Cyclocross frame and fork! 

Since #CrossIsComming and I have never built a disc frame OR a fork at all for that matter, I figured my next build should be just that. 

The thought of a frame with a taller head tube, higher BB, more laxed head tube angle, more tire clearance, internal cables, True Temper tubes just sounds too good to pass up! So many new (to me) things to do on this frame.

The real challenge will be the fork. Never built a fork at all let alone a disc fork with a 15mm thru axle but hey, let’s give it a shot! 
Starting with the frame, I chose True Temper tubing. They’re made in the USA and may be the last American bicycle steel tube supplier for a while. While the lugs I am using are made in Asia, I do try to keep frame parts as American as I can. That’s why I have Paragon Machine Works dropouts, front and rear. PMW’s low disc mount rear dropouts are so simple to use and look amazing! The front dropouts are their new 15mm thru axle dropouts. These dropouts work with PMW’s own axles too! They have rack mount tabs but I will be removing those. I also have a Paragon front caliper mount that has a long fork blade stiffening extension on it. While I am using straight blades it’s nice to know if I wanted to bend the blades Paragons mount would be there to reinforce the bend. 

I really wanted to try internal cable routing. Nate Zukas (Zukas Cycles, Athens, GA) is an absolute master at this and he inspired me to do this! But I chickened out and only ran internal through the downtube and not into the DT and out the chainstays (through the BB). I’m happy with the results though. 

I also gave a shot at carving a “V” into the top head lug. Why not. Looks like it was done by a 7 year old. Ha! 

I have some more practicing to do. 

One Saturday I was home alone and I got started quickly! Knocked out 3 joints in an afternoon! I was pumped on the progress! 

I needed to build some tooling for the chain stay and seat stay slotting. Joe from Cobra Frames (www.cobraframes.us) came through AGAIN! He suggested a set of V blocks with a pin to allow one V block to follow the taper of the chain stay. So I made a set and they work bitchin’! (I can say that now because I live in California)

They work like this:

I also am going to try a stainless steel headtube badge on this mother feller. 

Cut in the shape of the S&M shield as I have relied on many S&M BMX parts for, idk, my entire BMX days. Even today! So, thanks Chris Moller for always making serious quality parts! 

On to the seat cluster. This is, what people say, the joint that gives the builder a chance to show off his artistry. Since I have no artsy side, I figured I’d give it my all. But first I needed a way to hold the tubes in rotational phase and at the same angle. My non artsy fartsy side came up with this double V block. 

The 5mm Alen wrench in the slots keep the two SS’s in phase and the V grooves hold the tubes. Then in a machine vice at an angle. What angle? Any frikin’ angle. This is art not math class damn it! Oh, that little strip is a chunk of leftover top tube. It’ll make sense soon. (If not already)

This little pic stitch kinda tells the rest of the story. (Now reread that last sentence in Paul Harvey’s voice. And if you don’t know who he is you probably have never cranked up windows on a car or used a rotary phone!)

Now just to braze the SS’s to the seat lug. Let’s get artsy! 

I am REALLY happy with how it came out! I know I over filled it. Hey, it’s not the Mona Lisa that’s for sure! 

Back to dropouts for a moment. I removed that little tab where the red arrow is just to make the transition from dropout to seat stay flow a little nicer.

I’m really happy with how the Paragon Machine Works Low Disc dropouts came out. I also like that I can get a longer derailleur mount from them too if I wanted to go up to an 11-40 cassette. 

At this point the frame is mostly done. The tire clearance is sweet, rear alignment is dialed, front end looks good to the best of my abilities, happy happy! Now I just need to do a couple cable guides along the top of the chain stays and braze the head tube badge. Here is where it is today.

FYI, the top tube is not bigger in diameter than the down tube. Haha! 

Edit (9/29/16): Here’s the mock up. 2° sloping top tube lookin good! It’s at powder coat now. Watch for updates sooooon! This is sitting now with a Surly Disc Trucker fork because I won’t have the fork done by CX season

So, next it’s onto my first fork build! I already made a jig, I just haven’t used it yet. This outta be good. I need to come up with a disc tab fixture. Sure I could buy one, and there are some nice ones out there, but I enjoy making my own fixtures as much as I enjoy building the frame. 

If you’ve made it this far you probably have little to do right now as I tend to babble about this stuff, makes me all giddy. And if you can get past my misspellings and ghramar errors then you’re a friking CHAMP! HIGH FIVE! 

As always, stay safe out there! Love your family, adopt your pets and RIDE YOUR DAMN BIKE!!! Whatever you have, whatever terrain you want, however far you want, Strava if you want, wearing whatever you want (as long as you at LEAST have a helmet on)! Just ride. It’s good for your body, mind and the planet.

Allan Varcoe

Advertisements