October 20, 2008

Big Dummy Fender Odyssey

Fall is here.

A few weeks ago, anticipating some wet weather, I decided to slap some fenders on my Big Dummy. It seemed simple enough. I've mounted fenders before--but not on a Big Dummy. Little did I know this would turn into a three week project.

First, many bike shops don't stock the wider fenders that the 2.35" wide Big Apples I'm running demand. So I had my LBS order some silver SKS P65 full mount fenders. I don't exactly understand why, but after I was told they would arrive in two days, they didn't show up for nearly two weeks. However, LBS karma was with me and I only faced a few light drizzles over the interval.

After I finally picked up the fenders and brought them home, I started looking at the Big Dummy to figure out just how I was going to mount them. The Big Dummy frame and fork have literally about 50 braze-ons for all kinds of brakes and racks--and fenders. Rather than just making something up I decided to take some time and look around online to find out how other BD owners had opted to mount fenders. This took a few days since I hit a run of evening work meetings. Vic did this and Dylster did this. Both used Planet Bike fenders. I had PB fenders on my old commuter but figured I'd try something different since they wouldn't transfer onto the BD.

So the first free night I had, I mounted the front fender.



The front fork has eyelets for fenders at the ends of the drops as well as braze ons mid way up the fork. While tempting, the lower eyelets aren't compatible with disc brakes--the caliper gets in the way of the fender support. So I attached the supports to the upper braze on. I like this option because the supports ended up shorter and, I think, tighter and more stable.

The SKS fenders come with these little plastic mounts for some sort of quick release of the front fender supports. The piece below gets bolted onto the eyelet or braze on at the tapered end, and then the support clicks into the opposite flat end.


I tried using them, but with the tension the supports are under when the fender was properly aligned, the supports kept popping out. So I kept it simple and just screwed the supports directly onto the fork.


There is also a bracket that attaches to the fork crown. With the monster tire clearance of the fork, the fender sits off the tire more than I'd like, even when adjusted to its lowest level (best appreciated on the top photo). I could have figured out some way to extend this down, but decided to worry about that another time.

The second free night I had, I mounted the rear fender.


This one was a little tricky. I struggled with whether to run the fender supports along the inside or along the outside of the rounded part of the rear frame extension. I've seen it done both ways (see linked photos above). I ultimately decided that it didn't really matter and the bottom line was simply to make sure to apply tape to the frame so that where the support abuts the frame it won't get scratched up. Also, the eyelets for the rear fender supports were a few inches behind the dropouts, which was somewhat counter intuitive. I finally opted to run the fender supports outside of the frame, as you can see, since it subjectively required less bending of the support.


Securing the front part of the rear fender to the bridge behind the bottom bracket was fairly simple, requiring only a small bracket that sits flush with the fender and a single bolt.


What I didn't show was trimming the supports that extended beyond the outer edges of the fenders. The supports extended quite a bit beyond the fenders as a result of using the upper braze ons on the fork and the more posterior position of the eyelets for the rear fender. I probably dulled them badly, but just cranked on some cable cutters to do cut them. The fenders did come with these little plastic covers that fit in the brackets for the fender supports, covering the end of the support.


I didn't use these but could put them on later. After getting the curve of the fender just so, the last thing I wanted to do was loosen everything back up and have the supports pop out of the brackets.

Overall I'm pleased with how the fenders look and how solid they feel. I don't hear them rattle around like the Planet Bike fenders did on my old commuter. I like how tight the rear fender is along the tire and will have to come up with a way to lengthen the bracket along the front fender to get it to look the same.

There you have it. In the end, fenders are quite easy to mount on a BD, and they really look nice and natural. So now that they are on, I'm wondering how long it will stay dry. Maybe until later today?

Next up--setting up the indoor trainer (NOT for the BD).


  1. Good post/pics - your fenders look great. I'm in the midst of my own Karate Monkey fender odyssey. Mostly different eyelets, different set of problems, but I have the same thing going on with the mondo fork-to-tire clearance.

  2. Hey I'm trying to mount the P65's onto my Big Dummy now. A quick question, did you have to shorten the supports at the front and if so what did you use to shorten them? Thanks!

  3. If you use the upper braze ons like I did, you will have to cut them a significant amount. Once I had them adjusted and the funky bolts at the edge of the fender tightened, I used a set of cable cutters to clip them off. May not have been the right tool for the job (I could almost hear them getting more dull), but worked--quickly and simply. I suppose a hack saw would also work.

  4. Here is the issue:
    The rear P65's fenders can fit over my Maxxis Hookworm 2.5's, but it cannot fit under the SnapDeck (I made my own SnapDeck).
    Do you have any suggestions as to how this might work?