I have 2 Ultegra CS6700 cassettes, an 11-23 & a 12-30. According to Shimano they are as
11-12-13-14-15-16-17-19-21-23
12-13-14-15-17-19-21-24-27-30
Has anyone mixed these 2 before for an 11-30? Which cog would be best to drop out? the 12 or maybe the 14? Thoughts?
In the end, I don’t think is very practical. You end up with a cassette that has this weird huge gap somewhere in the range. Or two weird gaps. But if I had to try it, I would probably drop the 12 (or 13) and the 16
11-13-14-15-17-19-21-24-27-30.
11-12-14-15-17-19-21-24-27-30.
I don’t even know if this would work and I sure wouldn’t want to ride on that cassette…
If you can afford it, I think you are much better off buying an 11-27 or 11-28. You can get 6700 level for $55. You can get 5700 level for $36
Old road bikers would often mix cassettes for different courses. Used to do it all the time. You just gotta be careful when shifting at a big jump between gears to avoid binding the rear derailleur. But if you’re careful and shift slowly (at those big gap points) and soft pedal on the pedals, you can do it. For example, at Tour of the Gila where the second day was 70 miles of flat road followed by a very steep climb, we’d mix a “pine cone” of narrowly spaced gears with a “bail out” of a 28 or 30 to climb the final segment. Again, you gotta be careful when shifting under load at those big gaps…
I have 2 Ultegra CS6700 cassettes, an 11-23 & a 12-30. According to Shimano they are as
11-12-13-14-15-16-17-19-21-23
12-13-14-15-17-19-21-24-27-30
Has anyone mixed these 2 before for an 11-30? Which cog would be best to drop out? the 12 or maybe the 14? Thoughts?
I’ve done this and just dropped the 12
I have an 11-32 coming from PBK, it was something like $56. I’m hoping to use it with a 6700 rear derailleur. My 12-30 fits in there really easily now.
jaretj
I have 2 Ultegra CS6700 cassettes, an 11-23 & a 12-30. According to Shimano they are as
11-12-13-14-15-16-17-19-21-23
12-13-14-15-17-19-21-24-27-30
Has anyone mixed these 2 before for an 11-30? Which cog would be best to drop out? the 12 or maybe the 14? Thoughts?
In general I am pretty sure the smallest two cogs are specific to that position. So you could replace the 12 in the 12-30 with an 11, but you couldn’t replace the 13 in the 12-30 with a 14. Other than that you can do what you want, but I would suggest rethinking what you are doing. For instance, if something is steep enough that you need a 30, how much time would you really be spending pedaling in an 11 on the way down? If you’re just going to be in a tuck coasting maybe you don’t really need an 11 and you’re better off without big gaps. BTW, the gap in gear inches between 50 or 53 13 to 11 is HUGE. Are you putting a cassette together that will leave a problematic gap just so that you can avoid spinning more for a few minutes on a descent?
I stopped using 11 by anything other than 23 a few years ago because I absolutely hated missing the 16. I did a lot of 40+ mph descents with a 50x12 top gear because I knew that I could just sit in the pack on the descent and then on the flat sections I’d have the 16 when I needed it instead of being in that no man’s land where the 15 is too big and the 16 is too small.
I solved that problem this year by upgrading to 11 speed. I’ll never have to make that choice again.
On the other hand there are occasionally unique situations where doing something weird like this makes sense. I did an uphill TT once that had a short descent in it. Back in the 8 speed days I put together a 12,14,15,16,17,19,21,23 for the race. For my backup wheel I had a 13,13,14,15,16,17.19.21.23 because I basically had a 12x23 and a 13x23 that I mixed and matched. The most memorable thing about that race was afterwards riding down with my friends on my other rear wheel and telling them, “We’re going pretty fast now. I’m going to shift into my other 13” 
if you need a 30, do you really need a 11?
In the end, I don’t think is very practical. You end up with a cassette that has this weird huge gap somewhere in the range. Or two weird gaps. But if I had to try it, I would probably drop the 12 (or 13) and the 16
11-13-14-15-17-19-21-24-27-30.
11-12-14-15-17-19-21-24-27-30.
I don’t even know if this would work and I sure wouldn’t want to ride on that cassette…
If you can afford it, I think you are much better off buying an 11-27 or 11-28. You can get 6700 level for $55. You can get 5700 level for $36
+1
Assuming that the 11 is necessary:
You want the gaps to get bigger as you move towards the inside of the cassette (so that the incremental ratio change is as similar as you can get it). You’re pretty much stuck with the 24-27-30 because those are built as an assembly so the smoothest choice would be
11-12-13-15-17-19-21-24-27-30, with gaps of 1-1-2-2-2-2-3-3-3.
Alternately,
11-12-13-14-16-18-21-24-27-30, with gaps of 1-1-1-2-2-3-3-3-3, but it includes the magic 16.
Or, you can look at the inside ring as something other than just a bailout ring and design it into your overall gearing plan, and then there really isn’t a problem.
Thanks everyone, I’m just wanting to play around a bit with gearing. I’m a bit on the heavier side so, I can’t climb worth a crap but I pass all the skinny’s on the downhill side with my 12-27. Basically I’m burning my legs up climbing and spinning out on the down. Kind of frustrating, but minor in the big picture.
Funny what is now thought of as a huge gap was the norm back in the 80’s. My first road bike had five cogs. Not sure what came with the bike but best guess is something like 13-15-18-21-25. In '87 or '88 I got a bike with 6 cogs. What a bonus. I remember swapping out cassettes quite a bit based on the race you were doing. I recall having one that was something like 11-12-13-14-16-18 that I used for a local Wednesday night race (Eldo). If you’ve ever seen American Flyers, you’ll know what I’m talking about.
I recall having one that was something like 11-12-13-14-16-18
We used to call those “corn cobs”. Aah, the good old days!
I recall having one that was something like 11-12-13-14-16-18
We used to call those “corn cobs”. Aah, the good old days!
And a 52=42 front !
JB
Yes! I went away from cycling for about 12 years and thought “WTF?” when my new bike came with a 53/39 and 9 cogs on the cassette.
Try dropping the 14 and combining the two to get:
11-12-13-15-17-19-21-24-27-30
Should work perfectly, it will have a nice spacing without any major gaps. But with the large 30 tooth cog, you’re gonna need a GS type rear derailleur for great shifting.