Spinningnoob

Okay I'm still out there looking for bikes and recently have been to my 4th or 5th bike shop and they put me on a 54cm Jamis Ventura Race. It felt great but I honestly didn't realize it was a 54cm during my ride, I thought I was on a 56cm the whole time. However, when I was at TriathlonLAB, they put me on a 56cm saying it was my size but mentioned I can go 54cm if I wanted to get aggressive.


Measurements:
Height: 5'10"
Inseam: 33"
Arm Length: 25.5"
Shoulder Width: 16"
Weight: 149lbs
Shoe Size: 9 US
Sternum Notch (from the ground): 58"
Flexibility: Poor, with feet 8" apart I can reach just above my ankle after full warm-up and it's painful.


These are my results on WrenchScience based on quick do-it-yourself measurements with the help of a friend:

Frame Size Center-to-Center: 54
Frame Size Center-to-Top: 56
Handlebar Width: 42
Overall Reach: 68.14
Saddle Height: 74.01




A) My question is, what does it mean to "get aggressive" with sizing?

B) What will the differences be and how will the seat to handle-bar settings differ?

C) Am I over-evaluating this size thing? Is it as-easy-as choosing which one I like more between the two and then making fine adjustments with the seat and handlebar adjustments?

AngryScientist 

generally the smaller size will result in more saddle to bar drop and a longer stem. this is more "aggressive" because it will make your riding position lower. this may or may not work for you.

bike nominal sizes differ by manufacturer and particular frame.

find a shop that is willing to give you a good fit before (and after) you select a frame size.

there are tons of stories of people's first bike just not fitting right. a lot of this comes as your body adapts to the road bike position, but part of it can be avoided by a competent shop that is willing to put in the time to get you on the right size bike.

Creatre

I actually have very similar measurements as you, and had this same debate. I could really be on either a 54 or 56 as well. I went with the 56, just because it was the same size I had before (not knowing I could do either) and figured my body was more adjusted to that size. Now that I've ridden more and have become more flexible, I may decide to go with the 54 in the future. I'd say go with your instinct on which feels better, but honestly I think you would be fine on either one.

pilechko

It's probably easier to get a proper fit on a bike that's slightly too small than on a bike that's slightly too big.

coasting 

i'm your height but a bit shorter in the legs. I had to choose between 54 and 56 and I went with 56. I am proportionately long in the upper body short in the legs so on the height, I have very little seatpost showing and I don't have much clearance from crotch to top of frame (horizontal top tube). This means I do have a good top tube length. I use a 110mm stem and the fit is just fine and I have 20cm spacers under the stem. If I had gone with 54, the height would have been better but I would have needed more spacers and a longer stem. I thinkt the top tube length is more impertant to get right.

djlarroc

Good thread. I'm in the same boat. Looking at the same options. I'm about 5'9+". 33" inseam.

Currently riding a 54 cross bike. Fits good, but what do I know. Now, looking at 56 road.

One shop asked about my flexibility and I didn't know. How can you check that? Is that the only flexibility test?

DaveSSS 

When asking for advice, include a link to the bike's geometry. It's also wise to post your actual saddle height and the amount of saddle to bar drop that you can tolerate (if known).

https://www.jamisbikes.com/usa/thebik...hrace_geo.html

There are possible drawbacks to each model. The smaller size only has a 140mm head tube, which may require a lot of spacers under the stem and/or a high rise stem, if you're not flexible and can't tolerate very much saddle to bar drop. The larger size has a lot more reach and would require a 20mm shorter stem. With the long reach of the Shimano brake hoods, you might need a stubby 90-100mm stem.

I'd probably buy the smaller size and hope to improve your flexibility over time. Flexibility can be improved with a little effort.

caloso

If you're in between sizes, you should be able to get an identical fit on either the 54 or 56 depending on saddle set back, seat post height, stem length and headset. But they may handle differently.

coasting 

in what way? is the smaller more responsive?

caloso

I would think so, as a general proposition, it would have a shorter wheelbase which would make it more "responsive" (if you like it) or "twitchy" (if you don't).

