Ok I know this could get controversial but I have the luxury of owning a relatively dated CX bike and a custom steel gravel bike.
I am convinced I can tell the difference in how they handle and even if I wasn't racing on the CX bike it would still be bike of choice at this time of year for nadgery, muddy, rootsy singletrack rides.
Buuuuut... outside of racing I would really love to be able to stuff 40mm minimum and possibly even 45mm tyres in there, I'm a heavy guy and there's only so many times you can bottom out your rims trying to pedal over roots, inserts or no.
So what makes a CX bike a CX bike? Biggest difference between my CX and my gravel is BB height (60mm vs. 75mm) with lesser differences in chainstays (430mm vsm 435mm) and wheelbase (1035 vs 1045).
I wouldn't have believed I could notice 10mm differences in chainstays or wheelbase so I'm guessing a lot of it is in the BB height.
I had to check but I think the headtube angle of the gravel bike is actually STEEPER than the CX bike, I'm sure I had a reason for that at the time 🙄
This is all angling towards thinking about getting a custom steel CX bike for next year with CX geo but space for bigger tyres...
This is all angling towards thinking about getting a custom steel CX bike for next year with CX geo but space for bigger tyres...
Not sure how much local league regs vary from UCI but the max size in UCI-sanctioned events (and usually therefore in most races run under British Cycling regs) is 33mm. The Three Peaks CX race allows up to 35mm tyres.
Worth noting before you go getting a bike that'll take 50mm tyres!
https://www.bikeradar.com/advice/buyers-guides/gravel-bike-vs-cyclocross-bike
Yeah not a concern for me, I'm in masters (and not very fast) so even in British National Trophy races, UCI rules don't apply to me. I raced 38mm tyres in the first round of the Scottish CX series.
Those links confirm my thoughts I guess, although I hadn't factored in the lower stack of the CX bike, I was thinking I would try and build in some extra stack to relieve the wrists a bit, but sounds like I might lose some of the handling characteristics I'm enjoying so much!
On 38c on my CX bike but I don't race. Bought a lightly used one a couple of years back. I do fancy a gravel bike, but more all road - the CX isn't ideal for bike packing as it has no mounting points. CX bikes are closer to race bike geometry than gravel.
I've not looked at the geometry numbers but my only point of comparison is between my VN Amazon and my Topstone.Â
While I'd classify the Amazon as a touring bike it was also sold as a CX bike. I rode mine lots as a "gravel bike" before that was really a thing (often saw it referred to as Monstercross). Loved it in that guise, with both 700x40 and 650x47 options.Â
I was dubious about the "need" for a gravel bike but found the Topstone on a deal and was completely swept away by how different it felt to ride (again in both 700x40 and 650x47). It's more nimble accelerates faster and holds speed better in undulating terrain. It does have carbon-rimmed wheels, and is almost 2kg lighter, which must have an impact.Â
I've not yet loaded up the Topstone for a longer bikepacking/touring trip so can't compare on that front.Â
As regards punctures and rim damage, I'm convinced you are simply running your tyres too soft. Maybe it's your expectation of what a gravel bike/tyre is capable of but I don't exactly hold back on rockier terran. If you're a bit heavier than me, you're still hardly a Clydesdale but wider rims and tyres will always help.Â
Would you have to sacrifice rim brakes for a suitable rim/tyre combination?
As regards punctures and rim damage, I'm convinced you are simply running your tyres too soft.
Yeah possibly, am always trying to find the sweetspot of fast/comfortable/protecting rims, and bear in mind my comment above was based on running 33mm tyres though, there's not much volume to play with!
Would you have to sacrifice rim brakes for a suitable rim/tyre combination?
Almost certainly, I've discovered a rigid fork that would allow me to run cantilever brakes and 45mm tyres so in theory am sorted, but for the CX races I'm definitely suffering cloggage around the brakes which can't be helping my already pitiful chances 🙄
..the CX bike it would still be bike of choice at this time of year for nadgery, muddy, rootsy singletrack rides.
/
I wouldn't have believed I could notice 10mm differences in chainstays or wheelbase so I'm guessing a lot of it is in the BB height.
The CX bike handling tricky singletrack well could be partly due to the higher BB. Higher BBs feel easier to weave through tricky bits plus less likelihood of pedal strikes means we're more inclined to get a crank rev in here and there to help. CX bike probably also corners better than quite a few gravel bikes do now.Â
From CX to gravel, gravel bikes changed the handling priority from short technical races to long untechnical rides, the low BB was probably the main change until MTB geometry experiments came into it. Considering the terrain a lot of end up on riding gravel bikes in the UK I think the CX-ish BB heights weren't a bad thing, but I do prefer a lower BB on tarmac.Â
Almost certainly, I've discovered a rigid fork that would allow me to run cantilever brakes and 45mm tyres so in theory am sorted, but for the CX races I'm definitely suffering cloggage around the brakes which can't be helping my already pitiful chances
Get discs - almost all CX bikes use them now and it also gives you a massively greater range of wheel options.
