Converting a road bike to a cx bike?
 

I'm curious, do most folks just slap some "all-terrain" type tires on a road bike or do the opposite on a mountain bike? Is there more to it? I'm just a MTB/roadie wondering about this interesting in-between world...

The bikes are mission specific there is no adapting.

Ah come on, that's just false.

People ride MTB's in CX all the time, I've even seen people on full squish MTBs hacking it out on the course.

The main limitation with using a road bike would be fitting tires (most of todays road specific bikes will not clear a CX tire) and brakes, dual pivot brakes are not optimal for CX. But that's not to say you couldn't use a road bike.

EDIT: Really the determining factor would be the rules for equipment set forth by the sanctioning body of the race.

Here is the bike ridden by the best cross racer in the world:
http://cyclingnews.com/tech/2009/pro...ago_c50cross09

Most amateur cross racers ride a variety on that theme, although most with not-quite-as-nice bits, perhaps aluminum or steel frame instead of carbon, etc etc.

What other modifications need to be done beyond new tires?

Really just to try it out, tires is all you need, if you get serious about it, i'd look into getting a CX specific bike.

You need a frame, fork, and brakes that will fit around the new tires.

While it's true that modern road bikes lack the tire clearance for a proper cx tire there are road bikes that make fine conversions. After all that's what the original cyclocross bikes were road bikes adapted for "mudplugging".
a.) Find yourself a U.J.B. (universal Japanese bike) from the '70s or early '80s.
b.) Pick parts from a broken cyclocross bike or collect from ebay and craigslist.
c.) Assemble and tweak to your satisfaction.

The end resullt might look something like this...

http://img213.imageshack.us/img213/1103/fuji0154u.jpg

http://img213.imageshack.us/img213/2473/fuji0155.jpg

There are some early '90s hybrid bikes that were more road bikes than the comfort/hybrid bikes of today and would make a nice conversion project. Trek Multitracks (7900 was Easton ProGram, 750 and 790 were butted True Temper, below were straight cro-mo) would work well-- not too heavy, canti bosses, decent original parts mix, and should be fairly cheap if you luck into finding one.

I did two CX races on my old Trek 660 last fall. That's basically what I did: fit the fattest tires I could (which happen to be pretty much the thinnest CX tires you can find). Worked great for the dry and dusty September race:

http://i2.photobucket.com/albums/y18.../delpasocx.jpg

Not so great for the muddy November race.

http://i2.photobucket.com/albums/y18...DSC02944-1.jpg
The brake calipers just jammed with mud and I had to stop a few times to dig it out. Not optimal. I think I may have to save up a few bucks and find a proper CX frame on eBay for next fall.

That's a sweet looking bike, got more/larger pics? :thumb:

What tires/size are these?

Kenda Kwicks. I think they're labeled as 30mm but they're more like 28.

Thanks for the compliment. Sorry the craptastic cell phone photos are the best I got.
In person it has more...uhh...character.
Funny thing is I have a brand new '09 Scott comp and I would just about as soon ride this old beater.
The fork certainly compilments the smooth ride of the steel frame.