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12/25 cassette vs. 12/27 DA?(11 posts)

12/25 cassette vs. 12/27 DA?jefe
Jun 4, 2002 11:20 AM
i ride 150 miles per week. beginning hill climber. i'm buying a new CF bike with DA triple.

12/25 or 12/27?

Jun 4, 2002 11:23 AM
With a triple and a 27 you can climb the side of your house. You'll get better spacing and more useful gears from the 25.
re: 12/25 cassette vs. 12/27 DA?brider
Jun 4, 2002 11:23 AM
If you're going with a triple, the 25 should be enough to get you up anything short of a cliff.
what about 12-23?weiwentg
Jun 4, 2002 11:29 AM
unless you live in a very mountainous region, 12-23 and a triple should be enough, right? that 16t really comes in useful (at fast cruising speed, the difference between 15 and 17t is about 10 rpm).
Jun 4, 2002 11:28 AM
What do you climb and how good of a climber are you?

On Saturday I did a steep hill near me (and although I must climb worse than everyone on this board, I think I'm not that bad). I have a triple and a 12-27. I was sitting while in my lowest gear, and was turning around 45 rpm during the steepest parts of the climb. I can stand at shift into a higher gear (usually 2 or 3 cogs higher), but this particular hill is longer than I can climb while standing (about a mile before the first real break).

Ride what you need to get up the hill.
Jun 4, 2002 11:31 AM
I have a Dura-Ace double with a 12X23. In the hills of NH I feel only a little over geared. With a triple you should be ready for almost anything.
I also ride 150-200 miles per week and consider myself an average rider.
re: 12/25 cassette vs. 12/27 DA?mwood
Jun 4, 2002 12:11 PM
If you are riding a ton of vertical w/ lots of 10%+ pitches and you really are a "beginning hill climber", maybe running a 12/27 at first makes some sense, so you have a complete bail out gear for the final climbs in a given ride.
I doubt you'll need it, however. I just had a bike built with a triple and 12/25 and have never used the 30 X 25. This includes riding lots of steep, long grades here in the SF Bay Area, and I'm an average rider.
What type of riding do you plan to do?dsc
Jun 4, 2002 12:34 PM
If the terrain that you ride is not very hilly, or if you plan to try your hand at a little racing, by all means take the suggestions of some of the other posters, and go with the tighter spaced cassette.

On the other hand, if your goal is training for centuries or beyond, again depending on the terrain in your area, you may want to have as many gears as possible at your disposal. I run a DA double w/ a 12x27 on the back. It is enough to get up some of the 9-10% grades around here, but I'm telling you, at about mile 80 or so, if I know there is another big hill left before I'm done, I am wishing for that triple!

So assess what type of riding you plan on doing, where you plan on riding, and make your decision based on those facts. Do be aware that your climing ability will improve as you get more miles in your legs, however, don't risk any knee injuries now. Good luck.

An now for something completly different.Len J
Jun 4, 2002 12:45 PM
I'd get the D/A 12X27 with the bike and then I would buy an Ultegra either 12X21 or 12X23 Excel has them for $38. For most rides the corn cob cassette with the triple is going to be plenty of gearing & give you smaller jumps between gears. A 30/23 at 80rpm is about 7mph which should get you up most things in a training ride.

The 12X27 will be great to have for those long hilly rides (or multiple day long hilly rides) where you are trying to conserve energy early in order to have something left for the end. BTW if you train with the 12X23 & then switch to the 12X27 you can do most of your climbing in the 24 tooth cog and save the 27 for the bailout.

12/23, 12/25, 12/27, and a lockring remover.JS Haiku Shop
Jun 4, 2002 12:45 PM
it's not a permanent feature of the bike. if you feel you'll use the lower gearing, then go for it. i personally alternate between a 12/25 and a 12/27 on my 105 triple. after you've done it the first time, removing and changing cassettes on a 9-speed takes about 3 minutes. this is also a nice way to get your cassette and spokes/hub *really* clean.

yes, you can just about climb up the side of a house with a 30/27 combo. perhaps i'm just not as good a climber as the majority here, since i was happy to have the 27, used it frequently, and was trying to "grow more gears" on a recent hilly century. this might all depend on your conditioning and mentality, but...i'd rather have and use the gears than walk.

btw, there's a big one coming up in september that might find me putting a mountain bike rear derailleur and 12x34 cassette on the triple. again, i'd rather ride low gears than walk & push the bike. remember, DFL beats DNF, every time!

also btw, i have few problems staying near the front of the fast weekly group rides on my triple/27-fitted bike. i just have bigger steps between some gears.
feel the same waylaffeaux
Jun 4, 2002 3:55 PM
Maybe only the upper 20% of riders frequent these boards, but I use my 30/27 on climbs quite often and when I'm out there I'm often passing people. I earlier said that I climbed a hill on Saturday in my 30/27 combo and struggled at 45 RPM in the steepest sections. Well, during that ride I passed two people and none passed me (going the same direction). Know what you can and can't ride, and get the gears that allow you to climb. Pushing a bike sucks.