Get discs - almost all CX bikes use them now and it also gives you a massively greater range of wheel options.
To be honest I doubt I'd be buying carbon and there's still plenty of good aluminium rim brake rims out there, but yeah probably discsÂ
So what makes a CX bike a CX bike? Biggest difference between my CX and my gravel is BB height (60mm vs. 75mm)
Yes that is the key difference and the BB height is similar to a track bike whereas a road and gravel bike would have similar BB height. Â The higher centre of gravity decreases stability meaning the bike changes direction more easily. Â And although it may only be 10-15mm it is noticeable as I have ridden many CX bikes, track bikes and road bikes.
Ok cool, so let's assume it is the BB height I'm noticing.
The Giant TCX has a good rep as a CX race bike you can also stuff wider tyres into, so that should be my benchmark, if I can get custom steel for a similar price I'll probably do that but I know the steel bike will be a kilo heavier.
Very basically CX bike - road bike with less clearance than an "all road" bike if sticking to the UCi rules with corresponding twitchy quick steering to cope with twisty sharp turns in the park.
Gravel bike- up to 55mm clearance if you get the right frame set with more forgiving head angle, minimal chance of toe overlap but still engaging enough steering wise to enable you to ride off road sections with a bit of peril that your modern XC MTB would make a snoozefest
What is the difference between the bar height/reach of the two bikes? I think a lot of people fail to appreciate the change in handling from quite minor alterations to the stack/reach of a CX/gravel/road bike. Owing to the shorter wheelbase and steeper HA they are much more sensitive to bar position changes than an MTB, and it's very easy to end up with too much weight through the rear wheel and not enough through the front. That feels comfortable because you're sat up and the weight is off your hands, but the front can then become quite vague, and you may find that when you go back to a slightly lower stack height you have much more confidence when cornering. I would expect a CX bike be lower in stack and longer in reach, assuming they are the same size? Might be worth experimenting with different handlebar positions on the gravel bike.
99 spokes will let you compare geometry of commercial bikes.
When I looked at this it was mostly bb height and a little bit of length as you found. Gravel bikes being that bit more stable.
Some did do odd things to reach, pushing it out and then using a shorter stem. It is really hard to compare but also trail numbers vary. This can make the bike feel more stable.
Many more modern CX bikes can take big tyres. No one is buying CX bikes now so the less specialist manufacturers are using the same frames as their gravel or all road bike. I know my virus CX bike takes 45mm tyres so I use it for gravel (more than CX in terms of hours). A lower bb for CX can be a pain but you'd get used to it. These things often don't matter as much as you think after a few races.
A lower bb for CX can be a pain but you'd get used to it. These things often don't matter as much as you think after a few races.
Oh yeah totally, I very much doubt it's making any difference to my position in races, it's more that I'm legitimately enjoying the handling of the CX bike on specific terrain (i.e. the sort of terrain I'm most likely to be riding in winter).
The 60mm BB height quickly excludes a lot of the wider clearance frames on the market, the Giant TCX seems to be the only one I've found with a 60mm BB and clearance for 45s. Even at full RRP it's going to be cheaper than custom steel so I guess that's that decision made!
might be teaching you to suck eggs, but with your 15mm higher BB, are you measuring the cockpit fit (ett or reach plus stem, bar height etc) relative to the ground or relative to the BB?
What is the difference between the bar height/reach of the two bikes? I think a lot of people fail to appreciate the change in handling from quite minor alterations to the stack/reach of a CX/gravel/road bike.
might be teaching you to suck eggs, but with your 15mm higher BB, are you measuring the cockpit fit (ett or reach plus stem, bar height etc) relative to the ground or relative to the BB?
I do need to keep checking I'm getting my comparisons right!
But basically yes, bar height is ultimately adjusted with respect to saddle height (achieving a more aggressive drop than my gravel bike as the CX bike doesn't get used for longer distances). Since the saddle height is adjusted with respect to the centre of the BB, the actual BB height doesn't matter. Basically everything ends up 15mm higher off the ground.
A new Giant TCX in M/L is almost identical to my current CX bike but 5mm shorter. The size L is 5mm longer and 20mm higher stack.
I'm attracted to the extra stack height, for versatility in case I did want to use it for longer days, and just general aesthetics/robustness as it's 20mm fewer spacers below stem.
BUT I think the M/L with a layback post (which I run on all my bikes anyway) would probably be the better choice, gives me more wiggle room with the reach as well.