How much of a difference does a bike upgrade actually make?

[Crankin]

She means an endurance bike, not the kind of comfort bike you are talking about. But, you knew that.
All I know is that I don't feel slower on my Silque than I did on my Kuota. While, I am not "fast" by any means, nothing has changed, except the smoothness of my ride and no twitchiness.

[OakLeaf]

Right, but I think when the OP said the bike shops were all trying to sell her "comfort bikes," she meant the kind I was describing. That's all!

[MarieV]

No, Oakleaf, I think the bike shops are showing her WSD carbon bikes that tend to have more relaxed geometries (shorter top tube, taller head tube) compared to men's/unisex carbon bikes. She already has a Dolce and wants something faster, so there's no way she's testriding 30-40 lb. comfort bikes.

I was trying to point out that relaxed geometries have their place. Most WSD bikes are aimed at shorter women, and they tend to have shorter top tubes and taller head tubes since women tend to have longer legs and shorter torsos. The men's/unisex bikes with comparable length seat tubes usually have top tubes that are often 2-3 cm longer since men tend to have shorter legs and longer torsos.

Crankin, isn't your Trek Silque also a carbon bike? If so, I'm not surprised that you're not any slower on your Silque carbon bike than on your Kuota carbon bike. I would think the more aggressive geometry on the Kuota would only make you faster if you're riding really long distances in the aero position, especially if you couldn't achieve as low a position on the Silque.

However, the OP should totally be able to feel a difference between an aluminum Dolce and an Amira or any other carbon bike during a long test ride with hills.