General Cycling Discussion - opinions needed

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milkprosecutor
03-10-10, 02:02 AM
im inbetween two 49 cm bikes both the same stand over height of 29.7"

my inseam is just about 28.6"

think id be better off going smaller?
or could i just deal with it

bruce19
03-10-10, 04:06 AM
I'm certainly no expert but I've used a formula I found in a Greg LeMond book about 20 yrs. ago and it's always worked perfectly for me. His coach said to measure your inseam floor to crotch in bare feet. In my case it was 32.5", convert it to CM (82.5) and multiply by .665. This gave me a frame size of 54-55 cm measured center to center. In my case I can ride bikes in a range of 53-56 cm but that 54-55 is the sweet spot.
rumrunn6
03-10-10, 06:14 AM
I think I read somewhere that it is wise to have 2" clearance between the top tube and your crotch flat footed.

AdamDZ
03-10-10, 07:19 AM
I think I read somewhere that it is wise to have 2" clearance between the top tube and your crotch flat footed.


With today's various frame geometries this may not always be true.

Adam
rumrunn6
03-10-10, 08:24 AM
agreed - especially a sloping top tube. I mean where would you even measure a sloping top tube ...?
ddez
03-10-10, 10:49 AM
Most manufacturers measure sloping top tube stand over 12ins from center of saddle down tube ,about where you would stand when off saddle.
rumrunn6
03-10-10, 11:34 AM
I suspected that but its nice to have that confirmed
stapfam
03-10-10, 01:04 PM
Standover height is the least critical measurement on a bike. The more critical measurement is top tube length. That will denote whether you re going to be comfortable on a bike or be too stretched or cramped.

Compact frames will have a standover height- like for like in frame size- that is less than a conventional frame. But as I have said- Standover height is not critical. I only have one bike that has a clearance on the top tube and that is a Mountain bike. And that clearance is only just there.

So 49cm- you must be a shortie like me. We do have a problem in getting bikes to fit. To an extent we have to compromise a bit on fit. I can get the bikes to fit me- but with the saddle at the right height- I cannot touch the ground. My legs are 2" too short. That is the same on all my bikes and I ride a 49 and a 51cm. Attachment is of my 49cm Giant OCR3 as you can see- I could lower the seat by a good amount if required. and bar height/ reach can be adjusted by a change of stem.

So find a bike shop and see what they suggest.