12-25 to 12-27

[JMacII]

Currently running compact with 12-25. I'm in a new area with some very steep hills round here, 12%+ and just lots of climbing in general. Most rides seem to be hitting that 1,000ft/10 miles ratio. Thinking a 27 might help me spin better up the steep stuff. How big a difference will I notice, and will I need a new chain?

Thanks.

[eBAUMANN]

youll notice a difference. personally, id rather have an extra 2 teeth on top and not need it, than not have it and need it. every cassette is have is 28t or larger for that reason ;)

you might need a new chain depending on how short you made it the first time.

[mgm777]

You will notice a difference. I run a Shimano compact with a 12-27 and am happy to have that extra gear when I am grinding up a 15 mile climb. There is a noticeable difference when shifting from the 25 to the 27. As for a new chain, I'm not sure. That said, I always install a new chain when I install a new cassette, but that's just me.

[sweet_johnny]

^ both of these.

You'll notice the difference.

[JMacII]

Thanks guys. In addition, I also will continue to HTFU.

[tumbler]

You'll definitely notice a difference. I'm dealing with the same struggle here, having moved from NYC to SF. Yesterday's ride was 2500 ft over 19 miles and I was dying for one more downshift on some of those super steep hills.

I don't own a Niner, but I often look at my toptube and imagine that Niner sticker telling me what to do...
https://s-media-cache-ak0.pinimg.com/236x/ee/17/f1/ee17f1ad4c4998f1fcd4256ef2fb9d33.jpg

[downtube]

Or This...

http://cycling-passion.com/wp-content/uploads/2013/08/Jens-Voigt-Trek-Madone-7-2014-shut-up-legs-2.jpg

[FlashUNC]

You'll notice it. And as you get stronger, nothing wrong with having it there as a bailout for bad days.

[soulspinner]

Good to know. Just got my first 27 ever...:bike:

[thwart]

What... you're debating a 27?

I really like the option of a 29 around here. But then again, I'm old and feeble...

[redir]

I almost exclusively use a 12x27. Standard 53x39 but still I use the 27 a lot and I went from 23's to 25's and the difference is very noticeable. I much prefer to sit and spin as long as I can before having to stand.

[rnhood]

With a compact, I recommend an 11-27. The 12 is just not enough gear for the fast rides (whether in a group or with a following wind). If your typical rides log 100 ft/mile then the 27 is definitely the way to go (e.g.; 11-27).

[kgreene10]

I've got a 39/28 and I'm considering a 36 up front. I can mash up hills but after a while at 60rpm, you pay the price.

[tv_vt]

If it's hilly, you may also want a bigger gear for the downhills. Don't know how many gears you're running (9, 10, 11), but whatever, I'd look into an 11-28 as an option along with the 12-27.

[OtayBW]

12-27 is my go-to around here. 12-27 with a compact will get you up and over rolling hills of ~12%-15% grade, and shorter grades up to ~18%-20% consistently. Anything more sustained than that at that steepness, I'd be looking for a 29 or...?

[sloanfiske]

I'm surprised at the difference going to 27. It made a bigger impact on those grades that change from 7-9 to 11-14 than I thought it would.

[dekindy]

Switched from 12-27 to 12-25 and regretted it immediately.

The older you get the lower gears you will need so give in to the inevitable so that you will keep enjoying riding.

[R3awak3n]

all my road bikes have a 27 in the back, I sure need it.

[tuxbailey]

I have 13-26 10s now, will 12-27 be a better option? Do I need to change the chain?

[R3awak3n]

I dont think you would need to change the chain.

[dpk501]

Even the pros do it.

I run 12-28 shimano cassette with my campy. You'll need it.

Currently running compact with 12-25. I'm in a new area with some very steep hills round here, 12%+ and just lots of climbing in general. Most rides seem to be hitting that 1,000ft/10 miles ratio. Thinking a 27 might help me spin better up the steep stuff. How big a difference will I notice, and will I need a new chain?

Thanks.

[ajhapps]

Dude, I made the same move about 12 months ago. One bike has a compact with an 11-23... and I am dying on pretty much every single ride. Just about to make the switch on my other bike to a mid-compact with 11-26 and thinking I've made a mistake (going from compact / 11-28). I'll now not have a "climbing" setup. Guess I need to ride more?

