Cyclocross - If You Were Having a CX Frame Built…

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Cynikal
05-04-10, 12:49 PM
Ok, here’s the deal. I’m taking a frame building course this summer and I plan on building a single speed cross frame. I plan on racing this bike on occasion plus a little commuting. What little details would you add if you could build a frame? Here are a couple of things I’ve thought of so far:

1.Angling the track ends to the angle of horiz dropouts. This will allow the brake pads to remain constant for gearing changes.

2.I would like to build a stem with an integrated cable stop.

3.There will be fender braze-ons.

4.Integrated barrel adjuster on the rear cable stop.

5.I’m still debating on running full housing across the top tube. Pro’s or Con’s?


Is there anything you think I should add?


grolby
05-04-10, 02:23 PM
Better than angling track ends would be using horizontal dropouts, period.

On 5, clever cable routing will be required to use a road derailer.

caloso
05-04-10, 02:33 PM
Double braze-ons on the track ends and rack bosses.

A con for full housing on top of the TT is that moisture and sweat tends to get trapped under the housing and rust forms there. What if you did full housing but put the guides at 3 o'clock? It would be high enough not to interfere with shouldering and may allow the moisture to run off.


Cynikal
05-04-10, 02:41 PM
That is a good point about a horiz dropouts but I have a nice set of Paul track ends that I would like to use.

this frame will be a single speed so I wouldn't need to route cables for a RD, just the rear brake.

Caloso, good point. I understand that full housing has big pro's when doing really muddy races but as you know our races are pretty dry so I'm undecided.


Better than angling track ends would be using horizontal dropouts, period.

On 5, clever cable routing will be required to use a road derailer.

grolby
05-04-10, 07:19 PM
That is a good point about a horiz dropouts but I have a nice set of Paul track ends that I would like to use.

this frame will be a single speed so I wouldn't need to route cables for a RD, just the rear brake.

Caloso, good point. I understand that full housing has big pro's when doing really muddy races but as you know our races are pretty dry so I'm undecided.

I guess if you have the parts.

And obviously I have reading comprehension issues. Singlespeed, of course.

flargle
05-04-10, 07:26 PM
That is a good point about a horiz dropouts but I have a nice set of Paul track ends that I would like to use. Another vote for horizontal dropouts. But OTOH there's something cool about trackends, but I've seen angled ones and they just look wrong. My 5c.

TimJ
05-04-10, 07:33 PM
You sure you'll be able to angle them? Paul dropouts also have retaining screws, if they're angled the screws may have to be taken out and unusable.

Cynikal
05-04-10, 11:29 PM
Thanks TimJ, hadn't thought about that.

bmwboarder
05-05-10, 12:45 AM
Here is my rear cable stop that was put on my frame. It came out quite well.
http://www.mybikespot.com/photo_med.php?id=121

Also, I didn't go with full housing for the rear brake, and it was fine for the first full season, and I hit up some muddy and snowy races. Its at 3 oclock too. And lastly, go with 1 1/8 front if you can, they even have it for lugged frames now (if that is what you are doing).

http://www.mybikespot.com/photo_med.php?id=2

flargle
05-05-10, 05:51 AM
1.Angling the track ends to the angle of horiz dropouts. This will allow the brake pads to remain constant for gearing changes.Another option: run a White Industries DOS 17t/19t freewheel in 2x2 mode with 40t/38t chainrings.

Cynikal
05-05-10, 10:03 AM
Thanks BMW, your's looks great! Did you build the whole frame or modify an existing one? The frame I plan on building will be lugged and definitely 1 1/8 for fork availability. I like the toptube stops at the 3 o'clock position, I'll do that on mine.

I'm thinking of going with a rear stop like this but with an integrated barrel adjuster.
http://www.kirkframeworks.com/images/JK_cross/JKC_brazeons/DSC_1554.jpg

Edit, found a finished pic of the rear stop.
http://www.kirkframeworks.com/images/JK_cross/JKC_complete/DSC_2287.jpg

Cynikal
05-05-10, 10:13 AM
@ Flargle, that is a possibility. So far I have planned a more retro style of build. I have both a clincher and tubular set of dura-ace freewheel wheels that are in very nice shape and a tri-color 600 crank that I would like to use. The brakes will probably b a polished cr720 for the front and IRD CAFAM's for the rear.

bluenote157
05-05-10, 10:55 AM
I recently did some triple cable guide braze-ons on my top tube. I have 5 brand new single cable guides if you want them. However you probably only need two. PM me if interested.

bmwboarder
05-05-10, 11:33 AM
The frame was a custom build from the ground up. An old racing buddy was building his first few. I think he did a darn good job :)

I like that cable stop. One thing I wonder is if a full cross bar/cable stop would add any stiffness to the back end or not. Probably not if the top of the seat stays are done right, but I still wonder...

Are the dura-ace hubs bolt-on?? Good luck with the new frame. I'd love to hear more about it too (which tubing you use, and final weight especially).

Cynikal
05-05-10, 01:15 PM
Your buddy did a great job from what I could see.

According to Kirk, this style of stop is but lighter and stiffer. In fact here is his quote, "The brake stud has been brazed and the reinforcement is about to be added. The single arm stud is both lighter and stiffer than the traditional bridge style brake cable stop. This gives better braking feel and modulation."

The wheels are not bolt on but with good skewers I don't foresee any issues. As for the tubing and other details, since it's a class I don't have that much control over those details since they are provided with the class. I will post more information during the class and when the build is done.

Thanks everyone for the suggestions and please keep them coming if you have more.

bluenote157
05-05-10, 02:20 PM
Here is my rear cable stop that was put on my frame. It came out quite well.
http://www.mybikespot.com/photo_med.php?id=121

Also, I didn't go with full housing for the rear brake, and it was fine for the first full season, and I hit up some muddy and snowy races. Its at 3 oclock too. And lastly, go with 1 1/8 front if you can, they even have it for lugged frames now (if that is what you are doing).

http://www.mybikespot.com/photo_med.php?id=2

How did you paint it? is this powdercoated?

flargle
05-05-10, 02:39 PM
What's the downside of moving the cable stop closer to the bosses? According to Lennard Zinn's theory, it would make brake squeal/shudder less likely.

Cynikal
05-05-10, 02:58 PM
I've read Zinn's theories on that as well and thought they were mostly aimed at carbon forks. I've never had squealing or shuttering from a steel fork so I figured it wasn't relevant to this build. As I reread your post I'm wondering if you are referring to the rear stop. If that is the case, I've never had squealing issues with a rear brake that I could fix with adjustment.

bmwboarder
05-05-10, 03:29 PM
How did you paint it? is this powdercoated?

Yes it is powdercoated. Definitely the way to go for cyclocross.