Shimano Ultegra CS-R8100 12-Speed Cassette (11-30 T or 11-34 T) Expired

For all the complaining about the tech on cars, Id LOVE to have a CVT on my bicycle!

Yes, some people upgrade parts one at a time, or from fewer speeds to more. Drivetrain components are consumables, so it's always good to have your next chains, cassettes, and chainrings on hand. Get them when they're on sale, because once a groupset goes out of production the prices can soar. If the pandemic has taught us anything, you can't count on being able to get compatible chainrings 2 years in the future.

You've phrased your question as if upgrades would need to happen often to keep up with the changing number of speeds. For reference, 10 speed shimano road came out in 2004. 11 speed came out in 2012. 12 speed in 2021. People who ride a lot typically get a new bike on a shorter timeline than that. 13 speed shimano road? It'll probably be around 2030 before the top 3 groupsets (DA, Ultegra, and 105) have moved to 13 speeds. At this point 105 just recently moved to 12 speeds, and they're not done releasing 12 speed groupsets yet.

12 speed isn't really necessary over 11, and 13 even less so for road riding on doubles. At this point it's not innovation, it's just filling one of the gaps in the cassette. The real innovation happens first in MTB groupsets, then gets trickled down to road. If it weren't for the cylcing media pretending that the number of speeds is uber important, and marketing departments wanting to be able to say "we have moar, and moar is better!" then we'd still probably be on 11 speed.

Gravel benefits more from more speeds, up to the point where lifespan dips due to cogs which are too thin to last that long. Gravel ranges have much more noticeable gaps to be filled, but you'll have to try hard to convince me that having 15-16-17-19 instead of 15-17-19 really makes any noticeable difference to more than 1% of the cycling population.

Yes, some people upgrade parts one at a time, or from fewer speeds to more. Drivetrain components are consumables, so it's always good to have your next chains, cassettes, and chainrings on hand. Get them when they're on sale, because once a groupset goes out of production the prices can soar. If the pandemic has taught us anything, you can't count on being able to get compatible chainrings 2 years in the future.

You've phrased your question as if upgrades would need to happen often to keep up with the changing number of speeds. For reference, 10 speed shimano road came out in 2004. 11 speed came out in 2012. 12 speed in 2021. People who ride a lot typically get a new bike on a shorter timeline than that. 13 speed shimano road? It'll probably be around 2030 before the top 3 groupsets (DA, Ultegra, and 105) have moved to 13 speeds. At this point 105 just recently moved to 12 speeds, and they're not done releasing 12 speed groupsets yet.

12 speed isn't really necessary over 11, and 13 even less so for road riding on doubles. At this point it's not innovation, it's just filling one of the gaps in the cassette. The real innovation happens first in MTB groupsets, then gets trickled down to road. If it weren't for the cylcing media pretending that the number of speeds is uber important, and marketing departments wanting to be able to say "we have moar, and moar is better!" then we'd still probably be on 11 speed.

Gravel benefits more from more speeds, up to the point where lifespan dips due to cogs which are too thin to last that long. Gravel ranges have much more noticeable gaps to be filled, but you'll have to try hard to convince me that having 15-16-17-19 instead of 15-17-19 really makes any noticeable difference to more than 1% of the cycling population.

You sound really knowledgeable in this stuff.
I am not new to cycling, but am new to looking at specific components on my bike.
I got a Trek FX Sport 4 last year and am enjoying it.
I ride it really hard in a mix of 50/50 pavement + gravel.

Do you have any recommended reading to get into the details of how components work together and the various specs / meanings behind them?
I'd like to - as you suggest - nab some well priced components while on sale, and upgrade my bike for smoother shifting / faster top speeds.
If I understand correctly, the Shimano Ultegra line would in itself be an upgrade to my Deore setup, but past that I'd struggle currently in trying to pick out which components I'd need to get to make a meaningful upgrade to my ride!

I guess I'm behind the curve then. I still have 2 Trek 9 speeds, and a Trek 10 speed and a 2016 Diamondback Century 2 endurance/ gravel bike with 11 speed that is still new in the box.

.https://files.bikeindex.org/uploa...PH1_01.jpg [bikeindex.org]