MY CUSTOM CYCLOCROSS PROJECT

[simonanks69]

hey guys,

well at the moment i am going to build a custom cyclocross bike from scratch, with the help from my boss/ frame builder.

the bike is going to built out of steel tubing and hopefully will be a sram force/ ultegra Di2 equipped....
the perpose of this bike is for a school project and to race on, since im in need of a cyclocross bike..

I created some rough sketches before finally deciding on what type of geo to choose.
hopefully i can use a true temper s3 tubing or a columbus spirit tube set.

i have also created a blog: http://cyclocrossdreams.blogspot.com.au/" onclick="window.open(this.href);return false; which tracks all my progress.

THANKS

[Briscoelab]

Your BB drop is VERY low on that drawing. Pretty much the highest BB I've ever seen on a CX bike.... it might handle a bit odd. Also, the chain stays are a bit long for a racing bike, but not outrageous. I like a ~425mm chain stay on my cx bikes. Everything else looks reasonable.

[simonanks69]

i revised the geometry, any feedback?

[Briscoelab]

77mm of BB drop is too much Seriously, I'm not trying to be a pain. But, most CX race bike have BB drops of about 61mm (Ridley, considered to have a very high BB.) to 70mm (considered low, like Specialized Stevens, etc).

I personally like about 65-67. I think if you are anywhere in that range you will be OK and can live with it. If you come more from a road background, I would opt for a bit lower BB. (i.e. more drop) of about 67mm. It will help with stability in cornering at speed.

[rockdude]

I prefer BB drop in the 70mm range. I also have a custom in the 80mm range. If you race tight smooth courses the 80mm drop kicks butt. If you race lots of rough terrain with off cambers the 70mm will help with hitting the pedals. I hate bikes with drops less than 70mm. I also like a shorter rear end. 425cm or a hair longer depending on clearance issues. Otherwise I would go with this build.

[Frans]

Good for you for putting in a bit of slope for the TT. It looks more compact than horizontal and I've yet to understand why sloping is an issue. I'm a bigger guy (184cm) so rider bigger frames so perhaps i've not encountered the issue.

The technique I use is the grap the handlebar and TT - reasoning is why lift the bike higher than is absolutely necessary? It's wasted energy...

What kind of material? What kind of HT? What fork? What kind of BB? What kind of cable routing?

[euan]

sloping is fine on larger frames but on the smallest it can make it difficult onto the shoulder without bashing the frame against it. I don't know what your courses are like but the ones I compete often have longer runs up steps or steep muddy banks which require the extra hand to help you up.

[simonanks69]

thanks for the feedback guys, really appreciate it
i did my FINAL sketch for the bike, keeping in mind all of your suggestions.



another question, what tubing set should i use, incorporating the integrated seat post? i've emailed english cycles, but i haven't received a reply keep in mind want to keep it fairly light

thanks

[LongSlowDistance]

the perpose of this bike is for a school project and to race on, since im in need of a cyclocross bike..

Where are you going to school?

[simonanks69]

I attend scopus memorial college.
Does anyone have any suggestions for tubing which will incorporate the ISP?

[Briscoelab]

If it is being tig welded, I think that Life tubing is a good mix of light weight and acceptable stiffness.

[simonanks69]

even for the 711mm seat post

[Briscoelab]

No, I think Life would be light for a steel ISP tube of that length. But, it's best to check with a builder.

What type of head are you thinking of using? We have some Speedvagens, one with the Thomson head and the other with the Enve. Both are really nice.

[bones]

135mm rear spacing and disc brakes would make is complete.

[simonanks69]

i have to use canti's since im using a pair of training wheels to minimise cost.