Need help with a sizing issue...
 

I have been looking to get my first road/tri bike.. I likely for cost purpose and comfort going to go with a Road bike and add the aero bars and maybe the saddle post mod for Tri's.. My question is that on a road bike I would get a 56cm... I am a 5'10... several LBS and fellow training partners are telling me I should drop down to 54cm if I am going to do the mods... several others are saying STAY with the 56cm and just get the "mini" areo's and I will be fine.... so it is half a dozen one way or the other. Just for clarification.. If I was to buy a road bike and hadn't mention tri's.. I size out to a 56cm...

What I would like to know is will the 2 cm make that much difference either way, if so can someone explain this to me.. Both sizes feel fine riding, I am a newbie, so i can't tell a difference.. Is the difference so minimal that it really doesn't matter? Would I be just as comfy on the 54cm..? Or is it preferable to get the 56cm since without the tri's modifications that is what I would size out at.

Do any of you have any suggestions or explanations for me..

Thanks from a newbie... btw: I have my first tri next month.. I will be riding my 29er mountain bike it looks like... unless I get a roadie in the next week or 2..

56cm.

Thanks for your reply..

This is a tough crowd.. very hard to get a respsonse..

i'd stick with the 56.

"My question is that on a road bike I would get a 56cm"

How did you come to this determination. There is a lot more to proper sizing than simply applying a multiple to your inseam length. Size 56 is not the same across all frame manufacturers.

2cm difference in frame size is significant. As a newbie you may not initially notice the difference but after you get a few miles you will. I think it best to always go smaller when presented with the choice assuming you don't end up with excessive saddle to bar height differential and you are good length wise.

Do a search on hit site for "bike fit", "size", "frame size" etc. There is a ton of fairly decent info on bike fitting on this site.

Thanks... I have been looking for a couple of months now.. so I am not "totally" new... I have shopped in person at 4 different stores.. 3 of which are in nearby towns not my own... All of them say 56cm is the size for me for the models that I am looking at..... but when I mention that I might want to drop aero bars on it and do the seat mod.. then I start getting different opinions on staying at 56cm or going down to 54cm...

So, I think you misunderstood my question or I didn't present it clearly..... it is not what do "you" think I measure at... it is rather should I drop down 2cm in size to use a road bike for Tri's. I am getting varying recommendations by the "sizing professionals" and I am not sure if a part of the answers are predicated on their available stock that they are pushing on me.. I was wondering if any other members dropped down a size or if they stayed at their true size.

I gave a longer reply on the other forum you posted this on. :)