Looking for ideas for DIY mud flaps for fenders. I got what I thought were "SKS Longboard" fenders in the 65mm size for my e-bike running 2.15" Big Apple tires, but they're not nearly as long as the narrower Longboard offerings, and the mudflap is that little short rubber piece that angles out instead of extending down 6" or so. There's still about 8" of clearance from the tip of the rubber piece down to the floor, much higher than other Longboard fenders.

I thought about taking a couple of pieces of a larger size old inner tube and laminating them together with vulcanizing cement, then cutting out a long-ish shape and attaching it somehow to my fenders. I want them to extend farther down, both front and rear - rear mainly to try to keep junk off my utility trailer. It rained on me coming back from the grocery store last weekend and the front of my trailer got super nasty from junk off the rear tire.

I've posted this before, after riding home in freezing rain ice had formed all over my drivetrain. The very next day I DIY this using an old mouse pad.

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It's not perfect, but better than not having it.

Plastic jugs can be sacrificed.

My thoughts are that a plastic jug piece might be too stiff, but a piece of inner tube too flimsy, which is why I had the thought of doubling up inner tube pieces with cement in between. If I can attach it the full width to the curved cross section of the fender, that should add a bit of rigidity but still allow the bottom edge of the flap to move.

I used a piece of rubber I had lying around, about 2mm thick. Cut it to shape with scissors and used 2 4mm bolts and nuts to attach them. Had to drill my plastic fenders, used a Swiss Army Knife awl for that:

I did only the front fender, but I used a yoga mat and some nylon fasteners on my old MTB-based commuter.

You know, I love SKS Longboards but I think some of these DIY solutions might have an important advantage over the Longboards. The mud flap on the Longboards (at least the really long ones you're talking about) is kind of rigid and ends up pointing forward. I had never really considered the implications of that until last Friday when this happened to me:



The mud flap acted like a scoop and picked up this stick as I rolled over it. I'm not sure if the breakaway stay mount did it's job or if the stay bolts were just loose enough to give. Or maybe the fender just flexed a bit. In any event, the fender was pretty tight to the tire before and I ended up with enough room that this just slowed me down and made an awful noise.

Anyway, it occurred to me that a loose flap hanging near the ground is actually a good bit better than a scoop.

I've used old rubber boots. The rear half of the bootleg, roughly shaped. I saved a strip of the sole for a reinforced mounting area.

Sort of the idea I had for the front. Does the back one not rub the tire?

Did you check Google? Because this is a very standard DIY project. I used carpet protector from the hardware store. It's sold by the foot. One foot is enough to make about 10 mud flaps.

Just a piece of rubber and some fasteners from the hardware store.

This is what I have on my current commuter. with the first two sets of700x32 tires, clearance was really tight and I have had small pieces of wood, leaves and stones get caught up in there. The new set of Continental Touring Pluses say 700x32, but look more like 28s and the amount of debris "scooped" up by the fender is far less.

Cascadia 29er mudflaps, fit 65 mm fenders, 130 mm length, $5.00 including shipping from Planet Bike small parts department.

It rubbed a little at first, so I attached a strip of thin aluminum to keep it away from the tire.

I went to Home Depot and bought the cheapest all leather tool belt I could find. It was 2" wide and the western style embossing "swelled off" after the first rainy ride. Looks much classier on aluminum fenders than plastic jugs or rubber stair tread.

I use flexible plastic cutting board material . Light, cheap, many bright colors and can be cut to shape with household scissors.

I have made them from leather scraps. I have some waterproof black leather, presumably chrome tanned, that is good for this purpose. I have also used a veg-tanned horse hide that might be a little too flimsy but it has worked so far. I mounted a red reflector on the rear one, which keeps it from flopping around too much. The front one is pretty wide, and I thought it would take a scoop-like shape, but when it's dry it curls up to the rear. When it gets wet, it straightens out and actually drags on the ground. That isn't a problem, though.

The end of the fender has to be lower than the axle; otherwise the mud flap rubs on the tire and can get pulled up under the fender. That has happened to me, and it's definitely a problem.

Nothing is better than thick old rubber boots that have the perfect curved form. Figure out the best place to cut it, then drill 2 or 3 holes. Best if it is between the fender and a bracket. For additional shaping and stiffening I have folded a stiff wire around the dangly bit.

This is a good one. Committed to memory banks for future reference.

This is timely, I have been thinking of material to use for mud flaps. Was about to throw the tide jug into the recycle bin when I noticed how it was shaped. Perfect!

Got out the scissors and rough cut the material. Will now trace a pattern and transfer it to the plastic. More work then needed but I want it to look decent. I like that it is coloured safety orange. I am looking at the other jugs of detergent, whole range of colours.

HORRIBLE IDEA. What happens if it bumps into a curb or something ??? CRASH
It needs to be flexible.

.???

Great idea on tide jugs.

Thanks! It will be a worthwhile experiment. I'll let everyone know how it turns out.

Hey, I thought about what you were trying to get across and I think I know where your worry is. You think if I come off a curb the mud flaps will catch. Am I right? Anyway, the plastic is flexible when I cut it to final size and I do not ride on sidewalks ever. I ride, commute everyday and have done so for most of my life.

I appreciate your concern!