RoadBikeReview.com's Forum Archives - General


Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )


NEED HELP - size for a road bike(6 posts)

NEED HELP - size for a road bikemkrause33
Mar 24, 2003 12:26 PM
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.

Thanks,
Mike
depends on your proportions..._rt_
Mar 24, 2003 12:34 PM
your best bet is to go to as many of your local bike shops as you can and try out as many different bikes/sizes as you can.

without, at the very least, an inseam measurement it's impossible to say. you could ride anything from a 48 cm to a 54 cm. i'm 5'1 and i've ride a 50 cm trek and a 49 cm bianchi.....but i have relatively long legs for someone my height.

rt
re: NEED HELP - size for a road bikeal0
Mar 24, 2003 1:11 PM
Visit a http://www.wrenchscience.com. This is a good starting point.
re: NEED HELP - size for a road bikemkrause33
Mar 24, 2003 1:28 PM
Thanks for the info. I would say I have a 28" inseam. Legs are not very long...
ok, then..._rt_
Mar 24, 2003 1:36 PM
you'll probably want to look in the range of 48 to 52 cm...also, look at bikes that have a compact frame design (e.g., giant). i have a 31.5" inseam and would not be able to stand over a 52cm frame unless it's a compact.

rt
More precision requiredKerry
Mar 24, 2003 5:16 PM
http://www.bsn.com/cycling/ergobike.html
http://www.coloradocyclist.com/BikeFit/index.cfm
http://www.sheldonbrown.com/harart-frames.html
http://www.rivendellbicycles.com/frameinfo/Frame_Sizing.htm
http://www.peterwhitecycles.com/fitting.htm

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.