Tuesday, February 01, 2022

Why I Would Not Choose A Cyclo Cross Bike

Cannondale Super X (Image courtesy of Cannondale)
 NOTE: Large doses of "my opinion" will be handed out in gloppy dollops today. You've been forewarned.....

This past weekend the World Championships for the discipline of cyclo cross was held in the USA. I thought since that is - perhaps - top of mind yet, it might be fun to compare and contrast cyclo cross bikes with "gravel bikes" and see where they are different and why I would not choose to use one for gravel riding. I also want to point out some 'slight of hand' that some companies are using in the gravel bike market. Okay, let's jump in!

The Purpose Of The Bike: Before I get into details, it may behoove ourselves to look at what the intentions for a cyclo cross bike are versus a gravel bike. This is stop 'Number One' on the way to understanding why I, and many other early gravel riders, were not satisfied with cyclo cross bikes. 

The purpose of a cyclo cross bike is very specific. It needs to be a quick handling bike. This means that on a continuum of handling from "Stable" to "Unstable", a cyclo cross bike is going to lean a bit toward the "Unstable" side. That is what "quick handling" means. This does not mean the bike is unrideable! So, don't read into this in that manner. Going too far in the "quick handling/Unstable" direction can lead you to a bike that is nervous, hard to handle in demanding situations, and cause more rider fatigue due to the effort necessary to keep a bicycle like that on-line. But when done correctly, a bicycle with a bent toward the "Unstable" side can cut corners in a faster, better way, and will react to rider input with less energy and will reward you with faster cornering speeds. 

Cyclo cross bikes also need to be able to be pedaled in deep ruts due to the demands of sandy or muddy courses. They also need to be good at 'hopping' techniques and be able to clear barriers when hopped. A higher bottom bracket from the ground aids the rider in this manner. Generally we see this expressed in "Bottom Bracket Drop", which is the distance from a line drawn through the axles of the wheels when looking at the side view of a bike, and then measuring from that centerline to the centerline of the bottom bracket spindle. Less "drop" means better at hopping, clearing ruts, and barriers. 

Cyclo cross bikes also tend to have shorter wheel bases for - again- deft handling through corners. Cyclo cross courses often have hair pin corners and a cyclist in a CX event needs to be able to cut around those corners in the quickest manner possible. 

Partial view of a geometry chart for Canyon's CX bike. (Image courtesy of Canyon Bikes)
Specifics: Now let's take a look at exactly where and how a cyclo cross bike achieves its design intentions versus a 'gravel bike'. First off I want to draw your attention to the head tube angle in the chart. This is for a Canyon cyclo cross bike.. Typically we see a steeper head tube angle, (nominally around the 72+ degree range here) and that is done to keep the wheel base short and to keep the over-all "trail figure" lower. Both aid in keeping the bike good at tight cornering. (More toward the "Unstable" side of the spectrum) The Cannondale- above- takes a different route to the same over all trail figure range by having a slightly slacker head tube angle, but a lot of fork offset, which brings that handling back toward where the Canyon's is. (Confused by the whole "fork trail thing"? Hit this link for my explanation of it)

Next I wanted to point out the bottom bracket drop. Here we see it is listed as being "bottom bracket offset", but it is the same measurement. You'll notice that it is around the 66mm range. Great for hopping and clearing barriers. On the Cannondale, it is around 68mm. 

Next- Stand over height. This determines if you can straddle your bike without touching the top tube with your crotch. On the examples I am using here, I would strike the top tube in a quick get-off in the size bike I am suited for. (Around a size Large/58cm) And I have fairly long legs compared to my torso. This would be a far more worrisome issue if I were built with short legs/longer torso. 

Finally, cyclo cross bikes are meant for short duration efforts where a pit area is available and therefore rider support is assumed. So- you are typically not going to get all the accoutrements of a gravel bike like fender mounts, rack mounts, multiple water bottle mounts, or a top tube bag mount. You also probably are not going to get a bicycle made to be comfortable and easy to handle on long, grueling rides. 

In 2012 I advised Raleigh designers to make what became the Tamland model.

