the contents would be secure but not easily accessible on the bike.
Cyclists are not the only outdoor enthusiasts interested in waterproof bags. After a visit to
a local outdoor gear retailer, Gilbert found this 32 liter waterproof backpack for $35. Designed for
water sport activities, it even includes an inflatable baffle to ensure the bag would
float if accidentally dropped in water. Although a nice feature if we ever plan to "packraft" with
our Brompton, the real question was can it be attached securely to the Brompton carrier frame.
Two nylon webbing straps with quick release buckles did the trick, however the lack of
internal stiffening structure inside the bag made it droop down around the frame bottom bracket.
To solve this issue, we added a dollar store gardening knee pad cut to fit
as bottom support, it could also be used as a butt pad during picnic breaks.
To complete the assembly, a backpack bottle pouch was added to the back.
Gilbert successfully used this solution during our month-long trip to japan in 2014.
This solution required no tools, was relatively easy to mount and had plenty of available extra
capacity. In addition, the existing backpack straps made it a breeze to carry around the airport or
when commuting. One problem remained, it was awkward to access the bag contents via the side opening.
We really needed a solution with the top opening.
When Gilbert looked at waterproof messenger bags, the Ortlieb XPress caught his attention.
Originally produced in three sizes 15, 25, and 35 liters, they had been discontinued by
Ortlieb a few years, back but remained available on the second hand market.
The medium-sized bag, in addition to having the required volume, also had an aspect ratio that
closely matched the Brompton carrier frame. We were able to require this bag for $30US.
The bag is meant to be worn over the shoulder, so it doesn't have any mounting hooks.
Attaching the bag to the frame was easy. First fold the two upper strap attach points over the frame
and secure them in position with reusable tie wraps,
then pass the closing straps around the side of the frame before closing the bag.
To further secure the bag to the frame Gilbert wrapped a large baggage strap around the
entire assembly. This strap also supports the rear water bottle pouch and spare front tire
via carabiners clipped to the two bag mounting tabs.
Note that we use the same strap to pack the Brompton for air travel in box, Dimpa or suitcase.
Gilbert has been using the solution for six years now.
It satisfies all the required criteria: no tools, secure mounting, 25 liters,
easy to use. It's ready to compete against the Borough Waterproof anytime.
As the number of Ortlieb XPress bags available on the second hand market dwindles,
an alternative solution could be the Ortlieb Office bag. Slightly smaller, at 21 liters,
it has a similar aspect ratio to the XPress while offering an even more robust construction.
Furthermore, it comes with a bicycle rack mounting system that can be easily adapted for the Brompton
carrier frame. The mounting rail is designed to be set at a plus or minus 15 degree angle,
depending if the bag is to be positioned on the right or left side of a rear bicycle rack.
In our case, we need to reposition the bracket horizontally 27.4 centimeters above the bottom
of the bag. We purchased our Office bag used, this version has a QL2 mounting system,
note that the latest Office bag has an updated system and its adaptation will differ.
We just needed to drill a few holes, this proved to be relatively easy as the rail mounting hardware
was made to be user serviceable. We covered the remaining holes with bicycle tube patch material.
Obviously, this option diverges from our premise of not modifying the bag or requiring tools.
The suggested alteration doesn't compromise the waterproofness of the bag and is easy to do and
it offers a high quality solution that can compete with Brompton branded bags costing three times as much.
Its drawback is that like the Borough Large Waterproof bag, it lacks the ability to adjust
the closing mechanism. In that respect, the previous solutions with adjustable straps
are superior. To design your own waterproof bag, you need to highlight the characteristics you wish you
would find in off the shelf bags: easily adjustable volume, ease of access content while cycling, ease
of transport while off the bike, external attach points, external pockets, internal pockets, maybe
you'd like to be able to switch your DIY solution between your Brompton and a non-folding bike.
The bag you want may not be available for purchase or may be too expensive.
On the other hand, maybe you already own the ideal solution and didn't know it. All you need is some
imagination to figure out how to secure it to your Brompton and start your own long distance
adventure