OT: Converting 12-28 to 11-28 cassette???

[Daniel Chao]

I'm not happy with my 12-28 cassette and would like to convert it to 11-28 (Shimano 9000).  If I bought a new 11t first position and 12t second position cog and took out the 16t cog, think I would be good to go?  Is there anything special about the third position cog,, etc??  

Here's the spacing for the two cassettes

11-28: 11-12-13-14-15-17-19-21-23-25-28 (the goal)
12-28: 12-13-14-15-16-17-19-21-23-25-28 (current)

[Alan Antonuk]

It will work, shifting might be a bit rough where the shift-ramps/gates don't quite line up (e.g., where you've changed it), but this is likely to be minor depending on how picky you are about smooth shifts.

-Alan

[Patrick Kitto]

The 11t is an overrated cog. 

16t is way more useful unless you have a 45mph sprint. 

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[Ryan Anderson]

Does Shimano have an official layout for 11-28? How does that compare?

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[Jason Thorpe]

On Jul 7, 2014, at 10:12 PM, Ryan Anderson <ry...@michonline.com> wrote:

Does Shimano have an official layout for 11-28? How does that compare?

It’s not just “how it compares” in terms to which teeth-count are present… different combinations use different timings for the shift ramps.

But yes, Shimano does have a standard 11-28 in the Ultegra line.

-- thorpej

[Maxence Nachury]

Funny that you ask. I was in the same situation last year wanting to “take it to 11” and ended up replacing my 12-28 with a 11-28.

According to Shimano, what you propose won’t give you a factory 11-28. 

[Rob]

On Monday, July 7, 2014 10:12:44 PM UTC-7, Ryan Anderson wrote:

Does Shimano have an official layout for 11-28? How does that compare?

http://si.shimano.com/php/download.php?file=pdf/dm/DM-CS0004-02-ENG.pdf

page 4.  the differences on 11-28 and 12-28 are the 11,12,13,16,17 (and lock nut).

Frankly, if you want an 11, if you have an 11 from a 10 speed setup I'd just use that and the lock nut, remove the 16 and see how it works.

I have an 11-28 10 speed which I got a 16 for and correct size lock nut and just tossed the 11 cog and it works fine.

[Daniel Chao]

max - thanks for the info sheet.  looks like all i need is a new 11t and 13t and i can replicate factory spec.

you guys don't find the 11 sp useful for low grade descents?  i've been struggling to keep up with the crew; spinning out in the 12t.

[Jeffrey Skokan]

Maybe time for you to go 53 on the big chain ring?!?

[Maxence Nachury]

Part# for the large sprocket carriers are different between 11-28 and 12-28.

As others have chimed, shifting ramps are tailored to one cassette. I would just eBay the old cassette and buy a new one. It would always be in the back of my mind that shifting *may* not be 100% great. Just that thought, that is 10W lost.

On Jul 8, 2014, at 5:46 PM, Daniel Chao <daniel...@gmail.com> wrote:

max - thanks for the info sheet.  looks like all i need is a new 11t and 13t and i can replicate factory spec.

you guys don't find the 11 sp useful for low grade descents?  i've been struggling to keep up with the crew; spinning out in the 12t.

[Patrick Kitto]

oh, right. compact cranks. I forgot about those. 

even a 50x12 is 39mph at 120 RPM. 53x12 get you to 41.5mph.

an 11t cog paired with a compact at 120rpm is 42.8, and with a standard crank is 45.4.

if a 50x12 is 'spinning out' either work on your tuck and recover, or work on leg speed and get them gams up and over 130rpm

On Tue, Jul 8, 2014 at 9:11 AM, Jeffrey Skokan <jsk...@gmail.com> wrote:

Maybe time for you to go 53 on the big chain ring?!?

--

[Jeffrey Skokan]

I forgot about compact cranks too.  I just assumed Daniel was running 52 on the big ring.

[Nat Futterman]

I think 11t makes sense with a compact (though I'd go for a narrower range than 11-28 at the expense of a little low end with a compact)

Along the same lines, with a traditional, I wish 12-28s were easier to come by in 10-speed (since I don't need the 11t; same idea as what Rob did).  I have one (SRAM) but my Shimano drivetrain persistently shifts it just enough less well to be annoying.  I don't especially want to trade the (useful) 16t for a (less useful to me) 11t, but I've contemplated it for the noise/shift quality.

Rob - how does your home-made 12-28 work?

[Jason Thorpe]

> On Jul 8, 2014, at 10:01 AM, Nat Futterman <nat.fu...@gmail.com> wrote:
>
> I think 11t makes sense with a compact (though I'd go for a narrower range than 11-28 at the expense of a little low end with a compact)
>
> Along the same lines, with a traditional, I wish 12-28s were easier to come by in 10-speed (since I don't need the 11t; same idea as what Rob did). I have one (SRAM) but my Shimano drivetrain persistently shifts it just enough less well to be annoying. I don't especially want to trade the (useful) 16t for a (less useful to me) 11t, but I've contemplated it for the noise/shift quality.

