WhyFi

Tell me about it - happens to me all the time.

tomato coupe

I hate it when that happens.

Ataylor

Gotcha! Thanks. 🙂
It does help. More so on an intellectual level than experiential, since I neither race nor do I go on group rides. I mean I think I always knew deep down that this sport was complex and didn't simply involve sitting on a bike and pedaling fast, but it's still somewhat surprising to me that such a small gap between cogs can affect someone significantly enough to leave them trailing behind their group. I might just have to join a group one day - at least until I hit the 17th cog on my 11/28 - just to see (from behind, of course) what all the fuss is really about.

woodcraft

FIFY

Ataylor

If I understand you correctly, SoSmellyAir mentioned that above, about how some have a more broad power band that can handle wider cadences without worry. For the rest of us, however? A bike bar in one hand and binoculars in the other comes to mind. Or at least that seems to be the conventional wisdom around here.

WhyFi

To be clear, it's a small difference, but it's a small difference that can make a big difference in the right situation. Think about being 2 seconds slower over a quarter of a mile - that's not much at all, right? But at the same time, it's enough that you could lose the wheel of the person in front of you, which means that you lose a good chunk of the benefit of their draft, which means that you're going to slow down even more because you're going to see increased wind resistance, which is going to open the gap between you and them even more, which means even more resistance, etc, etc.

If you don't ride in situations like that or if you're stronger than the people that you ride with, or if you're not looking to squeak out long-standing PRs, etc, then all of this means pretty much squat.

woodcraft

Riding closely behind others can reduce the effort needed by up to 1/3 because of less wind resistance & the faster the speed, the more it matters. In groups, riders commonly take turns at the front and then rest at the back of the group, so the group as a whole can go faster than the individuals can.

Falling behind the group by just a few bike lengths at >20mph can lead to losing the group and it's advantage entirely. This is where having just the right gear ratio matters, being able to keep up at crucial moments.

For the bar & binoculars scenario, having a bike with nice slack geometry for no-hands riding is most important, IMO.

Ataylor

I mean I started this thread to see whether or not I would feel a tangible difference between cassettes, not for racing purposes, and was told that I would. In my mind, I felt like the overall ride would be more enjoyable (subjective, I know) if the shifting was actually smoother (or, less disruptive, as HTupolev put it). I'm looking at this whole thing through the lens of a very inexperienced worldview. I didn't know what cog meant two weeks ago. In all honesty, I'm still not sure if I'm using the right word. I also didn't know my cassette was an 11/32 until two weeks ago. I just ride my bike. That's it. So if any of this turns out to be true? Great. If not? So be it. I'll use the information I gathered from you guys for any group rides I may be a part of in the future. No biggie either way.
Oh, that's what's you meant. I always assumed it effected riders to some degree, but a 1/3 reduction in effort is pretty crazy.
Can't say I fully understand the no-hands/slack geometry thing, but I'm sure the advice is sound and practical for us drifters, so I'll look into it.

Ataylor

Anyway, ya'll. Thanks again for your help. I'm all set on this end, so there won't be a need for me to check for updates to this thread as often anymore. So I bid you guys a safe and happy riding season. Hope each of you enjoys it in good health. Take care.

SoSmellyAir

That's why it's good to have a glass of red wine -- assuming that the wine is good -- the night after you ride. I hear it is good for the heart.

SoSmellyAir

Let us know how it goes with the 11-28 cassette. I hope it is as life changing for you as the 12-25 was for me.

rm -rf

Di2
You are getting Di2? It's a very fast, very reliable shift on any rear cassette. And the front is quite fast and drama free. I shift all the time, often for just a few pedal strokes, then shift again. A few years ago on a group ride, we went around a bend in the road and right there was an unexpected short steep climb. The three Di2 riders shifted way down, and were climbing the 30 foot hill in the small chainring and low gear, sitting down. The mechanical shift riders were still in their big ring, mashing up the hill. They didn't even attempt to shift the front.

28 vs 32 as a low gear
The 32 is 14% easier. The ratio, 32/28 = 1.14 That's a little more than "one more gear", since gear shifts can range from around 5% to maybe 15% or so. 10% is a reasonable rule of thumb for typical shifts.
My 32 is the difference between sitting or having to stand up on a 10-12% grade. And it's extremely helpful on really steep grades, like 15-18%

Close ratio cassettes
Some riders don't seem to notice if they have big jumps between gears, so that their cadence changes quite a bit. Others want a cadence all the time that's "just right". It's way less critical at easier paced riding, where cadence is often a bit lower anyway.

A few years ago, I liked a local cycle club ride that was fairly flat and a bit too fast for me. It would hit 20-23 mph at times, and I was going all-out to keep that pace. So I'd shift to the next larger cog, but then I'd be spinning too fast. Shifting back to the harder gear, I'd be pushing too hard on the pedal. It was back-and-forth, trying to find that good cadence.

From a BF post, I ended up making a Shimano 14-32. Perfect for that ride!

14-32 cassette
This is the largest 5 cogs from an 11-32 (on two cog carriers), and the other 6 from the 14-28 "junior racing cassette"
The 50-34 front and 14-32 at typical flat road cadences:
This has very close shifts from 18-25 mph, just where I needed it. And the low gears to get up the occasional steep hills.
The downside is that it spins out at 28-29 mph. That's okay, I'll just coast on steeper downhills.
And the 34 chainring tops out around 17 mph, instead of 21 mph with an 11-32.
The other problem with this gearing: shifting the front chainring needs 4-5 shifts in the back, instead of about 3 shifts. But the Di2 can do that quickly and easily.



11-32
During Covid, I only rode with 3-5 riders, and no drafting. We would push hard on climbs, but cruise on the flats. So close gearing isn't necessary.
Here's the standard 11-32. Big jumps between shifts in the 20-25 mph range.
Good spacing in the 15-20 mph range, for either the 50 or 34 chainring. That's good for many riders.
(note that this chart goes to 35 mph, not 30.)