CHECHO

Ok, here’s the deal. A couple of months ago I finished my single-speed bike. I started the project just for fun to have a backup from my commuter and to build a bike from the scratch, but in the end the new one is very competent and I’m using it more to exercise than for commute. The thing is that I live in a very flat city, but with good climbs in the surroundings that I would like to, eventually, explore biking… so I was wondering up to what point it’s feasible to climb with no gears? Or, what’s that inflection point where you have to move inevitable to gears? I guess that the answer depends to many factors, including physical resistance, gear, experience, etc… but I just want to hear your experiences regarding climbing using nothing but your SS.

BTW my setup:
Crankset: 170mm 49 tooth
Tires: 700 x 23c
Cog: Shimano 18 Tooth
Steel Frame 52mm
Total weight: 9,3kg

Thanks!!!

Johnny Mullet

There is no shame in walking your bike up a hill especially if it's a single speed. Just saying.

seau grateau

Your gearing isn't too high. You'll probably find some ascents that you can't muscle through, but whatever. Go find a hill and ride up it, see how it goes.

FBinNY 

It's simply a question of having good hydraulics.

While spinning is fine for normal riding, at some point you have to be able to produce torque and that comes down to powerful quads, which you'll only develop by climbing in big gears. I'm not arguing for riding using big gears and strength vs. developing speed for normal riding. That's been settled for most people long ago, speed is faster and easier on the body.

But you want to have the option of using big strength when and where you need it, especially if you ride SS or relatively narrow gearing.

So my advice is simple, go out and find the hills, find the steepest ones you can climb at all, and the longest ones you can get to the top of, and build them into a normal routine. When they get easier -- and they will -- look for steeper and longer.

There are also some specific techniques that will help overcome steep hills.

One is to slalom up, which lengthens the climb, thereby making it shallower.

Another is to push back on the saddle, which is like raising it slightly, and to use your ankles to increase the length of the power arc. Since you only produce effective power for 2 arcs per rotation, lengthening the arc means that less force is needed at the peak to produce the same amount of power output.

Lastly, drop your ankles at the top of the stroke, then recover them using your calves as you pass the horizontal. This opens the leg somewhat at the top of the stroke improving the leverage through the knees. It also angles your foot to better power through a longer arc, pushing forward and down to start, and hback and down to finish.

Note, that these are different pedaling techniques that will not be practical for steady riding, but can be another tool in your kit, to be pulled out when needed.

But in the final analysis, single speed or multi geared, climbing is about power and torque, and you only get these by climbing hills that seem too tough to climb.

franswa

Yup. Exactly what I was going to say ^^

kingston 

Paul Rozelle’s 24-hour fixed-gear Mont Ventoux ride is one of my favorite stories of all time.

ThermionicScott 

And he wrote this wonderful treatise: https://www.bikeforums.net/singlespee...r-bicycle.html

TimothyH

I ride 48/16 with 170mm cranks and standard road wheels/tires. That works out to 79.1 gear-inches. It is very hilly here in North Georgia. I am 52 years old and in decent shape. The bike is 8.3kg.

5% grade is tough for me. If the hill is short enough I can spin up and over but if it is longer then I have to stand and work hard to keep the cadence up. 5% for a half mile would really hurt. I try to avoid anything beyond 6%. With anything 4% or below it isn't so much the grade but the length of the climb.

Real road bike bars with proper brake hoods help tremendously. The droopy pista bars were the second thing I changed on my bike after the saddle.

Keep in mind that your 49/18 with the same cranks, wheels and tires is 71.8 gear inches, a bit lower geared, and so things will likely be easier for you. The advise to go out and try is wise. A million people telling you things on the internet won't give you as much information as riding up one hill.

kingston 

You are a beast! My springtime gear is only 66" (45x18)

The Octopus 

Hey, y'all. Octopus here. Super-stoked to see people still chattering about riding big hills fixed, and that those old posts of mine are still useful to people. I just reread the advice one, and I stand by it. That stuff is tried and true.

This past Sunday and Monday, I just rode a 600k (375 miles) on fixed, running 48x16 through some pretty lumpy terrain. Still at it, and still having fun. And very excited to hear others interested in doing big rides on the cog. Get out there and have a blast, folks.

-Paul

TimothyH

That is good. I hadn't seen it. To be fair, much of it is applicable to road riding in general, geared or without, especially the parts about posture, not rocking the bike wildly, etc. Some of the SS specific stuff in the article is very good.


Not really.

There is a guy near me, built like a rhino, who rides some insane gear and crushes it. There is a girl at one of the shops down in Atlanta who rides the group rides with a single speed bike, rack with boom box on the back blasting tunes. Dares the fellas to try and keep up.

There is always someone better. I'm just happy to be reasonably healthy at my age.

79pmooney

Actually, pista bars can be sweet for fix gear climbing. I have a setup with medium deep and wide pista bars with V-brake levers. Really good for epic fix gear climbs. The huge levers are great out of the saddle handles and when I do sit down, the arc of the pista bars rotates my wrists in, elbows out and opens up my lungs. And on those epic climbs, rarely do I want to cruise on the hoods. That's the luxury of the geared crowd who can spin up hill.

My first season using this setup was when I rode the Crater Lake Cycle Oregon. I came to really appreciate it on day 6, our 4th day straight of 5000' plus. That morning started out with a 16 mile climb. Everything about the bike was perfect. (I was using a low gear - 42 X 23 - and flipped the wheel at the top of the climb. But judging from relative pedal RPMs I saw, few were using a gear that big.)