You'll definitely notice a difference. I'm dealing with the same struggle here, having moved from NYC to SF. Yesterday's ride was 2500 ft over 19 miles and I was dying for one more downshift on some of those super steep hills.

I don't own a Niner, but I often look at my toptube and imagine that Niner sticker telling me what to do...
https://s-media-cache-ak0.pinimg.com/236x/ee/17/f1/ee17f1ad4c4998f1fcd4256ef2fb9d33.jpg

[jpang922]

If I did a hard climb without using the largest cog I consider it a personal victory. But it's nice to have a plan B.

[Duende]

With my compact 50/34, I just switched from 11-25 to a 12-29.

25 was a bit rough for climbing the Bay Area, but doable. Main reason I changed was because of the compact set up. With the 50 upfront and 25 in the back, I found that I was FR shifting an awfully annoying amount of times.

Way more often than I ever had in my years of riding non compact.

Although I really wanted to swap my crankset back to standard, I didn't want to spend the $$$ just yet. Putting a 12-29 in the back saved me some cash and a lot of tedious FR shifting to boot (which on campy 11, is not the best to begin with)

I say go for it. Although you might want the 29 cog too. :)

[redir]

I have 13-26 10s now, will 12-27 be a better option? Do I need to change the chain?

I think it would be a better option. My Campy bike still has a 13x26 and it's okay but I can defintely tell the difference with the 12x27. Others have mentioned that for descending a higher gear will be better. That's true for a lot of people but for me at 200lbs I just tuck and still pass the little guys pushing an 11 ;)

But it is nice to have the gear to pedal even going down but the difference between a 26 and a 27 is actually noticeable.

No need for a new chain but if your chain is old and you buy a new cassette then it's generally a good idea to get a new chain as well.

[beeemmjay]

Happy to follow along here- I've been weighing the same options. Im running a 50-34 with 11-25 now, and considering a switch to 12-27. You've all been pretty helpful with positive direction to the 12-27.


Sent from my iPhone using Tapatalk

[downtube]

I live in the bay area and am a big guy. (225) Riding the hills around here I need a bigger gear as I get older. I went from 11-25 on my bikes to a 12-27 (10 spd) on one bike and a 12-29 (11 spd) on the other. Both work very good for me, glad to have another cog. Not so worried about descending, my weight combined with good wheels results in some pretty good descent speeds, at least fast enough for me. Both campy set ups shift perfectly. Also, I always put on a new chain if I change my cassette.
chuck

[Mark McM]

To put it in perspective: The gear ratio difference between a 25 and a 27 is pretty close to the difference between a "standard" and "compact" crank - and most people find there is a significant difference between standard and compact cranks.

[Russian bear]

I'm neither old, nor feeble and I'm all about that 11-29 (with a standard in the front). It's nice to have and it makes you chain line better in the 26, 23, 21.

[distanc3]

Went from a 13-26 (came with the bike) to a 12-27. It sure helped when I needed it. It gave me more range in my case but the extra two teeth from 25-27 will help you a lot too.

I still have the 13-26 and if its a long cruising riding, the single teeth increment ride like dream!

[OtayBW]

All with 700-23 wheels, 172.5 crank arms (sorry for the lack of formatting):

12-25 with 53/39:
116.1 85.4
107.1 78.8
99.5 73.2
92.9 68.3
87.1 64.1
81.9 60.3
77.4 56.9
73.3 53.9
66.3 48.8
60.6 44.6
55.7 41.0

12-27 with 53/39:
116.1 85.4
107.1 78.8
99.5 73.2
92.9 68.3
87.1 64.1
81.9 60.3
73.3 53.9
66.3 48.8
60.6 44.6
55.7 41.0
51.6 38.0

12-25 with 50/34:
109.5 74.5
101.1 68.7
93.9 63.8
87.6 59.6
82.1 55.8
77.3 52.6
73.0 49.6
69.2 47.0
62.6 42.5
57.1 38.8
52.6 35.7

12-27 with 50/34:
109.5 74.5
101.1 68.7
93.9 63.8
87.6 59.6
82.1 55.8
77.3 52.6
69.2 47.0
62.6 42.5
57.1 38.8
52.6 35.7
48.7 33.1

Getting down into the low ~30s gear inches makes a lot of the tough climbs manageable. The 12-27 with a compact is the way to go for me around here! (and thanks once again to Sheldon Brown!)

