Monday, September 24, 2012

Comfortable Seat and Easy Hill Climbing

"Oh, no! My new bike is great but now I can't ride up a hill!"

Is this you?

Seat Tubes have Changed
Is the slack seat tube angle a feature, or a bug?
Lately there has been a move in bike frame design, especially for city bikes, toward a "slack" seat tube angle. Designers made the tube that the seat is attached to lean further back, relative to the pedals, so today's riders can more easily get on the bike and put feet down at intersections. As we all become a less athletic group of people, with increasing obesity, this simple change keeps bicycling possible for many of us. Lots of city bikes, including some of the bikes we discuss in this blog, have become more "slack". The Electra brand of bikes are designed largely around this idea, and American style "cruisers" are also notorious for it. Even Bakfiets made the seat tube somewhat slacker when they redesigned the Cargobike a few years ago (the ones with the fin on the bottom are less slack than the ones with the loop near the pedals). Workcycles did it with some of their bikes, too, compared to old Gazelle, Batavus, etc designs. Frequently this is advertised as a feature.

Now Your Heels Touch The Ground, But The Hills Get Harder
"Aaaah! I'm falling backward and
it's hard to pedal!" The mannikin
should be leaning forward with
his elbows sticking out.
Unfortunately, there is a side effect. With a slack seat tube, riding up a hill becomes a lot harder. Your body weight is less in line with the direction you are pedaling in: "down" moves further back as the bike points uphill, but your feet and legs are pointing more forward. You have to lean forward just to balance yourself on the bike. You can't stand up well because there isn't enough room in front. Look at a Tour de France racing bike or anything else designed to help you go fast or climb hills easily and one feature you won't find is a "slack" seat tube angle. (Recumbents, where you sit on a padded chair and the pedals are way in front of you, are a different kettle of fish since you can push off against the seat back instead of using gravity).

Many cities, like Chicago and Amsterdam, don't have hills so it isn't an issue, but if you live in San Francisco or even somewhere with moderate hills like New York City, you might want to fix this. Fixing it in Chicago or Amsterdam can probably help you go faster on the flat, too.

So fix it!
There is a simple fix you might want to try, and a more complicated one if you need more. With some of these bikes you just can't get the seat to be comfortable and also get up a hill happily, but with most bikes you can.

You know how the seat is attached to the seat post? The clamp there? See how the rails on the bottom of the seat can slide back and forth in the clamp? Just loosen the clamp a bit, slide the seat as far forward as you can get it, and tighten it again. Somewhere between this position and the original one is a really comfortable place that will let you pedal on a hill too. Maybe you can point the front of the seat less upward too at this point. You might also want to raise the seat, so your knees are straight when your heels are on the pedals. We arrange ours so we can sit on the seat and just barely reach the ground on both sides with our tiptoes. (There's another trend in bike design that affects this, raising the bottom bracket, but you can read about that somewhere else. More modern bikes are built so you have to slide forward off the seat to touch the ground at intersections if your seat is set for efficient pedaling. It's yet another reason to prefer vintage bikes.)

Seats in General
A seat should be completely comfortable to sit on as you ride. Back, forth, up, down, angled up or down or side to side in front - there are a lot of ways to adjust them. The first thing I adjust is the height, with my heels on the pedals and straight knees; then I make the seat as level as possible and move it back and forth until I'm happy. (When I'm riding I put the balls of my feet on the pedals, which gives my legs a little more room. At this height you should be able to just barely touch the ground with your toes.) If I feel like I'm sliding forward as I ride (ouch!), I move the seat forward more and possibly raise the front angle a little. Sometimes if it's too far forward that doesn't help; then I try moving it backwards a little. If my thighs hurt from pushing on the seat, usually (but not always) forward also helps. Finally, when the height and the back-and-forth position are right, I angle the seat up or down if I need to. Usually level is best. The more upright your seating position is, the wider a saddle you will like, too.
The height of your handlebars and the distance forward you have to reach also affect comfort- if you like leaning forward with weight on your hands you'll choose a different seat adjustment than if you like to sit bolt upright with no weight on the hands.
or even as far as this
from far back, to this
You really have to ride it around a little and test it out, but you'll find a position that feels made for you like old comfortable shoes if you keep at it. A half an inch, about 1cm, in any direction can make all the difference. As a leather saddle forms to your body, things get even more comfortable, but a fancy saddle is really not necessary as long as the position is OK.
Ride it for an hour or two and adjust it a little more. The rules of thumb you see on other sites about how your knee when bent at so-and-so many degrees should be 1.6 cm forward of the midpoint of the etcetera are useless and foolish, in my opinion, so just find a position you like. Peter White has a helpful approach to this problem on his website too.

Fix it More?
Does sliding the seat forward improve things but not enough? Try flipping the seat clamp around. Often the seat post tube goes in front of the clamp bolt, and by turning the clamp over, reinstalling it backwards, or twisting the seat post around the other way, you can move the seat even further forward. This is often needed on Brooks saddles, which have very little adjustment in their notoriously short rails.  With old, standard seat clamps you take the seat off, twist the loop of the clamp from the front to the back, and put it back. On less-old ones there might be a lip blocking the top of that loop, so you take the clamp off the seat and put it back on the other way. On a modern seatpost with integrated clamp you can flip the whole post around and install the seat "backwards".
These seats are really far forward to compensate
for the bottom bracket and crank position
that permit good folding
Look at the Brompton and you'll see that this kind of seat attachment is part of the plan (to compensate for the pedals in front of the seat tube) so it must be safe to do.

Even More?
If even that isn't enough you can get an extension for the clamp, a 2 or 3 inch piece that makes the seat post into an upside down letter "L". Early Bakfiets used to use them (to make the angle slacker, but they tended to break), and Brompton still makes them I think. They are probably a special order item but any bike shop should be able to get them. Point the extension forward. Or you can look for a BMX style bent seat post and point it the wrong way, toward the front. Then a regular seat post clamp can be used with the loop pointing down. If you need to do this to be comfortable you may find it worthwhile to look at a different bike.

Now Go Ride
You might not need to do everything in this post, but if you find that little ramp up and over the highway to be a big problem on your city bike or Bakfiets, moving the seat forward can really help. You can also level the seat out and stop leaning forward so much, taking weight off your numb hands or private parts, by doing this. Go ride around and fiddle with it a little more until your bike is as comfortable as you can make it - it's almost certainly going to be better than it was when you started.

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