Shimano 11 - 30 cassette on Ultegra Di-2 ten speed

Discuss light weight issues concerning road bikes & parts.
Post Reply
Posts: 3
Joined: Sun Jul 21, 2013 1:29 pm

by skiboycey

Hi to all.

I am posting this for people interested in enlarging their road cassette as they either live in the mountains, weigh a lot, or, like me, both.

I fitted Ultegra Di-2 to my Scott CR1 and, as a result, had to go from a triple to a double front chainwheel. As I'm also using Rotor oval rings this meant my lowest gear became a 34 front, 28 rear. This is OK for me up to about a sustained 9% grade when my preferred climbing cadence of around 80 begins to tail off, thus dropping efficiency. As I live in the French Alps, I spend plenty of time on climbs that are a sustained 11% to 13% and this becomes really difficult at my weight (85kg), fitness and desired cadence.

I thus constructed an 11-30 cassette from two other Shimano Ultegra Cassettes. To do this you will need to buy a 12-30 version and an 11-23 version of the Ultegra cassettes. You then keep the 'spider' of the 12-30 one, which will give 30,27,24 plus the first loose cog which is 21. Out of the 11-23 you then take the 18, 16, 14, 13, 12, 11 and this makes your ten speeds - 30,27,24,21,18,16,14,13,12,11. The difference with the 11-28 is quite marked as you get two 'bottom out' gears (30 & 27) instead of one (28). There's a 3 tooth jump from 21 to 18 instead of 2 teeth from 21 to 19 in the middle and, of course, you loose the 15 tooth cog which is very useful on the flats with a 50 front chainring but, as in life, everything's a compromise. I'd tried the 12-30 and liked it but missed the 11 tooth cog on descents where, in spite of being middle aged, I still get a kick out of taking downhill KOM's on Strava and can't stop smiling when I hit 100kph. The old speed devil just won't go away, at least for now...

The whole thing shifts perfectly on Di-2 and there's no problem with chain tension or the derailleur not handling it. You just have to get the chain length right. My other wheels with 11-28 and 12-25 cassettes still drop in and work perfectly.

Hope this is useful to anyone looking for this type of solution. To those who say 'get fitter' or 'lose weight' to not need the extra cog I'd say 'sod off and try carrying a 20kg rucksack up the hill on your skinny 65kg bodies and see how it feels'. Ha ha! We all also know what type of body the girls like and it's not skinny streaks of piss. Double Ha ha!

Cheers and best regards (even to the skinny lads), Mark

Posts: 399
Joined: Sun Mar 02, 2014 6:36 pm
Location: NY USA

by BikeAnon

Thanks for posting this.

by Weenie

Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA

by eric

skiboycey wrote: We all also know what type of body the girls like and it's not skinny streaks of piss.

I'm a skinny freak at 6' and 145 lbs. And I'm in my 50s.
The other day a female fitness instructor at the gym hit on me. She looks about half my age.
This isn't the first time that's happened. Then there's the young girls in cars that yell at me because they like my butt.

I think we can put that myth to bed. So to speak.

Now to cassettes. I've used 30t cogs along with a 50/34 crank for extreme climbing races. The last time I did something similar to you- took the Ultegra 12-30 and an 11-21 and made a lighter 11-30 out of it. But doing it with the 11-21 means that you can use the 19-21 set off the 11-21. You need two of the 10sp cog spacers between the ultegra carrier and the DA end carrier. It also gets you the 19t. I use that and the 21t a lot on climbs, it's only when it gets steep and long that I need the larger cogs.

I've done this on Cervelo R3s with Shimano 7800, 7900 and Sram red 2013 derailleurs. No B screw adjustment needed. Shifting is not quite as clean as a non bastardized cassette but it's more than acceptable.

Of course the cheaper way to do this is to just take the 15t cog out of the Ultegra 12-30 and add an 11t cog and 11t lockring. The weight is not that much more than the expensive combined cassette solution if you use an aluminium DA lockring instead of the heavy steel Ultegra one.

For 11sp, Sram's announced an 11-30.

Post Reply
  • Similar Topics
    Last post