Step 2: Getting Started: Planning and Measuring

After puzzling how to mount my fenders so that they didnt interfere with my brakes, i decided that each fender would be made as two separate parts, one bit behind the brake, one bit in front. in the front of the bike, those pieces would mount via a metal plate onto the brake bolt. but because of a peculiarity of my bike, the rear ones would have to clamp onto the seat stays of the bike. as i said earlier, i wanted 3/8ths of each wheel to be covered by fender. i divided this up as 2/3 of the fender behind the seatstays (or front fork) and 1/3 in front. i calculated that with a 14 inch radius, the longer piece of fender would have to be around 20 inches long, and the front piece half that. so to outfit my bike, i would need three 20 inch fenders, one of which would be cut into two pieces, with half going on the front wheel, and one half on the back wheel. I also decided to make a set of fenders for a friend, who also built a bamboo bike, and will be my touring partner. so i needed to make six 20 inch fenders to outfit both bikes.

so this is the stage at which you need to figure out how much wood you will need. because of my racing stripe, i needed wood 1.5 inches wide and .5 inches wide (so that a light-dark-light pattern on the top layer would still be 1.5 inches wide).

here is how i figured out how much to get:

 each 20 inch fender needed:
 2 layers 20"x1.5"x1/8"
 1 layer formed of 2x 20"x.5"x1/8" and 1x 20"x.5"x1/8" of a different(in my case darker) wood
3 fenders per bike (split between both wheels)
2 bikes
10 linear feet of dark wood in .5"x1/8" 
20 linear feet each of same light wood in .5" and 1.5" x 1/8" wood

I got a little extra of both woods in all widths, just in case i messed anything up.

I'm thinking of doing this minus the plywood form. For the sake of scrap wood preservation and laziness, I was contemplating using the bike's wheel for the form. I don't know if I'll leave the tire on or not, but either way I'm going to try clamping it down using a tie-down strap wrapped around the entire circumference. Think it'll work?
I've made a version (not quite as nice as these!) of wood fenders using the wheel as a form, leaving the tire on the wheel and taping down a spare length of bicycle (or motorcycle for more room) chain along the length of the tire between tire and wood to build some space while keeping the correct shape. It takes some finesse while clamping but worked like a dream!
I think thats a great idea...simplifies things a lot. make sure not to get glue on your wheels! and I would use clamps...not tie downs, as you do need quite a bit of force. By the way, i have now used these fenders on a two month, 3000 kilometer bike tour of france and spain. I had the fenders on the bamboo frame i built. check out my blog<br><br>bamboobiketour.wordpress.com<br><br>Adie
I was making my own set based on your directions, and I found a novel way to clamp the wood down while it dries. I ran out of normal clamps about halfway through, so instead I found a ratchet-strap in my garage and figured out how to secure it around the whole mold. Once around, I tightened it as much as possible, so instead of multiple clamps providing localized pressure I had a single strap providing equal pressure around the whole thing. Worth a shot if you're building more!
yeah thats a good system. <br>Ezra at fastboy cycles (s\check out his fenders, they are sweet) has a system that uses a long metal ruler, which is bolted down at each end, giving similar pressure through tension. <br> <br>hope the fenders worked out.
How did the parallelogram pattern strength hold up once finished?
strengthwise it seemed ok, it just didnt end up very tidy, i never used them because i had enough of the normal pattern.
What are you using for fender stays?
i used 3mm thick stainless steel rod that i got at a metalworks/welding place. i drilled through the fenders, threaded the rod through, bent it 90deg on either side of the fender. then i got some 1mm thick stainless sheet metal, and cut rectangles, about 20mm by 15. towards one end i drilled a 3.5mm hole for the end of the stay, towards the other end, a hole that matched the bolt holding my rack on. i threaded the rod through the hole in the plate, cut it to approximately the correct length, bent it 180deg back onto itself so it couldnt come off, then bolted it to the rack braze-on. to fine tune the stay length, you can just rotate the plate around the mounting bolt. <br>I realize that's quite wordy. if you are actually making these, and are confused, i can dig up some photos. <br><br>Adie
Hey, thanks for the link over to my instructable. It makes me wonder how many others have built bikes? I'm about to dig into your fender instructable to throw some fenders on a coulple of my frames. These look nice, and easy to do! I'm probably going to go Carbon and Wood laminate, just for something a little different! Not sure how it'll work out, with such different materials, but worth a shot! Thanks again for the link, and for this well written instructable! <br> <br>Eric <br>
hey, the fenders are really great, they go great with the bamboo. thank you for your instructable! I built mine fixed/free and took it on a two month bike tour of france and spain, the frame held up really nicely!
I've spent the last hour or so reading your blog from the trip, and it sounds like an absolute blast, but also incredibly difficult on a fixie! Good job! Are you still riding the bikes?
Yep, I ride about 20 miles (commuting to work) 4 or 5 days a week. Doing it on a fixie was definitely tough! Although the tour was great fun, all the most dificult and least enjoyable bits (hills, lol!) would be so much better on a geared bike!
You know what this reminds me of? A body of a long bow. If you make an instructable on how to do that, tell me. Cuz I've been trying to find out how to make a long bow.
What kind of elasticity did the finished product have?
its pretty damn stiff, id say. you have to actively try in order to make it bend.
Just one quick question (after the following compliment). Looks grand!<br><br>Now the question...How did you calculate &quot;spring back?&quot; That is to say, when one removes the final laminated piece, there is invariably a degree of relaxation wherein the final piece does not retain the exact curvature of the template. How did you calculate that or did it just work out? Inquiring minds want to know...<br><br>To reiterate, great job...Looks grand!
thanks,<br>and i didnt make any calculations. i just used the radius of the tyre, knowing two things. a) that it would &quot;relax&quot; when taken off the form, as you said. b) that i would mount my fenders with approx .25 to .5 inches of clearance, so the &quot;springback&quot; would approximately match the effective radius i was after. it wasnt particularly scientific :) <br><br>--Adie
Many thanks for your reply and explanation...I must try this...<br><br>Again, good job on an excellent project...
Wood these be strong enough for a motor cycle?
well, the nicke thing about laminating wood is that you can do as many layers as you like, and it just gets stronger and stronger. as it is, with three layers of wood, they are very inflexible, and if you had a sturdy mounting system im sure it would work!
this is amazing, i was just cleaning out my work space and stumbled on some walnut and mahogany veneer, i also happen to be in need of fenders haha! im excited to see how you mount them.<br>good luck!
I'm excited too! heh, i think i have a system that will work. we shall see :)
Whew! I am VERY interested in how you do this, so I'll stay tuned for updates! Thanks!
thanks! i hope i dont dissapoint :)
Did I miss something? This seems incomplete.
correct. i will be adding pictures and more staps as i get to them. i was surprised they featured it given how incomplete it is!<br>
Yep, definitely not a complete project. I'll stay tuned for the rest, though.
yeah, i just started yesterday, should finish this week. ill be updating as i go along.

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