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Road Bike Sizing(3 posts)

Road Bike Sizingmkrause33
Mar 24, 2003 8:22 AM
I am looking to buy a new or used road bike and need some help with sizing.

I am about 5'5"? Roughly what range of sizes should I be looking at?

Any suggestions on a good value/brand for a starter/used road bike.

Road Bike Sizingbent_spoke
Mar 24, 2003 2:44 PM
A good site that will take you thru bike sizing is & for future reference you can do a search of this site to find previous postings on a given topic.

A starting point in getting a new bike is to determine how much you have to spend. With this information, someone might be able give you some thoughts on things to check out. Also, you can check the bike reviews section to get an idea of what people think of a particular bike. Again, a search will get you info on the "pro/cons" of buying new or used, etc.
Just like the thread aboveKerry
Mar 24, 2003 5:36 PM

For adjusting the fit of the bike, there are roughly five starting points:

1. Seat height (top of saddle to center of pedal axle) at 108-110% of inseam.
2. Saddle parallel to ground.
3. Saddle fore/aft adjusted so that a plumb bob from the bony protrusion just below the kneecap passes through the pedal axle when the cranks are horizontal. This is known as KOPS (Knee Over Pedal Spindle)
4. Front hub axle obscured by the handlebars when riding in your "regular" position (drops, hoods, or tops).
5. Top of handlebars 1 to 4.5+ inches below the top of the saddle depending on your flexibility and size.

These are all starting points for "average" proportioned people, and many folks like to move away from these starting points as they learn what makes them more comfortable, powerful, or efficient. You want to get the fit of the frame as close as you can, then do minor adjustments with the stem, seat post, saddle position, etc.

A lot of this is personal comfort, and we all tend to adapt to a given position over time. For example, a given stem length may be right for you, but it may feel long at first. I use the "handle bar obscures the front hub" rule for my fit, but others claim better position (for them) with the hub in front of or behind the bar. I'm 6' tall and ride with 11.5 cm drop from saddle to bar, probably more than most people would like but fine for me. Some are suggesting zero drop from saddle to bars - it's about comfort, efficiency, and aerodynamics. The ERGOBIKE calculator is pretty good, but it is not infallible. I would suggest riding some miles (over 100 total, and over 500 would be better) and see if you adapt to the position. There are no hard and fast rules, just general guidelines, when it comes to these things.