The thing is...

Even on entry level bikes, the frame is the same from Claris to 105. Unless different forks.
The cost difference being components.

I bought a sora bike over 105 for the color. Sora came with qt.
I threw on Ultega Outboard. Bought a praxis crank.
So I stiffened it 2 ways , 1 being the bb and 1 being crank/chainrings.
And I also regeared at same time. Win, win win.

My loss being it was a 1100 bike. Then I sold it for $700.

So while I do argue for changing the bb / crankset. $25 bb , and $50-100 for used crank.

A decent used bike with 105 could be had for 600-800

While you might get 300-400 out of yours.

I tinker all my bicycles though. It is the hobby I spend money on. It is just part of life.


If you can afford it... do the upgrade.

Some of us will buy 3 chains per cassette.

While others won't buy a chain until they need a new cassette, new rings and a chain.

Some won't buy tires until they see cords.

Some people ridecrubber garden hoses. I'll take brand new garden hose tires off, and buy gp5000 tires.

It is your ride, make it into what you want to ride!