Darth Lefty 

Do I want Rogue Panda frame bags for my bamboo mountain bike? You bet I do

JonnyHK 

Not sure I'd want a rogue Panda anywhere near my bamboo bike!

helixbikes

Progress report from my end: I am nearly done with the cutting and bending portion of the exercise, only the seat
stays remain before it is time to break out the JB Weld :

Before the Calfee kit came in, I didn't even know "miter" was a word. Predictably, my first cut went very poorly (the bracket does not align the piece vertically!), so my seat tube is 1-2cm shorter than it should be. I'm so paranoid of screwing up further, that it takes forever: each 5 minutes of video is easily an hour and a half of my time. It doesn't help that the videos diverge from the parts sent on occasion: the video doesn't take into account bent seat stays, and the ridges on the dropouts are on the opposite side than the video. Bending the aluminum parts is much harder than the video makes it look: I'm currently on crutches and have to get a friend to help out on those bits, and even he struggled on the first one.

Following the video can be very frustrating, as attention to details is pretty key: Craig does not walk you through everything, but instead assumes that you are paying full attention at all times. For example, in the seat stays portion, one of the seat stays is magically cut in between frames: follow along, young whippersnapper! Overall, it's easily the most fun I've ever had in my garage.

If Calfee really wanted to make this user-friendly, they'd take a blithering idiot like me, see all the head-scratching moments, and use it to improve the video. Instead, I think it will likely remain the cost of entry. I am extremely skeptical at this point that my frame will be level and symmetric enough to be a good ride. A wee bit of hope remains, however. I went a bit overboard on buying components for the build, so I've got an investment to protect at this point.

Good luck to the rest of you builders out there!

Darth Lefty 

Nice! Did you have any kind of bug with the top tube angle? It looks under parallel with the lines and I thought when I laid mine out that the seat tube looked too short compared to the lines.

What are you planning for build? I'm thinking 1x10 for mine. There were a lot of bikes for sale this year that used the big Sunrace cassette and Deore or X5/X7 shifting, and similar level fork and brakes.

You're going quicker than I ever will manage, I think. I got nothing done this weekend, spent it all between toddler, preggo, and new nursery. I regret nothing!

helixbikes

Yes, my top tube angle doesn't appear to match reality, nor does the length of the head tube. At some point I have to throw my hands up in the air and say: this is a bamboo bike, 1 degree here or 1mm there.

My goal is to build a bamboo knock-off of the Salsa Cutthroat Force build (see attached image), with the 1x11 SRAM Force groupset. Had I realized how inexact my own build would work out, I would have opted for cheaper components. I figured up front that I was building a ride-able work-of-art, but as I said, I'm still super skeptical about the ride quality. What I wouldn't give for a hologram of Craig Calfee to be there beside me to tell me that I'm doing it wrong.

I ended up renting the tools from Calfee, which at $100 for 2 weeks, is strongly encouraging me to get through this phase of the build quickly. That said, with kids to take care of and a broken foot, it's been hard to sneak out into the garage to git'r done. Life always seems to interfere in more ways than one can predict ahead of time.

Canaboo

What are your ride quality expectations?

helixbikes

I've never ridden a bamboo bicycle, but I'm expecting a ride quality similar to 1980's steel frame. By the time I'm done smothering JB Weld and bandage material all over it, I suspect the frame itself will weigh 7lbs. My total build weight expectation is ~24lbs, which is heavy by modern standards, but hopefully vibration resistant.

My main ride quality concern is around keeping the BB and dropouts level. Everything after that is just gravy.

Darth Lefty 

For me, I'm expecting ride quality to be pretty much entirely driven by the 2" or bigger tires, and suspension fork. I would not be terribly surprised if my bike's weight comes up in the thirties.

Darth Lefty 

7 pounds of frame (quoted on Calfee site but it might have been for road weight)
5 pounds of fork
5 pounds of drivetrain and brakes,
5 pounds of wheels
2 pounds of tires, maybe more like 3 with sealant etc.
1 pound of handlebars, stem, grips
1 pound of saddle
1 pound of headset and seat post and misc bits

27 pounds... must be forgetting something

Canaboo

There is something to be said for thinning the walls of the bamboo. It will ride a bit "loggy" otherwise.

Henry III

I would within the time you have the jig. Just take measurements and photos of the jig pieces and build your own instead of trying to rush and build the frame in the little spare time you have. That way you'll have a jig for the next frame you build.

Darth Lefty 

I really can't tell if you're pulling my log. Leg. I meant to say leg

Canaboo

You could just use solid pieces of wood and make a functional bike. Bamboo left more or less solid is essentially that.

Canaboo

How is the second miter coming along?

Darth Lefty 

Let's just say it's stuck in a tiny corner of my Venn diagram right now!

Darth Lefty 

Just because it was in my power today, and because I was worried about it, I got out the plan and made some measurements. These are with a 4ft ruler with 1/8 hashmarks so not super precise.

