Dany6

Hey guys,i need someone to help me understand how big of a difference i can make when choosing a cassette ratios and whether it can cause problems or not.
So,let's say i have 11-26 cassette and that i struggle a little bit when i hit a hill,so i decide i'd like to ease things up a bit and get 11-28 or even 11-32 tooth cassette,first what difference would it make to go from 11-26 to 11-28 in a manner how easier it'd be to climb?unnoticeable difference or just a slight difference?
And would that cause any problems with rear dereailleur or maybe chain etc,and do i have to change chainset/chainrings (don't know how i should call it properly) ratio then as well or i can change cassette ratios without affecting chainset at all?
I'm sure that going from 26 to 32 teeth would probably make a big if not huge difference on a hilly climb,but in result for making a big difference (from 26 to 32) i'd might need to change a rear derailleur (cage) as well then right?

And now reverse,what if i choose to go from 11-26 to 11-23 cassette how big of a difference would it make there?going from easier to harder.Would it make a noticable difference when climbing a hilly areas or just a slightly bit?

Now for example,let's say i have 11-28 or 11-32 tooth cassette and i wanna drop to 11-23,it can be possible that i have short rear derailleur so now i have to buy a longer one right?I mean both scenarios are possible right?,it can turn out i'd need both shorter or longer cage if one of them needed am i right?

And the last question,let's say i have 11-28 tooth cassette,can switch just the 28th cog with a bigger one let's say 30 or 32 tooth cog,or it's impossible.
That's it,so every advice and explanation would be very much appreciated and taken to knowledge .

I struggle at English a bit but i hope y'all will understand my questions.
Thanks .

Steve B.

Here's a good gear chart calculator. It allows you to input varies chainring combos as well as the different cassettes available. You can display in gain ratios or gear inches (which is what I understand). Note that what cassette you can use is dependent on which rear derailleur you have as there are limits as to the number of cogs that the derailer can handle,. As well, changing to a casette with larger cogs usually requires a new and longer chain. When you know the model of derailer, you can look up the capacity's on the manufacturer website.

https://mike-sherman.github.io/shift/

Iride01 

More teeth on the rear cog or less teeth on the front chain wheel means easier pedaling up a hill. But you can go too far with easier, because you'll be slower and be pedaling for a longer time to get to the top. So you trade something to get something.

Anytime you change to a different tooth count on the rear or the front you need to assess whether your rear derailleur can handle that change. Some will, some won't. The manufacturers of DR's give the specs for you to use to figure out whether it can work or not. Usually they are conservative but the minor difference between your bike and another's might make the specs right on the money. And there can be big difference from the same DR model line as to what they can handle from one version to the next.

Will going from a 30 tooth rear to a 32 tooth rear make a difference for you? It might. If that keeps you from grunting a few times as you climb your hills then it'll be keeping you from simply wearing yourself out. However if you constantly are in the large rear cogs for most all your ride, then the entire range of gearing on your bike is wrong for you.

big john

Yes, a 3 tooth bigger cog will make a difference you can feel. If you go to smaller cogs you don't need a short cage derailleur but you might need a shorter chain.
Do you think you need to make a change?

Dany6

Now i understand it a bit more,thanks a lot .

So most changes for rear cogs i have to take care of rear derailleur as well.
No,no i don't,only for hills.

Ah i get it now.
I don't think i need to,for now all seems fine.

Iride01 

Some DR's will handle a wide range of cassettes. Others won't. So you should know before you go off and buy a cassette to change your gear ratio as sometimes changing the chainwheels and even the entire crankset is a better option both gearing wise and cost wise.

So no, you don't have to change the DR just because you changed the rear cassettes tooth count. But you will if that new cassette is outside the specifications of your current rear DR.

There is also the idea that if you ride the hill enough times, your legs will get stronger and you won't need the lower gear ratio.


Oh....... you will likely have to get a longer chain if you go to a bigger cog on the rear. Even if we are talking a 2 tooth increase. Depends partly on how the person that sized the previous chain. If they left it on the longer side maybe not. If they left it almost too short then maybe so.

biker128pedal

On your question of swapping out just the larger cogs on a cassette. I looked into that last year. The problem is the largest 4 or so cogs are connected.

