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Discussion Starter · #1 ·
I hate to ask, I know lots of questions are asked about Bike fit. I truly tried to find one relating to mine but was unsuccessful. Here is my question, I presently am riding a Klein in a 54CM, it is dangerously close in the inseam area (I have a 29' inseam am 5'9" tall) However, bike is comfortable to ride. I am looking at building a bike from the ground up and have an opportunity to purchase a 52 CM frame. Most of the frame dimension are the same, with a few only that are slightly different. Should I go for it and get the 52? I did read that you should try for the smallest frame possible and use Stem and seat movements to get a good fit. Any insight will be much appreciated. Thanks.
 

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Where did you read that you should try for the smallest frame possible??? That is bad advice. I think this trent toward compact frames and such has lead to people riding smaller bikes then they should when they are traditional geometry. At 5'9" I'm guessing 54cm is the right size for you. My wife is 5'6" with a similar inseam length and she rides a 54, 52 would deffinetly be too small for her. If your bike is comfortable to ride then stick with a 54cm.
 

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General Rule of Thumb

JRF said:
..."I have a 29' inseam am 5'9" tall"

Basic rule of thumb it to take your cycling inseam (not to be confused with your pants inseam) measured in cm's and multiply by .65 to get your c-c frame size and .67 cm for c-t size. Based on this, should be riding a 48 - 50 cm frame depending on how it's measured.

My guess, based on the fact that you are currently riding a 54, is that you measured your inseam wrong. Check the following link and make sure you are measuring correctly. Another guess is that a 52 cm frame would work for you assuming the top tube is fairly long.

Good luck.

Ed

http://www.coloradocyclist.com/bikefit/
 

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Frame size

There was an interesting article about frame sizing on the Rivendale site a few months ago. Their take was that the current trend to smaller frames is not good. Well written piece as much of their stuff is. Give a look.
 

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Not just inseam

1 or 2 cm matters for bike fit, just because you are comfortable riding a frame that is not the right size for you doesn't mean that you should keep with it. a 52 sounds really small for a guy your height but you could have very short legs. I am not sure how you measure the sizes for bikes. Not sure whether the geometry is traditional, compact or semi-compact which makes it all very confusing actually.

I tend to stick with the stem+actual top tube length= reach rule so that all my bikes regardless of geometry are the same reach. Go to www.wrenchscience.com and measure yourself 3 times! Then go buy your frame. Doesn't hurt.

Regards,
Sean
 

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century rider
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My experience....

JRF said:
I hate to ask, I know lots of questions are asked about Bike fit. I truly tried to find one relating to mine but was unsuccessful. Here is my question, I presently am riding a Klein in a 54CM, it is dangerously close in the inseam area (I have a 29' inseam am 5'9" tall) However, bike is comfortable to ride. I am looking at building a bike from the ground up and have an opportunity to purchase a 52 CM frame. Most of the frame dimension are the same, with a few only that are slightly different. Should I go for it and get the 52? I did read that you should try for the smallest frame possible and use Stem and seat movements to get a good fit. Any insight will be much appreciated. Thanks.
I was in the same spot as you are a couple of months ago, I used to ride a 54cm c-c steel frame with 54cm top tube and pretty much comfortable with it. though it seemed a bit big when sprinting out of the saddle. I also have a TCR1 med, almost the same dimensions. BTW I'm 5'8" about the same inseam as yours. Then I chanced upon a "cheap" Ti frame but sized 50c-c, 53cm c-t with a 53.5cm top tube. I got the same dimension from the steel frame with just a longer seatpost, the stem was ok as I even had to move the saddle forward due to the slacker head angle. The ride is better, more stable and easier to sprint out of the saddle coz of the smaller frame. The top tube should be your more bigger consideration as you can tweak the seat height with a longer seat post. One more thing, check if you could get the handlebar height on the 52 properly as the head tube would be considerably shorter than the 54.
 

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Agreed, check the head tube height. Your handlebars will be around 2cm on a smaller bike. Your saddle-to-BB dimension doesn't change, but you'll be in trouble with the spacer police if you want to keep the bars in the same relative position.
 

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scruffy nerf herder
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Well, the age old answer... "it depends" applies here.

Why? You may ask... is because all 52 CM frames are not created alike.

