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I see bikes all over called cyclo cross, or cross this, or that cross with frames that do not seem like cyclo cross frames to me.

For those that are interested in CX, what in your mind are the elements of a frame being a True Cyclo Cross frame? Which design features must be present to keep the frame from just being a hybrid or touring frame with shorter stays?

I have been involved in CX since the 1970s; so my ideas on the pure cx frame maybe too strick. Wondering what others think

thanks

Mike

Cynikal 

Canti mounts, clearance for wide tires, top mounted cables and non compact geometry are the big ones for me.

MIN 

+1

but not the top mounted cables. that's personal preference.

merlin55

top mounted cable are so that when you are running, carrying the bike with the top tube on your shoulder

MIN 

yes that's the logic but in practice there are plenty of cross bikes which are bottom mounted. i prefer to not have cables weakening my grip over the top tube.

dzinehaus

something that you can sling over your shoulder quickly. robust enough to take a hit.
something that you are ballsy enough to take out on a day that you wouldn't even take out your beater bike on.

Heyduke

Everything said so far.

The top mounted cable guides also help (slightly) keep the crap off your cables.

My Yeti has no rack/fender eyelets so I guess it's more of a racer but the eyelets are nice to have on CX bikes because they are so versatile.

I don't prefer it, but some manufacturers make semi-compact, compact and even super-compact CX frames. Their reasoning: for step-over mounting clearance.

flargle

Can you name one?

Cross remount is over the back of the saddle, not step-through.

Smallest frame sizes (i.e. sub 50) might have slopier top tube, just to fit 700C wheels.

justinb

That said, I agree on preferring non-compact geometry, even though 95% of my carries are suitcase rather than shoulder... the top tube is that much closer to my hand. Also agree that the top tube plays no role in dismount-remount... my leg comes around the back for dismount, and I jump on the back of the saddle for remount.

Heyduke

That's just what a manufacturer told me.

My ARC-X slopes significantly too and the frame is an XL.

Then there's this LEADER.

flargle

95%? Almost every cross course I've raced has a section that's best shouldered, but has fewer than 20 portages total. YMMV

Yes, a lot of makers use a sloping top tube, but the idea that it's to make mounting the bike easier is ludicrous, regardless of what some alleged "manufacturer" says.

A sloping top tube is probably easier to suitcase, because your right hand doesn't need to go as high while carrying.

That Leader frame's top tube, in addition to being sloping, also has a cable running under it, make of that what you will. I don't think people consider Leader frames to be "true" anything, cyclocross or otherwise.

justinb

I do realize it's atypical, but I can only remember one true run-up out of 5 different courses I raced on last fall. Almost everything else was the high-speed, middle-of-straight double barrier kind of thing where suitcasing was more appropriate. We only had one wet race too, for what it's worth.

akatsuki

Instead of top-mounting the cables, why not just put cable housing over the entire length of cable so that they don't get gummed up (I haven't done this, but I was just wondering)?

I don't have too much of a problem with compact frames, I think having a lower grip on your frame means you don't have to lift it quite as far up to get it over stuff - so there is a bit of a trade-off.

justinb

In practice, I don't find that I lift my bike very far at all. It's more of a lift and then use the left hand on the bars to tilt the whole bike out, enough to clear the barriers.

Obviously, in a crowded field this becomes less of an option.

M_S

I've been told it's bad form to tilt the bike outwards because it's less likely to be stable when you put it back down.

My bike is compact geo with downtube cable routing, oh well.

mrtornadohead

[QUOTE=akatsuki;6871417]Instead of top-mounting the cables, why not just put cable housing over the entire length of cable so that they don't get gummed up (I haven't done this, but I was just wondering)?
...QUOTE]

I thought of this immediately when I started monkeying around with my Concours frame - it had no cable stops, just braze ons for cable routing, so the cable housing makes the full run from shifter to derailer. I do suppose some people will say that there is the extra drag on the cable and sluggish performance but with teflon cables and modern housings I find it a non-issue. On top of that I managed to have some "extra" krytox for the cable housing extis/entances.

As for the original question posed, cyclocross began as bikes made up from old frames hanging around and whatever was in your parts box. Modern 'cross bikes as one can tell, have several different preferences. But in general, higher bottom bracket, lower-trail geometry for quick handling, clearance for wider tires of course, and gearing a bit lower than what is used for standard "road" bikes, and handlebars are typically a bit wider and higher. After that I think you start getting into preferences more than definitions.

dirtyphotons

because then the cables still dig into your shoulder. imo, top mounted cable routing is not optional or a matter of preference in a cross bike.

exactly. this is the one and only cross specific benefit to sloping top tubes that i acknowledge. still not enough to make it worth the trouble shouldering. i ride smaller frames, and compact geo means it's almost impossible to quickly get my arm through the triangle. if you could make a 52 cm frame with a sloping top tube, high(ish) bottom bracket and still have a nice spacious triangle, (and 700c wheels of course) that'd be pretty awesome. but i've never seen it done.

the leader cross frame is in my mind the perfect example of a company just slapping canti mounts on a crit frame and calling it a cross bike. and by starting this thread that seems to be the sort of thing that mike's trying to avoid.

Heyduke

LEADER doesn't sell the "CX" bike any longer so perhaps this is why.

climbhoser

Higher BB, lower trail, clearance for wider tires, disc or canti mounts, top routed cabling, more upright geometry in general (i.e. shorter TT for a given effective ST length).

I'm not picky, either compact or not, I can get both up and over barriers.

trelhak

For the really nit-picky stuff:

chainstay bridge undrilled and no bottle cage bosses. (No room for a bottle when you're putting your arm through the main triangle, nor will you be installing caliper brakes.)

dirtyphotons

^agreed that those are hallmarks of a race frame.

still, i don't think a drilled bridge or bottle mounts (or rack, fender and disc mounts, for that matter) make the frame any less raceworthy.

as someone who uses his cross race bike for other purposes, i'd rather have em. if it were something that somehow inhibited my ability to race on the bike, i'd probably rather not.

evan_phi

...anything that can get yer *** across a finish line?

M_S

Cantilever brake bosses, for sure.No offense meant to those racing Poprad discs.

jfmckenna

For me shouldering is very important. I'd rather shoulder a bike for stairs or long run ups rather than roll it through the mud. So compact geo is out. Top mounting cables I like too. And one of the best and imo most important braze ons that I have ever seen was a bottle cap opener on the chain stay.

Some frames have no braze ons not even for water bottles but I say go ahead and put everything on it I mean why not make the bike versatile? Your not going to race cross on that bike for ever so some day you may want to make it a commuter and or it makes it more resellable.

adebrunner

Why canti brakes? Nothing else still uses that method right?