cam117

I’d like some advice on a choosing and installing a new cassette. I just bought a new set of wheels or my Trek 1200 triple and now I’d like to get a new cassette so I don’t have to swap them back and forth if I want to ride the old wheels.

Since I have a triple and I rarely use the largest cog while in my small chain ring, I thought that I might go for a setup with a tighter grouping or a little more top-end speed. I typically ride in the 18-21 mph range. I currently have a 12-25, so I definitely want to get something other than that.

Based just on an initial glance at a few catalog sites, I’m leaning toward one of the following options:
• 11-23
• 12-21
• 12-23

So here are my question(s)
• What gear range should I get. Why?
• What component level should I get (Ultegra, 105, etc..) Why?
• If I go with an Ultegra-level cassette, will I need to change my chain or anything else

Here’s my current set-up:
• Shifters Shimano Tiagra STI, 9 speed
• Front Derailleur Tiagra
• Rear Derailleur 105
• Crank Bontrager Select 52/42/30
• Cassette Shimano HG50 12-25, 9 speed

demoncyclist

11-23. Get a new chain too, just so you don't put any unneccesary wear on the new cogs. 105 level is fine. I might even go with a SRAM cassette and definitely a SRAM chain.

Psimet2001 

11-23 or 12-23 sound right for your situation. You don't need to replace your chain with this swap, but it definitely wouldn't hurt, and is something that I would do on my own bike. I agree with the SRAM comment for both the chain and cassette. Any Shimano 9spd cassettes would work just fine with no need to change anything.

djtrackie

get a 11-23 and if you get Dura-ace (with titanium cogs) you'll save 50 grams.

FrankBattle 

Usually, tighter spacing is better. Based on that alone, and picking from your list, the 12-23 would be best all round for you. The assumption here is that it gives you enough gearing for your terrain. It's really pretty simple, 11 is one tooth further from 23 than 12 :-) So, the 12-23 would be tighter than the 11-23. You may never notice the extra tooth on the top end by picking the 12 over the 11.

I have all the above cassettes + the 12-27. I used to think that you couldn't tell the difference in shifting, but the 12-23 is what I ride most (the other bike has a 12-25) and I will say that the 12-23 shifts through all 10 gear combinations (9, in your case) the fastest and smoothest.

As far as component set level, the Ultegra is probably the better value. It's lighter than 105 and more durable than the Duraace. Weight? A pair of sunglasses and your jersey weigh more than 50 grams. So just ride topless and sans sunglasses and you've saved a few hundred over trying to go Duraace.

*wondering why we (me included) continue to worry about 50 or less grams of savings/gains; I wonder how much a good number 2 in the loo weighs*