I’ve been tempted a few times to go to mid-compact (52/36), but it seems that even when I get stronger, I manage to get older and fatter, so 50/34 is where I stay. My favorite cassette is 12-27, but I have an 11-25 that I deploy strategically (for events like El Tour de Tucson, for example). But another advantage to getting fatter is that I can descend fast without having to turn the cranks, so there’s that.

-- thorpej

[Nat Futterman]

A few months ago, I went from compact + 12-27 to standard, and spent a while playing around with it to figure out what was low enough; I ended up settling on 52/38 with 12-28 which, kind of irksomely, achieved basically exactly the same thing as compact with 11-25.  (I switched crank length at the same time, so the standard crankset wasn't a total loss.)  I'm tempted to go back, but I do like the 14 tooth gap between chainrings a little better.

I've also contemplated a mid-compact, or one of the new DA9000 or similar cranks in 52/38 but with a 36t ring to switch to when I need the low-end.  That being said, switching between, say, 11-25 and 11-28 cassettes would probably be simpler.  Alas, all signs point to yet another new crankset...

[Daniel Chao]

even a 50x12 is 39mph at 120 RPM.

--- 120? not these legs!

[Rob]

On Tuesday, July 8, 2014 10:01:52 AM UTC-7, Nat Futterman wrote:

Rob - how does your home-made 12-28 work?

works great. 

[Daniel Vigil]

While taller than a 50/34, a 52/38 is still a compact (I believe the industry branding is "semi-compact") crankset unless you have some exotic bcd config that I'm ignorant of (very possible!)

I think the only advantage of an 11t on a typical SF2G route might be a psychological placebo... which admittedly is where most of the battle of getting dropped takes place: the 6 inches between your ears are far more significant than a slight gear inch tweak. So if it makes you more confident, then go for it.

But yeah I'm trying to think where I've dumped it into the 11 on typical peninsula commutes: crystal springs ice plunge, skyline @~ Sneath, 84 east from woodside into rwc, maybe some parts of sand hill? I just can't think of many segments where I'm going over 40mph and still pedaling.

[Peter Chang]

2014-07-08 20:31 GMT-07:00 Daniel Vigil <danv...@gmail.com>:
> While taller than a 50/34, a 52/38 is still a compact (I believe the industry branding is "semi-compact") crankset unless you have some exotic bcd config that I'm ignorant of (very possible!)

you can get a 38 in 130bcd. on some cranks the chain will hit the
chainring bolts though.

> I just can't think of many segments where I'm going over 40mph and still pedaling.

ride fixed and you get to pedal all the segments :-)

\p

[Jason Thorpe]

I agree… I don’t see much advantage to having an 11T cog when I’m riding to work. It’s the days I’m riding my bike not-to-work where I might find it useful (descending Hwy 9 during a lunch ride, for example :-)

-- thorpej

[Nat Futterman]

52/36 is definitely called semi-compact; not sure about 52/38 but isn't isn't an especially common size in general but is possible on either 110 or 130. First cranks I've noticed coming stock with it are 4-arm 110 BCD à la DA9000 (which aren't exactly considered either) though it's possible someone like FSA has offered it. In any case, I'm using it on 130BCD (and don't have any crank/chain interference on 7800 cranks). It wasn't stock, though the 52t big ring is (made for 52/39, a now-slightly-old-fashioned flavor of traditional).

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[Peter Chang]

2014-07-08 23:18 GMT-07:00 Nat Futterman <nat.fu...@gmail.com>:
> It wasn't stock, though the 52t big ring is (made for 52/39, a now-slightly-old-fashioned flavor of traditional).

i think this is hilarious because i was branded a pussy for swapping
my 42 (from the traditional 52/42) for the smallest that could fit at
the time (39).

cue mitch.... i used to be a pussy. i still am, but i used to be one too.

\p

[djconnel]

I agree an 11 cog is fairly useless unless you're running a small big ring like 44 or 46. I like that option, though, as it makes for tighter front shifts with a 34 or 36 small. Even then the 11 is only for gradual, straight descents in a group, or in strong tailwinds. I use 11-26 as my standard cassette but also have 12-23 and 12-27 climbing cassettes.

Efficiency at 120 rpm takes just a bit of practice, but it's worthwhile to attain it, as it spares muscles.

[Jason Thorpe]

> On Jul 9, 2014, at 10:16 AM, djconnel <djco...@gmail.com> wrote:
>
> I agree an 11 cog is fairly useless unless you're running a small big ring like 44 or 46. I like that option, though, as it makes for tighter front shifts with a 34 or 36 small. Even then the 11 is only for gradual, straight descents in a group, or in strong tailwinds. I use 11-26 as my standard cassette but also have 12-23 and 12-27 climbing cassettes.
>
> Efficiency at 120 rpm takes just a bit of practice, but it's worthwhile to attain it, as it spares muscles.

Indeed, instead of buying wonky cassettes, get a set of rollers.

-- thorpej