Adjusting the Seat
You'd be surprised how many bikers are riding on misadjusted seats -- seats
that are making life much harder for them. The angle of the seat, height of the
seat, and forward-backward placement of the saddle make a big difference in your
ability to respond to the demands of the mountain.
What kind of seat: Bikers who don't go off-road often prefer a wide
seat -- particularly bikers who are placing a wide load on that seat. Real
mountain bikers avoid wide-butt saddles, because the saddle won't slide readily
forward between your thighs when you roll into an o-my-gosh downhill. We also
avoid gel seats, both because of the weight, and because these seats inhibit
quick moves -- either side-to-side or forward-back -- of your butt on the
saddle. Women will usually need a wider seat (insert your big-butt joke here),
because the ischial tuberosities of the pelvic bone are more widely
spaced. In general, rock bikers like the slimmest, slickest seat that will
support them. The UtahMountainBiking shop can get you a high-quality
seat.
This is a quick-release seat post clamp. It's great for changing seat height easily with changing terrain. The down-side is the joint isn't as strong.
Adjust the seat height by loosening the clamp where the seat post goes into the seat tube.
Move the seat to its new position, then tighten the clamp. (If you're
a big guy riding a smallish
bike, make sure you have three inches of seat post inside the seat tube!)
After adjusting forward-backward and saddle angle -- as I discuss below -- you may need to readjust the height of the
seat post again.
This is a standard hex-wrench seat post clamp. This holds the seat more securely during rough riding, but isn't as convenient to use. Most riders who use this type of clamp set the seat to a good compromise height and leave it there.
Forward-backward position: The seat should be in a position where you can readily stand up. When you're on a slight incline, you should be able to rise off the seat without pulling or pushing on the handlebars to get yourself upright. If the seat is too far back, you'll find it hard to get your body forward to power yourself up a steep section, and hard to get your weight on the handlebars when riding up a tight switchback. Too far forward, and you can't ride a modest downhill while sitting. You may need to experiment a bit to find the position that gives you the best results.
Tightening the clamp onto the rails of the saddle. Note the seat position is a bit forward -- this position is good for climbing.
To adjust the seat position, loosen the bolt (or bolts) that aim upward into the seat clamp
mechanism of the seat post. Slide the rails forward or back, then tighten
up again. For an "official" starting position for the seat, see our section on fitting the bike to your body.
Seat angle: The seat angle determines how much the seat contacts the front of your crotch, versus your butt. If the angle tilts forward too much, you tend to slide off the seat as you peddle. If the front tip of the seat aims upward, it puts pressure on the base of a male's scrotum during the ride. (The compression here can cause impotence -- which is incompatible with guy biker's image of "total stud.") Adjust the seat angle until you feel no pressure on your crotch, but don't slide forward off the seat as you ride. Normally, the horn of the seat should be just a tad higher than the back end when the bike is upright with both wheels on the ground. This gives you a bit of "longer leg" when you move forward to climb a steep uphill, and makes it a bit easier to slide backwards off the seat as you enter a steep downhill.
Adjusting the seat angle on a two-bolt seat. Note how far back this seat is. This is a "downhilling" position. The rider will find it more difficult to get forward when it's time to climb.
On some seat posts, the seat angle is determined by changing the balance between the front
and the back mounting bolt. If you have a bolt in front AND in back of
the seat post clamp,
loosen one slightly while you tighten the other.
If you have a ratcheting angle adjustment (such as the red-trim seat shown in the position-adjustment photo), loosen the bolt until the teeth of the ball and socket come apart. Set to the new angle, then tighten down.
Single-nut clamp on a child's bike.
Many children's bikes have a seat mount like the one at left. When the nut is loosened, the
rails can slide forward or back, and the angle of the seat can be changed.
When you think you've got both forward-back and tilt where you want it, hold the seat in that position while you begin tightening the clamp.
