smd3

Can I use a 32 tooth cassette with my standard crank. (SRAM Force group)

A bit of background. I'm a fairly strong rider, but I'll be tackling Passo Stelvio next month. I think I could grind it out in my current 12/26, but I'm going to try to summit Zoncolan at the end of august. I know I'm going to need an easier cassette for that. I was considering swapping the 39 tooth chainring too, I think I might be able to get a 38.

I don't want to buy a SRAM XX, or hopefully any new RD, I think I can grind out the Zoncolan on the 32, a 28 might not be enough. I tried to climb it a couple of years ago on a 34/25 setup and only made it about a third of the way. (this hill is insane)

Bioluminescence

I'd like to see this hill. Have any pics?

zitter

you've never seen or heard of the zoncolan? it was the hardest stage at the giro, it averages something like 11-12% for 10+ km

to the OP: for a 32 cog, you should get an apex RD

Bioluminescence

Wait, I missed the name. I don't follow cycling sports at all, so it's new to me.

I'll google it.

Puget Pounder

Correct. Chances are that your current RD maxes at about 28T.

RoboCheme

Or a Rival Mid-Cage RD, which is what I need to use my 11-32 cassette. My old bike has a MTB RD (Deore Xt), which is paired with a 11-34.

Barrettscv 

+2 on the Apex middle cage rear derailleur and consider a compact crankset also.

https://www.performancebike.com/bikes...1545500_400181

Kind of Blued

The only way to know if YOUR legs can make it with a specific gearing is to do the math and compare gear inches you've used on climbs you've done.

Hit up Sheldon Brown's Gear Calculator and start plugging in the numbers.

P.S. Passo dello Stelvio and Mounte Zoncolan are on my bucket list. Color me jealous.

smd3

Thanks, I'm going to look in to the APEX RD. This is compatible with my Force brifter?

I'm riding a Pedal Force QS3, with Force BB30 crank, so swapping back to a compact isn't really an option I want to tackle.

The last time I tried Zoncolan my easiest combination was a 34/25 that's 36.7 gear/inches.

My current setup of 39/26 is 40.5 gear/inches, a 28 tooth cassette puts me at 37.6. I'm stronger than I was last time I tried, but not that strong.

39/32 is 32.9, which I should be able to do.

I'm really fortunate, I'm in the Air Force, and I've been stationed at Aviano AB since February of '08. I got to see the Giro pass through in '09, and this year too. I've been able to ride some awesome roads! This is my last summer, we will be heading back to the states in February.

kimconyc

I did the Stelvio (from both sides), Gavia, Marmolada, Sella Ronda, etc. last summer on a 34/25. Stelvio (assuming you are talking about Prato) is not that bad, it's just really long.

Let's put it this way...I was riding with a lady (granted, she is a racer ) up Stelvio and she crushed it on a 39/25.

kimconyc

Possibly the longest short climb ever.

https://bike.strangerpixel.com/wp-con...ro_profile.jpg

Contador was using a 34/32 up this climb; it's no joke.

smd3

I'm not familiar with Stelvio, but other than the late July heat I don't This will be a supported ride, too. A quick web search shows it as an average grade of 7.5%, which isn't bad.

The Piancavallo road, which I climb fairly often has slightly worse grades at some points, but not quite so long. (https://pastasugo.posterous.com/piancavallo)

Zoncolan is average 11.9%, with a max of 22%. (10km).

I_Like_Bike

I climbed the Brasstown Bald on a standard crank and 28-11 cassette. It was really slow though. Half a mile up I wished I had a compact crank. Then another mile and I wished I had a compact crank and a 32-12 cassette. When I reached the section of 20% I wished I had a motor. Just thought I would let you all know that.

kimconyc

There will be no "July heat", trust me on this one. You might even get a nice snow storm at the top of Stelvio. It's usually the Cima Coppi when featured in the Giro.

Stelvio has a ton of switchbacks you can recover on, just don't push too hard before you get to the actual 48 switchbacks. You have to climb through a forest area from Prato to get to the actual 48 switchback climb.

Just pace yourself and you will be solid. A good idea might be knee warmers and a gilet or very compact wind-breaker.

smd3

Thanks, that's good info. I tend to be under-prepared clothing wise. I frequently do a nice climb, only to freeze on the way down. I need to get a nice packable jacket.

byrnemm

I'm new to biking and.. wow. Does this mean my standard 53/39 11-23 standard sucks at climbing?

cyclezen

I'd keep the 28 and get a compact front (50/34) along with a new chain (no sense shortening the old chain). Pretty decent external BB compacts (use current BB cups...) can be gotten for not much dosh and then you should also have a nice gear spread for the entire ride. That gives a 32.8 inch low. Everything else stays the same...
A very simple cranks swap, even a caveman can do it...
I think it can be done for under $200 USD (here in the states) with some shopping around...

ericm979

That depends on your fitness, the climbs you're riding, and your prefered climbing cadence.

But since you are new that gearing is probably too high.

Average grade is not that useful for gearing. For example the South Lake climb out of Bishop has an average of only 6%. But there's some parts that are much steeper- an extended section of about 10% and some 18% ramps near the top. If you gear for a 6% climb you'll be hurting on those parts (plus it goes to nearly 10,000' and you have to factor in reduced power due to altitude).

Bioluminescence

Holy crap. No hills anywhere near here like that.

But then again, I am in IL...

kimconyc

Monte Zoncolan:

Passo dello Stelvio (what you see in only half the climb):

NotZeroSix

^^^^ jesus!!!!!!!!!!!!!!!

rangerdavid

Holy crap. No way......

Bioluminescence

I take it it's against the rules to get off your bike and walk?

cato_mcfly

I do short stretches of 15-18% on my 34-25, but I'm out of the saddle. I don't think I'd want to be out of the saddle too much for that sort of climb. I'd go smaller than 34 (triple?) up front and 32 in the rear :-)

d8168055

SRAM Apex RD and 32T cassette was used in the giro... https://www.theroaddiaries.com/?p=4540