DScott

a. aggressive means lower and more reach... not good if you're not very flexible.

b. seat to handlebar distance is adjustable... what's more important is seat to pedal relationship. Make that right, then fix the reach issue.

c. pretty much yes... a good fitter will make it all work.

In LA, Nate Loyal (out of Helen's SM) is truly the guru of fit... though there's good guys at Cynergy, too, IME.

My personal favorite is Sueken at Veloworx... Lincoln Blvd near Navy. Worth a look, if you haven't already.

I have no idea about Trilab or Zombies, though I tend not to trust the tri guys for roadie fit. Different animal, IMO.

Spinningnoob

Wrenchscience.com gave me the "general" feeling of how it should be gauged. Basically, with your feet 8" apart, where ever your fingertips reach will tell you how flexible you are. Fingertips to center of shin, to ankle, to toes, to the ground, and palm of hand on the ground. So if you could only touch the middle of your shin and you start feeling pain = poor and if you can get the palms of youR hand on the ground, you're very flexible. That's how I guagued it.

DScott

If they are made to fit identically, I doubt you'd really notice a dfference. Other than a placebo effect, that is...

At best, the smaller frame may feel a bit stiffer, and a shorter stem may make the steering feel a bit quicker, but the bike should ride the same either way.

Spinningnoob

The bikes in question: (the ones I've tested and use as my experience)

2010 Jamis Ventura Race 54cm

2011 Felt F85 56cm

The bike I want to buy:

Fuji Roubaix RC 54cm

DaveSSS 

https://www.fujibikes.com/Road/Perfor...x-ACR-2-0.aspx

caloso

Yeah, you know the more I think about it, it's probably theoretical but you couldn't tell in practice.

colombo357

The smaller bike is "more aggressive" as in it's better for tight corners and jumps. Just look at BMX bikes.

If you enter a race with lots of jumps, you'll be glad you had the smaller frame. 2cm isn't much, I have appendages way longer than that, but it's enough to make the difference between landing a flipwhip smoothly and casing the landing.

Spinningnoob

I updated my link above.

That is the ACR 2.0, the one I've been looking at is the RC.

Top tube lengths:

2011 Felt F85: 560mm

2010 Jamis: 538mm

2009 Fuji Roubaix: 550mm

The Jamis felt like I had a lot of weight on the front with the saddle at an eye-balled height which was probably too low. My head was over the handlebars, I felt most of the weight up front in the drops. Very different to how I felt in the F85.

The Felt was stretched out, I felt most of the weight on the saddle. The gentleman spent some time adjust fore-aft and height on a trainer. The saddle was fairly low and I was more upright.

Considering the top tube on the Fuji it just might be the right compromise? I'm very anxious to try it out. I think I'll be going with the 54cm.

And the think these past 2 - 3 weeks I've been asking for 56cm's everywhere.

coasting 

i get annoyed with having so little seat post with the bigger frame. i cant put a rear light on and a saddle bag.

darkadious

i don't really think reaching to your toes has much connection with flexibility on the bike. my friend touch palms to the floor but hates riding on the drops.

Spinningnoob

Yea, I don't know if it corresponds to flexibility on the bike but flexibility in general can be gauged that way I think.

DaveSSS 

Never compare the TT lengths by themselves. You need the STA to go with it, in order to define reach. Each degree that a STA is steeper increases the reach by about 1cm. The comparable TT length of the Jamis would be 543mm. compared to the Fuji. I don't have the 2011 Felt geometry, but some Felts are really odd.

Spinningnoob

I have the 2011 felt geometry:

https://triathlonlab.com/product/2011...road-bike.html

Same STA as the Jamis, 73.5 degrees.


Good point, I've been working on flexibility so as-if I'm buying some leather boots that will "wear in" the 54cm will do that best, I think I will follow this advice. Most every reply has been for the 54cm in some way.

bikerbob2

why not just get a 55

pilechko

Agreed. I'm the opposite -- not at all flexible by that measure, and I also have a herniated disc in my upper (cervical) spine, but I am much more comfortable on an aggressive geometry bike, and like to ride in the drops.