parakeethouse

My frame size should be 54.5cm CC

Theres a bike I really want but they only have 54cm

Is that gonna be a problem or should I most definately go with a 55cm?
I mean its only 1cm...
What can I do to overcome this 1cm?

What are your experiences?

thanks for any help!

timmhaan

if your looking at a specific brand bike, the frame sizes probably increminent in 2's (like 54, 56, 58 etc.), so you may not be able to choose 55 anyway.

MichaelW

What top tube length do you want. this is more important than +- 1cm of exposed seatpost.

Avalanche325

Keep in mind that the typical "frame size" measurement is the seatpost length. Sometimes from the BB to the top of the seat tube, and sometimes from the BB to the center of the top tube (I see now that you said CC). The big thing is that this is NOT the most important measurement. The most important single measurement for a good fit is the top tube length.

As far as the seat tube goes, adjusting the saddle height takes care of that, within a reasonable range of course. What you need to get as close as possible is the reach. Different length stems are the big adjustment there. Like timmhaan said, most brands are made in 2cm increments. Some are on the odd numbers and some on even. CC and CT can be 1cm differance right there.

I did test ride a brand that came in 56 and 59 and I just didn't didn't fit on either one.

If you haven't already done so. Go to one of the on line fit calculators and find out what top tube and stem length you need. https://www.competitivecyclist.com/za...LCULATOR_INTRO The manufacturers have all of these measurements in their frame geometry specs. Then ride some bikes that are in the ballpark. A good LBS will swap stems with no charge, and should even do so for a serious test ride. I found that the more you know about sizing before you go into LBSs, the better off you will be. Most still do the "Standover.......looks good to me" method.

parakeethouse

thanks much, I did do the Competitive Cyclists measurement and have the figures at home. Will check'em when I get home.
This really, really helps out alot.

WOW, THIS FORUM ROCKS!

miamijim

Remember the figure you get for a frame size are irrelevant because every company builds thier frames and measures them differently.

You want a frame with 'X' standover height and a top tube length to match your body....Dont buy a bike a because its a 55 or 54 or 68. Buy it because it fits.

Its like this...you can buy 2 different bikes that fit perfectly. One could be a 54 the other could be a 57. The numerical value doesnt matter.

MichaelW

Auto calculators cannot tell you what stem and TT combination you should ride, they can only make suggestions based on averagely proportioned riders using the bike in a standard style.
You can move the bar position up and back, to give a touring style (or for triathalon position with aerobars), or forward and down for an aerodynamic time-trial position.
You can use different size frames to achieve a suitable TT length, ie get a bigger size if you want a longer frame. Brands vary in the proportions of height/length,a nd there are different styles such as compact frames, where standover clearance is irrelevant.

You can achieve your desired reach with a variety of TT/stem combinations. Its best to balance theres 2 factor, extra long or short stems can affect the steering response. For your size frame, a 10cm stem would be normal, but you can change +- 2cm with acceptable results.
check out the peter white cycle fit guide.

Don Cook

If you would be theoretically perfectly matched to a 54.5cm frame then either the 54 or the 55 would be just fine. There is far more rider comfort and fit derived from the saddle, saddle position fore/aft, saddle position vertically, stem height, stem length, adjustment of the drop bars, than you would ever be able to find in a 1cm difference in the frame seat tube length.

condor63

Ride the sizes within your stature and decide,as changing stems and crank's can be a hassle- not including one could reach the perfect fit by upping to the next frame size, the LBS will fit for free on a new purchase most of the time. I'm 5'8" with a 31.6" inseam,LBS suggested 54cm Trek 5200 after a professional fitting,but I went with the 56cm and felt less constrained and breathing was easier, on the 54cm it seemed I alway's needed to conform to the bike to get comfort,56cm comfort came naturally.