FatBottomedGirl

Hi,

I live in Paris, and its surroundings are desperately flat.
I own two bikes for the road (and one for offroad, but not the topic): a touring Trek and a racing CAAD 10.

I would love to explore a bit the french Alps both from a sportive point of view and purely for the landscapes and so on,...
Problem with my desperately flat hometown is that my ride and trainings feature very little climbs! And while I know I can climb 500meters at 15% how will I do in 10km at 10%??

Since my goals are both sportive and touristic, I can have two approaches in my trip: the touring bike with some clothes and food in panniers,... or the race bike with only the saddle bag to to repair punctures.
It can really go either way.

If it were only upto me I would go with the racing bike (it feels more classy to climb the Alpe d'Huez on a bike that "looks" more like the ones of the cyclists in the Tour de France right? I know it's silly... but well...) but I don't know how I stand as far as climbing is concerned with my gearing.

I am pretty sure that the 28t front chainring along with the 34t sprocket on the touring bike can get me up the steepest hills.
But I honestly don't know about the CAAD's gearing. I have a 50/34 compact and a 12/13/14/15/16/17/19/21/24/27 cassette. How steep can I go with that?
I've honestly only used the 34/27 combination once in the mentionned 15% 500meters climb. And even if it was 15%, it was only 500meters...

I am mediumly trained: ride a bike everyday to and from work and an average of 120km each weekend just for fun in Parisian close countryside.

I don't really care about the overall speed of my climbs, I just don't want to have to just walk after 5 minutes of climbing.

Sorry if this feels too ridiculous. And thanks!

RPK79

Just do it. Can't know until you try. Right?

Homebrew01

You can climb a hill about "This" (See my arm tilted at an angle) steep ...

merlinextraligh

It's impossible to answer this with any certainty, without knowing how ift you are (i.e. how many watts you can put out on a sustained basis).

However, my bet is you'll be ok with the 34/27.

If you can make it up the 500 meter 15% grade in the 34/27, comfortably, turning over a decent cadence, you'll be ok on any of the big climbs in the Alps.

If however, you're out of the saddle, grinding at 30 rpm, and about to fall over dead at the top, you likely need a lower gear.

So go find a reasonably steep hill, put it in the 34/27, and pedal up it at a reasonable cadence. If the effort feels like something you could sustain for an hour your gearing should be ok.

Seattle Forrest

That's a pretty easy gear. I'm going to guess you can do a 25 % grade with it. Might take a lot out of you, but you should be able to do it.

Also if you do hill repeats, it's amazing how quickly they'll make you stronger.

merlinextraligh

What's "easy" depends on the individual.

34/27 at 70 rpm is almost 7mph.

For the OP at his weight to climb a 10% grade at 7mph he's got to put out 327 watts. 327 watts for an hour is a pretty big ask for a recreational cyclist.

svtmike

Sorry, this is way way off.

I'm in the neighborhood of 195 lbs. A grade in the mid to high teens requires an output of at least 270W at 4-5 mph, and at that gearing cadence would be below 50 rpm. That's a nasty grind, especially for a female (FatBottomedGirl is a female maybe?) where power/weight is typically lower than for a male.

A 25% grade would be more like 450 watts sustained to do 4mph.

When I go to tackle hills like that, I take a 30/36 low gear. Allows me to keep the cadence to something civil (70 rpm or so) while still laboring up the hills at my slog pace.

justkeepedaling

You should be fine, I agree.

I wish I had a 34, instead I have a 42

RoboCheme

It's impossible to comment on your capability, but I'll relate my experience to see if it helps.

I ride a 50-34 compact with a 11-32 cassette. I need it to go up some of the 15% hills around here.
Last year I did Alpe d'Huez on a rental compact with 12-25 gearing. Not as low as my bike, but no problem since the steepness section was only about 12%.
Then we did Mt Ventoux. I had a compact with 11-28 gearing. Again, no problem since the steepest sections were only 13%.

Our goal was the same as yours - avoid the Walk of Shame.

So if you can do 500 meters of 15% with you CAAD, I'd go with that. You may struggle on the steep section, but you probably won't have to walk. You might try and find profiles of the hills that you'd like to try

Jay Olson

Back in the day, I went on a 3-day mini-tour that rode some epic climbs of the Tour, including Alpe d'Huez. My bike was made of steel (just like the tour riders) and had a low gear of 39x28. At the time, I was living in flat Stockholm, and not riding that much. I made it to the top of Alpe d'Huez without having to get off and walk. It was long, slow, and hard, but no where near the hardest thing I have ever done. 34x27 is lower than 39x28, so it should be fine for someone who rides often.

MikeWMass

I would think you would be OK on grades in the mid teens. I am also skeptical about the 25% grade, I weigh less, ride 34/27 low gear, and the few hills over 20% around here are climbed only as special events, and very slowly. If you are really concerned, try it first on the tourer, and see what gear you need to use for the climbs.

gregf83 

Assuming you're a young (26 yr old) reasonably fit male capable of putting out 3 w/kg for a sustained (i.e. 60m) period you should be fine going up a 10% hill at 60rpm with your current setup.

Personally, 60rpm is a tough way to climb for an hour so if you are planning on doing longer 10% climbs I would look at getting some lower gearing.

