There are no steadfast rules when comes to choosing the perfect size bicycle. But to help you on your way, here is a simple guide to get you started on finding that new bicycle at just the right size.
Personal preference is just as important as the typical manufacturers guidelines for buying the right size bike. For instance, would you like to be sat more upright on your bike or would you prefer to have a bike sized to obtain better performance? The cyclist wanting to be seated more upright on their bike would need a slightly larger frame than the cyclist aiming to get the best performance out of their bike. You'll find out why the difference in just a moment...
Frame sizing guide
Bicycle frames are usually measured on the length of the seat tube. And, getting a basic idea of the size of frame you require will depend on your inside leg measurement.
Measuring up
To find out the right size frame you will require, take your inside leg measurement, then subtract around 9 inches off for a road bike (or a bike to be used as a road bike) or subtract 12 inches off your inside leg measurement for a mountain bike. This total will give you the typical size of frame right for you with in mind to the type of bike you're looking for.
An example, someone with a 32 inch inside leg measurement would be suited to 23” road bike, and a smaller 20” mountain bike.
Finding what fits best
When you stand over the bicycle frame your feet should rest comfortably on the ground, and it's most important that you should have enough clearance of the top tube (crossbar)
Top tube clearance guidelines:
- Mountain bike 3”-5”/7-13cm
- Racing bike 2”-4” 5-10cm
- Hybrid bike 0.5"-3”/1-8cm
- Touring bike 1”-2.5” 2cm-6cm
If you would prefer to sit upright, choose a slightly larger frame but that still gives you enough top tube clearance. But for a more athletically ridden mountain bike for example, a maximum top tube clearance is usually required. A mountain bike typically not only needs to be smaller frame-wise than a road bike for example, but also will need to have a maximum top tube clearance too. This is to ensure a safe ride on the bike under rough conditions.
Further Reading
Other ways to make your bike fit just right
Beginner cyclists and those returning to cycling do like to have their saddle low enough so that they can both sit on the seat and have their feet comfortably on the ground at the same time. But this often inhibits the lower leg power and adds additional stress to the knees, making riding a whole lot more taxing and uncomfortable.
In these links below are more articles discussing this additional aspect of bicycle fitting. With some extra guidance on making your bike fit just right for a more comfortable ride.
The Height of Your Bike Seat
Tilt and Position of Your Saddle
