12-21 or 12-23?

Lumen

I'm currently using an 11-25 (I think) SRAM Red cassette.

I want a closer spaced cassette for racing. Probably DA or Ultegra.

I don't need an 11t as I'll be moving to a standard double shortly, so I guess 12-23 is the default option.

Shimano do a 7800 12-21, but not in 7900. I'm unfussed about getting the older cassette, but wonder why they have discontinued it.

Anyone got experience of a straight through cassette like the 12-21?

tunney

Lumen wrote: »

I'm currently using an 11-25 (I think) SRAM Red cassette.

I want a closer spaced cassette for racing. Probably DA or Ultegra.

I don't need an 11t as I'll be moving to a standard double shortly, so I guess 12-23 is the default option.

Shimano do a 7800 12-21, but not in 7900. I'm unfussed about getting the older cassette, but wonder why they have discontinued it.

Anyone got experience of a straight through cassette like the 12-21?

I hate the jumps in a 25. An 11-21 won't be a linear step down, its a jump from 21-19.

Why would you use a DA cassette - unless you're at 4% BF the weight savings aren't that big a deal, go for an Ultegra.

An 11-21 and a standard double - whats next big boy pants?

doozerie

Personally, I'm a big fan of close ratio cassettes, but two things you should consider when deciding between them are:

* Do you need a 23? Have you needed one during your races so far and do you plan to take part in races with a profile where you are likely to need one?

* Does the 12-23 lose you any gear(s) that you are very prone to using? For example, some people would hate to have to jump from 16 direct to 18 - the loss of that 17 would be an issue for them.

You could buy both blocks, of course, and swap between them for each race according to the race route. In a flattish race you probably won't need a 23 and the closer ratio of a 12-21 could prove very beneficial.

Lumen

tunney wrote: »

An 11-21 won't be a linear step down, its a jump from 21-19.

There isn't an 11-21 as far as I'm aware, but I don't need the 11 anyway. So the options are 12-21 or 12-23.

tunney wrote: »

Why would you use a DA cassette - unless you're at 4% BF the weight savings aren't that big a deal, go for an Ultegra.

That would be the sensible option durability-wise. I'm trying to avoid looking like a skeleton so there are limits to the extent that I can weight-weenie myself.

Have you used a 12-21?

Lumen

doozerie wrote: »

Do you need a 23?

Have you needed one during your races so far and do you plan to take part in races with a profile where you are likely to need one?

Based on experience so far, I am unlikely to need to go below 20kph.

39-21 @ 80rpm is 19.2kph, so in theory a 12-21 should be fine.

Perhaps it's more losing range on the big ring that might be the issue with 12-21, so the question is more like "can you have a cassette that is so closely spaced as to be annoying?".

I don't know why Shimano have withdrawn the 12-21 in the 7900 range.

Raam

I guess I shouldn't say that I raced a 27 in the last few. Oops, too late. I have a 12-23 block at home but I just haven't bothered to put it on since holiers.

Lat year I used a 12-25 block, but then, I'm a lightweight.

mloc123

Sorry to hijack, I am looking at getting an 11-23 cassette... did I read somewhere that some freehubs will only take a 12t? Something to do with the lockring size?

doozerie

Lumen wrote:

Perhaps it's more losing range on the big ring that might be the issue with 12-21, so the question is more like "can you have a cassette that is so closely spaced as to be annoying?"

I think the most likely source of annoyance would be if your most commonly used/comfortable gear(s) fell either on or just below the lowest gear available on the big ring. That might leave you having to switch between the two front rings more often than you'd like in a race. How you ride plays a big part here obviously (e.g. whether you prefer to spin faster in the same gear to accelerate for short bursts, or whether you prefer to change up a gear). It might be hard to avoid hovering in or around the "between front rings" gears though regardless of which cassette you choose, but it is a factor to consider when weighing up the pros and cons for each cassette.

Quigs Snr

I think that the 11-23 is the best racing cassette, at the eddie tobin in Enniscorthy last year, in a severe tailwind going up a main road, I was completely spun out in a 53-12 (I admit that I cannot ride at a very high cadence however and tend to prefer grinding it out Jan Ullrich style). Similarly, if you find yourself on a hill like Mamore Gap you might be glad of the 23 !

Mloc, if these is a freehub that cannot take an 11 it will be a very niche wheel indeed. Most Pro's would ride with an 11 and a large amount of amateur racers so you would really be limiting your market bringing out a serious wheel that is effectively useless for a sprinter or TT rider.

