asp2011

I have a Giant Bike and am training for a road ride across Iowa (ragbrai). The ride will have 21,000 of climbing; fifteen thousand in the first two days. I am struggling when I am climbing in the bay area, mainly in Marin by Mt. Tam is where I ride. My cadence drops when I climb, and often I have to stand up to keep my bike moving uphill.

I have a standard crankset (ultegra, with two cranks, one with 53 teeth, and one with 39 teeth). My rear cassette is 12-25. I've gotten strong by riding a lot recently, but perhaps I should change my crankset or cassette to make climbing easier. Suggestions?

mechBgon

One of the most straightforward ways to add lower gears would be to get a Deore XT RD-M771 rear derailleur, a 10-speed Shimano or SRAM 11-32 cassette, and a new (longer) chain. The low gear would be about 28% lower. You'll have bigger jumps from gear to gear, but it sounds like the lesser of two evils here

edit: I'm assuming your system has a 10-speed rear cassette now. If it's 9-speed in the rear, then of course use a 9-speed cassette.

bikepro

Are you sure the large chainring has 59 teeth? That seems very large when paired with a small ring of 34 teeth. That makes a huge gap when shifting from one ring to another. If it has 59 teeth, I would change it to something like a 50 tooth. The 50/34 would give you a typical compact crankset. If you still have problems, you could change to a larger cassette on the rear. How large you can go here depends on the rear derailleur capacity.

Barrettscv 

Most of the hills in Iowa are steep, but short. Your crank with the 34t chainring is a compact double. That crank should work fine.

Is you bike a 2x9 or a 2x10? If you have a 2x9, Harris provides a 13-30 nine speed cassette that should work perfectly for the terrain. See: https://harriscyclery.net/itemdetails.cfm?ID=702

You should be able to use this with your existing derailleur, but be sure to install a new chain.

If you have a 2x10, consider the Sram Apex 11-32 ten speed cassette and use a new chain and long cage derailleur like this: https://harriscyclery.net/itemdetails.cfm?ID=950

asp2011

I was wrong. The crankset is 53 and 39. I have ten speed cassette. How does change your response?

asp2011

You're right. Its 53 and 39. Sorry, for the mistake.

mechBgon

The 11-32 cassette, a new chain, and a 9-speed Shimano mountain derailleur would still be a viable plan. I suggested the XT model, but it's worth mentioning that it doesn't have a cable adjuster, so if your frame doesn't have a cable adjuster, you'd also want to add an inline adjuster, or simply pick a derailleur that has one, like the Deore that Barrettscv linked to.

Just to point out a couple pitfalls:

1. if you do go with that plan, don't get a 10-speed Shimano mountain derailleur. They use a different cable-actuation setup. The 9-speed models are the way to go.

2. also, be aware that there are some mountain rear derailleurs that are sprung in reverse. They "home" on the biggest cassette cog, not the smallest. These are referred to as "low-normal" or Rapid Rise. If you like how your shifters work now, stick with a top-normal, non-RapidRise rear derailleur.

Kimmo 

It may be simpler to get a compact double crankset. Use your existing chain (might not even have to shorten it) and derailleurs; just lower the front one. Maybe you need a compact-specific front derailleur, I'm not sure. But they're cheaper than rear derailleurs.

That'll give you 50 & 34 rings, and a 13% lower first gear. If you're tallish (say, over 5'9"), you'd prolly find 175mm cranks a boon too. Pretty much the only downside (apart from looks IMO), is you lose top gear (50/12 is roughly 53/13).

Barrettscv 

Like Kimmo said, try a compact crankset. You will be able to use your existing chain and derailleurs.

Seek out something like this: https://cgi.ebay.com/105-Shimano-5650...item588e2602ea

This item is a 175mm crankarm size, check to see what length of crankarm is on your bike.

bradtx

asp2011, I doubt that you'll find any steeper climbs that you now face in the Bay Area, but the distance of the climb could very well be greater. I don't think a 53-39 is ideal for the Bay Area and if I lived there (my son was transferred there so I have a fairly good idea of the terrain) I'd change to a compact or a triple crankset.

I'd swap in a compact crankset (a compact's chainrings may be transferrable to your present crankset, worth checking on) and ride that before any other changes.

