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Discussion Starter · #1 ·
Hello,

I'm currently in the planning stage of buying a bike but have not had much luck with some of the shops I've gone to, even a couple that were recommended to me in a different thread. For the most part part all the shops have tried to put me on anything from a 54-58cm frame and while some felt close others where way off.

This lead me to Wrenchscience.com and I used their fit calculator, I had someone help me out. Their calculator gave me measurements that sort of reinforce what I believed, that the larger frames were way off. The 54cm felt right but on a couple of occasions I was steered away from that size for larger frames.

For anyone that has used the wrenchscience site, How close to accurate is it? I'm 5'10 with a short inseam right at around 31.5 inches and it recommened a center to tube of 54cm (center to center of 53cm). It also recommends a total reach of 63.69cm (636.9mm).

With the above measurements it looks like I could fit on a 53cm Tourmalet which has a 53cm seatube measurement (measured center to center) and a toptube measurement of 533mm. Taking the recommended reach lenght and top tube measurement I would need a a stem 105 or 100mm; am I correct? Please note that I am only using this frame as a refernce since I had the geometry specs handy. I'm not set on this particular bike.

Lastly, any other 5'10 riders with short legs think I'm close? I've lost faith in most of the shops I've gone to and would like to feel a little more informed when I go back. I tend to take the recommendations of the shops employees but I'm wary after being burned in the past (I purchased a too small mountian bike based on the shops recommendation). Not to mention that this is my first real road bike and I'm new to how it should fit.

TIA,

Agustin
 

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Based on my mistakes, I’d say

Find some one in the LBS who isnt an idiot.

If this is not posible, then go with what you feel is right based on what you know.

Pick out the bike and put it on a trainer, and put some miles on it, figure out what doesn’t feel right, and make adjustments from there, before you decide.

The most important thing is to not feel guilty for taking up their time. Even an entry level bike is a lot of money IMHO.

I hope this helps…
 

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I am the same heigth with a 30" inseam and I ride a 54cm. My bike is a 2005 Specialized Allez sport. I think that the bike is just a tad to big. The 52cm was to small so I got the 54cm. I have made some adjustments to it and it feels pretty good right now. I am also on the heavy side so I figure as I lose weight I will continue to get more and more comfortable on the bike.
 

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KendleFox is right about finding competent help.

Wrenchscience.com gives you a lot of reassuring numbers, but it can't look at you, talk to you, ask you question about your bike riding, ask you how this feels and how that feels. It's also important to know that your fit dimensions will change as you ride. Even riders with many years of experience will, for example, pick a stem for their new bike based on a vague "this feels right" notion - and then go through one or two more stems of different lengths before they find their sweet spot. Fit is a dynamic process. IMHO, wrenchscience.com reduces it to a static numbers game prone to many errors.
 

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People confuse choosing a frame size with bike fitting. Two different things. Choosing a frame size is pretty simple. You need a 55cm "effective" top tube length based on your measurements. That is the length the top tube would be if it were parallel to the ground when you ride it. ignore the seat tube length. It has little meaning in this age of sloping top tubes. A 54cm top tube will work well for you also, providing a very slightly more upright posture. The 54 will probably provide for a slightly longer stem as well and that's not a bad idea for a beginner since it will be less "twitchy" than a shorter one. A 56cm top tube would work reasonable well for you as well. In my experience, riders tend to prefer slightly larger frames as they progress in bike riding. As an example, I have a 29" inseam and I prefer 54cm top tubes although I can fit myself reasonably well on anything from a 51cm to a 55.

The problem with a beginner buying at a bike shop is that the shop sometimes will fit them to what they have in stock, not necessarily to what will provide the best results. I've seen it time and again. It isn't that they don't know what they are doing. In fact, they know exactly what they are doing.
 

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Trust your gut

You have to ride the bike. No calculator is perfect, but they do get you in the ballpark.

ALSO when they fit you, make sure you are NOT maxing out on anything - seatpost height, seat position, etc. As you ride, you may become more flexible, change your style, etc. and you'll want the wiggle room.

Ride a bunch and go with what you most enyoy riding.

By the way, I am 5'11" with a shorter inseam/longer upper body . I just bought a 2005 Tourmalet on Saturday - 55cm frame. Took my first ride this AM - Pure Joy! The bike felt like a DRAMATICALLY better fit than all of the other bikes I tried. They were all in the right range - 54 - 57 depending on the bike. The 57s really felt a bit big. But I believe it was the geometry of the Tourmalet that made all of the difference. I tested a trek 1200 and the tourmalet of similar size and it was no contest.
 

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If that 31.5 is a true "cycling inseam" (I assume it is based on the fact that you went to wrench science) then you may be a very good candidate for a compact geometry (sloping TT). Because if you get on a bike keyed to your inseam (i.e., emphasize standover), there's no way you'll be wanting to go bigger than a 54. Do you even have any clearance standing over a 54? I ask because my cycling inseam is 31.75" and most 54s are a close call for me.

And then if you are 5'10" my guess is most 54s will be a little short in the TT for you. With a sloping top tube, you can deal with your shorter standover without having too short a reach. I'd take a look at the sloping TT options from Giant and Specialized.

And I agree with others that sounds like you've gotten really crummy advice. If your cycling inseam (not pants inseam) is truly 31.5" then what goon thought you could ride a 58?
 

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Discussion Starter · #9 ·
I wanted to thank everyone for their feedback. I plan on trying again tommorrow and I feel more comfortable with the information that I've picked up. Hopefully I will be driving home with a new roadbike on my roofrack. Wish me luck.
 
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