Bicycle Waterproof Tail Bag 840D Nylon with Welded Seams
High-frequency welded 840D nylon that is sealed rather than water resistant
What It Is and Who It Is For
A seatpost-mounted tail bag in 840D nylon bonded to a TPU waterproof membrane over a PP interlayer. The seams are high-frequency welded rather than sewn and the opening uses a hemmed seal, which is what makes the bag fully waterproof. It measures 16.5 by 10.5 by 8.5 cm and weighs 135 grams, with a reflective logo on the tail.
Why Buyers Choose This Part
Welded instead of sewn
High-frequency welding fuses the fabric rather than stitching it, so there are no needle holes for water to track through. The hemmed seal at the opening finishes the job.
840D nylon on the outside
The heaviest denier in our bag range, which is the right choice for a bag that takes direct spray off the rear wheel.
Reflective tail logo
The logo on the back is reflective, which puts a bright mark exactly where a following driver looks.
Problems It Solves
- Sewn seams leak because every stitch is a hole
- Rear wheel spray hits a saddle bag harder than rain does
- Dark saddle bags hide the one part of the bike a driver sees first
Who It Is For
- Commuters who ride in all weather
- Bikepacking and audax riders carrying tools and a tube
- Brands building a waterproof luggage range
Application Scenarios
- Daily commuting in wet climates
- Long-distance and audax riding
- Carrying a tube, levers and a multitool
Technical Features
- 840D nylon with TPU membrane and PP interlayer
- High-frequency welded seams and hemmed seal
- Segmented hook-and-loop internal pocket
- Hook-and-loop seat post attachment
- Reflective tail logo
- 135 grams
Published Specification
| Material | 840D nylon + TPU waterproof membrane |
|---|---|
| Interlayer | PP |
| Segmented hook-and-loop fastener | |
| Seat post tie | Hook-and-loop fastener |
| Size | 16.5 x 10.5 x 8.5 cm |
| Weight | 135 g |
| Craft | High frequency welding |
Every figure in this table is transcribed from the VALORIDER catalogue specification for this product. Nothing has been estimated.
Product Views
Compared With the Alternatives
Against the Waterproof Frame Cross Bag this uses heavier 840D fabric rather than 600D, because a tail bag takes more spray. Against the sewn Triangle Bag it is genuinely waterproof rather than water resistant.
Customisation and Manufacturing
Welded bags are built on the high-frequency welding line, where the branding has to be applied without breaking the seal. That usually means a welded or heat transferred mark rather than stitching, because a stitched label would put needle holes back into a bag built to avoid them.
- Welded or heat transferred branding, never stitched through the membrane
- Fabric denier and membrane specified per panel
- Reflective placement set at sampling
- Polybag or colour box packing
Fitting and Living With It
Step 1
Mount under the saddle with the hook-and-loop tie around the seatpost and rails.
Step 2
Pack tools inside a cloth so they do not rub the membrane from the inside.
Step 3
Close the hemmed seal fully. The seal, not the fabric, is what keeps the water out.
Step 4
Rinse road salt off after winter rides and let it dry open.
Others in This Part of the Catalogue
Waterproof Frame Cross Bag in Two Sizes
600D nylon welded shut in a 125 gram and a 90 gram size
View specification
Waterproof Triangle Frame Bag with Graded Fabrics
600D outside 420D inside 840D on the bottom where it matters
View specification
Waterproof Bike Pannier 27 L with Quick Release Clip System
27 litres on a clip system that attaches and detaches in seconds
View specification
Bicycle Phone Holder Bag with Rotating Base and Headphone Port
A 360 degree base a sunshade and somewhere to put your passport
View specificationGuides That Cover This Product
Why a Sewn Bike Bag Is Not Waterproof and a Welded One Is
Every stitch in a seam is a hole. High frequency welding removes them. Here is how to tell the two...
Read the guideDenier Explained 210D 420D 600D and 840D in Bike Luggage
Four numbers cover almost all bicycle luggage fabric. Here is what each one is for and why a good bag uses...
Read the guideBicycle Waterproof Tail Bag 840D Nylon with Welded Seams Questions
Is it actually waterproof or just water resistant?
How much does it hold?
Will it fit a dropper post?
Can the reflective logo be changed to ours?
Quote Bicycle Waterproof Tail Bag 840D Nylon with Welded Seams
Send the quantity, the destination port and any branding requirement. We will come back with the questions that decide the price.