It has been determined here on multiple occasions that the "size" of the frame measured in the typical ctc on the seattube, or the virutual ctc on the compact frames is not a reliable factor in whether a frame "fits". It is more important to have a top tube length that is appropriate. You may be interested to know that I am almost the exact same size as you, however consider myself being 'long-torsoed'. Based upon all of the fit calculations, they have me on an ideal ctc frame size of 48 to 51. However, you will be excited to know that I have road frames in my stable of: 51, 52, 53 AND 54.

The 54 is a stretch height wise... however, get this, the corresponding TT lengths are: 54.5, 54, 55 and 55 respectively. So, make sure you are measuring apples to apples in regards to bike fit! Best of luck.
 

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Discussion Starter · #9 ·
Thanks

Thanks all, the wealth of knowledge here always impresses me.
I guess I will have to get the old tape measure out to really know if this will work. The two Bikes I am comparing are a Klien Quantum and an AGEIS Victory. The Klien (54cm) uses the command Geometry which makes things a bit confusing when trying to compare to the AGEIS (52) more traditional geometry. I Guess I could always "roll the dice" and give it a try.
Thanks again for all your help.
 

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scruffy nerf herder
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well, the tapemeasure doesn't lie....

It is really not that difficult. Do you fit your current bike? If so, what is the TT length? If you get relatively close, you will likely be okay. You can do things to the cockpit to adjust a bit to your torso length, however keep in mind that things like seattube angle and headtube angle can do some kooky things relative to your relative fore/aft position and also your standover and bottom bracket height.

I would be willing to bet that someone tomorrow will hop on here and be able to provide the exact geometries of the two bikes.... thats just how they are around here and be able to show precisely what the differences are, in lengths, and in angles.... I will restate once again... we here on the board after about a bazillion posts and discussions have determined that the most important item in determining fit is NOT standover, is not seattube c-t-c, is not seattube c-t-t, but top tube c-t-c(or virtual c-t-c for sloping/compact).

After that... lets see the best performance upgrade is wheels, the best gruppo is shimano... haha.

Best of Luck
 

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You're Not the Boss of Me
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Are you sure about your inseam?

If that's true, it is remarkably short for your height, which means you have a lot of torso. I'm 5'7" (female) with a cycling inseam of not quite 31", and all of my rides are in the 52-54 range.

You probably should look at compact geometry (sloping top tube) which can accomodate your reduced standover without compromising your reach.

PS, you do not adjust reach by moving your saddle fore-aft. Saddle position is about pedaling dynamics, not top tube length.

Good luck.
 

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off the back
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when i got measured for a custom frame last fall, the measurements confirmed what i had suspected. i'm 5' 9 3/4", with an inseam that was measured at 79cm, which is about 31". the bike i have now is a 54cm seat tube, with a top tube of 54.3 cm. it fits me pretty well cockpit wise, but i have little standover clearance. i'm a bit longer of torso than of inseam.

the new frame i'm getting will have a 54.5 cm toptube, but a 52 cm seat tube.
 

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rufus said:
when i got measured for a custom frame last fall, the measurements confirmed what i had suspected. i'm 5' 9 3/4", with an inseam that was measured at 79cm, which is about 31". the bike i have now is a 54cm seat tube, with a top tube of 54.3 cm. it fits me pretty well cockpit wise, but i have little standover clearance. i'm a bit longer of torso than of inseam.

the new frame i'm getting will have a 54.5 cm toptube, but a 52 cm seat tube.
i'm about the same height(slightly taller) and inseam(slightly shorter) and was riding a 54x54, or what i thought was a 54, when i got a custom frame the seat-tube is now about 51 and the top tube was brought in to 53.5 but the head tube was stretched from a 12 to a 15.
 

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JRF said:
I hate to ask, I know lots of questions are asked about Bike fit. I truly tried to find one relating to mine but was unsuccessful. Here is my question, I presently am riding a Klein in a 54CM, it is dangerously close in the inseam area (I have a 29' inseam am 5'9" tall) However, bike is comfortable to ride. I am looking at building a bike from the ground up and have an opportunity to purchase a 52 CM frame. Most of the frame dimension are the same, with a few only that are slightly different. Should I go for it and get the 52? I did read that you should try for the smallest frame possible and use Stem and seat movements to get a good fit. Any insight will be much appreciated. Thanks.

52 sounds really small to me. Why are so concerned with standover height? How often do you actually standover the bike? Even in a crash it's rare you contact the top tube.

Fit while riding is much more important. I ride a 55cm with a 32 cycling inseam and I'm 5 91/2.
 
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