Mud flaps

KidWok

Member
Got my ST1 LE 19 months ago and have put on 6k miles so far. Last year was the wettest year on record in Seattle for quite some time. It was pretty obvious that the fenders wouldn't be long enough so I added mud flaps, as I have many times before on road and commuter bikes. I quickly discovered that speed pedelacs kicked up the water fast enough that the water stream atomized on contact with the mud flap. Over the last year, I've revised my mud flap design multiple times and now have one I'm really happy with. Here's how they evolved:

Version 1: Used the long side of an orange Tide laundry bottle and attached it to black plastic fender plug with two M4 bolts and lock nuts. As noted, high speed water spray atomized on contact, enveloping feet and drive train in a fine mist that flushed the lube out of the chain after any short amount of time on wet pavement.

Version 2: First tried folding the flap so that water impacted at an angle, which didn't noticeably help. Then drilled some holes to add a series of vertical strings (chalk line) along the inside of the flap. The idea was for the strings to wick the water down, which helped a little. This assembly started getting heavy and version two ultimately disappeared when the black plastic fender plug fell off mid-ride.

Version 3: Stromer sent me another plug. The plug has a small hole in it, presumably for water to not collect in the fender cavity. I drilled a 1/8th inch hole just above that on the inside of the aluminum fender so that I can run a small zip tie to make sure the plug is firmly attached (picture attached...you can barely see the pink zip tie covered in road crud). This time I also wanted to lengthen the flap so I used an old water bottle (LDPE) and the long section of another detergent bottle zip tied together, mostly because the orange looks good with the blue on the LE. This worked fairly successfully for some time, but the wind eventually blew back the flap so that it was flying almost horizontally. That actually was fine because it was enough to protect the drive train and I had started commuting in Hunter Chelsea rain boots. However, the LDPE bottle was repeatedly creased where it attached to the plug and eventually broke off mid-ride. The plug stayed put thanks to the zip tie.

Version 4: Now I'm using two halves of the water bottle (LDPE) for the top, connected to both inside and outside of fender plug. This creates a very rigid top half that keeps the lower flap in line with the fender. Played with various materials and have found that HDPE from a gallon vinegar bottle is light, durable, and flexible enough to be scraped and knocked around. Middle section of vinegar bottle where label is attached yields two flaps, but at this time I'm still only running a front flap because I don't care about spraying behind on my commute. In addition to vertical lines, I've now added a pair of zip ties horizontally in the middle of the lower HDPE section, which holds the curvature of the flap and elevates the lines off the plastic. This dramatically reduces the amount of mist at high speed as it seems the gap between the lines and the plastic create a pocket for the disrupted/decelerated spray to mix with any remaining mist and exit downward. Version 4 pic attached.

Version 5: Needed a flap for the rear due to towing my son around on a trail-a-bike, so I took another LDPE bottle and the other half of the HDPE to make another flap. Once more, the flap is attached to the fender plug with two M4 bolts and the plug is zip tied on to the fender body. Having realized that a large gap between the strings and the plastic lower flap greatly reduces mist, I decided to run the strings horizontally with holes drilled along the side edges, instead of vertically as before. This serves to both hold the flap in a eye pleasing parabolic curve and maximized the de-misting pocket. Am now running version 4 on front and version 5 on rear. Version 4, with its vertical endpoints at the bottom of the flap has always collected a bunch of leaves, dead worms, etc. Version 5 clearly stays cleaner and does a better job eliminating mist. I ran out of vinegar again today, so the front flap has now been updated as well (pictures attached).

This has been a fun design challenge and I hope it helps other speed pedelac owners get the most out of their bikes year-round.

Tai
 

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rannyv

Active Member
Thanks, and I'm surprised there are no comments or other dedicated mud flap threads. I just sold my old e-bike after purchasing a new one and it had the perfect off-the-shelf mud flap. Wide, long and heavy rubber. I cannot for the life of me either find it online or in my records. Rain is coming to the northwest soon - it's actually starting already - and fenders alone will not keep the rider dry.

