pierre29177

Hi , i m looking for a new bike and i found three bike and I found four bikes that could fit but im scared about sizing.
i ride a bianchi pista which is a 53 with a 53.5 top tube length and a charge plus 59 with a 53cm top tube length. im 172cm...5'8"

i found good deals on those bikes. :
1. the eddy merckx alu team which is a 50 cm but i m scared it's gonna be too small and i can' find a geometry chart for this bike.
2. The colllnago dream lux. size is 54.
3. The cannondale saeco teal replica caad3 52cm
4.the trel oclv 5200 in 54 cm ...

So , could you tell me which bike could fit me regards of the size? Some advices about those specific bikes. i m new to road bike.
thanks a lot for your help....sorry for my bad english.
Pierre

gc3

None of us can help you more than you plugging your measurements into this bike fit calculator at competitive cyclist that will at least tell you which of those bikes fit you best....meanwhile, check bikepedia and research the geometry of those bikes

pierre29177

ok at competitive cycle they said seat tube cc 52cm and top tube 53. regards to those size : can i eventually consider the 54cm trek 5200 which has a top tube of 54,6? if i use a shorter stem ?

Fiery

If in doubt, it will be easier to make a smaller bike fit than a larger one, as long as the steerer hasn't been cut too short.

pierre29177

But my principal concern is about the top tube length. i don't really understand the importance of the steerer?

shoota 

I have three very close friends that are all 5'8". Two ride 54cm and have longer legs than torso and the third has even legs/torso length and rides a 52. The top tube will determine how stretched out you feel. All that being said, if you get a bike in the 53-54cm range you can make it fit with the correct length stem and proper adjustments.

pierre29177

Thanks Shoota . it's what im thinking too. i m gonna go for the trek oclv 120 which is 54 cm. price is quite good: 300$ with shimano ultegra.

shoota 

Yeah that's a good deal. Make sure there are no cracks in the carbon.

edit: on second thought I recall that those era treks have a slightly longer tt than st. Something like 54.8cm tt for a 54cm st frame. I would double check on that because approaching 55cm on the tt might be pushing it.

pierre29177

i check on the net and the top tube has a 54.6 cm for the 54cm. my actual bike (bianchi pista) has a 53.5 top tube length with a stem of 60mm. so the trek could be a bit too big... that's difficult

shoota 

Well not necessarily. A 60mm stem is really really short for a road bike.

pierre29177

yeah it's a short stem for sure but i was just using my bike from my house to my school (it's fixed gear). i started to ride 70 km every sunday with this bike and now i want a proper bike to make bigger distance. on longer distance i felt that the stem was a big too small. i m gonna go to try the trek and see if feel right on it. i guess they let me try the bike for 30 minutes.

shoota 

I'm sure it will be fine. Just make a note of how long the stem is if you can remember.

Carbonfiberboy 

I'm 66", fairly short legs, love my 5200 52cm. A 54 is a little big for me.

pierre29177

so if i am 68" / 172cm / 5'8" a trek 5200 in 54 should fit me? i also have the possibility to have the trek 5000 in 52cm ?

Carbonfiberboy 

Trek measured those frames a little oddly IMO. 52 is center to top of seat tube. C-C on the top tube is only 52 cm. I ride another bike that works fine and measures 52 C-C and 54 C-C on the top tube, with a 110 stem, so quite a bit larger bike than the 5200 52cm. If that bike were measured to top of seat tube it would be a 56. So I think the 54 would be the choice.

pierre29177

compare to my bianchi which is a 53 seat tube and 53,5 top tube, the trek 5' has 1cm of extra top tube, it's 54,6. the 52 trek is 53,1. only 0.4cm difference from the bianchi. Is there other important measurement that will modify the size of the bike???

Carbonfiberboy 

If the bike is at hand, measure it yourself and compare to your Bianchi. However, riding it is the thing.

merlinextraligh

In all likelyhood the 54cm Trek is too big for you. Assuming the reach for the Bianchi is right, that means you'd need a 50mm stem on the Trek.

It would be a much better idea to buy a bike that puts you on a 100mm stem, or thereabouts. That way you have a reasonable size stem, and you can adjust shorter or longer as needed. If you try to stretch on to the 54cm bike with the shortest stem available you're SOL if it's too much of a reach because there is no way to go shorter.

Fiery

When going for a smaller frame, it is easy to gain additional length by changing stems, but it is not so easy to gain additional front-end height if the steerer is too short.

On the other hand, when going with a larger frame, steerer length is not a problem as long as you are not looking for a lot of drop, but there is a limit to how short you can go with the stem before the handling starts to suffer.

pierre29177

ok thank you , bike fitting is quite hard im gonana try both of them and pay attention to the steerer . What is the limit of stem size;the one on my bianchi is 60 i think it's quite small, the one on my charge plug is 100mm but i i didn't notice a diffrence in the handling.

merlinextraligh

Theoretical limit is 30mm, but it's typical for road stems to come in sizes from about 80-130mm.

You can find longer than 130 and shorter than 80, but beyond those the pickings get slimmer.

Lots of people will argue that very short stems make for twitchy handling.

Personally, I would try to aviod going below 80mm for aethsethics, stem selection flexibility, and to a lesser degree handling.