As for changing to a cassette with a different range. It is noticeable for 2 or 3 tooth change. Ya also have to consider the larger jumps between cogs with wider range. I have a Domane that came with an 11-34 11-speed. Where I ride most the hills are not long or steep so I prefer an 11-28 for closer ratios. I really should have gotten an 11-26.

DaveSSS 

You can't have your cake and eat it too. More range means larger gap somewhere. Shimano took it too far with their large 11-13-15-17 gaps on their 11-34. Most riders want 11-12-13-14.

biker128pedal

I’ll save the 11-34 for the mountains. At least by coming with it there was a long cage derailleur to allow the options.

grizzly59

Here's another gear calculator just for fun

Bicycle Gear Calculator

guachi

Yup. I have two Domanes, each with the 11-34 and the gearing is off as every jump is at least two. If they were going to make a cassette that was easier for hills or for less fit riders then they could have made a 12-34 11sp like 12-13-14-15-17-19-21-24-27-30-34 or something. That makes the gaps from one gear to the next 1/1/1/2/2/2/3/3/3/4 instead of the current 2/2/2/2/2/2/2/2/3/4.

The big reason I switched to an 11-30 instead of the 11-32 is the 11-30 is 11-12-13-14-15-17-19-21-24-27-30 for jumps of 1/1/1/1/2/2/2/3/3/3. The 11-30 is identical to the 11-28 for its first 8 gears so you get all the goodness of closer set gears for most of the gearing and then larger jumps when you hit the steeper hills.

Racing Dan

Lots never use the very tall gears or only need one to push against going down hill. After all 11-12-13 and possibly even 14 is in the 25 mph+ range at normal cadence, if combined with a 50t chainring. They would need a much smaller chainring to actually benefit of the small gear jumps in the tall end. Or its just wasted.

Bicycle Gear Calculator

Racing Dan

Depending how fast you are either one of 11-30 or 11-34 might be the better option. If you are not that fast the 11-34 has more gear selections with Smaller gaps in the midrange vs the 11-30 that in turn has better selection in the very high end.

For me the 11-34 would give me more usable gears, with smaller gaps, in the gear range that I actually use the most. Only occasionally would I miss the 12 or 14 that the 11-30 has.

From the big ring I would have two more gears (8) in the 45" to 90" gear inch range than the 11-30 that only has 6 in the 50" to 90" gear range. The 11-34 would also let me stay in the big ring a little longer.

https://ritzelrechner.de/?GR=DERS&KB...30,34&UF2=2150

tomato coupe

Yeah, if you spend most of your time below 20 mph, the 11-34 looks like a better option. (I suspect that applies to the majority of the general cycling population.)

philbob57

I think the percentage difference between the rings is more important than the number of teeth. There's about a 10% difference between a 10-tooth cog and an 11, which is very close to the difference between a 30 cog and a 34. In fact, going from 10 to 11 is arithmetically exactly the same as going from 30 to 33.

Also, Sheldon wrote that the rivets between the cogs in cassettes aren't functional and removing them won't compromise the cassette's working. If he's right, custom cassettes without the little cogs are buildable, but I haven't done any experiments.

Racing Dan

The 15 should be good to about 23mph at normal cadence. Beyond that many are going down hill and you have to ask you self if having a selection of 4 or 5 gears for that range is warranted or you simply need 1 or two gears to push against, like the 11-34 provides. Me, I'm good with the 11 and 13 in the 11-34 cassette. Cant think of a single time I really needed/ wanted a 12 rather than 11 or 13.

grizzly59

This used to be the case, the rivets or tiny bolts just kept the stack together in the proper alignment. You could build up anything with loose cogs. But ... my newest 9-speed Shimano Ultegra cassette has the 3 biggest cogs (21-24-27?) riveted to a separate aluminum spacer / subhub that then splines onto the freehub. The cogs won't work without the spacer.

Atlas Shrugged

Most riders are indifferent and have no idea about the gearing gaps on their bikes. Given most new Ultegra and below-equipped bikes are provided with an 11-34 cassette with rarely a complaint It's more likely a niche group of people who are concerned with the gaps at the bottom end of their cassette.

Bah Humbug

I used to agree, but realized that for my morning training rides, I could combine it with a 46T single and spend most of my time in the middle of the cassette. Shimano probably intends it for use where the 11 (and maybe 13j are reverse-bailouts. Most casual riders rarely use the smallest cogs.