What Is A Gravel Bike?: So, what makes a gravel bike a......well, a gravel bike? You are probably catching on here to a few traits that are NOT what a cyclo cross bike has. So yes- A slacker head angle with not so much fork offset, leading to a handling package which tends toward the "Stable" side of the handling spectrum. I am not seeing terrain that requires hopping, riding in deep, muddy ruts, or sand, so a high bottom bracket is of no use to me. A lowered bottom bracket lends stability, and takes less effort to keep going straight on fast, loose down hill runs. So, a bottom bracket drop of 70mm or more is preferable. 

A bit longer wheel base figures are okay. Again, for down hill stability, but also for easing the chain stays out wider and getting bigger tires in there. For instance, while a 'legal' cyclo cross bike has a maximum specified tire width of 33m, that is NOT going to cut it around here, so I needed something that could handle a 42mm tire. Add in clearances for possibly muddy riding and that means a pretty specific frame design for gravel. Most cyclo cross bikes can not handle a tire that large and have great mud clearances. 

I also need water, and fenders at times, and maybe a place to mount a bag. I need 'compliance', not a large main triangle for shouldering a bike, so a sloping top tube with plenty of exposed seat post was better. All things not at all wanted for a cyclo cross bike. 

Before there were gravel bikes, CX bikes were used at Trans Iowa. (Image by J Kerkove)

So, here's something else that needs to be understood: Of course you can use a cyclo cross bike for gravel riding. Don't even hop on the comments telling me you've used a CX bike for years on gravel with no problems. I get it- Some people use fat bikes on gravel, some use MTB's, some ride unicycles. (Somewhere there has to be a uni-cyclist on gravel. I know it!) What you can ride is NOT the point here. What is better for me? Yes. THAT is the point. It just so happens that what I thought would work does work for many, many others. 

Finally I wanted to point out something I thought was all over with, but it has crept back into the conversation again. That is companies using the same geometry for gravel and cross. Typically I've seen the CX bike geo foisted off as being gravel bike goodness. It is definitely NOT as good as true 'gravel bike' geometry. I also know of a few companies using gravel bike geo and saying it is great CX geo. It definitely is NOT. Don't fall into the trap that this is good. Be careful when you look at gravel bikes or CX bikes to determine if the company you are checking out is just saving pennies by using one bike for both categories. Because that is what they are doing- cutting costs and making supply easier on them. It isn't doing the customer right.

I hope that points out the differences for those of you who may be newer to the gravel scene. I decided many years ago that a cyclo cross bike wasn't optimized for gravel riding, but that a cyclo cross bike is for what a cyclo cross bike is designed for. They are NOT specifically designed for back roads, gravel roads, or the like. A cyclo cross bike IS a very specifically designed tool for a purpose, so to those who say, or did say, that a cyclo cross bike is "good enough for gravel", I say phooey! You are not thinking about this equally. If you don't need a 'specific tool' for gravel, than the same logic applies to cyclo cross bikes. You know? Just use an old road bike, like the original cyclo crossers did. 

But thankfully we don't have to use poorly applied designs for purposes they weren't meant for. Thankfully we do have cyclo cross AND gravel bikes, (and triathlon bikes, BMX bikes, tricycles, and whatever else you can think of that needs a specific design.) I mean, really now.......we all could be riding penny farthings. Right? (sarcasm alert)

Of course we need gravel bikes for riding allroads. And yes- the name is dumb, but there is no going back now. 

Thanks for reading!

3 comments:

teamdarb said...

Clears it all up for me. Youtube videos sometimes cannot beat words in print. My take away is the CX bike is a dirt Crit bike. Now waiting for that RedBull Xtreme CX race featuring single speed fat and plus bikes with 3 foot barriers.

Derek said...

Looks like an older Lemond Poprad or Gunnar Crosshairs has another 20-25mm of wheelbase vs a road racing bike, and the Tamland 2 from 2017 another 20-25mm on top of that? Sounds comfy! Makes me curious what a 29er from same era was for geometry and wheelbase.

blooddoc23 said...

Thats a great discussion! I got a chance to check out the racing last weekend. Cx Worlds was really fun to watch and Centinnial Park there in NW Arkansas is incredible. I hope they have more big races there!