Thursday, December 19, 2013

Gringa Rebuilt

(click on image for larger view)

I knew in the back of my mind that, evntually, I would rebuild Gringa. The bike was too awesome not to. When I got hired at Bike Friday i saw my chance to do it; this time slicker and stronger. I spent a dozen or so lunch breaks poring over bike component catalogs, looking for the components with the best aesthetics. Of course, they all had to function well, but I really wanted stuff that was going to match the look i was going for. (When i told my mom she said "oh, i get it, you want to pimp your bike, like that in show with the cars." Priceless). One of the best parts about working in a bike factory is that, not only do i get factory prices on components, but i'm also surrounded by people that love to geek out on parts. The success of this bike is largely due to my friends at work.

I initially thought that it would be a fast project, but the foolishness of this position quickly became apparent. I started it out the same way i did the time before, with an existing mountain bike frame. I picked up the frame for $10 at the Center for Appropriate Transport. I was hoping for something with a top tube that lines up straight with the seat stays, like this Schwinn Frontier:

Didn't find something quite like that, but also didn't feel like buying one new, or waiting around for weeks in the off chance one would just show up amongst the used frames at CAT. So, what i got was good enough. I also figured that i could start building the bike using the frame and then swap it out later if i found one i liked more.

The first thing that I did was to cut off all the extraneous cable loops, stops and brake bosses. I then cut out the head tube and replaced it with one i built. The main priority here was to change the angle, I wanted the fork to have substantial rake to it. The other factor was strength- I decided to go 1 1/4" (which in hindsight was a probably a mistake). My logic was that i wanted a stronger, and therefore wider, tube for the steerer. After all, it was the steerer that broke on the first chopper i built.

I knew that we had suppliers for headsets, but i didn't realize how obsolete 1 1/4" is- its tough to find even star nuts in that size. The headtube i made was pretty robust, but getting the right angle in the mill to miter out for the new head tube was finicky- it left big gaps that i couldn't possibly weld, so i had to braze it.   


The large fillets required to fill the gaps put so much heat into the headtube that it warped. And, frankly they didn't look that good either. I was starting to see that i should have just built the frame from scratch.

I ended up having to grind the fillets a lot to smooth them out. It took way too much time and only looked marginally better. Lesson learned. I gave the bike a test paint on the head tube to see how the fillets would look with the paint on them. Unfortunately, they looked worse with paint on them. I was almost ready to scrap the frame, but a co-worker convinced me to let it slide.

The next thing to do was to figure out how long to make the steerer. There was no logic other than looks. So i propped up the bike on its wheels with the tube i bought running through the frame. I slid it back and forth until i got it to a spot where i liked it.

Once I had the steerer length decided i made a clamp for the fork. I thought this was going to be temporary solution to making so long a fork. I envisioned making it all as one piece, but there were several constraints that made that prohibitively difficult. The first was that the fork would be so long I would have to build a special rack just so it could fit in the oven to paint it. The second was that aligning it would also require the building of a special jig, which was way too much work. Having in two pieces, with a clamp, would solve both of those issues. 

I wanted to take the thing for a ride, but hadn't decided on a set of handle bars yet, so i built a pair. Also built a sissy bar for the seat. It came out ugly.


Looking at these pictures reminds me of another reason i wouldn't do 1 1/4" again, its pretty hard to find a stem. Even digging through Bike Friday's excess inventory and CAT's parts room the best i could do was 1 1/2". It had way more projection than i wanted and required shims.

It was exciting to slap some temporary components on it and take it for a ride in the parking lot.

I wanted the bike to be painted something loud and eye catching, candy yellow seemed like a good choice. I paid a visit to Forest Paints and got to see lots of different paint samples. The candy yellow looked spot on. Unfortunately, when i actually painted something with it the color was far too green for my taste. So i experimented using it as a top coat over lots of other base colors. Everyone's favorite was the green fork. The sissy bars came out a gross glittery brown that was popularly dubbed "sparkle poop."

In its multi-colored state I rode it out with a friend to see David Byrne and St Vincent play at the Cuthbert here in Eugene. It didn't have any brakes. The clamp holding the fork to the steerer also didn't work, or rather, it worked at first but got progressively looser by the end of the night. Riding home in the dark was dangerous and hilarious. I had to yell "no brakes" a lot at people on the bike path, thankfully they also thought it was funny.

When my real sissy bar came in I ended up needing to add some eyelets to the frame for the bar to bolt to. Using the existing eyelets on the dropouts would have got in the way of the disc brake. Oh yeah, i forgot to mention that i also brazed on some mounts for the disc brake, i was pretty pleased with how they came out.

I rebuilt the clamp using a much thinner material, the irony being that the super thick stuff i bought was less flexible and thus less able to clamp. There was also the issue of tolerances, the top of the fork was not painted, but the steerer was. That tiny little fraction of an inch actually made a difference. So the second time around i made the clamp thinner, painted both pieces equally and added another boss for an additional bolt. I also machined out the inside of the clamp so that it would sit nicely over the top of the fork's crown race. It looked much better this way.

Unable to find a stem in the right size I built my own. It didn't come out looking as well as I had hoped, but it was a significant improvement over the long 1 1/2" stem i bought used. I also made a spacer for it the exact length i needed because, again, 1 1/4" components are hard to come by.

I wanted the bike to be single speed, for simplicity's sake. To accomplish this i just used a single cog out of a cassette with spacers. I could have used manufactured spacers on the rear hub as well, but i figured since it had gone so well with the stem i'd make my own spacers for the cog on the hub.

The last thing to build was a small stand for the photo shoot. I needed something subtle that would hold the bike up as close to perfectly straight as possible. I used a small piece of scrap tubing and brazed a washer onto one end, bending it until it was the perfect angle to hold the bike in place. For the photo shoot it worked like a charm.

(sorry this one is sideways, I'll see if i can fix it later)

And here are the rest of the professional photos of the bike. They were taken by the very talented Heesang Byun. To see more of his work check out his website:

This project was a lot of fun to build, despite the hiccups. I'm pretty pleased with how it came out, but, of course, have plenty ideas about how i'll do it differently next time.

Thanks to Melissa Hart for the inspiration. Thanks to everyone at Bike Friday who helped out with it. Thanks to Heesang for the awesome photos. And thanks to these manufacturers for making the stellar components that made this bike possible:

Alex Rims
Black Ops
Cane Creek 
Origin 8

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