Cyclocross - What defines a TRUE CYCLO CROSS FRAME?

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

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

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

+1

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

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

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.

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.

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


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

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.

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.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.

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.


http://www.giant-bicycles.com/_generated/_generated_us/bikes/models/images/225/2008/TCX-0-White-Blue.jpg

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.

Can you name one?

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

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.

That said, I agree on preferring non-compact geometry, even though 95% of my carries are suitcase rather than shoulder...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.

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



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.

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.

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.

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.

[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.

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)?

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.



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

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.


That Leader frame's top tube, in addition to being sloping, also has a cable running under it, make of that what you will.

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.

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.

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

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.

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.)

^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.

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

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

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.

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

Why canti brakes? Nothing else still uses that method right?Cantilevers (especially the old-school wide-profile ones) offer better mud clearance than V-brakes. Also, road brake levers have too much mechanical advantage with V-brakes, so you need to add a travel agent between the two.

Disc brakes are outlawed in UCI-sanctioned road and cross races. Even in races where they are allowed, they still have a weight penalty compared with cantis. Cross courses don't have the sort of sustained, technical descents that cross-country races have.

Cantilever brakes are simple, light, reliable, and have more than enough stopping power. Like all other kinds of brakes, they have their loveable and not-so-loveable quirks.

Cantilevers (especially the old-school wide-profile ones) offer better mud clearance than V-brakes. Also, road brake levers have too much mechanical advantage with V-brakes, so you need to add a travel agent between the two.

Disc brakes are outlawed in UCI-sanctioned road and cross races. Even in races where they are allowed, they still have a weight penalty compared with cantis. Cross courses don't have the sort of sustained, technical descents that cross-country races have.

Cantilever brakes are simple, light, reliable, and have more than enough stopping power. Like all other kinds of brakes, they have their loveable and not-so-loveable quirks.

Well put.

135mm spacing so you can build some robust wheels with MTB hubs. Especially for disc equipped bikes.

There seems to be some miscommunication with the whole 'top mounted cables' thing. It's important that the cables that run along the top tube are mounted on top of it. Otherwise cables dig into your shoulder, get caught in your glove, etc.

Many cross bikes run some cables along the down tube. That seems to be more of a matter of preference, because I wouldn't imagine an old-school company like Gunnar still doing it without good reason.

135mm spacing so you can build some robust wheels with MTB hubs. Especially for disc equipped bikes.Wrong.

good eye schnee, i was talking about the former but looking back it seems others were talking about the latter.

due to preference and local course design i tend to shoulder a lot. when shouldering i prefer not to have any cables on the downtube because i almost inevitably pull them. sometimes it causes a skip in gears when i get back on, and i could easily see it causing me to dump my chain if i'm not careful.

the same could be said for suitcasing and cables along the top tube, of course, so i can see how that would be a matter of preference. sorry to MIN for misinterpreting.

I am wondering if there is an "ideal" size for the top tube. With tubing getting larger and shaped I have to think if there is a point of the top tube getting too large to handle easily, or it having a shape that hinders suitcasing.

Also, what about internal cable routing? Obviously, running the rear brake cable internally on the tt has been done on road bikes for a while but what about running the der cables thru the tt as well, or is that going to be too much of a mess to setup (yes, I have built up bikes with internal rear brake routing)? What about running the der. cables internally thru the down tube?

Just wondering out loud here.

internal cables make a lot of sense in adverse conditions, but they are marginally harder to engineer and manufacture, as well as the aforementioned issue of more cable decreasing performance of the brakes.

i don't CX (yet) but from a design perspective you're likely to be cleaning gunk out of an external cable more than an internal setup. the extra cost comes at a marginal added benefit.

Top tube routing for shifting stability and portaging, no braze ons whatsoever, 130mm spacing.

No exceptions.

Higher BB,

Why?

I'd have just the opposite; lower the BB.

My reasoning is two-fold; 1) the saddle height will be lower for re-mounts, and 2) the center of gravity will be lower making the bike easier to handle on technical courses.

Why?

I'd have just the opposite; lower the BB.

My reasoning is two-fold; 1) the saddle height will be lower for re-mounts, and 2) the center of gravity will be lower making the bike easier to handle on technical courses.

On the flip side, too low of a BB and you'll get pedal strike on off-camber or super-rutty conditions.