Brad

wrk101

+1 Start shopping for a compact crankset.

cyccommute 

It would be more economical to change the cassette, derailer and chain than to change the crank, depending on the level of components. A new 105 compact is going to cost around $270. A new 10 speed 11-34 or 11-36 cassette can be found for $60, a rear derailer will cost from $50 (LX) to $80 (XT) to $170 (XTR) and a chain costs whatever you want to pay. If you went with the XTR (and not including the chain cost), you'd still have to pay less than the 105 crank.

And you'd have a slightly lower gear (32 gear inches vs 36 gi). If you went with the 11-36 cassette, you'd have a low gear of 29 gear inches for the same price.

Kimmo 

I can just picture the OP's reaction at this point - gah, option overload!

serpico7

Yep, compact crank gets him to 36gi. Cassette option gets him lower for lower cost. Especially if he can switch to a cassette that doesn't require a mtb derailleur. What's the biggest cog on a 10sp road or touring cassette that will work with a short cage derailleur? 30t? 39(ring)-30(cog) would get him to 34.3gi, and if he can do that with only a cassette and chain swap, might be his cheapest option.

@Kimmo, if he went with a compact crank, I don't think he'll need to change FD. I used to ride a compact crank with a standard FD.

Hmmm. Are compact chainrings compatible with standard cranks? I didn't think they were. But if they are, that would easily be the least expensive option.

Kimmo 

I think Shimano did some cranksets with the compact-sized spider and normal-sized rings for a couple of years there somewhere.

Remember thinking they looked weird... IIRC it was around the time the hollow cranks started to trickle down.

Barrettscv 

The OP should have no problem finding a Shimano or Sram Compact for less than $150. This comes in about the same as a new cassette, derailleur & chain. If these parts are worn and need replacing, the new cassette, derailleur & chain is the better option.

One problem with the 11-36 cassette is the massive change in cadence between each gear. Keeping the standard crank also provides a number of gear combinations that are useless while crossing Iowa or climbing hills in San-fran. In-fact, a 53 chainring becomes almost useless on a long tour where his average speed is going to be 12-17 mph on any given day.

mechBgon

However, switching to a compact double only drops the low gear by about 14%. If someone wanted just one lower gear, so he didn't have to push as hard, then maybe that would be enough, but the OP reports he has to actually get out of the saddle to keep the bike rolling, so I lean towards the 28%-lower result of the 11-32.

Barrettscv 

Here is the comparison between the two gearsets;



Anything above 100 gear inches is going to need a steep decent and climbing in Iowa is limited to short sections of a mile or less. I would really be surprised if the OP could not climb the steepest section with a 34 & 25 combination. Just as important as hill climbing will be the wind in Iowa. Having a 15% + change in cadence can be a real handicap when fighting a 15 to 25 mph headwind for 6 to 8 hours.

Kimmo 

Good point.

fietsbob

A standard 110 bcd crank, yes. but I expect you have a 130 crank,
so you only go down to where the bolt circle is, 1 tooth less than 39.

I like triples. 52/42/26 & 50/40/24 on my 2 road/tour bikes.
Campag race triples, still square taper, 3 piece.

3rd chainring, is half the # of teeth of the big one.

Alan Edwards

I went 11-34 and 34-50 but I built my bike from scratch, are you planning a temporary change?? If it's temporary go cheap and get an Altus RD and a TX cassette, your 10spd for 100$.

davidad

Go down the page to the Tiagra triple. Add a 24t small ring to replace the silly racing triple small ring. https://www.bikeparts.com/productsear...%5D=656&pS=100
A 105 front Der. https://www.bikeparts.com/productsear...1&f%5B%5D=1328
If you use your present cassette you will a 25.7 inch low gear.

serpico7

Cool graphic representation.

Problem is we don't know how much power OP puts out or his cadence on the climbs. But having (as opposed to choosing) to stand on anything not very steep is a sign that the 13% drop from his current small gear to 34-25 isn't going to solve the problem.

Maybe we can get at this another way. OP, what hills in particular are you forced to stand on? Someone must know the slope of all the big hills in that area from having used Garmins and such.

Barrettscv 

A triple would be ideal, but he might need to change brifters along with a front derailleur & BB.

I was thinking about this crankset with 46 & 30 double chainrings: https://store.velo-orange.com/index.p...-crankset.html

at $200, it's a little pricey and not-in-stock currently.

serpico7

OP has an Ultegra crank. Is that 130 bcd? What would be the smallest chainring combo he can get on there?