As previously noted, the top tube lines on the plan are wrong. They line up with the top of the seat lug, if you did that you'd have nowhere to wrap.

The BB drop also seems wrong. The plan has about 1.375" or 35mm of drop. For a 29er shouldn't it be >2 inches? In fact it looks like a number for a 26er, right?

Chainstays are 18.75" which is long! Longer than a touring bike. Current style for 29ers is shorter. The circle marked "29 inch wheel" is actually about 29.5"

The three sizes are not quite proportional. The medium is about 17", the large about 19.5", the XL 21". The effective top tube is about 20.75, 22, 23.5. The seat tube leans back a little more at each size but I didn't have anything with me to measure the angle.

The head tube angle is like 70 ish. The axle to crown looks right.

Canaboo

The drawing is probably based on a welded frame where the tubes can be attached with less necessary surface area.

Chainstays are likely longer to ensure adequate clearance. Unless you bend aggressively or scoop out a bit more clearance you would run out of room with bulky wrapping.

Henry III

Exactly. The time and work needed to shape bamboo compared to just using longer tubes for clearance is probably why they run super long stays.

I thought for the Calfee kits the geometry was all figured out with the template he sends with the kits? Basically position the head tube, BB, and dropouts in the designated spots and cut and miter the tubes to fill the voids. Then JB in place and then wrap with the casting tape. I've watched the whole series of videos quite a few times and used the same method when I built my wood frame last year.

I'm not questioning your abilities but I think your digging too deep into it with the geometry. He gave you a map and all you need to do is follow it. Now if he sent you a pile of tubes and a couple rolls of casting tape and called it a 29'er frame kit and wished you best of luck then I'd be a little irrate. But you've got the geometry template and jig and just need to essentially connect the pieces.

Canaboo

Agreed. Place all of your metal pieces where they should be and at the correct angles and link them with the bamboo pieces. Whether the tubes contact a bit high or low is not changing your geometry.


I had someone say that the slightly higher seat tube actually changed the size of the bike.

Darth Lefty 

I can buy it about the stay lengths, but the high bb sure looks like a mistake

Canaboo

Just trace the BB shell where you want it then.

coupster

Its a little late, but if you want to check your geometry I highly recommend spending some time playing on www.bikecad.ca. When I built my bamboo bike I was trying to mimic my Cannondale Synapse while staying within the basic confines of a Hero bike kit. Changing lengths and angles on the computer is a whole lot less stressful than trying to do it on the fly. The free version doesn't produce a full scale drawing but the owner will email you a .pdf of your design and that can be scaled up and printed. I just drew one on a large piece of paper with a ruler and a protractor.

Darth Lefty 

It's pretty hard to get a minute to work on this thing when there's two babies and a 2yo, and it's always dark and rainy out on the deck! I had shelved it for a while but I determined that a lot of time I was spending waiting or surfing could be spent instead on prep work. So I've marked the miter cuts for the seat tube and down tube. If this guy knocks out before 2yo is done napping, I'll go outside and do the cuts.

Evening edit - cuts accomplished. I have this little flexible keyhole saw that I got for doing drywall,and I was able to save a lot of time with the rasp by getting it roughly to shape first with some off-straight cuts.

I'm going to copy the geometry of the Marin Bobcat Trail, a friendly midgrade trail hardtail with a 29er option at 17" size. I'm going to get my sheet of MDF here soon to put it on a pallet and sawhorses and lay it all out... I think it's safe to start this now that the rain seems to be tapering off.

@helixbikes how's your progress? Did you get wrapping yet?


Untitled by Darth Lefty, on Flickr

squirtdad

surfing or bike building...tough call

Darth Lefty 

More notes since the last time... Back at work now. So much for building it during leave of absence!

From memory, I'm thinking the fork length on the kit plan is wrong too, sized for a 26er fork. However since I've pretty much abandoned the kit plan I haven't gone back to double check.

I got some more fittings for holding up the head tube but I'm not really pleased with the result and won't show it to you unless it works out.

I laid out a top-view plan for the dropouts, chain stays, BB, and tire. I'm glad I did. The 29er x 2.3" tires are pretty difficult to cram between the 17.5in chain stays of the Bobcat Trail frame. Since the bamboo tubes are nearly 1in dia it's just not going to be possible. I increased them to 18.5 inches, as per above discussion. That lets the bend in the tubes bring them back to the BB and clear a 32t chain ring at 49mm chain line.

Why 49mm? An MTB triple has a chain line for the center ring of 47.5-50mm. A Hollowtech II like an XT has it at 50. I'm planning a 1x and a NW ring is 2x thicker than standard so it sits 1mm further in. explanation is here Boost Chainline and 1x Boost Chainring Selection ? wolftoothcomponents.com
I sketched up a plan in CAD of the Bobcat Trail frame and will try to put it on my table this weekend.