Plainsman

In a bit of a quandry. My group has been doing a lot of climbing this year, and we plan to continue to do so. Most weekends our rides include several grades over 20%, and sometimes they are decently long climbs as well. I currently run a 10 speed compact (50/34), with a a 12-30 rear cassette. I have thought about upgrading to 11 speed, but only because it would offer me an 11-32 cassette. In all other cases I'm perfectly happy with my Ultegra 10 (Say grades up to 13-14%). That said, do any of you climbers have experience with this switch? I'm wondering if that 2 tooth difference would be noticeable. When I'm slogging up a 22% hill, I'm willing to weigh every option. Pedaling slower (or faster) is not an option for me :-).

woodcraft

Sram 1070 12/32 10 speed cassette.

chasm54

To state the extremely obvious, the move from a 30 to 32 tooth sprocket will make a difference of less than 7%. Noticeable? Yes. Worth buying a new group for? Not in my opinion, especially when you could just install a 12-32 cassette.

noodle soup

Sure he could try a 12-32 cassette, but they don't work well with 10spd Ultegra derailleurs.

rms13

Why not?

Lazyass

Why? Do you plan on never becoming stronger?

bmthom.gis

You could also go down in chainring size. What are other people in your group riding?

Plainsman

Good questions. We have a variey in our group. Some are on 11-32 with 11 speed. Some do 11-28 ten speed. I hope I get stronger.I can push those grades with the setup I have. Realistically though, in an event over 100 miles with over 10,000 feet of climbing, any appreciable advantage is worth considering. I didn't know SRAM made a 12-32 cassette for 10 speed. Sounds intriguing, but thinking the gaps would be pretty noticeable. Will have to see if my 6700 RD can handle that tooth differential.

rpenmanparker 

It is not just about tooth differential. It is about largest diameter cog that the length of the derailleur arm can deal with.

Plainsman

Exactly. And I'm not sure if 6700 offers a mid cage?

Lazyass

This.

https://www.performancebike.com/bikes..._1156750_-1___

If a compact crankset and a 30T cassette isn't enough to get you up hills then you could go with a MTB cassette/XT conversion.

rm -rf

Wow, 20-22% grades. Where do you ride? 22% is where I start stalling out, having to really muscle the bike up the hill, going at 3 mph.


I don't know if a 32 cog is too big to fit your derailleur. (But if a 30 fits, I'm guessing it will work.)

12-30: 12 13 14 15 17 19 21 24 27 30
12-32: 12 13 14 15 17 19 22 25 28 32

Since the differences are at the low speed cogs, either will work the same on flatter roads. And the gear spacing of the 12-32 at low speeds is fine. I'd get the 12-32 if it can fit.

The 12-32 has larger gaps from 14-18 mph so it can go lower on the lowest cogs.

The tradeoff of all these wide range cassettes is the larger gaps in the middle of the range. I really like to have a 16 cog, which makes closer shifts in the 20-23 mph range, where I need all the help I can get. But I also want very low gears too! My old bike had a Campagnolo 13-29, but Shimano or Sram doesn't make anything like that.

~~~

These gear calc links pop up a message telling you that the settings are in the URL, so you can bookmark/favorite it for later recall. And any changes to cadence or gear selection are updated instantly on the charts.

Mike Sherman Gear Calc with 12-30 Link





Mike Sherman Gear Calc with 12-32 Link

69chevy

I'll sell you a SRAM 11-32t 10 speed cassette, mid cage 5700 105 RD and KMC chain.

You'll have exactly what yu are after and won't need a new groupset.

500 miles on these parts.

PepeM

20% is going to be tough no matter what.

Plainsman

Thanks, this is really good info. We ride in the mountains and foothills of North and South Carolina. The issue for me isn't whether or not a 34-30 combination can get me up the hill, it can. I'm searching for what can save my legs for the miles ahead when I'm hitting those grades repeatedly. You are right, those gaps are not as bad as I thought they would be. Would be worth seeing if I can make a rear derailleur handle a cassette that big. We had some climbs last week that hit at least 25% on one section, and at that point I'm grateful to just be able to turn the pedals.

69chevy

There is a 105 RD that can handle 32t no problem.

rm -rf

I found this table of cog radiuses. Measured from the cog center to the chain pin's center.

30 tooth 2.3917 inch
32 tooth 2.5506
Difference: .16 inch, right at 4mm. So use a 4mm hex wrench as a comparison to see how the top pulley would be affected.

Looigi

I read the subject line and the first thing I thought was man, that must have hurt.

dalava

- there are 10 speed cassettes that go up to 32t
- the only problem you would run into with 32t with normal RD is a) chain wrap, and b) pulley/cog distance. For a) it's not an issue unless you do big/big, but you are not, you are looking at 34/32. For b) you have the b-screw to play around with and probably won't be a problem

rmfnla

Longer cage does nothing for cog capacity; it's to take up the slack chain when in the smaller size combinations...

noodle soup

it is possible to run a 32t cog with a 6700 short cage derailleur, but it doesn't work well. The upper pulley will be slightly too close to the largest cog, which causes it to feel rough. It works, but not perfectly.

Plainsman

Problem solved I think. Shimano 105 5701 GS specs say it is rated for a 32T cog when paired with a double front chainring. SRAM makes a 12-32 10 speed cassette (PG1070). Sounds like both would work well with my 6700 shifters and 50/34 front rings, and the gaps will not be too terribly different from the 12-30 cassette I'm running now. About the same high end it appears, and the gaps come in at the low end, at which point I'm looking for the bail out gear anyway.

hammond9705

How much do u weigh? Unless you're pretty thin the cheapest answer would be to lose a couple of pounds....

79pmooney

I know this is going to get laughed out the door, but the rides you are describing cry for a triple. Say a 53-42-26 X 12-25. (Say 12-13-14-15-16-17-19-21-23-25. I don't ride Shimano so I don't know if these are available, but you could get close.) The 26 x 25 would be the same as a 34 X 33 but with much better choices in the middle. You can drop the 16 and add a 28 which would be like a 34 X 37. You would probably need an MTB derailleur.

Climbing on setups like that when everyone else is on a double is fun. You can shift for grade changes when they cannot.

Ben

dksix

How are you doing compared to the rest of you group now?