Cyclocross sizing

Chris said:

I know riding a bike is no comparison to asking but...

I read/hear that cyclocross bikes fit a little large than regular road
bikes. For example, I'm 5'7" and ride a 52cm compact geometry road
bike. Again from what I read, I "may" need a 50cm crsoss bike for
example. Is this a good or bad general guideline? I'm asking just in
case I decide to purchase on eBay, where I may not have the luxury to
try a bike/frame out. Thanks!

The higher bottom bracket means that a cross bike of the same ST size will have
a taller standover height.

Simply saying to go down a size or keep the same size can be very wrong with the
variety of geometries and body types out there. If you must buy without trying,
measure your bike for things like virtual TT, measure yourself for what SO you
can stand, and very carefully review what frames can fit within the envelope you
come up with.

Ron

Chris said:

I know riding a bike is no comparison to asking but...

I read/hear that cyclocross bikes fit a little large than regular road
bikes. For example, I'm 5'7" and ride a 52cm compact geometry road
bike. Again from what I read, I "may" need a 50cm crsoss bike for
example. Is this a good or bad general guideline? I'm asking just in
case I decide to purchase on eBay, where I may not have the luxury to
try a bike/frame out. Thanks!

It depends. Many, but not all, cx bikes have a higher BB than road
bikes, so a given seat tube length translates into higher standover.
Also, standover is not very relevant on a road bike, but impromptu
getoffs are more common on a cross bike. However, with sloping
top tubes, standover may not be an issue. Then you have the
problem of figuring out whether the bike size refers to actual seat
tube length or virtual seat tube length (to where the ST would be if
TT were horizontal). The best thing to do is probably to figure out
what top tube length you want, try a couple of bikes out, and read
frame geometry spec sheets carefully.

Chris said:

I know riding a bike is no comparison to asking but...

I read/hear that cyclocross bikes fit a little large than regular road
bikes. For example, I'm 5'7" and ride a 52cm compact geometry road
bike. Again from what I read, I "may" need a 50cm crsoss bike for
example. Is this a good or bad general guideline? I'm asking just in
case I decide to purchase on eBay, where I may not have the luxury to
try a bike/frame out. Thanks!

-Zilla

see: http://cyclocrossworld.com/Tech.cfm

Read Myerson's article on setup.

Scott

forget nominal sizes and focus on standover and TT length. Overall, you may
want a stem/TT combination the same or a touch shorter than your road bike.

"Chris" <[email hidden]> wrote in message
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Quoted message said:

I know riding a bike is no comparison to asking but...

I read/hear that cyclocross bikes fit a little large than regular road
bikes. For example, I'm 5'7" and ride a 52cm compact geometry road
bike. Again from what I read, I "may" need a 50cm crsoss bike for
example. Is this a good or bad general guideline? I'm asking just in
case I decide to purchase on eBay, where I may not have the luxury to
try a bike/frame out. Thanks!

-Zilla