Originally Posted by
bikenh
The one thing you don't mention though is the exact opposite side of the equation. The downhill.
Downhill can be very difficult (and dangerous) on a fixed-gear (and is conversely a breeze and a lot of fun on a single-speed or any other bicycle with a freewheel hub).
You'll want to pick a gear that lets you climb but that also permits you to descend in some reasonable comfort. You're really looking for what I call the "Goldilocks Gear" -- not too big, not too small. Too big, you can't go up. To small and you can't go down.
I could easily see the need for some darn good brakes or your going to blow your legs to pieces if you are riding in the hills/mountains on a FG bike.
When I've been in the midst of descending some huge mountains on a fixed gear, I thought every time that what I wanted was a drag brake.
I run both front and rear brakes (levers with hoods; no suicide or TT set ups!) and even then descending is challenging. Gravity wants to take the bike, and you, downhill and FAST! The act of braking puts a huge amount of pressure onto your hands and, especially on a long ride, they can get very sore and you can even risk nerve damage. I had some pretty good ulnar nerve tingling for a few weeks following the Gold Rush, which is an easy 1200K, but which involved an awful 70-mile descent out of the Sierra Nevada. Your hands (and back and shoulders and arms) will also get beat up on those big mountain descents. On top of that, you've got to manage the braking so that you don't heat the rims up too much (which will blow up your tube and especially on a front-tire blow-out, likely cause an uncontrolled fall at speed -- very bad!).
And all of this is before you even get to the issue of cadence. In my experience, the cadence you can maintain is a funciton of how long you've got to maintain it. Each person's "numbers" will be different than mine, but getting much above 100 starts to be work. It's not comfortable for long periods and I'm drawing on my cardiovascular reserves and I'm wearing out my legs in triple-digit cadences. On long -- 4000+ foot descents -- I try to keep things down to 120 or 130. But my "personal best" on short, sharp descents is 187rpm (which was good for just under 45mph in the gear I was in). Sort of like selecting a gear, you've got to select a cadence based on how long you have to maintain it and you want to pick one that's going to spread the pain around between your legs and your hands and upper body. Too much braking and you're upper body will be destroyed. Too little, and you're legs will be (plus you'll have a much higer HR, which isn't good either!).
I have also found that the more I ride fixed, the wider the range of cadences that I can maintain comfortably becomes. I can stay seated now on climbs that would have brought me out of the saddle in years' past. And I can spin
a lot faster than I could when I began riding fixed. I remember on the Gold Rush in '09 -- my first fixed 1200 -- another fixed rider in a lower gear than me put me out of sight on the descent of the Jarbo Gap. I couldn't believe how fast that guy could spin! I'd be able to stay with him now.
re: "braking" with your legs. The only time I ever use backpressure on the pedals for speed control is in a paceline. I never do it on descents. I like my knees (and my teeth). Replacing brake pads is cheaper than body parts. And don't skip- or skid-stop. It's fine for hipsters riding to the bar or in Alleycats, but it's destructive to you and your equipment. Riding distance fixed is tough enough on your body and your bike without skidding all over God's creation.....
Although experience will increase your "comfortable cadence range," so too will two other critical things that you should work on when descending. First, you've got to keep your upper body totally relaxed and loose and quiet. The moment you tense up or -- worse -- start to have any bounce in your upper body, it's all over. You're in the drops, your eyes are gazing way off down the road, and your mind is totally clear. You are NOT thinking about pedaling a bicycle. Your grip on the bars is super light. At silly cadences, this is a wonderful Zen-like experience. The moment you think you're going to lose that inner calm and peace, though, grab two fist-fulls of brake and shut it down.
The second element, related to the first, is that you're staying ahead of what gravity alone would do to the bike. You're pressuring the pedals. Even if you're braking, you're pressuring the pedals. This may sound a bit silly, but it's critical to keeping your upper body quiet. Finding the perfect cadence that would let you spin down the mountain at zero watts of output (as if you were coasting on a freewheel bike) is just about impossible. If you're looking for that, you're most likely going to be behind, negatively pressuring the pedals slightly. You're going to blow apart if that happens. Instead, descend the mountain or hill on your terms, not gravity's terms. Pick a cadence and a pressure and then keep those constant. Adjust your braking -- not your pressure on the pedals -- to keep it constant and you'll be solid and steady and in control (and not wear yourself out).
A final thought on big climbs and descents on FG bikes. If you're riding an event or on a big landmark climb, you need to plan some crowd control into your ride. If you might need to tack to get up a hill, do you have the pavement availble to do it, or are there riders and autos all over the place? If you've ever been frustrated on a geared bike on a climb that's crowded with cyclists walking and weaving all over the place, or with cars trying to pass clumps of riders and taking up all the pavement, take that feeling and multiply it by a thousand and it's what could happen to you on a climb on a FG bike. When climbing something that's crowded, you've really got to be looking up the road and trying to figure out your "line" and where people are going to be and how you're going to get through everyone safely (for you and them). Altering your cadence on a climb is a lot of work; you want to do it as little as possible!
Descending is even trickier, especially on an epic mountain that has a lot of tourists in cars and other cyclists on it. You need to focus on where you are, where you're going to be, how you can go through the switchbacks (remember pedal strike!)... all in the context of interacting with other riders and vehicles. I started my fixed-gear climbs of Mount Ventoux at about 4am for a lot of reasons, but one toward the top of the list was so that I could have a clear road -- no one descending when I was climbing -- to work with on the steepest pitch. Another fixed rider and I did the same thing on the Gold Rush, so that we could get up the dreaded Janesville Grade ahead of everyone else leaving Susanville on the last day of the ride without being in their way or them being in our way.
Apologies for the length of all this. Not a lot of people do long rides (or big climbs) fixed. And even fewer people write about it. I learned most of this the hard way, so I'm just trying to short-circuit the process for y'all and pay it forward a bit here....