This is part 3 of 8. Here is the start!
A quick overview of terms that are important:

• Fork Rake – Offset that places the fork ends ahead of the steering axis
• Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
• Trail – The distance that the axle trails the steering axis intersection with the ground
• Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
• Reach to Bars – Distance from center of seat to center of handle bar stem
• Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
• Seat Tube Angle – The angle of the seat tube in relation to the ground
• Toe Strike – How much of the foot interferes with turning the front wheel

Compromise 2.) Resort to Trickery:
Here’s a tricky one. If a bike has a modern carbon fork, a 70 degree head tube angle, a top tube length of 50cm, no toe strike, fairly decent trail of 79mm, and 700c wheels, has the company found the magic formula? No. They have artificially shortened the top tube by making the seat tube angle really steep. What does this mean for the rider? Really sore knees, or the seat pushed all the way back on the rails in order to get the knees in the right pedaling position. Once the seat is pushed back on the rails to accommodate for thigh length, the reach to the bars becomes the same as if the top tube were 53 or 54cm, and the rider is just as uncomfortable. Why do this at all? To list a 50cm top tube in the catalog. Many, many manufacturers pull this stunt. I call this misleading 🙁

Result – This one’s really not a compromise at all. You just end up with a bad fit, and bad design. Same as Really bad option number 1 with a little knee pain thrown in as an extra treat. Discomfort and pain always results in slower riding, and that’s one thing that everyone can agree on.

Important Note: Make absolutely sure that your salesperson uses a plumb line on your knee to ensure proper knee alignment. If they don’t use a plumb line, then leave without purchasing the bike as you are not dealing with an experienced bicycle fitter. If the bike you are riding has an extremely steep seat angle, chances are you’ll need a lot of attention to your knee position. I strongly recommend several rides before committing to a bike with a steep seat angle. A 15 minute test ride will not be long enough for any knee issues to arise.

Tomorrow: Do you want to Sacrifice Performance?
Find out Here!

Related Items

• Find wider 650c tires at 650biketires.com
• See photo galleries of 650c bikes at www.rodbikes.com
• Wheel size cliff notes – a digest version of an 8-part study in wheel size