So moving on from my recent thread about gravel bikes, I’m now seeing a few more CX-oriented bikes, eg Boardman CXR, Kinesis CX and Genesis Vapour, available for v good money secondhand. And I’m trying to ascertain how suitable these are for longer days in the saddle and getting a bit more gnarly.

For a CX restricted to 33mm tyres, is that an issue? Some people imply that switching to 38mm or 40mm+ is the sweetspot for on/off road and that’s one of the reasons I think a gravel bike is better suited to me.

Does the race-oriented geo make 4+ hr rides a compromise? My CAAD8 is fine for 2-3hrs but my shoulders ache for anything longer. Again, a more relaxed gravel geo seems a more logical fit.

Cheers all

Interested in this also, in my eternal quest for the perfect gravel frame I’ve been mostly overlooking CX frames.

The only geometry figure I’ve been looking at (wierdly) is BB drop, I wouldn’t want a super high BB on a bike being used on roads and tracks. I’ve definitely seen some CX bikes with a drop of 65-70mm which I think is relatively low. Not sure what a ‘high’ BB is on a road bike.

Stack and reach would be the key for shoulders aching I think? The Kinesis CX Race Evo looks lowish at the front compared to a Cannondale Synapse, but no lower than a CAAD8. I think most gravel frames err towards the Cannondale Synapse sort of stack measurements.

That said I’m running a set of Specialized Hover handlebars. Not the prettiest but they do add an extra 15mm stack and once you get used to the looks you stop noticing them. Purists might sneer but purists probably aren’t riding gravel bikes…

Edit: oh but re: tyre clearance, I’m running a 35 rear and 38 front, bike handles occasional lumpy off road forays quite happily. When CX manufacturers say 33c are they just saying that because it’s the UCI approved size? I’d be tempted to assume a 35 would go in fine…

My old race bike (Argon 18 Arsenic) really only had room between the chainstays to run 33mm CX tyres with anything like reasonable clearance. I do use 35mm Clement X’plor with it, but there’s really not much clearance and anything with knobs would be problematic. So yes – if they say 33mm then it probably will only take 35mm.
My much older bespoke 753 CX frame will take 40mm tyres – futureproofing from 1996!

I’ve run 32s, 35s and 40s. The latter were a revelation. I’d say that, unless you are racing, go for the bigger tyre clearance. My next project is a set of 650 wheels for 47mm tyres

Is yours the Amazon touring or Amazon CX Colin?

I found 35 was the sweet spot any bigger and I was on a compromised 29er or compromised roadbike

I’ve done the last two DR200s on a CX bike with no issues, granted it had room for bigger rubber but the rest of the geo issues is marketing bollocks. The differences in many cases between a CX and a gravel bike are miniscule or non existent.

38C I would say is the minimum for proper gravel tyre comfort

the rest of the geo issues is marketing bollocks

You saying the stack height difference between a racey CX bike and a long distance gravel bike aren’t likely to be significant?

Big difference between a smooth gravel & a bumpy stoney access road. I’ve just gone 47 up front, all depends where you ride.

Ta chaps. Looks like 35mm+ is still the preferred compromise which would knock a few CXers on the head.

Interesting note on the stack height and bars – had forgotten to think of that. Saw a weird one recently!

Am imagining a nice carbon CXer pushing high 30s and a bit of rise should be sound.

Re geo, I’ve just found this Excel geo comparison builder. Haven’t played with it yet but if it does what I think it does then geo at least should become more understandable.

My 10 year old Kuota Cross takes 40mm tyres, still running canti-brakes and I’ve done events like Dorset Gravel Dash, a number of SDW traverses and flung myself around a few trail centres, including quite a few blacks. I’d only ever run CX tyres for racing – have three pairs of tubular wheels – now running 40mm Schwalbe G-Ones tubeless and can keep up with my mates on road bikes. High volume, tubeless tyres certainly help on the comfort front as the carbon frame is brutally stiff. A lower BB, longer wheelbase and slacker angles can help give stability when bikepacking with gear – strapping a bar bag to the front of a CX-race bike makes a twitchier bike even twitchier, but not unrideable.

Touring.