I have a bike with long, ridgid finders, but those can be a problem when wheeling the bike down steps as the fender strikes the steps and can be damaged. Mud flaps to the rescue!

If anyone has solutions for off the shelf mud flaps, I'd love to hear were you found them. The rubber ones - not leather.
 

Trail Cruiser

Well-Known Member
Thanks, and I'm surprised there are no comments or other dedicated mud flap threads. I just sold my old e-bike after purchasing a new one and it had the perfect off-the-shelf mud flap. Wide, long and heavy rubber. I cannot for the life of me either find it online or in my records. Rain is coming to the northwest soon - it's actually starting already - and fenders alone will not keep the rider dry.

I have a bike with long, ridgid finders, but those can be a problem when wheeling the bike down steps as the fender strikes the steps and can be damaged. Mud flaps to the rescue!

If anyone has solutions for off the shelf mud flaps, I'd love to hear were you found them. The rubber ones - not leather.

There was a thread about mud flap but the title was "front fender pet peeve"

https://electricbikereview.com/forums/threads/front-fender-pet-peeve.23817/#post-149487

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E-Wheels

Well-Known Member

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Alaskan

Well-Known Member
Yup and less than $20 a pair. I attached mine with 3m double back tape. They make a black one with red tape that removes designed for more permanent, outdoor applications. Just do a good alcohol wipe prior to application and leave it on for at least 24 hours before putting any strain on the tape. It avoids protruding fasterners that might come into contact with the tire. Oops it looks like I forgot to remove the black tape I used when I put on the extra coats of urethane ;)

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smitty

Active Member
The Specialized Vado 6 looked at this problem and produced some really good mud flaps, along with some related fender work. The flaps are flexible and shaped to match the natural look of the fender. They might be adaptable for the ST-2 if they are available from a Specialized dealer...
 

PDX_Commuter

New Member
I have a 2017 ST2 and in preparation of the Portland rainy season I wanted mud flaps. I found some replacement part mud flaps from Planet Bike - cascadia alx 65mm that we’re only $7 for the pair from the Planet Bike website. Figured they were cheap enough if it didn’t work out it would be a big loss. They come with mounting screws but don’t fit cleanly over the plastic end cap of the ST2’s fender so ai couldn’t mount them via the slip on method. I ended up mounting the front only since I store my bike vertically and the rear mud flap would have gotten in the way. I’m traveling so can’t take pictures now but mounted them to the back of the front fender. First popped off the plastic end cap of the Stromer fender and then drilled two small holes that aligned with the included planet bike parts through the outer most layer of the stromer fender. I cut two strips of aluminum that I had left over from a previous project and slid them into the mud flap to hold the curved shape to match the fender (will likely paint these strips black later or find a single wider piece to make it blend in more. I used the included mounting screws and screw plate to fasten rubber planet bike mud flap on. It basically extends the fenders by an extra 3 or 4 inches and seems to prevent some spray from the front wheel.
 

Trail Cruiser

Well-Known Member
I have a 2017 ST2 and in preparation of the Portland rainy season I wanted mud flaps. I found some replacement part mud flaps from Planet Bike - cascadia alx 65mm that we’re only $7 for the pair from the Planet Bike website. Figured they were cheap enough if it didn’t work out it would be a big loss. They come with mounting screws but don’t fit cleanly over the plastic end cap of the ST2’s fender so ai couldn’t mount them via the slip on method. I ended up mounting the front only since I store my bike vertically and the rear mud flap would have gotten in the way. I’m traveling so can’t take pictures now but mounted them to the back of the front fender. First popped off the plastic end cap of the Stromer fender and then drilled two small holes that aligned with the included planet bike parts through the outer most layer of the stromer fender. I cut two strips of aluminum that I had left over from a previous project and slid them into the mud flap to hold the curved shape to match the fender (will likely paint these strips black later or find a single wider piece to make it blend in more. I used the included mounting screws and screw plate to fasten rubber planet bike mud flap on. It basically extends the fenders by an extra 3 or 4 inches and seems to prevent some spray from the front wheel.