[soulspinner]

All with 700-23 wheels, 172.5 crank arms (sorry for the lack of formatting):

12-25 with 53/39:
116.1 85.4
107.1 78.8
99.5 73.2
92.9 68.3
87.1 64.1
81.9 60.3
77.4 56.9
73.3 53.9
66.3 48.8
60.6 44.6
55.7 41.0

12-27 with 53/39:
116.1 85.4
107.1 78.8
99.5 73.2
92.9 68.3
87.1 64.1
81.9 60.3
73.3 53.9
66.3 48.8
60.6 44.6
55.7 41.0
51.6 38.0

12-25 with 50/34:
109.5 74.5
101.1 68.7
93.9 63.8
87.6 59.6
82.1 55.8
77.3 52.6
73.0 49.6
69.2 47.0
62.6 42.5
57.1 38.8
52.6 35.7

12-27 with 50/34:
109.5 74.5
101.1 68.7
93.9 63.8
87.6 59.6
82.1 55.8
77.3 52.6
69.2 47.0
62.6 42.5
57.1 38.8
52.6 35.7
48.7 33.1

Getting down into the low ~30s gear inches makes a lot of the tough climbs manageable. The 12-27 with a compact is the way to go for me around here! (and thanks once again to Sheldon Brown!)

Ya me too. With frequent 10-15 % grades and finger lakes 20 %ers, I cant do it any more with the 53/39...golden years my a!!...

[unterhausen]

I remember when I realized a 25 on the back wasn't big enough. I think that was the first time I felt like I was getting old. Now I run a 32. During the season I don't really need it, but there are some 19 percent hills around where it's really nice.

[brendonk]

I switched from a 12-25 to a 12-27 this season and just spent two weeks riding in colorado. It was very comforting to look down and have that extra gear just in case I needed it. I'm not getting any younger or lighter and I'm very happy I made the switch.

[classtimesailer]

When I put on the 12-27 I found most of my climbing was done on that 27. Now I only put that cassette on for loooong rides far from home. All my weekend rides are 100 ft/mile

[oldpotatoe]

With a compact, I recommend an 11-27. The 12 is just not enough gear for the fast rides (whether in a group or with a following wind). If your typical rides log 100 ft/mile then the 27 is definitely the way to go (e.g.; 11-27).

Gearing is completely personal but I think I would rather have the 16t rather than the 11t, IMHO. Plus 90 rpm, 50-12 is still almost 30 MPH..50-11 is 32mph.

That's fast for a level ride even in a 'fast group'. BUT YMMV, of course.

[soulspinner]

Gearing is completely personal but I think I would rather have the 16t rather than the 11t, IMHO. Plus 90 rpm, 50-12 is still almost 30 MPH..50-11 is 32mph.

That's fast for a level ride even in a 'fast group'. BUT YMMV, of course.

Thats what I did. Havent ridden with the fast kids in years...

[CampyorBust]

1000ft/10mi is a good amount of climbing in my book, definitely enough to warrant a 12-27. I have about 1000+ft/20mile climbing ratio in my parts, I run compact cranks on all of my bikes (the everyday riders) and very much enjoy having a 12-27 on some of my bikes. I can pedal my bike with 11-25 up the steep stuff just fine, however fatigue will set in quicker. Given the choice when buying new cassettes I go 12-27 over the 11-25 every time.

When I went on a trip to ride in some very hilly terrain (where I was basically either climbing or descending 85% of the time) I brought my 12-27 bike and I was very glad I did.

[axel23]

I haven't made the switch to a 27 tooth yet. Vanity, I suppose, but I'm still getting up the climbs okay with a 34x25. It obviously depends on just how steep (and long) your hills are. My fear is that I'll be spinning in place instead of bearing down.

As others have pointed out, there's not much downside to having a bail-out gear. Try the 27 with your existing chain. It'll probably work, although the 50x27 may push the limit.

Let us know how it turns out.

[Anarchist]

I made the move to 50/36 and 12-27 pretty much across the board when I was still in BC. In the mountains.

Best gear combo I ever found.

Now in Toronto, there are no hills to be found but I haven't changed anything and even like the set up here.

Seems to be pretty much the perfect setup for me.