I would suggest picking a climb between 6-8% average and see how you do. Worst case you take it easy and stop for a breather once in a while.

Seattle Forrest

He's going to spend a whole hour climbing that hill**********

According to your numbers, it's a sustained uphill for 7 miles!

Seattle Forrest

Meh. I've done a 26.02 % grade (steepest paved hill in Seattle) in 53x39 at that weight. Didn't happen the first time I got on the bike, but like I said, hill repeats help, and the OP has 34x27. I have confidence in her, even if you don't.

gregf83 

He wants to climb in the Alps so the climbs are long. Hammering up a short 26% hill isn't really relevant.

svtmike

Maybe we're talking apples and oranges. I'm not talking about a kicker where you have to go anaerobic for a short time. I'm talking about real hills -- sustained climbs where the rider's threshold power is what's in play. The length of the climb doesn't have to be anywhere near an hour for that to be the case.

bobones

I'm just glad you didn't ask, "how steep of a hill?"!

merlinextraligh

We're talking about the French Alps. A recreational cyclist will take longer than one hour to climb L'Alpe de Huez.

contango 

Sustained uphill for 7 miles, yep. The Alps are a mountain range so you could find hills that are sustained uphill for more than 7 miles if you felt so inclined. IIRC some of the climbs in the Tour were sustained inclines for 15km or more so you're talking about climbnig non-stop for 10 miles or more.

mr_pedro

Here is what I can make of it, it is all very rough, but should give an idea:
With the 34/27 you can probably maintain something between 6-7 mph at a cadence of 60-70 rpm.
You say you can do 15% 500 m climbs in 34/27, but it depends a lot on how fast you can do this? In the worst case, assuming a minimum speed of 6 mph means you can do 430W for 3 minutes.
That means that for an hour you could probably do about 35% less, which gives let's say 280W.
However on a 10% slope you would need about 290W to climb at 6mph.
The numbers are going to be very close, far closer than the accuracy of these estimations. I think you will at least be able to go for 20 minutes or so. But if you can last 1 hour or longer at that pace without rest, you just need to try.

ericm979

I suggest the OP get an Ultegra 12-30 cassette if he's using the race bike. It will probably work with the existing derailleur (I've done it on 7900 and Red) and will give one more gear just in case. It's better to have low gearing and not need it than to need low gearing and not have it.

contango 

There's really no way of knowing, terms like "mediumly trained" don't mean anything because we don't know what you mean by "medium", and a lot can vary based on nothing more than whether you're having a good day or a bad day. There's a hill near me that sometimes leaves me needing my granny gear (30-32 on my bike) sucking air like an asthmatic hippo, and sometimes I climb without even needing the granny ring (so I might be in something like 39-28).

The only way to find out is to try it, although I'd be inclined to try something between 500m and 10,000m before you dive straight in to the Alps. I'd love to ride the Alps but suspect I'd spend so much time walking up hills it wouldn't be much fun. If I want to go hill walking I'll leave the bike at home

10 Wheels

^ ^ ^ The easy fix. I put 12/30 cassette on my 10 speed compact 50/34. Was able to top a short 20% hill.

Carbonfiberboy 

Reality check. Alpine length climbs are all about endurance at a high power output. Top TdF level pro climbers manage about 5,000'/hr. With PEDs, more like 6000' is, I believe, the record. I believe the record on the the Alp, at 3300', is 37 minutes, or 5351'/hr. by Pantani, probably using PEDs. IME ordinary 155 lb. strong club riders do about 2500'/hr. on long climbs. On our tandem, my wife and I, at 132 y.o., manage about 1500'/hr. at our very best, more like 1200'/hr. on long climbs. Yes, so we're slow.

But 2000'/hr is a very good pace for anyone to maintain for over 1.5 hrs. Much of the Alp is a steady 10%, though the average is 8.1%. The Alp is 14 km. So to climb it at 2000'/hr. will take 1.65 hrs., or an average pace of ~8.5 km./hr or ~5.3 mph. That's a sustained 210 watts for the OP, pretty good. I know that my endurance goes down markedly at a climbing cadence below 75. If she goes to a 33 in front and a 34 in back, that still doesn't quite do it, but it's close at 9.1 km/hr at a 75 cadence. However, the key is the long 10% sections. At that same 210 watts, her speed will drop to 7.1 km/hr and her cadence will drop below 60. Ouch.

So she should find a long hill somewhere and, having a watch and an altimeter or GPS with same, or using Google Earth, find her endurance climbing pace, then go do the math:
https://www.machars.net/bikecalc.htm
https://www.hembrow.eu/personal/kreuzotter/espeed.htm

Choosing gearing is pretty simple really, once you know your climbing pace in feet or meters per hour and the gradient you will be climbing.

jeffpoulin

I live in the French alps and ride the hills here every day. I don't race, I just ride recreationally and commute to work. I have 7 bikes and 6 of them have triple chainrings. I like low gears and haven't encountered any paved roads that are too steep for a 30f/28r. There are lots of cyclists here with compact doubles and 12-27 cassettes (or even 12-25), but I rarely see them riding fast on long grades. It's doable, but IMO just not very comfortable after 10km of 9-10% grades (and there are cols here that climb for more than 20km). If I were you, I'd bring the touring bike with a bike bag for clothes/food and just explore.