Tried a friends carbon cx bike last night while doing some training on grassy playing fields. The bike was not actually wildly lighter than my alloy one based on the lift test, but felt like I was rding on air. Why? Added stiffness/compliance? Weight difference making more of a difference that expected? Simply down to differnet geo?

Either way I can’t wait to get a cabon bike now 😆

Not all (carbon) frames are built the same…

It’s all in the layup.

What they said. They can make it more vertically compliant or stiff or whatever they hell they want, where they want. Not all carbon bikes are super comfortable, some are designed to be super stiff, but retain some level of comfort (moreso than aluminium).

Are we talking about road type bikes here?

tyre choice/pressure, grips, handlebars, etc. all play a bigger role than frame material, (imho)

(people seem very excited about a carbon frame, for the awesome ride characteristics, but won’t bother experimenting with tyre/shock/whatever pressures, grip/tape choices, etc…)

Are we talking about road type bikes here?

cyclocross. it wasn’t just a bit better, it was total night and day. I was astounded.

Thing is it’s two different bikes. The wheels can make as much a difference as a frame, were the wheels a big upgrade too?

I’m not saying frame material can’t make a huge difference, but in addition other components could have added to this giving you the whole “wow” experience

Different wheels/ tyres.
A saddle that actually fits you better
Gel pads under bar tape

Hidden motor 😉

Lighter, stiffer wheels with tubulars makes a big difference to how a CX bike feels, particularly if you’re riding clinchers with tubes. Because you can run tubulars safely at lower pressure, it’s sometimes the difference between riding and walking.

tyre choice/pressure, grips, handlebars, etc. all play a bigger role than frame material, (imho)

And in any scientifically measurable way.

My money’s on significantly lighter/faster rolling tyres. The frame doesn’t make much difference, even in terms of weight, within reasonable bounds.