Is it my wheels or my cassette?

[WinstonWolf]

So, I've got a couple of road spec bikes.

My PX RT-58 running full Ultegra and PX AL 30 C wheels

My Bottechia CX bike running 105 and Shimano RS-10 wheels.

The PX is lighter and should be faster, but I just seem to be able to gain speed more easily on the Bottechia...

Other than the wheels the Bottechia runs a 50/36 front with a 12-27 cassette whereas the PX runs the more conventional 50/34 with an 11-28 cassette.

PX gearing:



Bottechia gearing:



I'm thinking the closer central ratio favours my (somewhat wonky) legs out on the fens where a close ratio lets me use my power best.

The Shimano wheels aren't generally well reviewed, but the PX ones seem to come up favourably for a budget wheelset.

What do we think? It'd be nice if it was the cassette as they're cheaper than a wheel upgrade

[TwistingMyMelon]

Could be gears, are they setup similiar? If I run my bikes side by side I can see instant differences

[WinstonWolf]

I was bike fitted to both by the same bloke, my Bottecchia is a bit too small for me, hence the larger roadie.

It's easy enough to swap the wheels over at some point to see if the PX actually runs faster, but I don't particularly want to swap cassettes at the same time.