OP,for serious single speed/fix gear climbing you need several things. Great hand positions, especially out of the saddle, that allow you to pull hard without injury or chronic problems. Drop bars are a real plus. Brake levers and hoods your hands really like located on the handlebars to give a solid, comfortable position to pull from out of the saddle. (This may well not be your preferred flat ground cruise location. If that is the case, you have to decide priorities. I have two complete cockpits; bars, hoods, stems, cables and brake calipers since the levers are of different types, one set up in normal road configuration, the other as described above.)

Second is shoes, cleats and pedals. You need to be able to pull up hard on the pedals. Simple math will tell you how steep a hill you can get up in any given gear just standing on the pedals and not pulling. At a 16% grade and a 72" gear and 7" (178mm) cranks, just standing on one pedal with all your weight you can keep the bike from rolling backward. Obviously this way too tough a gear to be able to pull the pedals through the top and bottom dead spots. But if you call pull up with all your might, you can pull them through/roll through. 16% and steeper is possible IF you are strong enough to do pull on the handlebars and pedals like a full body "clean" of a "clean and jerk". I used to go up Blue Hill outside of Boston on an 81" gear. 10% average for 0.9 mile. About 150' at ~18%.

It is all possible, just hard. But you will look at the guys who reach for those big cogs and little gears as wimps after you get there.

Ben

IAmSam

This thread/question really demonstrates what a damn shame it is that ▂▃▅▆█☆★✡✯IF NEW HERE☆★✡✯, please check in here first! (Former sticky index)█▆▅▃▂ has become such a wasteland that apparently nobody ever uses.

It is where the OP or other posters here could have found the very useful "article" by The Octopus that ThemionicScott cited. Guess there is no way to force anyone to use such things - but when I 1st came to this forum I found it extremely helpful to thoroughly digest its Sticky Index predecessor. Perhaps if one is a regular poster here but never bothered to check it out before...you should

ThermionicScott 

Hey Ben, if you don't mind, what is the way to calculate that? Frank Berto arrived at a crude rule of thumb for the grade that can be climbed in a particular gear in his "Dancing Chain" book, but didn't show his work.

It'd be fun to play with the crank length, gearing, etc. Thanks.

corrado33

And if you don't have the power or torque required, it seems like the perfect application for a geared bike... I know, blasphemy in the SS forum.

FBinNY 

gearing can compensate for torque, which is what it's about, but not for power. Power relates to how fast you can climb to a given height, and how you do it doesn't factor.

FBinNY 

It's a simple question of levers. Start by using the sine of the slope angle to calculate how much of your weight is supported by the chain tension, (your legs) then use basic rules of leverage to work that back to the pedal.

If I could draw here, I'd sketch it out, but you can do that yourself.

OTOH there's a short cut if you use gear inches. The ratio of your crank diameter to the (theoretical gear inch) wheel diameter has to exceed the sine of the slope.

BTW - this calculation is only to find the "stall" point where your full weight standing on the horizontal pedal will hold the bike from rolling backward. However that doesn't mean you can climb. You still have to bring the cranks around, which is where Berto's rule of thumb comes in.

There's also the question of how long the climb and what skills and power you can bring to bear. For example, by pulling up on the rear crank you can apply pedal force greater then your body weight, and that can be worked to overcome the dead spots. I expect that a skilled, strong climber can climb using gears someplace between the stall point and Berto's rule of thumb which is pretty conservative.

corrado33

Very true, my mistake.

gl98115

79pmooney

I did this last night and didn't check it. Getting a little more organized, I wrote it out again and discovered I forgot the bike weight. And apparenetly there is another mistake, either last night of today because the bike weight should have made the final slope less steep but it increased 2%. Again, this is not thoroughly checked, but here are the steps. You math and physics whizzes can correct my mistakes while I go for a ride.

Fb – Tangential force developed at rear wheel
Fp – Force on pedal
Wr – Rider weight, Wb – Bike weight, W total weight
H – hill rise, l – hill run, alpha – hill angle
In – Gear in inches, d – wheel diameter, Cr – Crank length

Basic physics: W sin(alpha) = Fb

Basic gearing: Fb = Fp (d/In) x (Cr/d/2) = 2Fp x Cr/In

Combining: Sin(alpha) = Fb/W and alpha = arcsin(Fb/W)
But: W = Wb + Wr and Fp(max, no pulling) = Wr
And: alpha = arcsin(2Fp x Cr/In)/(Wb + Wr) = arcsin(2Wr x Cr/In)/(Wb + Wr)

So, say Wr = 180, Wb = 20, W = 200, therefor Wr/(W) = 0.9
Cr = 7” (178 mm), d = 27”, In = 72” (the gear)
Then: alpha = arcsin(2 x 0.9 x 7/72) = arcsin(0.175) = 10.1 degrees
But: rise over run x 100 (ie “percentage) = 100 x tan(alpha) = 18%

Jixr

yall are making this way too complicated. If you see a hill, HTFU and go up it, no need to make it more complicated than is.

There is only one hill in my normal route that I can't climb, and to be fair, anything but a fat bike would have trouble climbing it

FBinNY 

I don't think anyone is making this complicated. Most are giving similar HTFU advice along with info on techniques that can help.

The rest is only about intellectual curiosity, and being realistic knowing the math has nothing to do with actually getting up the hill.

CHECHO

Well, what can I say... Agree...

CHECHO

thanks, great tips... I've tried slalom, but it requires an really empty road to be safe... I'll try the two others during next climbing attempts...

CHECHO

yes... that's right...