Belgian Knee Warmers has a good write-up on this. Different CX manufacturers use different philosophies on this. All I could figure out was the BB drop varied, but was no lower than a road bike of the same size.

I would like to see some manufacturers off small and medium frames with 650B wheels, so I can ride trails without constantly worrying about toe overlap.

internal cables make a lot of sense in adverse conditions, but they are marginally harder to engineer and manufacture, as well as the aforementioned issue of more cable decreasing performance of the brakes.

i don't CX (yet) but from a design perspective you're likely to be cleaning gunk out of an external cable more than an internal setup. the extra cost comes at a marginal added benefit.

Why not just run full housing? I'll be doing with my MB over the winter, seems like it would be beneficial to a CX bike as well.

Why not just run full housing? I'll be doing with my MB over the winter, seems like it would be beneficial to a CX bike as well.
I have been running full housing on my Trek XO1 for the last 2 years.
I guess I don't fall into the true cyclocross frame as it is my full time commuter, summer & winter. The full housing does keep out the extra road crap & winter salt/ice/slush...

On the flip side, too low of a BB and you'll get pedal strike on off-camber or super-rutty conditions.

Belgian Knee Warmers has a good write-up on this. Different CX manufacturers use different philosophies on this. All I could figure out was the BB drop varied, but was no lower than a road bike of the same size.

I think it really depends on the region.

Here in St. Louis we don't run courses that would put you at a disadvantage with a road-height or lower BB. In fact, some of the short-track XC courses could even be tackled with a cross bike.

The one point not mentioned yet seems to be light weight. A lot of current CX-labelled bikes have quite heavy frames. I recall when CX frames tried to be lighter than road frames.

I would like to see some manufacturers off small and medium frames with 650B wheels, so I can ride trails without constantly worrying about toe overlap.Tire and wheel availability is an issue with smaller wheels. I know some makers (DeSalvo, for example) design their smaller frames for 26" wheels, which gives you decent tire availability, although for cross not nearly as good as 700c. OTOH there are some very light wheel and tire options for cross-country racing, especially tubeless, that would work well for cross.

I've ridden, and owned a lot of cx frames. None have ridden nearly as good as...http://www.steelmancycles.com/eurocross.html

Disc brakes are outlawed in UCI-sanctioned road and cross races.

... only in the pro mens and womens races that is. For all other categories they are legal at UCI events.

Why not just run full housing? I'll be doing with my MB over the winter, seems like it would be beneficial to a CX bike as well.

I thought that's what was normal with internal cable routing. At least on my old Trek's you ran cable + housing thru the top tube. I think it can be done with minimal amount of internal-crap buildup. Perhaps rubber grommets at entry/exits?

But back to what makes a true 'cross bike... I think Surly and Riv have it right with the 132.5 spacing. Run whatever wheels you want. As for braze-ons for racks, fenders. I think they are nice to have but would be out of place on a true, dedicated cross bike. I vote for the lower bottom bracket but I haven't run a lot of courses, let alone outside of the midwest. That said, I will probably be running the frames *with* the braze ons as I am certainly not to the point of being competitive enough to purchase such a dedicated race frame.

Why?

I'd have just the opposite; lower the BB.

My reasoning is two-fold; 1) the saddle height will be lower for re-mounts, and 2) the center of gravity will be lower making the bike easier to handle on technical courses.

You're thinking more like a roadie. Remember, more than half the time a cross bike is used off road. The high BB also keeps you from from getting the crank stuck on ruts.

bb height's a tradeoff. lower bb makes for easier and quicker mounts.

You're thinking more like a roadie. Remember, more than half the time a cross bike is used off road. The high BB also keeps you from from getting the crank stuck on ruts.You're thinking more like a mountain biker. Remember, the original reason for the high bottom bracket had nothing to do with clearing "ruts", but to prevent toeclips (i.e. "mudcatchers") from dragging on the ground during dismounts and remounts.

http://www.belgiumkneewarmers.com/2007/12/how-high.html

You're thinking more like a mountain biker.

Touche!

Having tried both, the lower BB has worked far better for me, both for climbing and being able to quickly ride sharp turns by steering the bike, whereas a frame built higher requires more lean angle--a disadvantage in sharp turns as traction and control suffers.