Andy_K 

I just got one of the new 10-speed Tiagra 12-30 cassettes, and thought I'd post a review.

I'm using this with an Ultegra 6600 SS (short cage) rear derailleur, FSA Gossamer 46-34 compact double crankset, FSA Energy front derailleur and Ultegra 6600 shifters. The only concern I had was whether the 30T cog would give the derailleur trouble (the spec says 27T max). I'm happy to say that even with the chain on the 46T ring in front it shifts on and off of the big cog like a champ.

I put the new cassette on this weekend. I didn't change the chain length or adjust the derailleur cable tension -- just put the new cassette on the wheel and tried it out. The chain length is pushing the limit, but seems to be acceptable (the chain was cut to accept a 12-27). I might go a link longer when I install a new chain.

Here are pictures of it with the 46-30 and 34-12 combinations, showing the derailleur's range.






The shifting is outstanding. If anything, it shifts better than it did with the old 105/Ultegra cassette. That may be because of accumulated grime in the hyperglide bits of the old cassette, or it may be that the old cassette was just worn.

For comparison purposes, I cleaned up the 12-25 cassette I was replacing. The comparison cassette came on a used bike and the name plate is missing, so I'm not sure if it is 105 or Ultegra. It's definitely from the 5600/6600 series.

Tiagra


105/Ultegra


The finish is very different. The Tiagra is nickel plated, whereas the higher end cassette has more of a matte steel finish (which looked very nice out-of-the-box on an Ultegra cassette that I bought new). Of course, after a few rides they both end up black with chain oil.

The hyper-glide ramps look very similar if not identical. Here is a side-by-side picture of the 14T cogs, Tiagra on the right. (Click it for higher resolution.)



The 105 and Ultegra cassettes have only the lower three cogs riveted together, while the lower seven cogs of the Tiagra are riveted. The three riveted cogs on the higher end models are joined to a bulky one-piece metal spider, whereas the new Tiagra cassette appears to have plastic spacers between all of the riveted cogs.

I don't have an accurate scale to give weights. My REI luggage scale gave me readings of 250, 300 and 350 grams for the Tiagra cassette, so I'd guess it's somewhere around 300 grams. The drillings appear to be very similar to the Ultegra/105 cassette for similarly sized cogs, and the bigger cogs aren't the massive expanses of metal that you see on some lower end Shimano cassettes.

With the 46-34 crankset, the 12-30 cassette gives me this gear range:

102.6 -- 75.8
94.7 -- 70.0
87.9 -- 65.0
82.1 -- 60.7
72.4 -- 53.5
64.8 -- 47.9
58.6 -- 43.3
51.3 -- 37.9
45.6 -- 33.7
41.0 -- 30.3

Compare that to a 50-39-30 triple with 12-25 cassette (my bike's stock gearing):

111.5 -- 87.0 -- 66.9
102.9 -- 80.3 -- 61.8
95.6 -- 74.5 -- 57.3
89.2 -- 69.6 -- 53.5
83.6 -- 65.2 -- 50.2
78.7 -- 61.4 -- 47.2
70.4 -- 54.9 -- 42.3
63.7 -- 49.7 -- 38.2
58.2 -- 45.4 -- 34.9
53.5 -- 41.7 -- 32.1

So I lose a little at the top end (which I couldn't really use anyway), but gain a bit at the bottom, while using a compact double crankset. For my commute, the 46T ring with a 12-25 cassette would cover 95% of the terrain I see, but I need that super low gear to get up the 10-20% climb at the end of my ride home, so this setup is perfect for me.

Watchdog

Wow, very comprehensive and informative review. Thanks.

I am a bit surprised an Ultegra short cage derailleur works with the 30T.

Barrettscv 

Here is a 12-30 installed with a Ultegra GS and a 105 triple with 50, 39 & 26t chainrings;

Andy_K 

Yeah. There's usually some padding in the specs. A couple of years ago I tried a 4500 Tiagra RD with a 32T cog, and that almost worked. The derailleur bounced a bit on the big cog. I figured there was a good chance this would work.

I was very happy to see the Tiagra group move to 10-speed because I think Tiagra is pretty good quality and I was looking for a cheaper 10-speed cassette without having to get it shipped from Japan to the UK and then back to Oregon. These new Tiagra cassettes are selling for $40 at Universal Cycles (which happens to be local to me).

Werkin

The important gear for me (30-34).




One link shorter than I would normally cut the chain for the little/little (12-34) combo, but there is adequate chain tension, and no risk of contact with the upper jockey wheel.




No issue with the little/big (12-50).




In theory this should never happen (30-50), but just in case this mistake is made, chain length is adequate.




The B-screw was turned almost all the way in for the smoothest transition from 27 to 30 tooth cog, no other adjustments were made.