Whether your kids are using their bikes to cruise to the park on the weekends or for daily transportation to school, the right fit means they'll be ready to ride safely. Among the adjustments you'll need to make is ensuring that the seat is at the proper height. Kids tend to need their seats adjusted slightly lower than adults so they can touch one or both feet to the ground since their growing, sometimes less-than-agile bodies need a little extra stability.
General Bike Size
Part of getting the right fit for your child's bike -- and thus the right seat height -- is ensuring she's riding a bike that's the right size for her overall. Before you start to make seat adjustments, have your child stand over the frame of the bike while wearing shoes she may be wearing while riding. For road bikes, there should be about 1 inch of clearance between her body and the top tube, the horizontal or angled tube that stretches between the seat post and the handlebar stem. For mountain bikes, there should be more like 3 to 4 inches. If she has the angled top tube that is common among girls' bikes, the space will also be 2 inches or more, but have her stand as close to the handlebars as possible to ensure there's at least 1 inch of clearance. If her pubic bone is hitting the tube, the bike is not the right size. It's also a bad idea to get a bike that your child can "grow into," reminds the Bike Radar website.
Feet on the Pedals
When you're sure that your child's bike is the right overall frame size, it's time to adjust the seat to an appropriate height. Hold onto the frame and handlebars and instruct your child to get onto the seat and place his feet on the pedals. Have him press forward on the pedals until one pedal is all the way to the bottom of the pedal stroke. At this bottom position, his leg should be ever so slightly bent. The bottom stroke shouldn't require your child to point his toes to keep touching the pedals -- that's a sure sign the seat is too high.
Feet on the Ground
Next ask your child to put at least one foot on the ground while remaining in the saddle. He should be able to get one foot on the ground while still staying seated. If he's a total beginner to cycling, it may be safer to have the seat adjusted to a height that allows him to touch both feet on the ground. That way, he can kick his feet to propel the bike as he's learning how to pedal and stay upright. He can also plant both feet on the ground if he needs to make an emergency stop.
The Comfort Question
When you're adjusting your child's seat -- either with a wrench or using the quick-release lever supplied on many kids' bikes -- take her personal comfort into account as well. The bike experts may have their recommendations for how high your child's seat should be, but that doesn't mean your child is going to be happy with those guidelines. Kids tend to like their seats lower than is recommended, reminds Bike Radar, so you may have to make a compromise. A seat that is lower than it should be is preferable to a seat that's too high, since your child will be able to reach her feet to the ground easily. So long as she's able to control the bike and the gears, allow her to ride at her comfort level. Over time though, you may encourage her to raise the seat to the recommended height. Explain to your child that too low of a seat can cause pain in the knees and make it more difficult to pedal efficiently.