Lumen

Quigs Snr wrote: »

I think that the 11-23 is the best racing cassette, at the eddie tobin in Enniscorthy last year, in a severe tailwind going up a main road, I was completely spun out in a 53-12 (I admit that I cannot ride at a very high cadence however and tend to prefer grinding it out Jan Ullrich style). Similarly, if you find yourself on a hill like Mamore Gap you might be glad of the 23 !

Thanks, useful insight.

I think I'll plump for 12-23 Ultegra to avoid the 17-19 jump. If I ever go fast enough to spin out the 53x12 I'll treat myself to a DA 11-23 upgrade.

It's probably the 15-17 jump right in the middle of the cassette that's bothering me now.

DirkVoodoo

mloc123 wrote: »

Sorry to hijack, I am looking at getting an 11-23 cassette... did I read somewhere that some freehubs will only take a 12t? Something to do with the lockring size?

You can normally buy 11t lockrings for various wheel/cassette combos.

Token do a Shimano 11t one: http://www.chainreactioncycles.com/Models.aspx?ModelID=38651

EDIT: Ah, nevermind, I think you are referring to the freehub diameter maybe?

doozerie

mloc123 wrote:

Sorry to hijack, I am looking at getting an 11-23 cassette... did I read somewhere that some freehubs will only take a 12t? Something to do with the lockring size?

Sheldon Brown mentions the issue for older Shimano freehub bodies.

doozerie

Lumen wrote:

It's probably the 15-17 jump right in the middle of the cassette that's bothering me now.

Maybe you can build up your own cassette if you can find the additional rings. Many cassettes these days are bolted/riveted together in groups of rings, but according to Sheldon Brown the bolts/rivets are completely unnecessary so you can safely split them apart. I'd wonder whether that is still entirely true for modern cassettes, but if so then you may have more options available.

Lumen

doozerie wrote: »

Maybe you can build up your own cassette if you can find the additional rings. Many cassettes these days are bolted/riveted together in groups of rings, but according to Sheldon Brown the bolts/rivets are completely unnecessary so you can safely split them apart. I'd wonder whether that is still entirely true for modern cassettes, but if so then you may have more options available.

I think I'll just sell it. Anyone want a SRAM Red 11-25 cassette? Not at all noisy or gappy, honestly. Lightest in the world and all that. :pac:

DirkVoodoo

11-23 Ultegra 6700 cassette on sale on CRC for 45 euro.

Unless you think the odd 50 grammes saved from not buying a 11-21 7900 is worth 90 euro.

I think I already know the answer anyway.

Oh, here are the cassette breakdowns for 7900 in case:

The 11-21 includes- 11,12,13,14,15,16,17,18,19,21
The 11-23 includes- 11,12,13,14,15,16,17,19,21,23
The 11-25 includes- 11,12,13,14,15,17,19,21,23,25
The 11-27 includes- 11,12,13,14,15,17,19,21,24,27
The 11-28 includes- 11,12,13,14,15,17,19,21,24,28
The 12-23 includes- 12,13,14,15,16,17,18,19,21,23
The 12-25 includes- 12,13,14,15,16,17,19,21,23,25
The 12-27 includes- 12,13,14,15,16,17,19,21,24,27

biker_joe

Hi Lumen
I use a 23-11 ........ there is only one or two races in the calender where you need a 25, Shay Elliot and Munster ....
also if you don't like the ratios your talking about get a 54 on the front... but that might confuse you more !!
you could also a someone says do your own cassette, but it's more expensive ....
http://www.parker-international.co.uk/3981/Marchisio-Aviotek-Shimano-10-speed-Cassette.html

Biker Joe.

Lumen

DirkVoodoo wrote: »

11-23 Ultegra 6700 cassette on sale on CRC for 45 euro.

Yes, I ordered that.

DirkVoodoo wrote: »

Unless you think the odd 50 grammes saved from not buying a 11-21 79800 is worth 90 euro.

The basic problem is that those 50g are only worth something on a hillclimb when I'll need more than 21 teeth anyway. So I have difficulty justifying the €2/g saved, and the lack of durability of the Ti cogs. On a hilly cassette it makes more sense to use Ti as the cogs are bigger and get used less.

Lumen

biker_joe wrote: »

you could also a someone says do your own cassette, but it's more expensive

I read that those Marchisio cassettes have crappy shifting which rather defeats the object. No idea if it's true.