Road Cycling - correct road frame size????

I measured my inseam and did the calculations for a new road bike. The masi I'm interested in is measured from center to top. According to my math I require a ~56cm frame. There are 2 Masi's at this outdoor store in this mall and I went there today to buy one and the guy measured my inseam and did some math; he said i needed a 54 or something but that's center to center I guess.. oh well, they had like a 53cm in one (he said was too small) and the other was 56cm he said was too big.... I don't think he measured right so.. what to do now??

I have my eyes on a Felt 65.
If the store where I plan on getting it
doesn't have my size, I am hopeing
that they can get it in my size in if I ask them to.
If not, I will be very dissapointed.

Did you acually ride eithor of the bikes?
I have had bike shop guys steer me wrong before
but usually it is TOWARD a wrong size, (to make a sale)
not away from it.
:confused:

Did you ask if they could get your size?
If they said "no" I guess I would look somewhere
else. If you are unsure of your size, remimber this,
you can't always figure it out with a calculator.
You have to get on the bike.

Go back and ride the 56...bet it's going to be pretty close to right! If I paid attention to most of what is said, I'd be riding a 54, but I am comfortable and fit a 56. A friend of mine recently told me that many riders use a frame that is actually 2 cm too small. And Patty at my LBS recently told me that the more she learns about bike fit, the more she realizes that there are no hard and fast rules! If it feels good, go for it!

thomspins

What is the size of the machine you're currently riding? Please try to test ride the bike before buying it. That way you will know if it's not a good fit for your "style" of cycling. Measurements will only get you close, however a test ride should be part of the selection process if serious money is involved. The better shops in my area insist that you test ride first since they want you as a permanent customer.

Its easy to follow someones fitting formulae but they are mostly reverse engineering of what happens to work for some famous name rider.
There are some deeper discussions of fitting, and why bikes should fit this or that way.
Read up on

http://www.sheldonbrown.com/frame-sizing.html

He has some good like, esp the Peter White article on fitting.

Try www.rivendellbicycles.com for what Grant Petersen thinks.

What size TOP TUBE do you need?

That is the question.

Far too many people buy frames by seat tube and end up with wrong sizes. Usually too long or too short top tubes which is very bad.

You need to know that all brands out there use different geometries and are measured different. However top tube is always measure the same (c-c).

Do not visit web sites and such for sizes as from much experience they tend to be off.

Who is a better expert of your body then you? Nobody.

If you have acurrent frame that you are comfortable on, great!

Simply measure the top tube and stem and give that to the shop.

If they are knowledgeable (many are not) they will set you up on a correct and comfortable frame for you.

thanks a bunch for all the help guys, I got the 56cm. I rode it and with a few adjustments feels like a glove.. thanks