Road Cycling - 1 cm difference. does it really matter?

HI all.

Firstly. thank you for a great forum. this is my first post. there seems to be alot of information about bikes in here.

here is my question.

i have the opportunity to buy a 55cm square frame Pinarello Prince (Frame Only). i now ride a nishiki equipped with shimano 600 and i went up to the bike shop where i have been going to for a while to get his opinion. He measured me up and said that i would need to get onto a 54 cm pinarello prince. i told him that i could buy a second hand (6 months old) prince and he said that it would be too big. could i get away with it or should i take his advice?

if i dont get that, i was considering the new Cannondale CAAD7. do you think this is a good alternative? if none of them, the wilier was another good option.

what do you guys think??

thanks
slick1:p

What you should really look at is the difference in the length of the top tube. You can offset a 1 cm difference in the seat tube by lowering the seat post.

I happen to have a Pinarello geometry chart in my computer. It says that the 54 cm has a top tube of 54.7 cm and the 55cm has a top tub of 55cm. Both have the same seat angle, 73˚ 45'. (I trust that this is the Prince geometry.)

I would think that the 3 mm difference in the top tube will not trouble you. But, you should double check your sizing needs. If the 54 cm is already an upward compromise, then the 55 is going to get you into trouble. Don't buy a bike that doesn't fit right.

Here are a couple of websites for you:
http://www.wrenchscience.com/WS1/default.asp
http://www.peterwhitecycles.com/fitting.htm
http://www.coloradocyclist.com/bikefit/

Some of them give you a worksheet to fill out, some of just give information.

By the way, pay close attention to differences in how the bikes are sized. Sometimes the "size" is measured from the center of the bottom bracket to the center of the intersection of the top tube, sometimes it is center BB to top of seat tube, sometimes it is top of BB to top of seat tube. You have to make sure that you account for these differences.

I hope this helps. A riding buddy of mine rides a Prince. Beautiful machine. But, if it doesn't fit, you won't be happy no matter how lovely it looks.

Cheers,
Jamie

Everyone is different but with only 3mm difference it seems like the 55cm will fit you fine. Worst case is that you get a shorter stem and you can fine tune with different bars for reach and drop.

Also note how high the BB is off the ground. You really want to know the standover hight, not just the seat-tube length.
If the bike has a higher BB and a longer seat tube, it could be too big. If the BB is lower down, it may fit you OK.

no of course it wont make any diff. cycling isnt the exact science they would like it to be & the beuty of the human body is that it can adapt & adjust in short time to minor changes.

seat tube lenght might be an issue, with the top tube lenght being so close a short stem 'might' fix it...

but IMHO don't buy something that is not the correct size for you, stems and seats might make it close, but if it doesn't feel right, then you may not be happy with it.

I think you can get away with it. I usually ride 56 cm and I ordered a 54 cm bike.

thanks for the advice. i am currently riding a Nishiki RC-7000 and it is 58cm C-C. i know the 58cm is too big so whether i go to a 55 or a 54, i really dont think it is going to make a difference.

thanks again. i think i will go for the pinarello prince.

slick1:)

I've always thought size made a difference. The bigger, the better - HA!

Get the largest frame that you can safely straddle. The higher handlebar will be much more comfortable. And because of the higher bar height, the bigger bike will actually have a SHORTER reach to the bar (measured saddle nose to bar).

Originally posted by cycletourist
Get the largest frame that you can safely straddle. The higher handlebar will be much more comfortable. And because of the higher bar height, the bigger bike will actually have a SHORTER reach to the bar (measured saddle nose to bar). Bull sauce.

that is a nice frame, anyway you look at it, as for the 1 centimeter difference, that one won't bother you.....

to me it depends on your ridding style. Some people sit on the bike and just steer it while others are all over it, front to back ect., ect.. I grew up riding BMX so I like to move around on the bike alot. The smaller the frame is in comparison to your size, The more you can move around on it.

Pokey,

get out your tape measure and check for yourself. Set your stem as low as possible. Measure from saddle to bar. Note the distance. Then set the stem as high as possible. Measure again from saddle to bar. Notice the higher bar has a shorter reach.

Originally posted by cycletourist
Pokey,

get out your tape measure and check for yourself. Set your stem as low as possible. Measure from saddle to bar. Note the distance. Then set the stem as high as possible. Measure again from saddle to bar. Notice the higher bar has a shorter reach. Yeah, I know that. It comes back about .3" for every 1" up.Ya ever notice that the bike in question has threadless HS and not a quill stem? Not so easy as it use to be.Another point,some people want em low,not like apehangers.Further,big bikes have long toptubes and longer stems.....So, It's still lame. REAL LAME.

Few years ago when I purchase my road bike at LBS after measuring my body they suggested a 54cm frame form me. but when I test ride It I feel comfortable at the 52 frame so I get the 52cm frame and I'm glad I made that dicision
:)

thanks all for the advice. i think that from going from a 58cm C-C nishiki RC-7000, to a pinarello 55cm (3 cm smaller) will be a great advantage to start off with because i am dropping 3cm. i dont think that extra 1 cm will make a difference. if he still has it available, i think i will go for it.

thanks all for the great advice.

slick1