As with adult bikes first check the standover height.
Fat bike standover height.
The bike s actual standover height is the the middle of the top tube.
Standover height can be a bit tricky to calculate depending on the shape of the frame.
Stand over the frame in the center with your feet flat on the floor.
Whatever the top tube style look for about 2 4 of clearance.
You can read about the different bike types from here.
This is why mountain bike manufacturers use small medium large sizing and give their own size recommendations based roughly on your height.
You will want at least one inch for a road bike and two inches for a mountain bike.
The standover height is measured from the top of the top tube to the ground and use the same measuring conventions used for road bikes and mountain bikes.
Take off your shoes and stand with your legs about 15 20 cm 6 8 apart.
Most people in americe probably wouldn t have any idea what 740 820 or 755 mm was much less a way of measuring that.
They should be able to sit comfortably see around them easily and grip the handlebars with a slight bend in their elbows.
Mountain bike city bike or road bike.
To calculate your bike frame size take your inseam in centimeters and multiply it by 0 575 for mountain bikes 0 665 for road bikes and 0 645 for trekking bikes.
If your inseam measurement clears the frame s standover by a bit say at least 2 3cm for a road bike and a bit more for a mountain bike then you should be ok.
Measure the height from the ground to your crotch.
Be sure of the type of bicycle you want.
Most kids bikes are designed so they ride in a more upright position.
There you ve got a frame that should fit pretty close.
Most mountain bikes focus on an extremely low standover height so the traditional method of standing over the bike flat footed doesn t really work either.
While using your height as a guide is one of the easier ways to get an idea of your frame size it won t give you a perfect fit.
You can have two bikes with the same frame size but differing stand over height.
Here s how to measure.
Bike fit frame geometry and standover height posted on february 22 2017 when you re buying a good bike you want it to fit like a good pair of shoes a natural extension of you so you can focus on what you re doing and enjoying not the equipment that got you there.
If you need to convert your measurements to inches divide them by 2 54.
I don t know about lowest but the rm blizzard is pretty good with a sh of 740mm on a large frame.