It's been awhile since I've posted anything bike related or something other than about John, so I'm taking the time to document a project I recently completed. I'd also like to give a shoutout to Joshua Putnam for providing some valuable advice.
A few months ago, I bought a pair of winter boots. Fairly weatherproof and they stay warm, even in below 0 weather. Unfortunately, I'm limited to a pair of Shimano SPD shoes when biking (or straps) which don't work out well in the winter, so I set out on a mission to change this.
WARNING: THIS WILL MAKE A MESS AND SMELL LIKE BURNING RUBBER! You should do this outside if possible.
What you will need (in addition to two SPD cleats and anchors/cleat nuts):
- Cheap plastic safety goggles. Trust me on this. The rubber goes all over the place. You'll want the goggles coated in rubber pieces. I say this as someone who wears prescription glasses with polycarbonate lenses.
- A dremel with various cutting/grinding attachments. I found this bit extremely useful in cutting away all the rubber on the bottom of the sole.
- A hand drill (corded is a good idea)
- A titanium drill bit. I forget which size bit I used. I think it was something like 6 or 7 mm.
- At least a dozen 1 inch M5 bolts. I used counter sink 10-32 bolts with a flat head, but I'd recommend using hex if possible. These are to screw the cleat in place.
- Stainless steel boot insoles. I got mine from McMaster-Carr for like $20 or $30. You'll want these to keep the boot sole from flexing. Trust me on this one. Even if it's hard rubber, a lot of stress goes on the cleats and the rubber WILL flex. Even if you can get clipped in, you'll also want to clip out reliably.
- Polycaprolactone (or PCL as it's abbreviated). I already had some laying around. This is a biodegradable polymer that becomes moldable at 140F. It has the texture of silly putty and becomes translucent when heated. As it cools, it hardens into a nylon like plastic and turns to a milky white color. Extremely useful stuff. I made a really crappy looking fender with it once.
- A heat gun. You'll be using this to heat up the PCL.
Optional (but useful):
- A drill press, for drilling out the holes on the steel insoles
- A ruler
- A vacuum cleaner
Slightly important note/warning/something to keep in mind. I did this on one boot until I got it to work before I tore up the rubber on the other. This might be something to keep in mind if you want to attempt this project, but I digress.
With all the stuff I listed above in mind, your first goal is going to be to use the dremel to cut away the rubber around the area where the cleat will go. Unfortunately, I didn't take any pictures, but when I did this, I kept the outside rubber intact and cut/grinded away all the rubber in the center from approximately the tip front of the boot where my toes are to the middle of the boot where the rubber is raised a little bit. This is going to take some time and is seriously going to make an absolute mess. The rubber has a tendency to get hot and become sticky, making it difficult to get off of tables/floors/skin/etc. That and when cutting/grinding the rubber, it comes off in small pieces that form a layer of rubber dust over your hands/wrist/dremel. I did this because it keeps the cleat recessed and doesn't feel strange walking around with the boots on.
Once you get everything cut away and the rubber where the cleat will go relatively flat, you want to keep cutting. Seriously. You'll want to make a little bit of a crater where the cleat will go. The reason for this is because you're going to fill it in with that polycaprolactone. The reason being is that the cleat, while it will be recessed, needs to be sticking out above where it is mounted so it will hook into the SPD clip on the pedal. Trust me on this. I went through a lot of time having to either reposition the cleat or add on more polycaprolactone. What you want is a completely flat surface of hardened polycaprolactone for the entire cleat to rest on. It comes in small plastic beads and I'd just heat them up in the craters with the heat gun and mold/shape them into place. PCL has a tendency to stick to other plastics/rubber when hot, so I would just push the moldable PCL into place with my fingers, compressing it as much as I could. Note: I work with my hands a lot and my skin is pretty rough and calloused. You might want to wear gloves when doing this so you don't burn yourself.
Next, you'll want to figure out where to position the cleat. Using the tip of the sole where my toes would be and the center of the boot as points of references, I mounted the cleat a little bit below the center of those two points. It seems the most logical thing to do. This is probably not going to work out. Here's why:
The boot sole is wider than a pair of SPD shoes. I found that for this to work, you'll want to mount the cleat slightly to the left or right, depending on the boot (further to the left on the left boot and further to the right on the right boot). The reason for this is that the edge of the boot is going to be right up against the crank arm and if the cleat isn't lined up right, you won't be able to hook it in the pedal. I ran into this problem and had to redill everything a second time. Fortunately, I was able to just heat up some more PCL to plug in the holes. You don't have to mount of off position too much. Remember that you can slide the cleat left and right in the piece of metal that goes in the center of the cleat that the screws go in.
Once you think you've found everything should be mounted, it's time to drill a hole. Take out the insole in the boot and drill a hole. Make sure you position the second hole to line up with the holes on the center piece of the cleat that the bolts go in. Once get the holes drilled, put the cleat on and run two bolts through the holes. Make sure everything looks straight and is fitting right. If so, the next thing to do is a bit of a pain in the ass.
At this point, you need to drill the holes out in the stainless steel insoles. This is a pain in the dick for two reasons:
- The holes have to be lined up perfectly (duh!)
- The anchor/cleat nut needs to be flush on the insole, which means you have to drill four holes that line up perfectly with the holes on the cleat nut.
You can do this really any way you want. What worked for me was putting the metal insole in the boot, taking a pencil and scratching out where the holes were lining up with the insole. Then I would take out the insole, put the anchor nut on it to make sure the scratches lined up with the holes on the cleat nut. If they did, I'd drill them out. After drilling them out, I'd put the cleat nut on the holes to make sure the raised part of the cleat nut fit in the holes I drilled, widening the hole if they didn't. Once you get the first two holes drilled, you get to drill two more so the cleat nut can be completely flush on the insole. One of the holes probably isn't going to line up, so plan on enlarging at least one hole.
Now that you've gotten this far, you're almost done. The next step is probably the most difficult, but it's the last step involved. What you need to do now is put the metal insole back in the boot, then put the cleat nut in the boot and feel around in the boot, guiding it into place so it rests flush with the holes you drilled on the stainless steel insole. Using a flash light, look at the bottom of the boot and make sure the holes on the insole are lined up with the holes drilled on the boot. Shift the insole around until this happens. Once you do, take a bolt and try threading it in. This is the part that I found is the most difficult. The more accurate the holes you've drilled out are, the easier this part is. Once you get the first bolt in, tighten it down all the way, but don't put in a second. Likely, you'll be able to feel that the end of the bolt is slightly sticking out of the cleat nut. Take another bolt and using the dremel with a grinding wheel, carefully shorten the length of the bolt. When you think you've gotten it small enough, try threading it in. I know I ground a few too short and had to grind down another until I got two bolts at the right length that'll thread in, but won't stick out the end of the cleat nut when screwed down tight.
Once you get one bolt ground down to the right size, tighten it down all the way. You're almost done. Just take out the longer bolt and thread another cut to size bolt in there. Tighten it down as much as you can. I'm serious. You want to He-Man these bolts into the cleat nut. After you've done this, try clipping in. If everything is lined up right and the cleat is sticking out enough for it to hook into the clip, this should happen after a few tries while you're learning where everything lines up. If not, you'll have to take the boot off, mimic trying to clip the boot in using your hands to guide the boot, and look at why the cleat isn't locking into the SPD clip.
Assuming you get it to clip in, congratulations! Now you get to do it all over again to the other boot. Good luck. I'll try remembering to post a picture of the finished results sometime.