Photos please. :):):)
 

Chuck E. Cheese

Active Member
I have a 2017 ST2 and in preparation of the Portland rainy season I wanted mud flaps. I found some replacement part mud flaps from Planet Bike - cascadia alx 65mm that we’re only $7 for the pair from the Planet Bike website. Figured they were cheap enough if it didn’t work out it would be a big loss. They come with mounting screws but don’t fit cleanly over the plastic end cap of the ST2’s fender so ai couldn’t mount them via the slip on method. I ended up mounting the front only since I store my bike vertically and the rear mud flap would have gotten in the way. I’m traveling so can’t take pictures now but mounted them to the back of the front fender. First popped off the plastic end cap of the Stromer fender and then drilled two small holes that aligned with the included planet bike parts through the outer most layer of the stromer fender. I cut two strips of aluminum that I had left over from a previous project and slid them into the mud flap to hold the curved shape to match the fender (will likely paint these strips black later or find a single wider piece to make it blend in more. I used the included mounting screws and screw plate to fasten rubber planet bike mud flap on. It basically extends the fenders by an extra 3 or 4 inches and seems to prevent some spray from the front wheel.



Is there a trick to getting the fender end caps off? I tried simply wiggling and pulling, but I felt as though I'd break something if I pulled any harder and they wouldn't budge..
 

Trail Cruiser

Well-Known Member
Is there a trick to getting the fender end caps off? I tried simply wiggling and pulling, but I felt as though I'd break something if I pulled any harder and they wouldn't budge..

Start twisting it first. once free to twist, you can pull it out at the same time while having a twisting motion.
 

PDX_Commuter

New Member
Here’s a photo with the front planet bike mud flap installed along with new continental top contact winter tires which feel like the have significantly better traction in the rain compared to the Big Ben. Still thinking about painting the aluminum strips I used so they blend in more but haven’t had the chance to yet.
 

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Trail Cruiser

Well-Known Member
Here’s a photo with the front planet bike mud flap installed along with new continental top contact winter tires which feel like the have significantly better traction in the rain compared to the Big Ben. Still thinking about painting the aluminum strips I used so they blend in more but haven’t had the chance to yet.

Check your bottom bracket for dirt and flying debris. I think the mud flap is not long enough to protect the underside of your ebike.

You may need one of these longer flaps.

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PDX_Commuter

New Member
What is the large thing attached to your valve stem?
It’s a bluetooth tpms. Somehow it appeared on my Amazon recommendations and ordered it. Meant for a car so it comes with 4. I put this on my st2 and another mtb I have. Unfortunately only compatible with schrader valves so couldn’t put it on my road bike. In theory able to set thresholds to get an alert on my phone if tire pressure is too low but in practice you can check pressure via your phone but have to be in bluetooth range and start the required app. I’m a sucker for gadgets and found it on sale (~$30) so thought it was worth a try.
 

PDX_Commuter

New Member
Was combing through some other stromer forums using google translate and came across this site https://www.vanzijptechniek.nl/product-categorie/bikeparts/stromer/ that actually had some parts that are 3D printed for stromer. They looked sleek and integrated in the photos so figured I’d give them a try. I ordered the 150mm and 190mm fender pieces and just got them in. It did take some work to push them in (friction holds them in) but they do look like the photos - flush and like they were made for the bike even though they are hard printed plastic. I also order a charger holder that mounts to the wall to keep it off the floor. The built in plug holder is a plus keeping the magnetic end from picking up random shards of metal in my garage. Definitely not cheap but looks pretty nice and pieces feel pretty sturdy.