Clydesdales/Athenas (200+ lb / 91+ kg) - Sizing help and questions ...

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 and 210lbs... 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.. and yes I am a clydesdale.. at least for now..

A 2cm difference is easily accommodated with stem and post changes.

My suggestion is to buy the bike for the most usage you will have, and change it when you need it for other things. Tri bikes are more compact, but you lay out on the aero's. Riding a Tri bike for a regular steed could be a bit uncomfortable in my opinion, unless you are going to be Triaholoic and do one a month or so.

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.

The answer to these questions, like much in cycling, is: it depends. I was out test-riding bikes yesterday and noticed a huge difference between a 54cm frame and a 56cm frame. I was looking at "relaxed" geometry road bikes (e.g. Specialized Roubaix, Cannondale Synapse, Felt Z-series, Giant Defy, etc) with sloping top tubes. On a 56cm bike, when the saddle was at the correct height it felt like the handlebars were much higher and slightly further away; almost like I was riding a chopper motorcycle. Conversely, on a 54cm bike with the saddle at the correct height the handlebars felt lower. To me, the 54cm frame felt more like what I expect a road bike to feel like. On the other hand, the 56cm frame had me sitting more upright which might be better for all-day comfort.

As txvintage points out, it's always possible to change the stem and seat post to change the fit. In my experience, that doesn't always work as well as one might hope. No matter what you do with stem and seat post, you can't change the location of the front wheel, the back wheel, or the bottom bracket. When I swapped the stem and seat post on my old 56cm road bike to make it fit more like a 54cm bike, I found that it made the bike feel completely different not only in terms of my comfort level but how the bike rode. Dialing out knee pain was more difficult with the new components, possibly because I'd just become so used to the old setup. And the bike felt decidedly more "lively" on fast descents, possibly because more of my weight was on the front wheel. The point is, it didn't just feel like a slightly smaller version of my old bike, it felt like a completely different bike...

So, while a 2cm difference may seem small it might be important depending on the geometry of the bike, your body measurements, and how you like a bike to fit or ride. If you don't have much experience riding road bikes, I would suggest buying from a shop that knows how to do a professional-quality (e.g. 1-2 hour) fitting job and get their advice on which size frame to buy. If that isn't possible, you might play around with the fit calculator on the Competitive Cyclist website then compare the numbers it comes up with to the geometries of the frames you're looking at.