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12-23 vs 12-25 - any real difference?(12 posts)

12-23 vs 12-25 - any real difference?Michelle
May 23, 2001 10:04 AM
Have to choose between putting a 12-23 or 12-25 on the new race wheels, but wonder if I'll really be gaining much with the 12-25. A buddy said he really noticed the difference between the two (on climbs of course), but wanted other opinions.

Part of me says, "take the 23, it'll make you stronger" the other part says "If it'll help prevent getting dropped on the hills, and ease some of the pain, take advantage"

Go 23Duane Gran
May 23, 2001 10:17 AM
You already pointed out the only place where it really matters... in hills. If you know that you will have some races in the hilly terrain, then it is better to have that extra gear. When referring to hills, I'm talking about stuff that takes more than a few minutes to climb, but you have to draw a personal conclusion. Most people are in the big ring for 90% of a race, so the only place where the 25 comes in handy is an extended hill.
I vote for 12-25bianchi boy
May 23, 2001 10:33 AM
I don't need that 25 very often, but it's sure nice to have when you need it. I rode up in the mountains over the weekend and it would have been a long and uncomfortable ride without that 25. In fact, I wish I had the 12-27. I like to spin up hills rather than get up out of the saddle, and that makes a difference in what you select. If you like to stand while climbing, the smaller ratio might be appropriate.
I'd use the 25--but you can swap it in about a minuteCory
May 23, 2001 10:38 AM
If I'm going to make a gearing mistake, I'd always rather be too low than too high. Don't forget, though, that changing a cassette is about a 45-second job once you learn to do it. You don't have to use the same one every day.
Take your cue from LanceTom C
May 23, 2001 10:44 AM
Take a look at the Armstrong interview in the May issue of Bicycling, Lance, of whom many here seem to have forgotten, kind of revolutionized time trialing by pushing cadences over 100 when for years very big gears pushed at cadences of 80-90 were the norm. He trains for these high cadences with a 39x23 and states that a 25 would be in fact be better. You argue with him.
Yes, there is a difference...Greg Taylor
May 23, 2001 10:48 AM
...and you already know that. As for race strategy, the "it will make you stronger" approach doesn't really help you in a race until you actually DO become stronger. Train on the 12-23, race the 12-25 until you spin the 23 up the hill.
Depends where you livepmf
May 23, 2001 10:48 AM
and what kind of rides you're doing. Grinding up hills in too low of a gear can damage your knees. Its unpleasant too. There is a big difference between a 23 tooth cog and a 25 tooth cog on a steep hill. Then again, on the flats, the cog differences in the 12-23 will be more subtle than a 12-25. You'll be able to find your ideal gear.

My advice would be to get both plus a chain whip and a cassette locknut tool. If you're going on a hilly ride, use the 12x25 (or maybe geta 12x27 instead for hilly stuff) and the 12x23 on the flats or rollers. Its easy to change cassettes and the tools are cheap. I find a vise grip useful for removing a cassette with a lockring tool.

I swap cassettes and chain rings quite a bit. That way you can get ideal gearing for what you want to do.
Huge difference on a hill...vram
May 23, 2001 10:56 AM
Depending on your form, it can come down to walking or pedalling up a hill. Since you are going to use the 23 for hill climbing anyways, why not err on the safe side and get the 25.

If you want to get stronger, climb on your big ring. Even if you could climb a tough hill with a 23, a 25 will allow you to climb more efficiently, ie. you won't go into oxygen debt as much...
re: 12-23 vs 12-25 - any real difference?DINOSAUR
May 23, 2001 11:07 AM
It depends.....are you going to do a lot of climbing? If so opt for the 25. I ride nothing but hills, some are 20 minute climbs until I level off or start to descend. I used to try to avoid the 25 and use it as a granny gear, now I use it when ever I can. I've found that I'm not a big gear masher, but a spinner, it's easier on your knees.
I'd say if you plan on doing a fair bit of climbing, I go with the 25, otherwise the 23 will work. I know some riders that have a 27, instead of a triple. On the other side of the coin if you go will the 25 what gear will you lose? What are you using now? You might lose a favortie gear, that you are used to using. What cogs are in a Shimano 12-23 and 12-25 cassette? Remember the pro's use different cassettes depending on the race. I think that Armstrong uses a 39X25 when he is in the mountain stages during TDF.
re: 12-23 vs 12-25 - any real difference?ScottV
May 23, 2001 12:13 PM
Really it depends on where your racing. When I raced I never needed anything bigger then a 21. But then most of the races where crits. Even the hilly raced only had short climbs. Did most races with a 12-21 (Campy).

The only reason I had a 13-26 was for recreational cycling. Nothing like one for those long climbs in Vermont. New bike has a 12-25 (10 speed). Should be interesting to see if one tooth makes any difference.
re: 12-23 vs 12-25 - any real difference?Michelle
May 23, 2001 12:44 PM
Thanks for all the feedback. Think I'll go with the 25 since most of the races have long brutal hills...

Happy training!
10 speed or 9?dave
May 23, 2001 4:58 PM
If you've got 9 speed, you'll really miss the 16 tooth cog, if you get a 12-25. But if you need the 25 for hills, you'll have to do without it. With 10 speeds, you get the 16.